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Page 1: Changing Times — The Challenges and Risks of Managing ... · Risks of Managing Aging Infrastructure Under a New Financial Reality ... Todd Mitchell, Paul Grosskruger and ... Parsons

United States Society on Dams

Changing Times — The Challenges andRisks of Managing Aging Infrastructure

Under a New Financial Reality

33rd Annual USSD Conference

Phoenix, Arizona, February 11-15, 2013

Page 2: Changing Times — The Challenges and Risks of Managing ... · Risks of Managing Aging Infrastructure Under a New Financial Reality ... Todd Mitchell, Paul Grosskruger and ... Parsons

CONTENTS

Plenary Session

USACE Experience in Performing Constructability Reviews . . . . . . . . . . . . . . . 1

David Paul, Mike Zoccola and Vanessa Bateman, Corps of Engineers; and Dan

Hertel, Engineering Solutions, LLC

Levees

Levee Evaluation with Ground-Penetrating Radar . . . . . . . . . . . . . . . . . . . . 3

Hussein Khalefa Chlaib, Haydar Al-Shukri, Hanan Mahdi, M. Mert Su,

Aycan Catakli and Najah Abd, University of Arkansas at Little Rock

How Enhanced and Economically Viable Engineering Analysis Can Help Levee

Owners Evaluate Their Inventory in Response to FEMA’s Proposed Approach for

Non-Accredited Levees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Todd Mitchell, Paul Grosskruger and Cornelia Dean, Fugro Constultants, Inc.;

and Bob Woldringh, Furgro Engineers, BV

Use of Fragility Curves in Assigning Levee Remediation Priorities . . . . . . . . . . . 7

Rich Millet, Sujan Punyamurthula, Derek Morley and Loren Murray, URS

Corporation

Probabilistic Evaluation of Levee Distress for the Sacramento River Bank

Protection Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Khaled Chowdhury, URS Corporation; Derek Morley and Mary Perlea, Corps

of Engineers; Wilbur Huang, California Department of Water Resources; and

Matthew Weil and Saritha Aella, URS Corporation

Integrating Levee Performance Assessments into Complex Flood Protection

Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

T. Mitchell, Fugro Consultants, USA; R. Kluskens, Royal HaskoningDHV;

B. Woldringh, Fugro Consultants BV; M.T. van der Meer, Fugro WaterServices;

R.G. Kamp and C. de Gooijer, HKV Consultants; M.M. Hillen, Royal

HaskoningDHV

Concrete Dams

Updated Stress and Stability Analysis of a TVA Dam . . . . . . . . . . . . . . . . . . 13

Dan D. Curtis, HATCH Ltd.; Husein Hasan, Tennessee Valley Authority; Frank

Feng and Bob He, HATCH Ltd.; and Justin Long, Tennessee Valley Authority

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An Advanced Model for Simulation of ASR Behavior at Roanoke Rapids Dam . . . . . 15

Brian R. Reinicker and Farzad Abedzadeh, HDR Engineering, Inc.; Robin G.

Charlwood, Robin Charlwood & Associates; and John A. Cima, Dominion

Resources Services, Inc.

Investigations to Evaluate Performance of Concrete Arch Dam Affected by

Alkali-Silica Reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Daniel D. Mares, Bureau of Reclamation

Structural Analysis of Corbels on an Aging Multiple-Arch Dam . . . . . . . . . . . . 19

Brad B. Watson, Victor M. Vasquez and Les Boyd, Freese and Nichols, Inc.;

Doug Witkowski, Lower Colorado River Authority; and James O. Jirsa,

University of Texas at Austin

Integrating Infrastructure Upgrades with Gravity Dam Repairs . . . . . . . . . . . . 21

Timothy W. Johnston, Gannett Fleming, Inc.; John A. Wilkes, Carpi USA Inc.;

Mishelle Noble-Blair, Fairfax Water; and Thomas B. Pursel, Gannett Fleming,

Inc.

Explicit Seismic Analysis of Mossyrock Dam . . . . . . . . . . . . . . . . . . . . . . 23

Dan D. Curtis, Hatch Associates Consultants; Gurinderbir Sooch, HATCH Ltd.;

and Toby Brewer and Andrew Schildmeyer, Tacoma Power

Strength Monitoring for RCC Dam During Construction . . . . . . . . . . . . . . . . 25

James Stiady, Kleinfelder; Frank Collins, Parsons; and Jim Zhou, Gerald E.

Reed III, Wade Griffis and Jeffrey A. Shoaf, San Diego County Water Authority

Practical Application of RFC Dam Construction Based on Cheap Mix Design

of SCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Qiong Wu, Xuehui An, Miansong Huang and Feng Jin, Tsinghua University

Filling an Expanded Reservoir — A Myriad of Considerations . . . . . . . . . . . . . 29

Kelly L. Rodgers, Gerard E. Reed III and Jim Zhou, San Diego County Water

Authority; Surraya Rashid and Rosalva Morales, City of San Diego; and

Thomas O. Keller, GEI Consultants, Inc.; and Anna E. Kolakowski, California

Department of Water Resources

Tailings Dams

Dam Break Analysis Applied to Tailings Dams: USSD Workshop Summary and

Perspectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

José L.M. Clemente, Bechtel Power Corporation; Robert E. Snow, D’Appolonia

Engineering; Carmen Bernedo, MWH Global, Inc.; Clinton Strachan, MWH

Americas, Inc.; and Andy Fourie, University of Western Australia

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Design, Construction, and Performance of a Seepage Cutoff Barrier in a Dam . . . . 33

Iván A. Contreras, Jon D. Ausdemore, Joe A. Welna and Rachel E. Franz, Barr

Engineering Co.

Seismic Design of Perimeter Slurry Walls for the Kingston Coal Ash Pond Closure . . 35

Alan F. Rauch, Stantec, Inc.; Rodney P. McAffee, C-CORE; and Yong Wu and

Luis J. Arduz, Stantec, Inc.

Foundations

Performance of Prewetted Loess Foundations for Embankment Dams . . . . . . . . . 37

William Engemoen, Bureau of Reclamation

Erodabilty of Seepage Barrier Materials . . . . . . . . . . . . . . . . . . . . . . . . 39

Nathan Braithwaite and John Rice, Utah State University; and David Paul,

Corps of Engineers

Blue Lake Dam Left Abutment Stabilization Design . . . . . . . . . . . . . . . . . . . 41

James H. Rutherford, Peter Friz, John Werner and Lingmin Feng, HATCH

Renewable Power; and Jerry Higgins, Colorado School of Mines

Hydraulics and Hydrology

Performance of RCC Strengthened Levee in Full-Scale Overtopping Tests . . . . . . . 43

Fashad Amini and Lin Li, Jackson State University

Scour of Discontinuous Blocky Rock . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Michael George and Nicholas Sitar, University of California, Berkeley

Finite Element Modeling of Trunnion Rods . . . . . . . . . . . . . . . . . . . . . . . 47

Mark A. Cesare, J. Darrin Holt and Robert F. Lindyberg, FDH Engineering,

Inc.; and Jim J. Lua and Xiujun Fang, Global Engineering and Materials, Inc.,

Effects of Bronze and Composite Sleeves on Trunnion Yoke Plate Stress

Concentrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Thomas J. Walker, Black & Veatch Corporation; Kevin Z. Truman, University

of Missouri-Kansas City; and Kurt A. Jacobs, Corps of Engineers

Hodenpyl Hydroelectric Plant — Spill Tube Headgate Replacement Project . . . . . . 51

Tor Hansen, Barr Engineering Company; Adam Monroe, Consumers Energy

Company; and Rusty Friedle, Gerace Construction

Inundation Mapping for Impending Record Reservoir Releases —Missouri River

Flood of 2011 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Thomas Gorman, Lowell Blankers, Laurel Hamilton, Colleen Horihan, Troy

Ingram, Tony Krause, Curtis Miller, Eric Morrison, Michelle Schultz, Megan

Splattstoesser and Neil Vohl, Corps of Engineers

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Saving Lives with 2-D Inundation Flood Modeling as a Dam Design Tool . . . . . . . 55

Milan Jankovic and Shane Willard, Bureau of Indian Affairs

IDF Determination Using Risk Analysis at the Norway-Oakdale Project . . . . . . . . 57

Eric J. Gross, Federal Energy Regulatory Commission

Modeling a Low-Head Dam Retrofit with a 2-D Hydraulic Model (Adaptive

Hydraulics) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Jeff Weiss, Jon Ausdemore, Tom MacDonald and Ron Koth, Barr Engineering

Company

Approach for Mapping Flooding Risk near Lake Okeechobee, Florida . . . . . . . . . 61

Guillermo Simón, Taylor Engineering, Inc.; and Ao Yi, AECOM

Comparison of Modern Day Inundation Modeling Techniques (2-D versus 1-D,

with 3-D on the Horizon) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Milan Jankovic and Shane Willard, Bureau of Indian Affairs

Dam Safety

Incorporating Uncertainties in the Estimation of Vulnerabilities for Security Risk

Assessments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

J. Darrell Morgeson, Institute for Defense Analyses; Yazmin Seda-Sanabria,

Corps of Engineers; Enrique E. Matheu, U.S. Department of Homeland Security;

and Michael J. Keleher, Institute for Defense Analyses

Semi-Quantitative Risk Categorization for Periodic Dam Safety Assessments . . . . . 67

Timothy M. O’Leary and Gregg A. Scott, Corps of Engineers

Minimizing Over-Conservatism in Dam Safety Modifications through the Careful

Use of Risk Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Daniel W. Osmun, William R. Fiedler and William O. Engemoen, Bureau of

Reclamation

Look Both Ways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Kim de Rubertis, Consulting Engineer; and C. van Donkelaar, McMillen, LLC

Interim Risk Reduction Measures Plans: Lessons Learned . . . . . . . . . . . . . . . 73

Jacob Davis, Corps of Engineers

Plan for the Safety of Aging Dams; Plan the Work, Work the Plan . . . . . . . . . . . 75

William J. Friers, CDM Smith; Neil R. Bonesteel, City of Troy, NY; Kapila S.

Pathirage, CDM Smith; and Chris E. Wheland, City of Troy, NY

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An Innovative Response Plan for Potential Seismic Failure Modes at Priest

Rapids Dam. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

James H. Rutherford, HATCH Associates Consultants Inc.; Dave Mishalanie,

Grant County Public Utility District No. 2; J. Groeneveld and Nikou Snell, Hatch

Ltd.; and Mohammed Badruzzaman, HATCH Associates Consultants Inc.

Increasing Prickett Dam Height for New PMF . . . . . . . . . . . . . . . . . . . . . 79

Michael McCaffrey and Tony Plizga, Parsons Brinckerhoff; Ben Trotter and

Todd Poehlman, Integrys Business Support; and Lorna Langone, Parsons

Brinckerhoff

Lake Delhi Dam Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

William R. Fiedler, Bureau of Reclamation; Wayne King, Federal Energy

Regulatory Commission; Neil Schwanz, Corps of Engineers; and William

Holman, Stanley Consultants, Inc.

Earthquakes

Overburden Correction Factors for Predicting Liquefaction Resistance Under

Embankment Dams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Jack Montgomery and Ross W. Boulanger, University of California, Davis; and

Leslie F. Harder, Jr., HDR Engineering, Inc.

Fault Rupture Risk Evaluation and Mitigation at the Isabella Auxiliary Dam . . . . . 85

David C. Serafini and Henri V. Mulder, Corps of Engineers

Seismic Analysis of the Baker River Hydroelectric Project West Pass Dike . . . . . . 87

Lin Zhao, Jason E. Hedien and Julie Stanaszek, MWH Americas, Inc.; and

Zakeyo Ngoma, Puget Sound Energy

Seismic Stability Evaluation of Anderson Dam, Santa Clara County, California . . . . 89

Marc J. Ryan, AMEC Environment and Infrastructure; Michael Mooers, Santa

Clara Valley Water District; Faiz I. Makdisi, AMEC Environment and

Infrastructure; James Nelson, Santa Clara Valley Water District; and Christopher

Slack, AMEC Environment and Infrastructure

Terminal Dam — A Small Facility with Big Problems. . . . . . . . . . . . . . . . . . 91

Tara Schenk McFarland, Bureau of Reclamation

Impact of Embedded Tower on Seismic Risk of an Embankment Dam . . . . . . . . . 93

Michael E. Ruthford, Chung F. Wong, Michael Ma and Vlad G. Perlea, Corps

of Engineers; and Michael H. Beaty, Beaty Engineering LLC

Development of the Calaveras Dam Replacement Project — Challenges and

Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Michael Forrest, Noel Wong and John Roadifer, URS Corporation; and Daniel

Wade and Gilbert Tang, San Francisco Public Utilities Commission

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Development of a Risk-Informed Approach to the Seismic Evaluation of

Hydropower Projects — Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Martin W. McCann, Jr., Jack R. Benjamin and Associates, Inc.; David W. Lord,

Federal Energy Regulatory Commission; Kevin Marshall, Grant County Public

Utility District; David Mishalanie, Grant County Public Utility District; Gene

Yow, Chelan County Public Utility District; and Bill Christman, Chelan County

Public Utility District

Development of a Risk-Informed Approach to the Seismic Evaluation of

Hydropower Projects — The Owner’s Perspective . . . . . . . . . . . . . . . . . . . 99

Bill Christman, Chelan County Public Utility District; Kevin Marshall and David

Mishalanie, Grant County Public Utility District; Gene Yow, Chelan County

Public Utility District; David W. Lord, Federal Energy Regulatory Commission;

and Martin W. McCann, Jr., Jack R. Benjamin and Associates, Inc.

Development of a Risk-Informed Approach to the Seismic Evaluation of

Hydropower Projects — FERC Perspective . . . . . . . . . . . . . . . . . . . . . . 101

David W. Lord, Federal Energy Regulatory Commission; Martin W. McCann,

Jr., Jack R. Benjamin and Associates, Inc.; Kevin Marshall and David

Mishalanie, Grant County Public Utility District; and Gene Yow and Bill

Christman, Chelan County Public Utility District

Environment

Reservoir Sustainability Workshop, Lakewood, Colorado, July 10-12, 2012 . . . . . 103

Timothy J. Randle and Kent L. Collins, Bureau of Reclamation

Sustainable Water Infrastructure in California . . . . . . . . . . . . . . . . . . . . . 105

Lawrence H. Roth, ARCADIS U.S.

Resolving Complex Challenges in River Restoration — The San Joaquin River

Restoration Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

William R. Swanson, Jill C. Chomycia, Jeffrey T. Payne and Heather Shannon,

MWH Americas, Inc.; Alicia Forsythe, Bureau of Reclamation; and Kevin

Faulkenberry, California Department of Water Resources

Decommissioning

Elwha River Restoration: Sediment Management First Year Results . . . . . . . . . 109

Timothy J. Randle and Jennifer A. Bountry, Bureau of Reclamation

Large Scale Dam Removal on the Klamath River — Monetizing the Social

Effects of Large Scale Dam Decomissioning . . . . . . . . . . . . . . . . . . . . . . 111

Ben Swann and Chris Park, CDM Smith

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Working Together with Minimum Budget to Breach a High-Hazard Dam . . . . . . . 113

Stephen L. Whiteside, CDM Smith; Emily Davenport, City of Valdosta, Georgia;

and Jose Maria Guzman, CDM Smith

Construction and Rehabilitation

Pine Creek Dam — Phase V Rock Investigation . . . . . . . . . . . . . . . . . . . . 115

Kathryn A. White, Corps of Engineers

Reducing Seepage into Inter-Gallery Drains Within the Narrows Dam Intake

Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

Stefan Schadinger, Parsons Brinckerhoff; Mark J. Gross, Alcoa Power

Generating Inc.; and Michael McCaffrey, Paul F. Shiers and Christopher

Godwin, Parsons Brinckerhoff

Early Contractor Involvement: Case Studies for Reducing Costs, Compressing

Schedules, and Improving Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

Del A. Shannon and John F. Bowen, ASI Constructors, Inc.

The Bid Process — Closing the Communication Gap between Engineer and

Contractor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Mark Landis, Schnabel Engineering; and Page Riley, Philips and Jordan Inc.

Development and Field Testing of a Pressure Sensing Grout Packer . . . . . . . . . 123

David Paul, Jeffrey Schaefer and Brook Brosi, Corps of Engineers; Patrick

Carr, The Judy Company, Inc.; and Chad Conti, GEI Consultants, Inc.

McClure Penstock Replacement Project — From Failure to Reconstruction . . . . . 125

Whitney Hansen and William J. Forsmark, Barr Engineering Company; and

Robert J. Meyers, Upper Peninsula Power Company

Lake Townsend Dam Replacement — Challenges in Building a New Dam at the

Toe of an Old Dam under Full Reservoir Head . . . . . . . . . . . . . . . . . . . . 127

Robert Cannon, Tillman Marshall, Greg Paxson and Frederic Snider, Schnabel

Engineering; and Melinda King, City of Greensboro

Seismic Remediation Design and Construction of Key-Block: Mormon Island

Auxiliary Dam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

M. Jonathan Harris and Michael J. Romansky, Bureau of Reclamation

Geotechnical Concerns in Addressing Seepage at a Rock-Filled, Wood-Faced

Dam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

John C. Stoessel, Southern California Edison; John Wilkes, CARPI USA, Inc.;

and Craig McElfresh, MCS Construction, Inc.

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Concrete Placement and Rehabilitation at the Hannawa Development . . . . . . . . 133

Bryce Mochrie, Parsons Brinckerhoff; Lee Talbot, Brookfield Renewable Energy

Group; and Kevin Finn, Parsons Brinckerhoff

Developing Great Hydroelectric Projects in a Challenging Social and Economical

Environment: La Romaine Complex, Situated in Northern Quebec, Canada . . . . . 135

Vlad Alicescu, Jean-Pierre Tournier and Pierre Vannobel, Hydro-Quebec

Reduce Risk of Cofferdam Failure with RCC — A Historical Perspective . . . . . . . 137

Daniel L. Johnson, Tetra Tech, Inc.; and Kenneth D. Hansen, Consulting

Engineer

Rock Anchors for Dams: A Five-Year Update . . . . . . . . . . . . . . . . . . . . . 139

Donald A. Bruce, Geosystems, L.P.; John S. Wolfhope, Freese and Nichols, Inc.;

and Jesse D. Wullenwaber, Schnabel Engineering, LLC

Rehabilitation of Temporary Composite Dams — Case Study: Mared Soil-Sheet

Pile Dam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

Saber Alidadi and Masoud Hakami, Khuzestan Water & Power Authority

Monitoring and Instrumentation

ROV Sonar Inspection of a Power Tunnel . . . . . . . . . . . . . . . . . . . . . . . 143

Florijon Dhimitri, Parsons Brinckerhoff; Richard Glenn, Glenn Underwater

Services, Inc.; Michael Sabad, APGI; and Olga Zabawa, Parsons Brinckerhoff

Libby Dam Hemispherical Bulkhead Inspection, A 30-Story Descent to a Dam

Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

Kenwarjit S. Dosanjh, Travis L. Ford and Samuel M. Planck, HDR

Engineering, Inc.; and Joshua J. Erickson and Michael T. Likavec, Corps of

Engineers; and Greg Mayer, Ropeworks/Mistras Group, Inc.

Performance Evaluation of Upstream Slope Protection During Reservoir

Drawdown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

Donald J. Montgomery, Christine T. Weber and Terrence E. Arnold, MWH

Americas, Inc.

Early Warning System at Creekside Dams — Putting it to the Test . . . . . . . . . . 149

Laura LaRiviere, Kleinfelder, Inc.; and Brian Boswell, Umpqua Indian Utility

Cooperative

Dam Safety Training for Dam Operating Personnel . . . . . . . . . . . . . . . . . . 151

Jay N. Stateler, Bureau of Reclamation

Efficiency and Automation: Are Automated Data Acquisition Systems More

Efficient than Manual Methods? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

Christopher J. Hill, Metropolitan Water District of Southern California

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Subsidence

Investigative Procedure for Assessing Earth Fissure Risk for Dams and Levees . . . 155

Kenneth Fergason and Michael Rucker, AMEC Environment and Infrastructure,

Inc.; and Michael Greenslade, Flood Control District of Maricopa County

InSAR as a Subsidence Characterization Tool for Flood Control Dam Studies . . . . 157

Bibhuti B. Panda, Michael L. Rucker and Kenneth C. Fergason AMEC

Environment and Infrastructure, Inc.; Michael D. Greenslade, Flood Control

District of Maricopa County

Characterization of Subsidence Impacting Flood Control Dams and Levees . . . . . 159

Michael Rucker and Kenneth Fergason, AMEC Environment and Infrastructure,

Inc.; Michael Greenslade, Flood Control District of Maricopa County; and

Lawrence Hansen, AMEC Environment and Infrastructure, Inc.

Laboratory Testing of Critical Hydraulic Conditions for the Initiation of Piping . . . 161

Mandie Swainston-Fleshman and John Rice, Utah State University

Ashton Dam

Can FERC’s Risk Informed Decision Making (RIDM) Save You Money? Yes!

A Case Study of Ashton Dam, Idaho . . . . . . . . . . . . . . . . . . . . . . . . . . 163

Frank L. Blackett, Justin F. Smith and Patrick J. Regan, Federal Energy

Regulatory Commission

Embankment Dams

Potential for Cracking around Outlet Conduits and its Impact on Seepage

Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

Keith A. Ferguson, Mahdi Soudkhah and Elena Sossenkina, HDR Engineering,

Inc.

Economical and Reliable Solutions for Arresting Surficial Slope Failures in

Earthen Dams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167

José Hernández, Corps of Engineers; Bhaskar C. S. Chittoori and Minh Le,

University of Texas at Arlington; Les Perrin, Corps of Engineers (retired); and

Ken McCleskey, Corps of Engineers; and Anand J. Puppala, University of Texas

at Arlington

Field Testing of Crushed Ignimbrite for Dam Filter Material . . . . . . . . . . . . . 169

Lelio H. Mejia, URS Corporation

Evaluation of the Central Filter at Saddleback Flood Retarding Structure . . . . . . 171

Dean B. Durkee, Gannett Fleming, Inc.; Sam Sherman, Flood Control District of

Maricopa County; and Frances Ackerman, Gannett Fleming, Inc.

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Devils Lake Flood Risk Management — Geotechnical Aspects . . . . . . . . . . . . 173

Paul D. Madison, Corps of Engineers; and Stephen L. McCaskie, Hanson

Professional Services

Effect of Anisotropic Permeability on Phreatic Line Recession in Homogeneous

Earth Dams Under Reservoir Rapid Draw Down . . . . . . . . . . . . . . . . . . . 175

V. Rashidian, Imam Khomeini International University

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1

USACE EXPERIENCE IN PERFORMING CONSTRUCTABILITY REVIEWS

David Paul1 Mike Zoccola2

Vanessa Bateman3 Dan Hertel4

ABSTRACT

The Army Corps of Engineers (USACE) is implementing risk informed decision processes for the dam and levee safety programs. These processes prioritizes projects that have actionable failure modes with significant consequences, so that risks to society are being reduced with reduced budgets available to federal agencies that significant infrastructure responsibilities. The “Total Design and Construction Process” stresses that design and construction teams are integrated throughout the design and construction phases. Developing a systematic approach, with experienced people representing the design and construction disciplines can identify potential issues and mitigate them before they manifest themselves during the construction phase. Wolf Creek Dam (USACE Nashville District) is classified a DSAC 1 (most serious classification) and is undergoing modifications to construct a cutoff wall to mitigate seepage and piping failure modes. The authors describe three scenarios of conducting constructability reviews to identify potential risks presented during construction and further develop project designs and approaches to minimize and appropriately allocate these risks. Three scenarios are described: 1.) Performing a constructability review of proposed engineering alternatives to address actionable failure modes for Isabella Dam2.) Performing a constructability review of potential high risk construction activities in Critical Area 1 (in karst foundation geology) for Wolf Creek Dam which identified possible failure modes and utilized event trees to estimate the risk; 3.) Performing a qualitative risk analyses of potential failure modes for Wolf Creek Dam which could affect the operation of the Switchyard/Powerhouse. These examples will demonstrate the value of various approaches to constructability reviews that were successful in reducing overall project costs and identified risks to both the owner and contractor. The project team must meld the appropriate approach to the current phase of the project. Constructability reviews during the feasibility stage would likely not be appropriate for the final design or construction phase. Properly conducted constructability reviews can significantly alter the course of the project and result in cost and time savings, as well as reduced risk. 1 Lead Civil Engineer, USACE Risk Management Center, 12300 W. Dakota Ave Suite 230, Lakewood, CO 80228, Phone 720-289-9042, [email protected] 2 Chief of Engineering, USACE Nashville District, 801 Broadway, Nashville, TN 37203, [email protected] 3 Engineering Geologist, USACE Nashville District, 801 Broadway, Nashville, TN 37203, [email protected] 4 President, Engineering Solutions, LLC, 11983, Bozeman, MT 59719, [email protected]

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NOTES

2

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LEVEE EVALUATION WITH GROUND-PENETRATING RADAR Hussein Khalefa Chlaib5 Haydar Al-Shukri6 Hanan Mahdi7 M. Mert Su8 Aycan Catakli9 Najah Abd10

ABSTRACT

The Big Dam Bridge (BDB) levee on the Arkansas River at Little Rock, AR, and the Lollie Levee near Conway, AR, were surveyed with Ground Penetrating Radar (GPR) to assess their structural integrity. GSSI SIR-30 and SIR-3000 systems with multi-frequency (200, 400, and 900MHz) antennas were utilized. The purpose of this study was to detect cavities, continuous animal burrows, and any deformation in the levee body. GPR profiles exhibited many sub-surface anomalies at various depths. Several holes were dug to inspect the true nature of the shallower anomalies to “ground-truth” the reliability of the GPR data. Steven Soil Sensor was utilized to measure the dielectric constant near the surface of the levees. These values were used to calculate the precise depth of the anomalies that were detected by GPR. Connected empty cavities, continuous animal burrows, clay clasts, and metal objects were found at different depths having different sizes. The depths of the located features ranged between 0.12m and 0.30m and their diameters ranged from 0.06m to 0.08m. Similar to the shallow anomalies, deeper anomalies with normal and reversed polarities were present throughout the GPR profiles which indicate that similar features exist at depth.

5 PhD Candidate, Applied Science Dep. University of Arkansas at Little Rock, 2801 South University, ETAS 555, Little Rock, AR 72204-1099, (501)569-8349, [email protected]. 6 Professor and Chair, Applied Science Dep. University of Arkansas at Little Rock, 2801 South University, ETAS 300O, Little Rock, AR 72204-1099, (501)569-8000, [email protected]. 7 Research Associate Professor, Graduate Institute of Technology (GIT), University of Arkansas at Little Rock, 2801 South University, ETAS 101C, Little Rock, AR 72204-1099, (501)569-8305 [email protected]. 8 Research Assistant, Applied Science Dep. University of Arkansas at Little Rock, 2801 South University, ETAS 555, Little Rock, AR 72204-1099, (501)569-8349, [email protected] 9 Graduate Assistant, Applied Science Dep. University of Arkansas at Little Rock, 2801 South University, ETAS 101 E, Little Rock, AR 72204-1099, (501)569-8349, [email protected] 10 PhD Candidate, Applied Science Dep. University of Arkansas at Little Rock, 2801 South University, ETAS 555, Little Rock, AR 72204-1099, (501)569-8349, [email protected].

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HOW ENHANCED AND ECONOMICALLY VIABLE ENGINEERING ANALYSIS CAN HELP LEVEE OWNERS EVALUATE THEIR INVENTORY IN

RESPONSE TO FEMA’S PROPOSED APPROACH FOR NON-ACCREDITED LEVEES

Todd Mitchell11

Paul Grosskruger12 Cornelia Dean13 Bob Woldringh14

ABSTRACT

Our nation faces ongoing challenges to balance the dire risks of levee failures with the enormous costs in mitigating all perils. Government agencies strive to balance practical expenditures with economic loss while maintaining life safety as the top priority. Thus, many communities in the United States are burdened with the challenge of mitigating flood risks with limited time and funds, and oftentimes have no alternative but to pass this burden on to property owners through the NFIP. This issue becomes very difficult for property owners to accept when a levee exists to defend their community, yet for reasons that are frequently difficult for the layperson to understand, those levees fail NFIP accreditation requirements and are not considered in the creation of Flood Insurance Rate Maps (FIRMs). Through plans to revise its approach to levee assessment with the proposed Levee Analysis and Mapping Procedures policy (LAMP), FEMA plans to enact new provisions for characterizing these levees that fail accreditation and thus affecting property owners in these flood risk zones. However, FEMA’s efforts will not fully resolve the problem. The fiscal responsibility for these newly provised characterization studies will fall directly on the levee owners. In many cases the levee owners will lack the funding to perform these studies and conduct the essential repairs necessary to make changes to the FIRM affecting landward side property owners. Similarly, many levee owners do not have the experience and knowledge to execute such studies in a way that will maximize effectiveness and contribute to a cost-effective remediation strategy. This paper explores a mechanism that shifts the paradigm from reach-level diagnosis and remediation towards a cost-comparable investigation that can result in precisely targeted remediation. FEMA, levee owners, elected officials, and all stakeholders at risk have the opportunity to benefit from a program that allows categorization of levees by FEMA’s new standards while identifying how to target selective areas for specific and tailored repairs that directly impact the acceptance grading of the levee and thus affecting flood insurance premiums for landward-side property owners.

11 Certified Mapping Scientist, Fugro Consultants, Inc., 4820 McGrath Street #100, Ventura, CA, 93003, 805-650-700, [email protected] 12 Fugro Consultants, Inc., Professional Engineer, 4651 Salisbury Road, South, Jacksonville, FL 32256, 904-253-7880, [email protected] 13 Fugro Consultants, Inc., GIS Manager , 4820 McGrath Street #100, Ventura, CA, 93003, 805-650-700, [email protected] 14 Fugro Engineers, BV, Principal Engineer, Veurse Achterweg 10, 2264 SG Leidschendam ZH, NL, +31-70-31-11157, [email protected]

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USE OF FRAGILITY CURVES IN ASSIGNING LEVEE REMEDIATION PRIORITIES

Rich Millet, GE, PE 15

Sujan Punyamurthula, GE, PE, PhD 16 Derek Morley, PE 17 Loren Murray, PE 18

Fragility curves can be defined as the relationship of the probability of failure P(f) versus some physical event or condition. In a flood protection system, the principal physical event or condition is the height of water against the levee. This paper describes the development of two simplified but pragmatic processes to develop fragility curves addressing the probability of failure P(f) versus water surface elevations (WSE) for a given levee segment/reach. Using either of these approaches, remediation needs of a levee system can be established and prioritized. The comprehensive development of probabilistic fragility curves is a complicated process and in many potential applications there is insufficient time and/or budget to complete such a rigorous task. This paper presents two simplified processes to develop fragility curves generating many of their benefits even when it is not possible to implement a rigorous probabilistic process. Processes are presented to address the cumulative potential of levee failure caused by four loading mechanisms: underseepage, through-seepage, landside slope stability, and erosion. Once fragility curves have been developed, a prioritization can be made of the reaches/segments of a leveed area with the lowest WSE for a given selected probability of failure; e.g., 5%, 50%, etc. Remediation can then be focused on these critical reaches/segments. Examples are presented to demonstrate the process.

15 Vice President and Program Manager, URS Corporation, 2870 Gateway Oaks Dr. #150, Sacramento, CA 95833, [email protected] 16 Vice President, Deputy Program Manager, and a/e Division Manager, URS Corporation, 2870 Gateway Oaks Dr. #150, Sacramento, CA 95833, [email protected] 17 Formerly Project Manager, URS Corporation 2870 Gateway Oaks Dr. #150, Sacramento, CA 95833; currently Chief, Soil Design Section B, USACE, 1325 J Street, Sacramento, CA 95814, [email protected] 18 Senior Project Manager, URS Corporation, 2870 Gateway Oaks Dr. #150, Sacramento, CA 95833, [email protected]

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PROBABILISTIC EVALUATION OF LEVEE DISTRESS FOR THE SACRAMENTO RIVER BANK PROTECTION PROJECT

Khaled Chowdhury, PE, GE19

Derek Morley, PE20 Mary Perlea, PE21

Wilbur Huang, PE22 Matthew Weil, PE23

Saritha Aella24

ABSTRACT The Sacramento River Flood Control Project (SRFCP) is a system of levees, weirs, pumping plants, and bypasses designed to safely convey Sacramento River and tributary flood flows. There are about 1300 miles of project levees in this system. The Sacramento River Bank Protection Project is a federal program that inspects the SRFCP levees and associated natural banks and berms, identifying and ranking erosion problems, and providing remedial repairs. In preparation of an environmental document for the project, USACE Sacramento District required an annual exceedance probability (AEP) evaluation for erosion and other failure modes to assist in the planning process. The other failure modes for the project included underseepage, through seepage, and landside slope stability. These failure modes may lead to structural degradation of the levee, increasing the risk of failure, flood inundation, and damage to interior of levees. An innovative approach was developed to assess the AEPs of 100 erosion sites in an expedited -manner. The purpose of the evaluations was to provide AEP estimates for four specified conditions. The technical approach for the project involved document review for past performances and geologic conditions, a site reconnaissance by an engineering team using a project specific data collection method, a sensitivity study of factors affecting calculation of erosion failure mode, and review of findings. The field observations documented 13 characteristics for erosion, 8 characteristics for underseepage, 5 characteristics for through seepage, and 8 characteristics for landside slope stability. Based on these observations, a weighted site characterization score was calculated for each erosion site for erosion and other failure modes. The past performance events at the erosion sites were also evaluated for the other failure modes based on the California Department of Water Resources Urban and Non-Urban Levee Evaluations Project data. This innovative and unique approach was instrumental in implementation of the planning process of Phase II of the SRBPP.

19 Project Manager, URS Corporation, 2870 Gateway Oaks Suite 150, Sacramento CA 95833, [email protected] 20 Chief, Soil Design Section B, USACE Sacramento District, 1325 J Street, Sacramento, CA 95814, [email protected] 21 Levee Safety Program Manager, USACE Sacramento District, [email protected] 22 Chief, USACE/CVFPB Projects Section, Department of Water Resources, 3464 El Camino Avenue, Sacramento, CA 95821, [email protected] 23 Senior Staff Engineer, URS Corporation, Sacramento, CA , [email protected] 24 Senior Staff Engineer, URS Corporation, Sacramento, CA , [email protected]

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INTEGRATING LEVEE PERFORMANCE ASSESSMENTS INTO COMPLEX FLOOD PROTECTION SYSTEMS

T. Mitchell25 R. Kluskens26

B. Woldringh27 M.T. van der Meer28

R.G. Kamp29 C. de Gooijer30 M.M. Hillen31

ABSTRACT

Great strides have been made in the past few years in terms of improving the characterization of levee performance and engineering assessments. The automation of several key steps in the evaluation of levees will continue to lead to improved risk assessments, targeted remediation efforts, and more effective investment by stakeholders. However, to realize the full value of these efforts, improvements in performance assessment also need to be linked to flood protection systems. The ability to identify very specific high-risk-of-failure locations on a levee can be of tremendous value to emergency management during episodic flooding hazards. Both nationally and internationally, efforts are being made to integrate the modeling of hazards of episodic events, such as hurricanes and seasonal flooding, with levee performance metrics in a “dashboard” environment. The dashboard will provide managers and operators of flood defense systems a powerful tool not only in their remediation planning but also in their efforts to deal with episodic flood events. Geotechnical integrity is essential for levee safety assessments. Several pilot programs have been carried out in both the USA and the Netherlands to improve the geotechnical modeling of levee strength. New insights are integrated in Fugro’s Rapid Engineering Assessment of Levees® (REAL®). REAL® incorporates levee geotechnical, geospatial, and geological characteristics in its assessment and allows for systematic, consistent, and repeatable evaluation at very closely spaced cross-section intervals and various water levels. This assessment and evaluation process is typically 100 times faster than conventional work flows. This paper will elaborate on some recent developments in 3-D and real-time geotechnical and geospatial levee engineering assessments.

25 Todd Mitchell, Fugro Consultants, USA. ([email protected]) 26 Ries Kluskens, Royal HaskoningDHV, The Netherlands, [email protected]. 27 Bob Woldringh, Fugro Engineers BV, The Netherlands, ([email protected]). 28 Martin van der Meer, Fugro WaterServices, The Netherlands, ([email protected]) 29 Robert Kamp, HKV Consultants, The Netherlands, [email protected]. 30 C. de Gooijer, HKV Consultants, The Netherlands, [email protected]. 31 Marten Hillen, Royal HaskoningDHV, The Netherlands, [email protected].

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UPDATED STRESS AND STABILITY ANALYSIS OF A TVA DAM

Dan D. Curtis32 Husein Hasan33 Frank Feng34

Bob He35 Justin Long36

ABSTRACT

The objective of this paper is to present a 3D stress and stability analysis of a dam that was initially analyzed using traditional two-dimensional stability analysis. The 2D stability analysis found that numerous blocks in the dam were unstable under the new PMF load condition. After further review of the initial 2D stability assessment, it was concluded that consideration of 3D behavior could reduce anchor requirements because some of the dam blocks were embedded in rock. A non-linear three-dimensional finite element model of the entire concrete dam including the intake and powerhouse was developed in the finite element program ANSYS. The model used surface contact elements at all of the vertical contraction joints in the concrete dam. These contact elements allowed relative opening/closing and sliding along these joints. In addition, similar contact elements were used at the concrete/rock interface. The model allows non-linear redistribution of forces due to opening/closing and sliding at these interface elements. The analyses considered normal, unusual and extreme loading. The results of the revised PMF analysis are presented herein. The stability of the dam was evaluated by gradually lowering the shear strength at the concrete/rock interface. An automated procedure was developed to iterate the uplift pressure as the dam/rock interface joint opened. As a result of the non-linear analysis, the anchor requirements were significantly reduced. Also, the exaggerated deformed shape of the dam clearly identified modes of failure for the entire structure. In addition, a non-linear analysis of the behavior of horizontal cracks in the spillway sluice gallery was undertaken and the results of this analysis will be presented.

32 Project Manager, HATCH Ltd., Amherst, New York 14228-1146 USA; [email protected] 33 Civil Engineer Specialist, Tennessee Valley Authority, River Operations and Renewables /Reservoir Operations Support, Knoxville, TN 37902 USA, [email protected] 34 Senior Civil Engineer, HATCH Ltd., Amherst, New York 14228-1146 USA; [email protected] 35 Civil Engineer, HATCH Ltd., Amherst, New York 14228-1146 USA; [email protected] 36 Senior Civil Engineer, Tennessee Valley Authority, River Operations and Renewables /Reservoir Operations Support Knoxville, TN 37902 USA, [email protected]

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AN ADVANCED MODEL FOR SIMULATION OF ASR BEHAVIOR AT ROANOKE RAPIDS DAM

Brian R. Reinicker, P.E., P.G.37 Farzad Abedzadeh, Ph.D., P.E.38

Robin G. Charlwood, Ph.D., P.E. 39

John A. Cima, P.E.40

ABSTRACT

Roanoke Rapids Dam is a 72-foot high, 3,050-foot long concrete gravity dam with four 26MW power generating units located on the Roanoke River in North Carolina. The dam was constructed in 1955 and has performed satisfactorily for most of its life. Studies performed in 2006 to 2007 discovered significant cracking along several monoliths of the upstream face of the curved portion of the South Non-Overflow Section (SNOS) and led to the conclusion that the dam is undergoing concrete expansion due to an Alkali-Silica Reaction (ASR), most notably along the dam axis. A system of crack grouting and deep, multi-strand rock anchors was designed and constructed to stabilize these monoliths and accommodate future ASR-induced expansion. During construction, the cracking was found to be more extensive than had previously been understood. A reassessment of stability mechanisms and temporary reinforcement allowed construction to continue with construction completed in May 2010. Following construction of the reinforcement, finite element modeling of the structure was initiated to more completely understand the historical behavior and provide a tool to predict future responses of the modified structure. This paper describes the initial development of an advanced ASR material model which provided a “State-of-the-Practice” level simulation of the ASR-induced concrete expansion behavior. The ASR material model was implemented within a finite element structural model of the full dam. Results from the finite element structural model are shared to demonstrate how the model simulates the ASR expansion behavior at Roanoke Rapids Dam from the onset of ASR effects up through the time of remediation. Comparisons between model results and historic instrumentation data are provided to demonstrate the calibration of the model with observed behavior.

37 Senior Geotechnical Engineer, HDR Engineering, Inc., 440 S. Church Street, Charlotte NC 28202-2075, [email protected], 704.248.3693 38 Senior Geotechnical Engineer, HDR Engineering, Inc., 440 S. Church Street, Charlotte NC 28202-2075, [email protected], 704.307.8927 39 Principal, Robin Charlwood & Associates, PLLC, 4010 Alder Avenue, Freeland WA 98248, [email protected], 425.478.1642 4 Consulting Engineer, Dominion Resources Services, Inc., 5000 Dominion Boulevard, Glen Allen VA 23060, [email protected], 804.273.3045

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INVESTIGATIONS TO EVALUATE PERFORMANCE OF CONCRETE ARCH DAM AFFECTED BY ALKALI-SILICA REACTION

Daniel D. Mares, PE41

ABSTRACT

The concrete arch dam is experiencing concrete expansion, cracking and deterioration due to alkali-silica reaction (ASR). The cracking and deterioration is enhanced by freeze-thaw damage. ASR is the specific chemical reaction between the alkalis in Portland cement and silica or silicates in the aggregate which, in the presence of moisture, forms a hydrophilic expansive ASR gel. The gel absorbs moisture and swells which results in cracking and expansion of concrete structure. The reactive aggregate has been identified as strained quartz, which was the coarse aggregate used in concrete mix during dam construction. Strained quartz is known to be associated with late reacting ASR. Evidence of the concrete expansion was observed at this arch dam in the late 1970's when structure deformation data collection was initiated. The concrete deterioration includes spalling, pattern cracking, de-bonding of coarse aggregates from the remaining concrete, and calcium carbonate deposits on exposed concrete surfaces. This paper summarizes the investigation and analyses that have been performed since the late 1990s. Investigations have included concrete coring and testing, petrographic examinations, seismic tomography, borehole geophysics, in-situ stress measurements, and deformation monitoring on the concrete dam and rock abutments. A structural analysis was performed to estimate present and future stress conditions at the dam. In-situ stress measurement data and deformation data were used to calibrate the structural analysis model. The analysis indicated that the upward expansion and upstream tilt of the dam would result in large upward reaction forces in the upper abutments.

41 Daniel D. Mares, P.E., Civil Engineer, Waterways and Concrete Dams Group, Bureau of Reclamation, [email protected].

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STRUCTURAL ANALYSIS OF CORBELS ON AN AGING MULTIPLE-ARCH DAM

Brad B. Watson, P.E. 42

Victor M. Vasquez, P.E.43 Les Boyd, P.E.44

Doug Witkowski, P.E.45 James O. Jirsa, Ph.D., P.E.46

ABSTRACT

Buchanan Dam, owned by the Lower Colorado River Authority (LCRA), is a 145-ft high, multiple-arch dam on the Colorado River. Completed in 1937 and stretching more than two miles, Buchanan Dam is considered the longest multiple-arch dam in the nation. The dam includes two multiple-arch sections with 35-foot and 70-foot diameter arches. As part of a comprehensive facility review, analyses of the arch sections were performed. As often occurs when re-analyzing old structures using current criteria, some results were unsatisfactory. The corbels on the buttresses supporting the arches were found inadequate in both strength and ductility. A risk assessment of the structure indicated the need for action. Expenditure for enhancing corbel capacity was estimated between $15 and $30 million. LCRA engaged Freese and Nichols, Inc. to perform in-depth evaluations before proceeding with such significant construction expenditures. The corbels were first reevaluated using American Concrete Institute (ACI) methodology. Due to differences between the ACI code provisions and the corbel geometry and reinforcement, these results were deemed inconclusive. As a result, 2-D finite element models were developed; however, the adequacy of the corbels could not be substantiated without additional information. Additional inspections of the corbels through visual observations and underwater video found no visible signs of cracking that would suggest overstressing. Also, a physical model study was conducted by constructing and testing two half-size specimens of a representative corbel section. The tests indicated that shear failure was unlikely. Failure was due to tensile cracking of the concrete section followed by ductile yielding of the steel reinforcement at the face of the corbels. Results of the physical tests were then used to develop refined analytical models. The analytical model results demonstrated the corbel had adequate strength to resist anticipated loads. Ultimately, the structure was deemed safe and a large expenditure was avoided through careful engineering.

42 Senior Structural Engineer, Freese and Nichols, Inc., [email protected] 43 Project Manager, Freese and Nichols, Inc., [email protected] 44 Senior Structural Engineer, Freese and Nichols, Inc., [email protected] 45 Principal Engineer, Lower Colorado River Authority, [email protected] 46 Professor - Janet S. Cockrell Centennial Chair in Engineering, University of Texas at Austin, [email protected]

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INTEGRATING INFRASTRUCTURE UPGRADES WITH GRAVITY DAM REPAIRS

Timothy W. Johnston, P.E.47

John A. Wilkes, P.E.48 Mishelle Noble-Blair49

Thomas B. Pursel, P.E.50

ABSTRACT The Upper Occoquan Dam, a 72-foot high, 1950’s vintage concrete gravity dam located on the Occoquan River, is one of two primary sources of municipal water supply for Fairfax Water, which serves nearly 1.7 million people in Northern Virginia. Although the primary purpose of the dam and reservoir is municipal water supply, the Federal Energy Regulatory Commission (FERC) has regulated this facility due to the presence of a hydroelectric plant. In 2005, as part of FERC’s potential failure modes analysis process, recommendations were made to conduct investigations and prepare alternatives for dam safety repairs to significant cracks in the 72-foot-high powerhouse intake wall. This paper discusses the engineering investigations and development of repair alternatives to address the structural cracks in the powerhouse intake wall, including eliminating the seepage that was occurring through the wall. An innovative and cost-effective solution that addressed both dam safety concerns and a need to upgrade the powerhouse intake structure to an outlet works that met current industry standards for reservoir emergency draw down was selected. Structural and stability concerns were addressed by placing mass concrete within interior wet well chambers and multi-level portals of the powerhouse intake. Outlet works capacity was increased by encasing four large diameter steel conduits within the mass concrete backfill and adding a new gated concrete control tower to regulate discharge. The potential for seepage paths to develop through the new mass concrete backfill was minimized by the underwater installation of a PVC geocomposite membrane liner waterproofing system on the upstream face of the intake structure. The upgrades and repairs were accomplished without lowering the reservoir level expanding the dam’s footprint or impacting the water supply. The project also included hydroelectric plant demolition and FERC license surrender.

47 Project Manager, Associate, Gannett Fleming, Inc., Camp Hill, PA 17011, [email protected] 48 Carpi USA Inc., Roanoke, VA 24018, [email protected] 49 Senior Plant Engineer, Fairfax Water Treatment Plant, Lorton, VA 22079, [email protected] 50 Vice President, Gannett Fleming, Inc., Camp Hill, PA 17011, [email protected]

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EXPLICIT SEISMIC ANALYSIS OF MOSSYROCK DAM

Dan D. Curtis51 Gurinderbir Sooch52 Toby Brewer, P.E.53

Andrew Schildmeyer, P.E.54

ABSTRACT Hatch Associates Consultants Inc. was retained by Tacoma Power, located in Washington State to perform an explicit seismic analysis of Mossyrock Dam. A finite element model was then developed for the arch dam and its foundation rock which includes the effects of dam-foundation-reservoir interaction. Non-reflecting absorbing boundaries were modeled along the foundation sides and also at the extents of the reservoir. The vertical contraction joints and the dam-foundation interface were modeled with contact surfaces capable of opening, closing, and sliding during an earthquake. The shear strength of the dam-foundation interface included only a frictional component of shear strength i.e., cohesion was neglected. The new seismic analysis of Mossyrock Dam indicates that the total deflections, accelerations, and stresses calculated using the LS-DYNA finite element model are significantly smaller than those determined with a previous, implicitly solved, ANSYS model. Also, the model was used to check the response with a known recorded earthquake at Mossyrock Dam. Because this new model appears to attract less load than the previous analysis, no tension cracks in the horizontal lift joints are now expected where the previous analysis indicated such problems would occur. However, the results of the new analysis indicated relatively large hydrodynamic loads act on the radial gates at the top of the dam when compared to the hydrodynamic loads computed using the Westergaard method.

51 Project Manager, Hatch Associates Consultants, Amherst, New York 14228-1146, USA and Hatch Ltd, Niagara Falls, Canada, [email protected] 52 Civil Engineer, Hatch Ltd, Niagara Falls, Canada, [email protected] 53 Chief Dam Safety Engineer, Tacoma Power, Tacoma, Washington, [email protected] 54 Professional Engineer, Tacoma Power, Tacoma, Washington, [email protected]

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STRENGTH MONITORING FOR RCC DAM DURING CONSTRUCTION

James Stiady55 Frank Collins56

Jim Zhou57 Gerard E. Reed III58

Wade Griffis59 Jeffrey A. Shoaf60

ABSTRACT

The San Diego County Water Authority (Water Authority) is currently undertaking the raise of the existing San Vicente Dam to provide both emergency and carryover storage to increase local reservoir supplies in San Diego County, California. The San Vicente Dam is part of the $1.5 billion Emergency Storage Project (ESP) and Carryover Storage Project (CSP) which will provide a more flexible conveyance system, and increase water supply reliability in case of catastrophic failure to the delivery system due to a major earthquake. The San Vicente Dam Raise (SVDR) project is a major component of the last phase of the ESP and consists of raising the existing 220-foot high gravity dam with 90,063 acre-feet of storage, by 117-feet to increase reservoir storage capacity by 152,000 acre-feet. Scheduled to be completed in 2013, the SVDR will be the tallest dam raise in the United States and tallest roller compacted concrete (RCC) dam raise in the world. The reservoir capacity will be more than doubled, making it the largest single increase in water storage in this region’s history. In this paper, the use of 7-day strength for confirming the RCC mix that had been placed and identifying the necessary adjustment for the subsequent RCC production is discussed. The confirmation purpose was achieved by monitoring the 7-day strength as the construction progressed and developing boundary to identify the outliers. The outliers were evaluated further in accelerated testing. The need for adjustment was evaluated by observing a developing pattern in the 7-day strength historical plot.

55 Kleinfelder, 5015 Shoreham Place, San Diego, CA, 92122; 858-320-2269, [email protected] 56 Parsons, 110 West A Street, Suite 1050, San Diego, CA, 92101; 858-342-9813, [email protected] 57 San Diego County Water Authority, 4677 Overland Avenue, San Diego, CA , 92123, 858-522-6837, [email protected] 58 San Diego County Water Authority, 4677 Overland Avenue, San Diego, CA , 92123, 858-522-6835, [email protected] 59 San Diego County Water Authority, 4677 Overland Avenue, San Diego, CA , 92123, 619-390-2310 x3206, [email protected] 60 San Diego County Water Authority, 4677 Overland Avenue, San Diego, CA , 92123, 858-522-6813, [email protected]

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PRACTICAL APPLICATION OF RFC DAM CONSTRUCTION BASED ON CHEAP MIX DESIGN OF SCC

Qiong Wu 61 Xuehui An 62

Miansong Huang63 Feng Jin64

ABSTRACT

Rock-Filled Concrete (RFC) is an innovative dam construction material which has been developed quickly in China since 2003. The concrete is produced by pouring the Self-Compacting Concrete (SCC) into the voids of large rock chunks, with a minimum size of 300 mm, in a formwork. We have employed two different RFC construction technologies in a number of hydraulic engineering structures in China. To date, all the practical applications have shown that using RFC in dam constructions has significant economic and environmental benefits. Total construction cost is reduced due to using large amount of rock chunks, which can amount to roughly 55% of the total volume of RFC. When producing SCC, we make full use of local raw materials (e.g. fly ash, limestone) and optimize mix design to obtain better workability and lower cost. With regard to energy consumption and greenhouse gas emissions, RFC method consumes less energy and generates significantly fewer emissions when compared with Conventional Concrete from materials manufacturing through the concrete casting phase. Moreover, applying RFC brings about quicker construction due to the omission of surface roughening and allowance for continuous SCC pouring. Further, RFC saves on labor and costs by simplifying the aggregate production, concrete mixing machinery and temperature control facilities, as well as eliminating the vibration process. Lastly, it is indicated that RFC is a potential and promising material for use in future concrete dams.

61 Ph.D candidate, Department of Hydraulic Engineering, Tsinghua University, Beijing, 100084, China, [email protected]. 62 Professor, Department of Hydraulic Engineering, Tsinghua University, Beijing, 100084, China, [email protected]. 63 Post-doctoral, Department of Hydraulic Engineering, Tsinghua University, Beijing, 100084, China, [email protected]. 64 Professor, Department of Hydraulic Engineering, Tsinghua University, Beijing, 100084, China, [email protected].

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FILLING AN EXPANDED RESERVOIR — A MYRIAD OF CONSIDERATIONS Kelly L. Rodgers, P.E.65 Gerard E. Reed III, P.E.66 Jim Zhou, P.E.67 Surraya Rashid, P.E.68 Rosalva Morales69 Thomas O. Keller, P.E., G.E.70

Anna E. Kolakowski, P.E.71

ABSTRACT

The San Diego County Water Authority (Water Authority) is a public agency that imports up to 80 percent of the region’s water supply. The pipelines conveying imported water to the County cross several major fault lines. In 1998, the Water Authority approved a $1.5 billion Emergency Storage Project (ESP) to increase local storage and provide a more flexible and effective conveyance system. The San Vicente Dam Raise (SVDR) project is a major component of the last phase of the ESP and consists of raising the existing 220-foot-high dam by 117 feet to increase reservoir storage capacity by 152,000 acre-feet (AF). The SVDR will be the tallest dam raise in the United States and tallest roller compacted concrete (RCC) dam raise in the world. The City of San Diego (City) is a key partner, as it owns and operates the San Vicente Dam and Reservoir. Recognizing the regional benefit to the expansion of San Vicente Reservoir (SVR), the Water Authority and City executed an agreement that outlines the obligations of each party to bring the SVDR project to fruition. Once the dam raise is complete in 2013, and in coordination with the California Department of Water Resources Division of Safety of Dams, the Water Authority will begin filling the reservoir to its new, more than doubled, capacity. The fill is planned in four phases. Considerations include limitations imposed by the strength gain of the new RCC, reservoir hold points for monitoring of dam performance, constraints imposed by other construction activities at the site, capacity of the pipelines that bring water to the reservoir, and imported water supply availability. Finally, the Water Authority must account for member agency demands for SVR supplies as well as other commitments to customers.

65 Senior Engineer, San Diego County Water Authority, 4677 Overland Avenue, San Diego, C 92123-1233, [email protected]. 66 Engineering Manager, San Diego County Water Authority, 4677 Overland Avenue, San Diego, California 92123-1233, [email protected]. 67 Engineer PE, San Diego County Water Authority, 4677 Overland Avenue, San Diego, California 92123-1233, [email protected]. 68 Senior Civil Engineer - Civil, City of San Diego, 2797 Caminito Chollas, San Diego, California 92105-5097, [email protected] 69 Associate Engineer - Civil, City of San Diego, 2797 Caminito Chollas, San Diego, California 92105-5097, [email protected] 70 Vice President, GEI Consultants, Inc., 2141 Palomar Airport Road, Suite 160, Carlsbad, California 92011-1463, [email protected]. 71 Senior Engineer, California Department of Water Resources Division of Safety of Dams, 2200 X Street, Suite 200, Sacramento, California 95818, [email protected]

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DAM BREAK ANALYSIS APPLIED TO TAILINGS DAMS: USSD WORKSHOP SUMMARY AND PERSPECTIVES

José L.M. Clemente72

Robert E. Snow73 Carmen Bernedo74

Clinton L. Strachan75 Andy Fourie76

ABSTRACT

The USSD Tailings Dams Committee organized a workshop in August 2011 that included 2 days of presentations and discussions on the topic of dam break analysis applied to tailings dams and possible applications to other slurried waste impoundments. The workshop presentations covered the following main topics: (1) regulatory aspects of dam break analysis applied to tailings dams, (2) predictive models and available software, (3) failure modes, and (4) tailings flow modeling after a potential dam break. A survey was developed and distributed to state and federal dam safety officials to seek feedback on regulatory aspects of dam break analysis applied to tailings dams. This manuscript provides a workshop summary that can be seen as the framework for a “state-of-practice” document. The purpose(s) of break analysis, methods used, and documentation of important assumptions are addressed. Commentary citing concerns raised during and after the workshop are also included as it was clear that our ability to conduct accurate and realistic dam break analyses is limited. This manuscript also attempts to outline directions for the focus of future research and development projects with the goal of establishing more realistic methods for tailings dam break analysis.

72 Chief Engineer, Geotechnical & Hydraulic Engineering Services, Bechtel Power Corporation, Frederick, MD, USA, [email protected] 73 Principal, D’Appolonia Engineering, Monroeville, PA, USA, [email protected] 74 Lead/Supervising Engineer, MWH Global, Inc., Denver, CO, USA, [email protected] 75 Principal Geotechnical Engineer, MWH Americas, Inc., Fort Collins, CO, USA, [email protected] 76 Professor, School of Civil and Resource Engineering, University of Western Australia, Perth, WA, Australia, [email protected]

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DESIGN, CONSTRUCTION, AND PERFORMANCE OF A SEEPAGE CUTOFF BARRIER IN A DAM

Iván A. Contreras, PhD., P.E.77

Jon D. Ausdemore, P.E.78 Joe A. Welna79

Rachel E. Franz80

ABSTRACT A tailings basin at a trona mine near Green River, Wyoming includes approximately two miles of earthen containment structures around the perimeter of the basin. The containment system has a documented history of seepage and sinkhole development which raised safety and environmental concerns. In attempts to mitigate seepage, a soil-mix cutoff wall was built. The soil-mix wall reduced some of the seepage through the overburden embankment material but did not extend deep enough into the underlying fractured rock which allowed pond water to flow under the dam foundation. As a result, a complementary permeation grouting program was initiated to create an effective cutoff under the soil-mix wall and within the fractured rock foundation to reduce the seepage and improve the overall stability. This paper describes a detailed history of the geology and seepage issues at the site, the soil-mix wall, the grouting program, and the construction and monitoring of the seepage barrier that effectively mitigated the safety and environmental concerns. In particular the design, construction, and performance of the seepage barrier are discussed in detail.

77 Senior Geotechnical Engineer; Barr Engineering Co., Minneapolis, MN; 952-832-2600; [email protected] 78 Senior Civil Engineer; Barr Engineering Co., Minneapolis, MN; 952-832-2600; [email protected] 79 Civil Engineer; Barr Engineering Co., Minneapolis, MN; 952-832-2600; [email protected] 80 Civil Specialist; Barr Engineering Co., Minneapolis, MN; 952-832-2600; [email protected]

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SEISMIC DESIGN OF PERIMETER SLURRY WALLS FOR THE KINGSTON COAL ASH POND CLOSURE

Alan F. Rauch, PhD, PE81

Rodney P. McAffee, PhD, PEng82 Yong Wu, PhD, PE83 Luis J. Arduz, PE84

ABSTRACT

Using slurry wall methods, a stabilized perimeter is being constructed around the two-mile circumference of the coal ash landfill at TVA’s Kingston, Tennessee, facility. The landfill is being built within the footprint of the ash impoundment that experienced a catastrophic, static liquefaction failure in December 2008. When complete, the new capped facility will contain roughly 12 million cubic yards of coal ash produced by the power plant over the last six decades, including ash recovered from the 2008 failure. The closed facility is designed to meet current regulatory requirements, and must withstand a 2,475-year seismic event. The lower deposits of coal ash will remain saturated and, like the deeper alluvial sands beneath the site, will liquefy in the design earthquake. The stabilized perimeter, consisting of a grid of walls beneath a new perimeter berm, will buttress the ash embankment and retain the liquefied ash under dynamic loading. Currently under construction, self-hardening, cement bentonite and slurry trench methods are being used to build the walls. Similar designs have been used to stabilize major embankment dams with liquefiable foundation deposits. This paper focuses on the engineering analyses used to design the perimeter containment, including: geologic and subsurface conditions, ground response and liquefaction analyses, slope stability analyses, dynamic simulations of liquefaction and seismic performance, structural modeling in three dimensions, and embedment of the wall base into bedrock.

81Stantec, Inc., 1409 North Forbes Road, Lexington, Kentucky, 40511, [email protected]. 82C-CORE, Capt. Robert A. Bartlett Building, Morrissey Road, St. John's, Newfoundland, [email protected] (formerly with Stantec). 83Stantec, Inc., 1859 Bowles Ave. Suite 250, St. Louis, Missouri, 63026, [email protected]. 84Stantec, Inc., 1409 North Forbes Road, Lexington, Kentucky, 40511, [email protected].

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PERFORMANCE OF PREWETTED LOESS FOUNDATIONS FOR EMBANKMENT DAMS

William O. Engemoen85

ABSTRACT

During its history, the Bureau of Reclamation (Reclamation) has built several dams on foundations which consisted in part or totally of loess and reworked loess materials. The loess encountered in these foundations typically consists of dry, low-density silts which when loaded are susceptible to significant collapse upon wetting. One of the methods Reclamation has used to treat these problem soils has been to prewet the materials prior to placing the embankment so that the majority of the settlement will take place during construction rather than upon reservoir filling. This method was frequently used in the 1940s through the 1960s. Four Reclamation dams from that era that utilized prewetting were studied in order to evaluate the performance of the prewetting operations. Settlement data from baseplates and cross arm devices were examined to determine the rates and amounts of settlement. At three of the four dams studied, prewetting was relatively successful in that 70 to 95 percent of the total settlement occurred during construction. One of the four dams, however, experienced as much as 55 percent of the total settlement during and after initial reservoir filling. Even on successful prewetting operations, significant post-construction settlement still occurred (up to 30 percent of the total settlement), generally occurring during first filling. The settlement data obtained from these instrumented dams were plotted to obtain a graph of settlement versus embankment height with varying thicknesses of loess, which provides a means for approximating anticipated total settlements for embankments constructed on loess foundations that will eventually become saturated.

85 Lead Civil Engineer – Geotechnical Services Division, Bureau of Reclamation , P.O. Box 25007, Code 86-68300, Denver, CO 80225, (303) 445-2960, [email protected]

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ERODABILTY OF SEEPAGE BARRIER MATERIALS

Nathan Braithwaite86 John Rice87 David Paul88

ABSTRACT

Seepage barriers (cutoff walls) are used extensively to retard seepage in dams and levees and to reduce the potential for seepage related erosion. A variety of materials are used as backfill for these barriers including: soil-cement constructed using a variety of proprietary methods, cement-bentonite (self-hardening slurry), soil-bentonite, plastic concrete, and conventional concrete. Recent studies and post-construction observations have indicated that cracking of seepage barriers is not uncommon due to wall deformation, thermal expansion, and contraction during curing. It is theorized that such cracks in some of the barrier materials listed above may be susceptible to erosion due to high velocity seepage flow caused by large differential pore pressures across the barriers. A laboratory modeling study is being performed to evaluate the erodability of a variety of barrier materials commonly used in current seepage barrier construction and to assess the potential for erosion to initiate and propagate in various configurations of adjacent soils. The study consists of two phases of laboratory modeling. Phase 1 evaluates the erodability of a wide range of seepage barrier materials under the hydraulic conditions (pressure and gradient) expected to be encountered in the field. The tests are performed by passing water through cracks formed longitudinally through 6-inch diameter by 12-inch long cylindrical samples of the barrier matertials. Because no soil is adjacent to the barriers, these tests measure the basic erodibilty of the barrier material. Phase 1 tests are being performed on samples of cement bentonite, soil cement, plastic concrete, and conventional concrete. The Phase 2 testing is being performed in a laboratory model where the barrier cracks are adjacent to a variety of soils and soil configurations. Models are tested using barrier materials found to be erosive in the Phase I testing. This modeling assesses the interaction of the eroding barrier material and the adjacent soils and evaluates the effects of processes such as filtering of the eroding particles and filling of the barrier cracks with soil. The results of both phases of modeling will be used to evaluate the potential for seepage barrier cracks to develop into more serious seepage problems.

86 Graduate Student, Utah State University, 4110 Old Main Hill, Logan, UT 84322, [email protected], 435-225-0911 87 Assistant Professor, Utah State University, [email protected], 435-797-8611 88 Construction Liaison, USACE Risk Management Center, 12300 W. Dakota Ave Suite 230, Lakewood, CO 80228, [email protected], Phone 720-289-9042.

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BLUE LAKE DAM LEFT ABUTMENT STABILIZATION DESIGN James H. Rutherford, P.E., P.Eng.92 Peter Friz, P.Geo., LG93 John Werner, E.I.T.94 Lingmin Feng, PhD, P.Eng.95

Jerry Higgins, PhD, P.G.96

ABSTRACT The height of the existing Blue Lake arch dam is 211 feet (64.3 m). The Blue Lake Expansion Project includes an 83 ft (25.3 m) dam raise. This paper presents the full range of civil, structural, and geotechnical analyses performed to design the left abutment of the raised dam. Challenges included design of a thrust block acting as a strut to transfer dam loads to bedrock with topography that drops away steeply at the dam contact; a cut-off wall to prevent the thrust block from being subject to hydrostatic loading and prevent seepage; and developing an approach to stabilizing rock blocks subject to significant dam thrust under a variety of load cases and boundary conditions. The various rock blocks were modeled using AutoCAD 3D as an analysis tool to determine the mass of the various blocks, extent and direction of hydrostatic loads on the block faces, and orientation of dam thrust loads relative to inertial and hydrostatic loading. The dam raise design required comprehensive non-linear time history finite element analyses to check the stresses for the dam. These analyses were used to design the dam structure and determine the forces from the dam acting on the left abutment for use in block stability analysis and design of the thrust block. The thrust block and rock stabilization design were based on worst case boundary condition assumptions. An economical design has been developed for the left abutment based on a state-of-the-art nonlinear dynamic analysis of the raised dam, an innovative approach to analyzing rock blocks subject to dam loading and careful design of the thrust block and cut-off wall. The left abutment design will be adjusted as new information becomes available from the exposure of subsurface rock from thrust block, dam abutment, and drainage tunnel excavations during construction.

92 Civil Structural Engineering Lead, HATCH Renewable Power, 6 Nickerson Street, Suite 101, Seattle, WA 98109, Tel: 206-352-5730; Fax 206-352-5734; email: [email protected] 93 Engineering Geologist, HATCH Renewable Power, 700 - 1066 West Hastings Street, Vancouver, B.C, Canada V6E3X2, Tel: 604-630-7354; Fax 604-683-9148; email: [email protected] 94 Civil Structural Engineer, HATCH Renewable Power, 6 Nickerson Street, Suite 101, Seattle, WA 98109 Tel: 206-352-5730; Fax 206-352-5734; email: [email protected] 95 Senior Structural Analyst, HATCH Renewable Power, 4342 Queen Street, P. O. Box 1001, Niagara Falls, Ontario, Canada L2E6W1,Tel: (905) 357-6998 ; Fax ; email: [email protected] 96 Professor, Department of Geology and Geological Engineer, Colorado School of Mines, 1516 Illinois Street, Golden Colorado 80401, Tel: (303) 273-3817; email: [email protected]

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PERFORMANCE OF RCC STRENGTHENED LEVEE IN FULL-SCALE OVERTOPPING TESTS

Farshad Amini, PhD, PE, F.ASCE97

Lin Li, PhD, PE, M.ASCE98

ABSTRACT Most earthen levee damages have occurred on the levee crest and landward-side slope after Hurricane Katrina as a result of either wave overtopping, storm surge overflow, or a combination of both. The goal of this study was to investigate the performance and develop design guidelines for crest and landward-side strengthening system – Roller Compacted Concrete (RCC). A full-scale experimental study on combined wave and surge overtopping of a levee armored with RCC was conducted in a two-dimensional laboratory wave/flow flume. Trials of surge-only overflow, wave-only overtopping, and combined wave overtopping and surge overflow with different combinations of upstream head, significant wave height and peak period were conducted on the RCC section. The overtopping hydraulic features were summarized during the tests. Time series of flow thickness and velocity on the levee crest and landward-side slope were measured. Pre-selected locations were investigated to determine erosion in the RCC section. Erosion of RCC surface was checked after each test. It was found that most of the erosion occurred after the first test and the erosion was related to initial quality of RCC surface. Flow parameters including time series of flow thickness and velocity at 5 locations on the levee crest and landward-side slope were measured. New equations were developed to estimate flow parameters on landward-side slope, including mean flow thickness, mean velocity, and wave front velocity for the RCC strengthened levee.

97 Department of Civil and Environmental Engineering, Jackson State University, Jackson, MS 39217, USA. 601-9793913, [email protected]. 98 Department of Civil and Environmental Engineering, Jackson State University, Jackson, MS 39217, USA. 601-9791092, [email protected].

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SCOUR OF DISCONTINUOUS BLOCKY ROCK

Michael F. George99 Nicholas Sitar100

ABSTRACT

Removal of individual rock blocks is one of the principal mechanisms by which scour can occur, particularly in unlined spillways and on dam abutments. To alleviate some of the complexity, commonly used methods for scour prediction tend to simplify the rock mass using rectangular block geometries or incorporate empirical relationships for the rock mass and do not actually model the physical scour process. Such simplifications can be problematic, particularly for block analysis, where the 3D orientation of discontinuities within the rock mass largely influence block removability. To better represent the 3D structure of the rock mass, block theory has been applied to evaluate stability of removable rock blocks subject to hydraulic forces. Block theory provides a rigorous methodology to identify removable blocks, determine potential failure modes, and assess block stability. This paper presents methodologies for application of block theory to scour analysis of an actively eroding unlined rock spillway at a dam site in Northern California.

99 University of California - Berkeley, 413 Davis Hall, Berkeley, CA 94720, [email protected]. 100 University of California - Berkeley, 449 Davis Hall, Berkeley, CA 94720, [email protected].

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FINITE ELEMENT MODELING OF TRUNNION RODS

Mark A. Cesare, Ph.D.101 J. Darrin Holt, Ph.D., P.E.102

Robert F. Lindyberg, Ph.D., P.E.103 Jim J. Lua, Ph.D.104

Xiujun Fang, Ph.D.105

ABSTRACT This paper describes an approach for experimentally calibrating a three-dimensional (3D) finite element model (FEM) of in-situ trunnion rods to a series of full-scale tests using a full-size trunnion anchor prototype. The FEM is used to predict the modal responses of a rod as tension increases. The prototype is then loaded to known stress levels and experimentally evaluated for its responses by placing vibration transducers on the rod. The measured responses are then used to fine-tune the FEM approach by changing material properties and adjusting details of the known threads and rod gripping devices. Ultimately, this approach could serve as a basis for calibration of models to determine tension from only vibration tests, thereby eliminating the need for rod manual lift-off testing.

101 FDH Engineering, Inc., 2730 Rowland Road, Raleigh NC 27616, [email protected]. 102 FDH Engineering, Inc., 2730 Rowland Road, Raleigh NC 27616, [email protected]. 103 FDH Engineering, Inc., 2730 Rowland Road, Raleigh NC 27616, [email protected]. 104 Global Engineering and Materials, Inc., 1 Airport Place, Suite 1, Princeton, NJ 08540, [email protected]. 105 Global Engineering and Materials, Inc., 1 Airport Place, Suite 1, Princeton, NJ 08540, [email protected].

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EFFECTS OF BRONZE AND COMPOSITE SLEEVES ON TRUNNION YOKE PLATE STRESS CONCENTRATIONS

Thomas J. Walker, M.S., P.E.106

Kevin Z. Truman, Ph.D.107 Kurt A. Jacobs, M.S., P.E.108

ABSTRACT

Nonlinear simulations were used to predict and further understand the load transfer between trunnion shafts and yoke plates within a tainter gate trunnion assembly. Traditionally, yoke plates have been sized for an average stress based on the projected bearing area between the trunnion shaft and the yoke plate; however, finite element analyses proved that the stress is not uniform across the thickness of the yoke plate. The non-uniform stress distribution is attributed to the transverse shaft rotations that exist at the supports, concentrating load on the inboard edges of the yoke plates. Further study showed that the installation of either a bronze or composite sleeve between the yoke plate and the trunnion shaft will reduce the magnitude of the stress concentrations. A series of finite element models was developed to investigate the effects that shaft diameter, yoke plate thickness, and sleeve material have on the trunnion shaft to yoke plate load path. The analyses showed that a trend can be identified between the magnitude of the edge stress and the L/D ratio (shaft clear span to shaft diameter). As the L/D ratio of the system is increased, the magnitude of the edge stress increases; however, when a sleeve with a lower modulus of elasticity is introduced into the system, it is observed that the magnitude of the edge stress is reduced. The L/D ratio is designed to be close to 1.0 in order to minimize the inboard edge stress; however, trunnion assemblies with larger L/D ratios are desirable from a tainter gate design perspective. Larger clear spans (L) simplify the connection between the strut arms and the trunnion assembly, and small shaft diameters (D) reduce the trunnion pin friction moment demand on the tainter gate strut arms. By installing a low modulus sleeve between the trunnion shaft and the yoke plate, the magnitude of the edge stress is reduced; therefore, the design can accommodate L/D ratios larger than 1.0 while still keeping the stresses below an acceptable level. The simplified detailing and the reduction in strut arm demand will produce a more cost effective tainter gate design.

106 Structural Engineer, Black & Veatch Corporation, Water Division, [email protected] 107 Dean & Professor of Civil Engineering, University of Missouri-Kansas City, [email protected] 108 Structural Engineer, U.S. Army Corps of Engineers, [email protected]

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HODENPYL HYDROELECTRIC PLANT — SPILL TUBE HEADGATE REPLACEMENT PROJECT

Tor Hansen, P.E.109

Adam Monroe, P.E.110 Rusty Friedle111

ABSTRACT

This paper summarizes a design-build project to replace spill tube headgates at the base of the Hodenpyl Hydroelectric Plant. The spill tubes are hydraulic conduits under the powerhouse that provide additional spill capacity during flood events. The authors’ companies teamed to design and replace the existing 80-year-old Broome gates which leaked severely. The leakage (estimated to be on the order of 300 cfs) was costing the owner in lost generation revenue. The new roller gates were designed to seat under gravity loads and maintain their seal under approximately 65 feet of hydraulic head. Each gate was sized to overcome the frictional forces acting to resist gate movement, including hydrostatic, hydrodynamic, and atmospheric pressures. In order to reduce the hoist load needed to operate the gate, low-friction self-lubricating bronze bearings in the wheels and Teflon-coated rubber J-seals on the gate were used. The gate was designed for the existing hoist with a factor of safety to assure the gate would operate. Structural modifications to the 9-foot-high by 12.5-foot-wide spill tube inlet to create sealing surfaces for the new gate seals were also designed and constructed. This work included construction of new reinforced concrete sills, jambs, and headers around the inlet with embedded stainless steel plates for sealing. The existing gate slots were also modified by adding a rail to bear the new roller gate wheels. To facilitate the work, a steel stoplog cofferdam and bracing system were also designed and constructed. The design included various-sized (depending on head) fabricated beams to limit defection and prevent impact to the existing trash rack. The cofferdam was installed and used under 65 feet of water.

109 Vice President, Barr Engineering Company, 4700 West 77th Street, Minneapolis, MN 55435, [email protected] 110 Dam Safety Engineer, Consumers Energy, 330 Chestnut Street, Cadillac, MI 49601, [email protected] 111 Project Manager, Gerace Construction, 4055 South Saginaw Road, Midland, MI 48640, [email protected]

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INUNDATION MAPPING FOR IMPENDING RECORD RESERVOIR RELEASES — MISSOURI RIVER FLOOD OF 2011

Thomas Gorman, P.E.112 Lowell Blankers, P.E.113

Laurel Hamilton, E.I.114 Colleen Horihan, P.E.115

Troy Ingram116 Tony Krause, P.E.117

Curtis Miller, P.E.118 Eric Morrison119

Michelle Schultz120 Megan Splattstoesser121 Neil Vohl, P.E.122

ABSTRACT The U.S. Army Corps of Engineers operates six mainstem dams and reservoirs on the upper Missouri River. In the spring of 2011, record run-off required large releases from the system. As the magnitude of the impending flooding became apparent, Corps officials decided that producing inundation mapping for the predicted releases would be of immense value to communicate the flood risk. Modeling and mapping methods developed by the Corps’ Mapping, Modeling and Consequences Production Center for rapid assessment of dam safety scenarios were used to develop inundation mapping extending about 1,270 river miles. This paper will provide background on the flood event and the Omaha District’s effort to develop more than 300 detailed flood inundation map panels in advance of damaging flooding. The distribution and dissemination of the information to federal agencies, states, communities, tribes, news media and the public will be discussed. Finally, the projected flooding will be compared with what actually occurred.

112 Hydraulic Engineer, U.S. Army Corps of Engineers, Omaha District, Omaha, NE, 68102, [email protected] 113 Hydraulic Engineer, U.S. Army Corps of Engineers, Omaha District, Omaha, NE, 68102, [email protected] 114 Hydraulic Engineer, U.S. Army Corps of Engineers, Omaha District, Omaha, NE, 68102, [email protected] 115 Hydraulic Engineer, U.S. Army Corps of Engineers, Omaha District, Omaha, NE, 68102, [email protected] 116 Hydraulic Engineer, U.S. Army Corps of Engineers, Omaha District, Omaha, NE, 68102, [email protected] 117 Hydraulic Engineer, U.S. Army Corps of Engineers, Omaha District, Omaha, NE, 68102, [email protected] 118 Hydraulic Engineer, U.S. Army Corps of Engineers, Omaha District, Omaha, NE, 68102, [email protected] 119 Geographic Information Systems Specialist, U.S. Army Corps of Engineers, Omaha District, Omaha, NE, 68102, [email protected] 120 Geographic Information Systems Specialist, U.S. Army Corps of Engineers, Omaha District, Omaha, NE, 68102, [email protected] 121 Geographic Information Systems Specialist, U.S. Army Corps of Engineers, Omaha District, Omaha, NE, 68102, [email protected] 122 Hydraulic Engineer, U.S. Army Corps of Engineers, Omaha District, Omaha, NE, 68102, [email protected]

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SAVING LIVES WITH 2-D INUNDATION FLOOD MODELING AS A DAM DESIGN TOOL

Milan Jankovic, M.S., P.E.123

Shane Willard124

ABSTRACT Today, when designing dams, great attention is paid to the downstream consequences that might be caused by dam failures. Using 2-D inundation flood modeling as a dam design tool can help to get approval to build a dam, as well as, prevent potential loss-off-life downstream of the dam in any flooding scenario. Tohajiilee Dam, also known as Canoncito Dam, is located in the Canoncito Navajo Indian Reservation in central New Mexico, about 35 miles west of Albuquerque. The dam was built in 1971 for irrigation purposes, for watering livestock, as well as a flood control structure. Approximately 18 miles downstream from the dam is a school for 400 students, together with surrounding recreation facilities. After an incident in April 2004, when one of the upstream dams failed during the flood event, the dam was breached with an open-cut trapezoidal section to pass the 100-year flood. After many discussions, in 2011, BIA made a decision to rebuild the dam. In the dam redesign process, the flood wave from the Inflow Design Flood (IDF) and corresponding dam breach, was simulated using a two dimensional modeling software, after which, the recordings from the animation of this event were analyzed. This simulation resulted in a portion of the school grounds being inundated by as much as 5 ft. With the help of 2-D flood inundation software, the possibility of diverting the water flow from Tohajiilee Dam to the nearby Canada de los Apaches River was tested, with the focus being to divert flood waves from the school grounds. During this modeling scenario, the use of an iterative procedure has provided the minimum dimensions of the channels and the berms. The results of the modeling shows a successful deterrence of these facilities by flood flow from the school area, which can best be seen in the corresponding animation.

123 Hydrology, Hydraulic and Geotechnical Engineer, Bureau of Indian Affairs, Division of Water and Power Branch of Technical Services (Contractors), 13922 Denver West Parkway, Building 54, Suite 300, Lakewood, CO 80401, Phone: 303-231-5237, Email: [email protected] 124 Geographic Information System (GIS) Specialist, Bureau of Indian Affairs, Division of Water and Power Branch of Technical Services (Contractors), 13922 Denver West Parkway, Building 54, Suite 300, Lakewood, CO 80401, Phone: 303-231-5230, Email: [email protected]

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IDF DETERMINATION USING RISK ANALYSIS AT THE NORWAY-OAKDALE PROJECT

Eric J. Gross, P.E.125

ABSTRACT

The Norway-Oakdale Project is comprised of two dams and reservoirs, Norway Dam and Lake Shafer, and Oakdale Dam and Lake Freeman. The dams are located on the Tippecanoe River in Northwest Indiana. Indiana Beach on Lake Shafer is one of the premier tourism destinations in the state. A 2005 investigation using traditional inflow design flood (IDF) methods found both dams to have insufficient spillway capacity to pass the IDF. While the dams are not particularly large, all modeled failures produced incremental damages downstream due to the density of the population in the river valley. The narrow valley geometry also made it nearly impossible to fit a spillway at either dam that would pass the IDF. The licensee approached Federal Energy Regulatory Commission (FERC) about performing a risk analysis to determine if there was a better IDF. FERC approved the request on the stipulation that there was no guarantee that the results would be accepted. Over the course of several years the licensee produced a Risk Reduction Assessment to bring the risk of overtopping due to insufficient spillway capacity to as low as reasonably practicable (ALARP). The main challenge for FERC as a regulatory agency was that there was no existing internal protocol for determining ALARP. The result of this effort was a set of IDFs (significantly lower than the conservative traditionally determined) for the two dams that FERC staff and management felt both reduced downstream hazard to a tolerable level and met the ALARP concept.

125 Senior Civil Engineer, Federal Energy Regulatory Commission, 230 South Dearborn Street, Room 3130, Chicago, IL, 60604, [email protected]

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MODELING A LOW-HEAD DAM RETROFIT WITH A 2-D HYDRAULIC MODEL (ADAPTIVE HYDRAULICS)

Jeff Weiss, P.E.126

Jon Ausdemore, P.E.127 Tom MacDonald, P.E.128

Ron Koth129

ABSTRACT Adaptive Hydraulics (ADH) was used to model a recently constructed low-head dam retrofit project in which boulders were used to create a step-pool sequence that allows fish passage. ADH is a 2-dimensional (2D) hydraulic model developed by the US Army Corps of Engineers. Detailed survey data of the retrofit project was taken by using a 3-dimensional (3D) scanner during a dry period in which no water was flowing through the project. The 3D scanner is capable of creating an accurate 3D surface by generating points within millimeters of each other. ADH was used to model the existing retrofit project, and the results were compared to HEC-RAS results. HEC-RAS, a 1-dimensional hydraulic model that was also developed by the US Army Corps of Engineers, is often used in the design of in-stream structures and retrofit projects such as these because it is a well-known model, easy to use, and does an excellent job of predicting upstream impacts a project may cause; however one of its primary limitations is its inability to model localized velocities. The modeling effort with ADH provides a more detailed view of the hydraulics through all portions of the retrofit project.

126 Water Resources Engineer, Barr Engineering Company, 4700 W 77th Street, Minneapolis, MN 55407, [email protected] 127 Senior Civil Engineer, Barr Engineering Company, 4700 W 77th Street, Minneapolis, MN 55407, [email protected] 128 Senior Water Resources Engineer, Barr Engineering Company, 4700 W 77th Street, Minneapolis, MN 55407, [email protected] 129 Senior Fisheries Ecologist, Barr Engineering Company, 4700 W 77th Street, Minneapolis, MN 55407, [email protected]

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APPROACH FOR MAPPING FLOODING RISK NEAR LAKE OKEECHOBEE, FLORIDA

Guillermo Simón, P.E.130

Ao Yi, PhD, P.E.131

ABSTRACT At 730 mi2 of reservoir area, Lake Okeechobee is surrounded by a 143-mile structure known as the Herbert Hoover Dike (HHD). The U.S. Army Corps of Engineers (USACE) built the HHD between the 1930s and 1960s after hurricanes caused extensive flooding. The USACE conceived the HHD as a levee, but after changes in its operation, the HHD is now classified as a dam. Today, authorities and technical experts recognize the risk that seepage and other failure mechanisms pose to the population of south Florida. The structure’s lack of certification affects flood risk designation on the Federal Emergency Management Agency’s (FEMA) Flood Insurance Rate Maps (FIRMS). Because FIRMS show 1% annual-chance flood elevations, which are tied to actuarial rates, the maps do not show one particular dam-break case. The approach to identify the 1% annual chance flood of complex levee or dam systems has not yet been solidly established for FEMA’s flood maps. This paper presents a method to identify flood risk based on advanced dam-break modeling, lake level statistics, and the use of fragility curves. MIKE-Flood provided dam-break hydrodynamic analyses for lake levels ranging between 14 and 21 ft-North American Vertical Datum 1988 (NAVD88 or NAVD) at 11 different locations—or reaches—around the lake. Similar to FEMA’s statistical analysis to characterize hurricane rates, the authors describe breach rates as a function of lake stage frequency and fragility curves. A Gaussian redistribution analysis provided statistical water surface elevations at every computational node of the dam-break analysis mesh. The resulting 1% annual-chance statistical surface produced water surface elevations recommended to identify flood risk on FEMA’s FIRMS.

130 Director of Engineering, Water Resources Group, Taylor Engineering, Inc., 10151 Deerwood Park Blvd. Bldg. 300, Ste.300, Jacksonville, FL 32256, (904) 731-7040, [email protected] 131 Project Engineer, AECOM, 7785 Baymeadows Way, Suite 201, Jacksonville, FL 32256, (904) 271-2900, [email protected]

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COMPARISON OF MODERN DAY INUNDATION MODELING TECHNIQUES (2-D VERSUS 1-D, WITH 3-D ON THE HORIZON)

Milan Jankovic, M.S., P.E.132

Shane Willard133

ABSTRACT Looking back through history, we cannot deny the important role that water has played for humans in the development of civilization. To meet this demand, many dams were built for things such as irrigation, potable water, flood control, hydro power, recreation, and more. Along with the benefits of controlled water, comes the increased danger of their potential structural failure, or multiple failures, and corresponding downstream human impacts. In recent decades, and with the constant increase of technology, more and more attention has been given to the analysis of existing, as well as soon to be designed dams with respect to their failures. The ever increasing advancement of computer technology has enabled us to rely more on numerical (less costly) models, and less on physical (more costly) models with the latter being used mainly to check the numerical model results and to calibrate software. The process of selecting numerical models (1-D, 2-D, or 3-D) and computer software is very critical and depends on many factors that are defined in detail in this paper. If a computerized model can be viewed as a "black box" that has been approved for use by an authoritative organization (for example FEMA), then the accuracy of input data into that "black box" is essential for getting accurate and precise outputs. In this paper, great care has been given to the consideration of the necessary input data, technology of the calculations and selection of appropriate input values. Depending on complexity, computer model calculations could take anywhere from several minutes, up to a few months. The results obtained from a computer simulation of the dam failure flood inundation model are usually presented cartographically as flood polygons and, more recently, as flood depths, flood velocities, and hazard raster (grids), as well as video animations. Results of several analyzed dams presented in this paper demonstrate that the 2-D models are preferred in many situations in order to gain a realistic picture of what could happen when a dam fails. The selection of the dam breach parameters, such as breach formation time and breach width are very critical to the quality of the output results. Animations, one product from a 2-D model, represent a high-level view of the modeling results with a temporal dimension that 1-D models lack. This tool can help us visualize what can be expected if this adverse event occurs.

132 Hydrology, Hydraulic and Geotechnical Engineer, Bureau of Indian Affairs (Contractors), 13922 Denver West Parkway, Building 54, Suite 300, Lakewood, CO 80401, 303-231-5237, [email protected] 133 Geospatial Program Manager, Bureau of Indian Affairs (Contractors), 13922 Denver West Parkway, Building 54, Suite 300, Lakewood, CO 80401, 303-231-5230, [email protected]

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INCORPORATING UNCERTAINTIES IN THE ESTIMATION OF VULNERABILITIES FOR SECURITY RISK ASSESSMENTS

J. Darrell Morgeson134

Yazmin Seda-Sanabria135 Enrique E. Matheu, PhD136

Michael J. Keleher137

ABSTRACT This paper discusses the modeling of some of the uncertainties that are intrinsic to security risk estimates, focusing on the implementation of the Common Risk Model for Dams (CRM-D) risk assessment methodology. Security risk estimates are a function of the probability of a specific attack, the probability that the attack will be successful, and the attack’s potential consequences. The corresponding risk metric is the “expected value of loss” of the potential consequences. Risk metrics, which are computed for multiple attack scenarios, are used to compare and contrast risk across a portfolio of dams and their critical components. These metrics are also used to assess the return on investment for various alternatives to manage security risks. Within the CRM-D, the probability that a given attack will be successful is defined as a subjective probability. This probability is estimated by subject matter experts (SMEs) based on their experience, knowledge, and training. A natural question about this approach concerns the level of confidence or degree of uncertainty associated with such estimates. This paper discusses the underlying causes of uncertainty in the probability-of-success estimates. A second factor involved in the estimation of the probability of successful attack is related to the availability of any external response forces that may contribute to the security of the facility. A number of uncertainties are involved in making this determination, including the delay in alerting response forces, the time needed for response forces to arrive, and the length of time it takes for the attack vector to breach existing defensive layers and traverse inter-layer distances. Examples incorporating these uncertainties into risk estimates are shown to describe their potential implications for decision-making. A third factor involved in the estimation of the probability of a successful attack is the potential degradation of the attack vector as it breaches defensive layers. Defensive layers with armed guards have the possibility of degrading attack vectors so that they become less capable of successfully completing an attack.

134 Research Staff Member, Strategy, Forces, and Resources Division, Institute for Defense Analyses, Alexandria, VA 22311. 135 National Program Manager, Critical Infrastructure Protection and Resilience Program, Office of Homeland Security, U.S. Army Corps of Engineers, Headquarters, Washington, DC 20314. 136 Chief, Critical Lifelines Branch, Sector Outreach and Programs Division, Office of Infrastructure Protection, National Protection and Programs Directorate, U.S. Department of Homeland Security, Washington, DC 20598. 137 Adjunct Research Staff Member, Strategy, Forces, and Resources Division, Institute for Defense Analyses, Alexandria, VA 22311.

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SEMI-QUANTITATIVE RISK CATEGORIZATION FOR PERIODIC DAM SAFETY ASSESSMENTS

Timothy M. O’Leary, P.E.138

Gregg A. Scott, P.E.139

ABSTRACT The ongoing, routine dam safety activities form the cornerstone of the U.S. Army Corps of Engineers (USACE) Dam Safety Program. An important part of these activities is an assessment of risks, which occurs during Periodic Assessments. This assessment provides a chance to evaluate the design, analysis, construction, and condition of a dam project in more detail. Given limited budgets and resources to conduct these assessments and a large and diverse portfolio of dams, an efficient streamlined process was needed for sustainability. This paper describes the new process for the USACE Periodic Assessment program, which includes an inspection, a facilitated Potential Failure Modes Analysis, and a semi-quantitative risk assessment. Example results and lessons learned from implementing the new process are also presented.

138 Senior Geotechnical Engineer, U.S. Army Corps of Engineers, Risk Management Center, Louisville, Kentucky 40202, [email protected]. 139 Lead Civil Engineer, U.S. Army Corps of Engineers, Risk Management Center, Lakewood, Colorado 80228, [email protected].

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MINIMIZING OVER-CONSERVATISM IN DAM SAFETY MODIFICATIONS THROUGH THE CAREFUL USE OF RISK ANALYSIS

Daniel W. Osmun, P.E.140 William R. Fiedler, P.E.141

William O. Engemoen, P.E.142

ABSTRACT Budget shortages in the Federal Government and elsewhere have led to cuts in available careful funds for critical infrastructure repairs in many fields, including dams. There is thus an increasing need for more efficient and cost-effective approaches to determining when dam safety modifications are warranted, as well as optimizing the cost and scope of such modifications. As a means of better defining the need and costs for remediation to existing dams, the Bureau of Reclamation utilizes risk analysis and risk assessment to make risk-informed decisions on the need for modification as well as to optimize the scope of the remedial efforts. Probabilistic approaches can be successful in reducing some of the over-conservatism inherent in deterministic approaches, but nonetheless need to be approached thoughtfully and carefully to avoid other potential areas of conservatism. The use of probabilistic loadings in lieu of the deterministic Probable Maximum Flood (PMF) and Maximum Credible Earthquake (MCE) is a critical component of any probabilistic risk analysis. However, simply applying a set frequency for a PMF or MCE can lead to significant over-conservatism. Another issue can be designing for “no incident” as opposed to “no failure,” where risk and design teams strive to ensure an extremely low probability of an incident, whereas a more cost-effective approach may be to ensure that a catastrophic failure does not occur. Additionally, given the uncertainties inherent in dam safety evaluations, some risk and design teams tend to make conservative assumptions to cover uncertainties, which can often simply lead to a compounding of conservatism. This paper will discuss some of the advantages of risk-informed dam safety decision making and design, and how to avoid some pitfalls of over-conservatism.

140 Geotechnical Engineer, Risk Advisory Team, Bureau of Reclamation, Technical Service Center, Denver, CO; 303-445-2980; [email protected]. 141 Civil Engineer, Risk Advisory Team, Bureau of Reclamation, Technical Service Center, Denver, CO; 303-445-3248; [email protected]. 142 Geotechnical Engineer, Risk Advisory Team, Bureau of Reclamation, Technical Service Center, Denver, CO; 303-445-2960; [email protected].

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LOOK BOTH WAYS

Kim de Rubertis, P.E., L.G., FASCE143 C. van Donkelaar, M.Sc., P.E., P.Eng144.

ABSTRACT

Most, if not all, dam failures and incidents are caused by human error. Errors may occur at any moment during a dam’s life cycle, from conception to abandonment. The purposes of this paper are to focus on the sources of error, to provide illustrative examples of the role human error plays in dam incidents, to encourage the reader to look beyond traditional measures of safety, and to suggest ways forward that will reduce the likelihood of dam failures and incidents. Because dams are made by humans, it follows that poor dam performance must also be due to humans. Key human causes of dam incidents include: design errors, faulty construction, operational errors, maintenance-caused incidents, and system failures that encompass several causes. Familiar examples such as Ivanovo, Lawn Lake, Sayano, Ka Loko, Swift 2, Taum Sauk, Teton, and others are used to demonstrate the role decision making plays in dam safety. Though most dam incidents are human-caused and therefore preventable, they are also, like human behavior, largely unpredictable. Due diligence, peer review, monitoring, and planning can reduce this unpredictability but not eliminate it. Those responsible for dam safety must then plan for the unexpected. The highway that leads to a safe dam has many intersections, but none more important than the crossroads where analyses and decisions enter the highway. Look Both Ways at that intersection.

143 Consulting Engineer, P.O. Box 506, Cashmere, WA. 98815. USA. (206) 669-3002, [email protected] 144 Canadian Operations Director, McMillen, LLC, P.O. Box 41141. Lake Country, BC. Canada. V4V 1Z7, [email protected]

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INTERIM RISK REDUCTION MEASURES PLANS: LESSONS LEARNED

Jacob Davis, P.E.145

ABSTRACT The requirement to develop a Plan for Interim Risk Reduction Measures (IRRMs) has been included in the new ER 1110-2-1156 “Safety of Dams – Policy and Procedures.” IRRM plans are required for submittal, review, and approval for all dams rated with Dam Safety Action Class I, II, and III. Briefly, the IRRM plan should discuss and implement appropriate measures that reduce both the probability of failure and consequences of catastrophic failure to the maximum extent that is reasonably practicable while long term remedial measures are pursued. The principle of “Do no harm” should underpin all actions intended to reduce dam safety risk. Even though IRRMs are not meant to permanently address a dam safety concern, the fact is that in a broad portfolio of dams with limited funds, the likelihood is high that some approved IRRMs will remain in place for a longer time than others. This paper and presentation will review the requirements of an IRRM plan per the guidance in the ER, provide examples of both good and bad plans/IRRMs, suggest what should and should not be included, clarify HQUSACE review policy, and provide a status update on IRRM plan reviews.

145 USACE-IWR, Risk Management Center, 13952 Denver West Pkwy, Bldg 53 STE 200, Golden CO, 80401, [email protected]

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PLAN FOR THE SAFETY OF AGING DAMS; PLAN THE WORK, WORK THE PLAN

William J. Friers, P.E.146 Neil R. Bonesteel, P.E.147

Kapila S. Pathirage, P.E.148 Chris E. Wheland, P.E.149

ABSTRACT

This paper presents the proactive, prioritized approach taken by one city to extend the useful life of a 110-year-old dam while working with a finite budget and addressing updated New York State Department of Environmental Conservation’s regulations. The city of Troy, New York (City), owns, operates and maintains nine dams. NYSDEC classifies the City’s Tomhannock Reservoir Dam, Wright Lake Dam, and Bradley Lake Dam as High-Hazard structures. Tomhannock Reservoir is a top priority and serves as the City’s principal water source, providing the community with an average of 17 million gallons of water per day. Revised regulations required Inspection and Maintenance Plans, as well as Emergency Action Plans (EAP’s), for the City’s three dams by August 19, 2010. CDM Smith prepared EAP’s and Inspection and Maintenance Plans and EAP’s for these dams in 2010. The City also authorized CDM Smith to perform a dam Safety Inspection (SI) for the Tomhannock Reservoir Dam (Dam). The SI found seepage and wet areas on the downstream slope of the embankment and deterioration of the primary spillway’s abutment walls. The 5-foot-diameter steel conduit running through the embankment was apparently leaking. The City developed a logical approach addressing the observed conditions that also meets regulatory deadlines. The first priority was the 5-foot-diameter conduit. To relieve internal pipe pressures, gate valves were opened at the downstream outlet, and a qualified diver was brought in to close the inoperable valve. Interested in investigating the nature of the observed seepage and knowing the dam’s record drawings provided insufficient detail for an engineering assessment, the City authorized an Engineering Assessment (EA) of the Dam in early 2011, nearly a year before regulations required. CDM Smith developed a geotechnical investigation program, including borings along the dam crest, at mid-height of the downstream embankment slope, and near the toe to provide data for the EA’s seepage and stability analysis. EA recommendations to construct an earth berm on the downstream slope of the embankment to increase the embankment factors of safety, replace the spillway abutments, and rehabilitate the leaking steel conduit were accepted by the City. CDM Smith began construction documents August 2012. Construction is planned to start in June 2013.

146 J. Friers, P.E. CDM Smith, 11 British American Boulevard, Suite 200, Latham, NY 12110, 518.782.4513, [email protected] 147 Neil R. Bonesteel, P.E. Department of Public Utilities, City of Troy, NY, 25 Water Plant Road, Troy, NY 12182, 518.237.0193, [email protected] 3 Kapila S. Pathirage, P.E. CDM Smith, Raritan Plaza I, 110 Fieldcrest Avenue, 6th Floor, Edison, NJ 08837, 732.590.4625, [email protected] 4 Chris Wheland. Department of Public Utilities, City of Troy, NY, 25 Water Plant Road, Troy, NY 12182, 518.237.0865, [email protected]

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AN INNOVATIVE RESPONSE PLAN FOR POTENTIAL SEISMIC FAILURE MODES AT PRIEST RAPIDS DAM

James H. Rutherford, P.E., P.Eng.150 Dave Mishalanie, P.E.151 J. Groeneveld, P.Eng.152 Nikou Snell, E.I.T.153

Mohammed Badruzzaman, P.E.154

ABSTRACT Priest Rapids Dam, owned and operated by Public Utility District No. 2 of Grant County (District), is located on the Columbia River in central Washington, approximately 25 miles south of Interstate 90. The project was constructed in the 1960’s and is comprised of left and right zoned rockfill embankments, 2 fishways, a gated spillway and a 10-unit powerhouse. The project is regulated by the Federal Energy Regulatory Commission (FERC) under license number P-2114. During the Potential Failure Mode Analysis (PFMA) conducted in 2004, two potential failure modes (PFMs) were identified related to stability of the spillway monoliths under seismic and post-seismic loading. Subsequent stability analysis identified potential slide planes if a spillway monolith base were to become cracked and the effectiveness of the grout curtain and drains were compromised. As a result, Hatch recommended that the District establish threshold drain pressures and a response plan in the event of a significant increase in uplift pressure following an earthquake. The long term solution for this condition would be to lower the reservoir to an elevation where the structure was considered stable. The District was interested in a more immediate response, one that would isolate and respond directly to a problem area. One response investigated was to raise (open) the gates of the affected monolith(s) to reduce the loading on that part of the structure. Hatch performed detailed hydraulic and stability analysis including computational fluid dynamics to confirm that stability can be achieved by opening radial gates associated with monoliths requiring reduced loading without rapid draw down of the reservoir.

150 Senior Project Manager, Hatch Associates Consultants Inc., 6 Nickerson Street, Suite 101, Seattle, WA 98109, Tel: 206-352-5730; Fax 206-352-5734; Email: [email protected] 151 Dam Safety/EAP Supervisor, Grant County Public Utility District No. 2, 15655 Wanapum Village Lane SW, Beverly, WA 99321 Tel: 509-754-6622; Fax: 509-754-5074; email: [email protected] 152 Hydrotechnical Lead, Hatch Ltd, Suite 700, 840 - 7th Ave SW, Calgary, Alberta T2P3G2, Canada; Email: [email protected] 153 Hydrotechnical Junior Engineer, Hatch Ltd, 500 Portage Avenue, Winnipeg, Manitoba R3C3YB, Canada; Email: [email protected] 154 Senior Civil Engineer, Hatch Associates Consultants Inc., 6 Nickerson Street, Suite 101, Seattle, WA 98109, Tel: 206-352-5730; Fax 206-352-5734; Email: [email protected]

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INCREASING PRICKETT DAM HEIGHT FOR NEW PMF

Michael McCaffrey155 Tony Plizga156 Ben Trotter157

Todd Poehlman158

Lorna Langone159

ABSTRACT The crest height of Prickett Hydroelectric Project Dam was increased to provide adequate spillway capacity and freeboard during high flow events including the Probable Maximum Flood (PMF). A PMF study was completed by Mead and Hunt in 2006 using the Wisconsin-Michigan Probable Maximum Storm Study. The outcome of the study provided a PMF which could be contained in the reservoir without using the fuse plug and which could be discharged through the existing gate structure without overtopping the dam, if certain dam modifications were made. The crests of all water retaining structures at the site needed to be raised. These changes included eliminating the fuse plug function by incorporating the existing fuse plug into a full-height water retaining structure, raising the embankment crests, raising the concrete structures, increasing the full opening spillway gate height to minimize the potential for debris blockage in the gate openings, raising the spillway gate hoist, and replacing one movable spillway hoist with three dedicated hoists. Design and construction issues of these changes are discussed, and conclusions are presented about the improvements to Prickett Dam.

155 Michael McCaffrey, Principal Engineer, Parsons Brinckerhoff, 75 Arlington Street, Boston, MA 02116, (617) 960-5041, [email protected]. 156 Tony Plizga, Senior Principal Engineer, Parsons Brinckerhoff, 75 Arlington Street, Boston, MA 02116, (617) 960-4972, [email protected]. 157 Ben Trotter, Project Manager, Integrys Business Support, LLC, 700 North Adams Street, Green Bay, WI 54301, (920) 433-5585-433-5585, [email protected]. 158 Todd D. Poehlman, Senior Project Engineer, Integrys Business Support, LLC, 700 North Adams Street, Green Bay, WI 54301, (920) 433-2561, [email protected]. 159 Lorna Langone, Geotechnical Engineer, Parsons Brinckerhoff, 75 Arlington Street, Boston, MA 02116, (617) 960- 5037 [email protected].

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LAKE DELHI DAM FAILURE

William R. Fiedler160 Wayne King161 Neil Schwanz3

William Holman4

ABSTRACT

Delhi Dam, Delhi, IA, breached on July 24, 2010 after several days of intense rain in the watershed above the dam. In response to this event, the Governor of the State of Iowa requested assistance from the National Dam Safety Review Board in providing an Independent Panel of Engineers to evaluate the cause of the overtopping and breach of Delhi Dam. In the interest of dam safety, the Bureau of Reclamation, the Federal Energy Regulatory Commission and the US Army Corps of Engineers supported this effort that included interviews, gathering and compilation of data, field reconnaissance and hydraulic modeling of differing operating scenarios. Based on a limited scope of work, the panel investigating the failure concluded that there were a number of factors that contributed to the dam breach. These included inadequate spillway capacity, spillway gate binding and a flaw in the upper portion of the embankment dam related to a reinforced concrete/sheetpile core wall. This paper will discuss the findings of the panel and the lessons learned from this case history.

160 Civil Engineer, Bureau of Reclamation, Risk Advisory Team, 86-68300, PO Box 25007, Denver, CO 80225, [email protected]. 161 Regional Engineer, Federal Energy Regulatory Commission, 175 North Center St., Winder, GA 30680, [email protected] 3 Civil Engineer, US Army Corps of Engineers, 180 Fifth St. East, Suite 700, St. Paul, MN 55101, [email protected] 4 Senior Project Manager, Stanley Consultants, Inc., 5775 Wayzata Boulevard, Suite 300, Minneapolis, MN 55416, [email protected]

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OVERBURDEN CORRECTION FACTORS FOR PREDICTING LIQUEFACTION RESISTANCE UNDER EMBANKMENT DAMS

Jack Montgomery162

Ross W. Boulanger163 Leslie F. Harder, Jr.164

ABSTRACT

Evaluating liquefaction of cohesionless soils at large depths, such as under embankment dams, requires an understanding of how both the penetration resistance and cyclic resistance ratios are affected by high overburden stresses. SPT-based and CPT-based liquefaction triggering correlations are derived primarily from analyses of liquefaction case histories at relatively shallow depths and therefore must be extrapolated to larger overburden stresses. The overburden correction factor (Kσ) is used to adjust the cyclic resistance ratio for the effects of overburden stress. Different curves for Kσ have been proposed by various researchers and the values associated with these curves can have significant influence on the prediction of liquefaction at large depths. A database of laboratory test results was compiled and evaluated in light of the current understanding of factors which can affect cyclic strength, including overconsolidation ratio, relative density and fines content. Identification of these factors has allowed for classification of data points which were not necessarily representative of liquefiable materials (clayey and/or heavily compacted sands) and may have biased previous relationships. This paper will present the updated database of Kσ laboratory test results, discuss important factors which can influence the interpretation of Kσ and present a comparison between current design relationships and the updated database. The implications of these findings for evaluating liquefaction triggering at large depths will be discussed.

162 Graduate Student, Department of Civil & Environmental Engineering, University of California, Davis, CA 95616, [email protected] 163 Professor, Department of Civil & Environmental Engineering, University of California, Davis, CA 95616, [email protected] 164 Senior Water Resources Technical Advisor, HDR Engineering, Inc., [email protected]

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FAULT RUPTURE RISK EVALUATION AND MITIGATION AT THE ISABELLA AUXILIARY DAM

David C. Serafini, P.E., G.E.165

Henri V. Mulder, P.E.166

ABSTRACT

Isabella Dam is located on the Kern River 34 miles northeast of the City of Bakersfield in Kern County, California. It provides major flood control, water supply, power generation and recreation benefits to the region. The Isabella Dam has been designated as a Dam Safety Action Class (DSAC) I project by the U.S. Army Corps of Engineers (USACE), requiring urgent and compelling action by USACE to reduce probabilities and consequences of failure. The Isabella Dam project includes two major embankment dam structures, the Main Dam (185 feet high and 1,695 feet long) and the Auxiliary Dam (100 feet high and 3,260 feet long). The gross capacity of Lake Isabella is 568,100 acre-feet. The Isabella project has three areas of deficiency: hydrologic overtopping, seismic/fault rupture, and seepage. This paper presents an overview of the Isabella Dam Safety Modification Study and, more specifically, the dam safety risk associated with seismicity and rupture of the Kern Canyon Fault underlying the Auxiliary Dam. The primary failure modes, including the approach taken to evaluate failure modes associated with fault rupture to assess the baseline risk condition at the Auxiliary Dam, are summarized. The paper also discusses the strategies explored to reduce dam safety risk from fault rupture using filters and drains. The gradations, thicknesses, and zonations of the filter and drain were critical in the evaluation of continued functionality and risk reduction. Finally, this paper highlights some observations in the use of the recently developed FEMA Filter Manual.

165 Lead Engineer, Civil Engineer, US Army Corps of Engineers, Sacramento District, 1325 J Street, Sacramento, CA 95814; [email protected] 166 Geotechnical Lead, US Army Corps of Engineers, Sacramento District, 1325 J Street, Sacramento, CA 95814; [email protected]

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SEISMIC ANALYSIS OF THE BAKER RIVER HYDROELECTRIC PROJECT WEST PASS DIKE

Lin Zhao167

Jason E. Hedien168 Julie Stanaszek169 Zakeyo Ngoma170

ABSTRACT

The West Pass Dike is located on the Baker River, approximately 8 miles north of Concrete, Washington. The dike forms part of the 170 MW Baker River Hydroelectric Project, owned by Puget Sound Energy and regulated by the Federal Energy Regulatory Commission. The dike is a 115-foot-high, zoned rockfill embankment dam with a crest length of 1,200 feet and crest width of 30 feet. Recent studies of seismic activity in the Cascadia Subduction Zone (CSZ) have resulted in an updated seismic hazard for the area. As a result, a re-evaluation of the seismic deformation and stability of the dike was performed using FLAC2D (Fast Lagrangian Analysis of Continua). Liquefaction and cyclic softening analyses of foundation and embankment materials, and post-earthquake stability analysis of the dike were also performed. As the dike is a high hazard structure, two Controlling Maximum Credible Earthquake (CMCE) events identified for the project were used in the analysis: a magnitude 7.0 (Mw) random crustal earthquake with a peak ground acceleration (PGA) of 0.25 g; and a magnitude 9.0 (Mw) event in the CSZ with a PGA of 0.17 g. The maximum computed earthquake-induced displacements are approximately 1.5 ft for the CSZ event and about 0.5 ft for the random crustal event, below the maximum allowable deformation of 2 ft. The computed post-earthquake factor of safety against slope instability is 2.8, exceeding minimum required factor of safety of 1.0. The results of this analysis suggest that the dike have adequate seismic performance during and following the CMCE.

167 Senior Geotechnical Engineer, MWH Americas, Inc. 175 W. Jackson Blvd, Suite 1900, Chicago, IL 60604, Tel: 312-831-3453, [email protected]. 168 Chicago Area Manager , MWH Americas, Inc. 175 W. Jackson Blvd, Suite 1900, Chicago, IL 60604, Tel: 312-831-3095, [email protected] 169 Civil Engineer, MWH Americas, Inc. 2353 130th Avenue, Suite 200, 520 Corporate Center, Bellevue, WA 98005, Tel: 425-896-6953, [email protected]. 170 Geotechnical Engineer, Puget Sound Energy, 355 110th Ave NE, EST 05E, Bellevue, WA 98004, Tel: 425-456-2584, [email protected].

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SEISMIC STABILITY EVALUATION OF ANDERSON DAM, SANTA CLARA COUNTY, CALIFORNIA

Marc J. Ryan171

Michael Mooers172 Faiz I. Makdisi173 James Nelson174

Christopher Slack175

ABSTRACT Anderson Dam, a 240-foot-high embankment dam, is located in Santa Clara County, California. The dam was constructed in 1950 and includes upstream and downstream rockfill shells and a compacted clay core. There were two significant findings from the study. First, it was determined that alluvium was left in place in some areas of the dam foundation. The alluvium is primarily clayey sand with gravel and is considered to be susceptible to liquefaction. Secondly, zones of finer rockfill were found within the lower portions of shells. A detailed review of the construction records showed that although this material was borrowed from the same source as other material used during construction, it was of much lower quality than the large size rockfill materials. This lower finer fill was also considered susceptible to liquefaction. The cyclic resistance of the alluvium and lower finer fill was evaluated using Becker Hammer Penetration testing. Seismic stability analyses showed that the alluvium and lower finer fill would liquefy during the postulated earthquake shaking. Stability analyses indicate that the slopes of the embankment would become unstable during and after earthquake shaking, likely leading to an uncontrolled release of reservoir water. The results show that the presence of the lower finer fill and alluvium, while limited in thickness, has a significant adverse effect on the seismic performance of the dam. The estimated permanent deformations were considered unacceptable for dam safety, and the owner is currently working on a program to remediate the seismic deficiencies.

171 Principal Engineer, AMEC Environment & Infrastructure, 2101 Webster St., 12th Floor, Oakland, CA, 94612. [email protected]. 172 Associate Engineer, Santa Clara Valley Water District, 5750 Almaden Expressway, San Jose, CA 95118. [email protected]. 173 Principal Engineer, AMEC Environment & Infrastructure, 2101 Webster St., 12th Floor, Oakland, CA, 94612. [email protected]. 174 Senior Engineering Geologist, Santa Clara Valley Water District, 5750 Almaden Expressway, San Jose, CA 95118. [email protected]. 175 Staff Geologist, AMEC Environment & Infrastructure, 2101 Webster St., 12th Floor, Oakland, CA, 94612. [email protected].

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TERMINAL DAM — A SMALL FACILITY WITH BIG PROBLEMS

Tara Schenk McFarland176

ABSTRACT Terminal Reservoir is a small off-stream reservoir located in northern California at the terminus of a canal. The facility, built in 1958 consists of two homogeneous embankments, approximately 24 feet high, a siphon that feeds the reservoir, and an outlet works that connects water delivery systems for cities downstream of the project. This facility is set in a seismically active area, close to the Green Valley fault. It is a right lateral strike-slip fault with a prominent geomorphic expression downthrown to the east and is trending north-northwest through the site. This fault zone is part of the larger Concord and Green Valley fault system, which is capable of producing frequent strong events. Through the site, the fault zone may consist of four strands. One strand is reasonably well defined, passing through both embankments and the reservoir. Frequent seismic events resulting in strong shaking and surface rupture are potential issues for this facility, based on preliminary information on the fault zone. Available information on the design and construction of the facility is sparse, and construction practices used are considered substandard for embankment dams. This paper evaluates the challenges the team faces in evaluating the facility with limited data, identifying data needs for designing a repair, and designing economical repairs for a small dam.

176 Civil Engineer, Bureau of Reclamation, Denver Federal Center, P.O. Box 25007 (86-68313), Denver, CO 80225, [email protected]

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IMPACT OF EMBEDDED TOWER ON SEISMIC RISK OF AN EMBANKMENT DAM

Michael E. Ruthford177

Chung F. Wong178 Michael Ma179

Vlad G. Perlea180 Michael H. Beaty181

ABSTRACT

Within the framework of risk analysis of embankment dams, a possible source of dam failure following the action of a strong earthquake is damage to appurtenant structures caused by embankment-structure interaction. In particular, the integrity of the outlet works is of major concern to dam performance since lowering the reservoir may become critical after damages induced by the earthquake. Rupture of an outlet works control tower and/or embedded conduit may also facilitate piping and erosion of adjacent embankment fill. These concerns require the analysis of the seismic behavior of the outlet works interaction with its surrounding fill. This paper presents a series of analyses of a lightly reinforced embedded control tower. Soil-structure interaction analyses were performed to determine seismic demands on the control tower for a wide range of earthquake return periods. Seismic analysis and evaluation of a control tower was performed to evaluate the demand capacity ratios for the range of earthquake return periods. Inelastic behavior of the structure was considered in the evaluation. The approach takes into account brittle failure modes due to fracture, anchorage, and splice failures of reinforcement, diagonal tension shear, sliding shear, and compressive spalling failures of concrete. Evaluated tower response was then used to develop fragility curves for risk assessment. The specific case presented in the paper was aggravated by the presence of a liquefiable cohesionless soil in the embankment foundation.

177 Technical lead, US Army Corps of Engineers, Sacramento District, 1325 J Street, Sacramento, CA, 95814, (916) 557-7302, [email protected] 178 Structural engineer, US Army Corps of Engineers, Sacramento District, 1325 J Street, Sacramento, CA, 95814, (916) 557-7305, [email protected] 179 Structural engineer, US Army Corps of Engineers, Sacramento District, 1325 J Street, Sacramento, CA, 95814, (916) 557-7298, [email protected] 180 Geotechnical engineer, US Army Corps of Engineers, Sacramento District, 1325 J Street, Sacramento, CA, 95814, (916) 557-5320, [email protected] 181 Principal, Beaty Engineering LLC, 16631 SW Timberland Drive, Beaverton, OR, 97007, (503) 746-7419, [email protected]

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DEVELOPMENT OF THE CALAVERAS DAM REPLACEMENT PROJECT CHALLENGES AND SOLUTIONS

Michael Forrest182

Noel Wong183 John Roadifer184 Daniel Wade185 Gilbert Tang186

ABSTRACT

Calaveras Dam is a major component of the San Francisco Public Utilities Commission (SFPUC) Regional Water System. Since 2001, in response to seismic stability concerns from the California Division of Safety of Dams about this 90-year-old hydraulic fill dam, the SFPUC has lowered water levels in Calaveras Reservoir to about 39 percent of its 96,850-acre-foot capacity. To restore reservoir capacity, a replacement dam and new appurtenant works were designed to remain functional after the design earthquake, which is a magnitude 7¼ maximum credible earthquake (MCE) on the Calaveras Fault located 0.3 miles from the dam. The MCE peak ground acceleration would be 1.1 g. Several downstream replacement dam types were evaluated in order to select a 220-foot-high earth- and rockfill replacement dam. The dam design considered characterization and preparation of a block-in-matrix foundation, seismic deformation analyses, and seepage control to address the highly pervious, deeply weathered sandstone in the left abutment. Based on geologic conditions and hydraulic considerations, a side-channel open chute spillway was selected that requires 450-foot-high cuts in the left abutment. The spillway structure and the high cut slopes were designed to accommodate the MCE seismic loading conditions. Physical hydraulic model tests confirmed that the curved spillway chute and stilling basin designed to minimize excavation could safely pass the PMF outflow. The multi-level intake includes a new 160-foot-deep, 20-foot-diameter tower and shaft with four joining adit/conduit levels.

182 Vice President, URS Corporation, 1333 Broadway, Suite 800, Oakland, CA 94612, [email protected] 183 Vice President, URS Corporation, 1333 Broadway, Suite 800, Oakland, CA 94612, [email protected] 184 Sr. Project Manager, URS Corporation, 1333 Broadway, Suite 800, Oakland, CA 94612, [email protected] 185 Regional Project Manager, San Francisco Public Utilities Commission, 1155 Market St., San Francisco, CA 94103, [email protected] 186 Project Engineer, San Francisco Public Utilities Commission, 525 Golden Gate Ave., San Francisco, CA 94102, [email protected]

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DEVELOPMENT OF A RISK-INFORMED APPROACH TO THE SEISMIC EVALUATION OF HYDROPOWER PROJECTS — METHODOLOGY

Martin W. McCann, Jr.187 David W. Lord, P.E.188 Kevin Marshall, P.E.189 David Mishalanie, P.E.190 Gene Yow, P.E.191 Bill Christman, PE192

ABSTRACT In a familiar scenario that has played out in other locations and in other times, the results of “new” scientific studies provide new information about the greater (or perceived greater) potential for earthquake occurrences that may challenge the integrity of critical infrastructure. In a deterministic, standards-based environment, new information can prove particularly problematic. In this particular case, a paper by Bakun, et al., (2002) provided additional information about the magnitude and possible epicentral location of the 1872 Chelan earthquake. For the Mid-Columbia region, this new work prompted a re-evaluation of ground motions at hydropower sites using current deterministic standards. At the same time, the Federal Energy Regulatory Commission (FERC) dam safety staff was laying the groundwork for a move toward adopting a risk-informed regulatory approach to dam safety. As part of this transition, the FERC recommended that the Mid-Columbia PUD’s (Chelan, Douglas, and Grant) work together to conduct a probabilistic seismic hazard analysis (PSHA) for the region. At this time the PSHA has been completed (JBA, et al., 2011) and the FERC has committed to incorporating risk-informed decision making into its dam safety regulatory program (FERC, 2009). With this backdrop, there are open questions as to how seismic safety evaluation of dams should be performed in the context of a regulatory environment in which some form of tolerable risk criterion will be integral to risk-informed decision making. This paper describes a methodology for conducting risk-informed seismic evaluations of dam systems, including a discussion of the context and perspective for its development, some of its foundational aspects, and its implementation. At this time the methodology is being implemented in a series of prototype applications. Once the prototype evaluations are completed, the lessons from these applications will serve as a basis to finalize the approach and develop guidelines for its future use.

187 Martin W. McCann Jr., Consultant, Jack R. Benjamin and Associates, Inc., Menlo Park, California, 650-814-0878, [email protected] 188 Senior Civil Engineer, Risk-Informed Decision-Making, FERC, Division of Dam Safety and Inspections, Portland Regional Office, 503-552-2728, [email protected] 189 Kevin Marshall, Grant County Public Utility District, Beverly, Washington, 509-793-1536, [email protected] 190 Dam Safety Engineering Supervisor, Grant County Public Utility District, Beverly, WA, 509-754-6622 , [email protected] 191 Principle Civil Engineer, Chelan County Public Utility District, Wenatchee, Washington, 509-661-4305, [email protected] 192 Bill Christman, Dam Safety Manager, Chelan County Public Utility District, Wenatchee, Washington, 509-661-4283, [email protected]

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DEVELOPMENT OF A RISK-INFORMED APPROACH TO THE SEISMIC EVALUATION OF HYDROPOWER PROJECTS — THE OWNER’S

PERSPECTIVE Bill Christman, P.E.193 Kevin Marshall, P.E.194 David Mishalanie, P.E.195 Gene Yow, P.E196 David W. Lord, P.E.197 Martin W. McCann, Jr.198;

ABSTRACT Dam owners’ responsibilities include protecting the public, environment, and resources while avoiding unnecessary investor/rate-payer cost increases (avoid operational failures for least costs). Our projects are in a seismically active region which is not fully understood; consequently, the recognition of seismic potential has increased several times over many decades. Therefore, meeting our public safety responsibilities for least cost with a deterministic-standards based approach is potentially unstable over time. We believe a Risk Informed Decision Making approach (RIDM in FERC’s parlance) to evaluating seismic safety for our projects in their seismic setting is more responsible and stable than the deterministic-standards based approach.

This approach utilizes risk and consequence evaluations to help us make better informed decisions for accepting existing conditions or spending money on modifications to reduce either the probability or the consequences of dam failure.

Recently Chelan, Douglas and Grant PUD’s completed a probabilistic seismic hazard analysis (PSHA) for central Washington (Feb. 2012). The next step that must be considered is how this information should be used in the seismic safety evaluation of our hydropower projects. The FERC has not yet developed guidance as to how this should be done. As a follow-up to the PSHA, Chelan and Grant PUDs are working with Jack R. Benjamin and Associates (JBA) and FERC to develop an approach for incorporating RIDM into FERC’s dam safety program.

This paper, presenting the owner’s perspective, is the second of three discussing this approach. The first paper describes the seismic evaluation methodology; the third provides the regulator’s perspective.

193 Dam Safety Manager, Chelan County Public Utility District, Wenatchee, Washington, 509-661-4283, [email protected] 194 Hydro Engineering Manager, Grant County Public Utility District, Beverly, Washington, 509-793-1536, [email protected] 195 Dam Safety Engineering Supervisor, Grant County Public Utility District, Beverly, WA, 509-754-6622 , [email protected] 196 Principle Civil Engineer, Chelan County Public Utility District, Wenatchee, Washington, 509-661-4305, [email protected] 197 Senior Civil Engineer, FERC, Division of Dam Safety and Inspections, Portland Regional Office, 503-552-2728, [email protected] 198 Consultant, Jack R. Benjamin and Associates, Inc., Menlo Park, California, 650-473-9955, [email protected]

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DEVELOPMENT OF A RISK-INFORMED APPROACH TO THE SEISMIC EVALUATION OF HYDROPOWER PROJECTS — FERC PERSPECTIVE

David W. Lord, P.E.199 Martin W. McCann, Jr.200 Kevin Marshall, P.E.201 David Mishalanie, P.E. 202

Gene Yow, P.E. 203 Bill Christman, P.E.204

ABSTRACT Recently the Mid-Columbia PUDs (Chelan, Douglas, and Grant PUDs) completed a probabilistic seismic hazard analysis for north central Washington. The PSHA quantifies the frequency of occurrence of earthquake ground motions that can be expected to occur at Mid-Columbia hydropower projects. The next step that must be considered by the licensees and the Federal Energy Regulatory Commission (FERC) is how to use this information in the seismic safety evaluation of dams. At this time, the FERC has not developed guidance on how this should be done. In 2011, the FERC committed to incorporating risk-informed decision making into its dam safety regulatory program.

The paper will address two general, but important questions:

• How can the results of the PSHA be used in the seismic safety evaluation of hydropower projects?

• How can risk-informed seismic evaluations of hydropower projects be carried out in the context of the FERC’s commitment to incorporate risk-informed decision-making in its regulatory processes?

To address these questions, the Mid-Columbia PUDs and the FERC are involved in a project to develop a seismic evaluation approach and to test the approach in a series of project applications. The steps include:

• Initial development of a prototype seismic evaluation process. • Application of the prototype seismic evaluation process to selected systems. • Re-evaluation and finalization of the seismic evaluation process.

This paper presenting the regulator’s perspective is the third of three discussing this approach. The first describes the seismic evaluation methodology and the second provides an owners perspective on the risk-informed process.

199 Senior Civil Engineer, Risk-Informed Decision-Making, FERC, Division of Dam Safety and Inspections, Portland Regional Office, 503-552-2728, [email protected] 200 Consultant, Jack R. Benjamin and Associates, Inc., Menlo Park, California, 650-473-9955, [email protected] 201 Grant County Public Utility District, Beverly, Washington, 509-793-1536, [email protected] 202 Dam Safety Engineering Supervisor, Grant County Public Utility District, Beverly, WA, 509-754-6622 , [email protected] 203 Principle Civil Engineer, Chelan County Public Utility District, Wenatchee, Washington, 509-661-4305, [email protected] 204 Dam Safety Manager, Chelan County Public Utility District, Wenatchee, Washington, 509-661-4283, [email protected]

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RESERVOIR SUSTAINABILITY WORKSHOP LAKEWOOD, COLORADO, JULY 10-12, 2012

Timothy J. Randle205

Kent L. Collins206

ABSTRACT A Reservoir Sustainability Workshop with national and international specialists was convened in Lakewood, CO July 10-12, 2012 to develop and describe practical options for managing sediment for long-term reservoir sustainability in the United States. The workshop was sponsored by the following organizations: • Federal Advisory Committee on Water Information, Subcommittee on Sedimentation • U.S. Society on Dams This paper presents the recommendations of the workshop participants related to reservoir sedimentation issues, sedimentation monitoring, reservoir sustainability solutions, and future research needs.

205 Manager, Sedimentation and River Hydraulics Group, Bureau of Reclamation, P.O. Box 25007, Mail Code 86-68240, Denver, CO 80225, [email protected]. 206 Hydraulic Engineer, Bureau of Reclamation, P.O. Box 25007, Mail Code 86-68240, Denver, CO 80225, [email protected].

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SUSTAINABLE WATER INFRASTRUCTURE IN CALIFORNIA

Lawrence H. Roth, P.E., G.E.207

ABSTRACT

In California, wise investment in water infrastructure drives sustainable economic growth. The critical challenge of the 21st century is to make water infrastructure sustainable while improving both our quality of life and the environment. Nowhere is this more apparent than in the California Delta, the heart of the state’s water system, currently the focus of water supply reliability, ecosystem restoration, and improved flood management. Although water is viewed as a renewable resource, it is not constant. Climate change will alter weather, hydrology, and river flows. A growing population and environmental needs have caused increased competition for a water supply that was once plentiful. Against the backdrop of aging California water infrastructure, it is vital that we plan for improvements using a systems approach to achieve resiliency and sustainability, and that we apply effective leadership to make sound decisions, manage risk, and adapt to change. Water projects that capture, store, and deliver water must be evaluated for sustainability based on an all-inclusive approach, clear definition of values, and smooth integration with other infrastructure systems. We build water infrastructure to last for generations – we must do things right and do the right things to ensure that it will be sustainable.

207 Principal Engineer, ARCADIS U.S., 950 Glenn Drive, Suite 125, Folsom, California 95630, [email protected]

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RESOLVING COMPLEX CHALLENGES IN RIVER RESTORATION THE SAN JOAQUIN RIVER RESTORATION PROGRAM

William R. Swanson, P.E.208 Jill C. Chomycia209 Jeffrey T. Payne210 Heather Shannon211 Alicia Forsythe212 Kevin Faulkenberry213

ABSTRACT One of the largest river restoration efforts in the United States is now under way in the Central Valley of California. The San Joaquin River Restoration Program (SJRRP) was triggered by a 2006 Settlement, following over 18 years of litigation, between numerous environmental interest groups, water users, and the Federal government. Since the 1940s, Friant Dam on the San Joaquin River has provided water to approximately 1 million acres of agricultural lands, but also led to the extirpation of salmon runs. The Settlement has two primary goals: establish naturally producing and self-sustaining salmon in a 150-mile reach of the river, and reduce or avoid adverse water supply effects to the water users. The Settlement specifies flow requirements, and numerous actions to provide adequate channel capacity, establish fish habitat, introduce salmon, recover water supplies, and address adverse effects to third parties. Limited flows were initiated in October 2009 to support experimentation and data collection, while the implementing agencies continue to address long-term issues regarding environmental effects, flood protection, water recovery, development of channel capacity and fish habitat, and reintroduction of salmon. This paper describes some of the major issues that are being addressed to implement the restoration program, including program structure, project planning and permitting, protection of private lands, coordination of restoration actions with ongoing water delivery and flood management systems, financing challenges, and public participation and education.

208 Vice President, MWH Americas, 2121 N. California Blvd, Suite 600, Walnut Creek, California, 94596, [email protected] 209 Senior Geologist, MWH Americas, 175 W. Jackson Boulevard, Suite 1900, Chicago, Illinois 60604, [email protected] 210 Senior Engineer, MWH Americas, 3321 Power Inn Road, Suite 300, Sacramento, California, 95826, [email protected] 211 Senior Geologist, MWH Americas, 3321 Power Inn Road, Suite 300, Sacramento, California, 95826, [email protected] 212 SJRRP Program Manager, U.S. Department of the Interior, Bureau of Reclamation, 2800 Cottage Way, Room W-1727, Sacramento, California 95825, [email protected] 213 SJRRP Program Manager, California Department of Water Resources, 3374 E. Shields Ave, Fresno, CA 93726, [email protected]

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ELWHA RIVER RESTORATION: SEDIMENT MANAGEMENT FIRST YEAR RESULTS

Timothy J. Randle214

Jennifer A. Bountry215

ABSTRACT The National Park Service, with technical support from the Bureau of Reclamation, has led the effort to remove Elwha Dam Glines Canyon Dams on the Elwha River near Port Angeles, Washington to restore anadromous fish and the natural ecosystem. Elwha Dam was completed in 1913 and formed Lake Aldwell. Glines Canyon Dam was completed upstream in 1927 and formed Lake Mills. Together, these were the two largest dams ever removed with a reservoir sediment volume of at least 24 million yd3 ± 4 million yd3. Concurrent removal of both dams, in controlled increments, began on September 17, 2011. Elwha Dam was completely removed by September 2012. About three-quarters of Glines Canyon Dam had been removed by October 25, 2012. Prior to dam removal, facilities were constructed to provide adequate water quality for existing water users and to provide flood protection. These facilities included water treatment plants, new wells, a new surface water intake, raising the height of existing levees, and the construction of some new levees. A sediment monitoring and adaptive management plan was implemented to compare measured effects with predictions and take corrective actions if necessary. Monitoring results confirmed that lowering the reservoir pool in a series of controlled increments and then holding the reservoir pool at constant elevation, induced vertical and lateral erosion of the exposed delta surface. Coarse sediments that were eroded from the exposed delta surface were re-deposited across the width of the receding reservoir. The pro-grading coarse sediments eventually completely filled the remaining reservoir volume. During reservoir drawdown, eroding fine sediments became suspended in the reservoir. A portion of these suspended sediments were transported past the dam site to the downstream river while the remaining portion of suspended sediment re-deposited on the lake bed and were subsequently buried by coarse sediment. The pro-grading delta sediment filled the remaining Lake Aldwell volume during April 2012 and filled the remaining volume of Lake Mills during October 2012. Subsequent dam removal resulted in the release of eroding coarse and fine reservoir sediment to the downstream river channel. Current monitoring activities are focused on measuring the continued reservoir sediment erosion and transport through the downstream river channel.

214 Supervisory Hydraulic Engineer, U.S. Bureau of Reclamation, Denver, Colorado, [email protected]. 215 Hydraulic Engineer, U.S. Bureau of Reclamation, Denver, Colorado, [email protected].

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LARGE SCALE DAM REMOVAL ON THE KLAMATH RIVER — MONETIZING THE SOCIAL EFFECTS OF LARGE SCALE DAM

DECOMMISSIONING

Ben Swann, PG216 Chris Park, AICP217

ABSTRACT

In the Upper Klamath River Basin, PacifiCorp owns and operates four hydroelectric dams on the main stem of the Klamath River as part of FERC Project 2082. Located 200 miles upstream of the Pacific Ocean in Northern California and Southern Oregon, Project 2082 has directly impacted anadromous fisheries by blocking fish passage and altering physical conditions on the Klamath River.

Klamath River anadromous fish runs (steelhead, Chinook salmon, green sturgeon and lamprey) have contributed substantially to commercial, recreational, and American Indian fisheries. All species have experienced dramatic population declines resulting in harvest reductions or outright fisheries closures.

PacifiCorp, following a failed attempt in 2006 to relicense Project 2082 without fish passage, entered into the Klamath Hydroelectric Settlement Agreement (KHSA) in February 2010 with the states of California and Oregon, the federal government, Klamath River Indian tribes and fisheries interests.

The KHSA established a roadmap for the study and removal of the four Klamath River dams by the year 2020. Dam removal requires an affirmative determination by the Secretary of the Interior which if completed would represent the largest dam removal project. An important component of the Secretary’s Determination is whether dam removal is in the public’s interest including effects on local communities and Indian tribes.

This paper presents the comprehensive results of the socioeconomic effects of dam removal on the local community, tribes, and the nation. Studies included effects to Tribal Trust resources, private real estate, regional and national economics, lost hydropower and green house gas, and a first-time nation-wide non-use value study that gauged Americans’ values and willingness to pay for a restored Klamath salmon fishery. The results are informative and will aid the decision making of other large dam owners faced with the prospect of mandatory fish passage or dam removal and its socioeconomic effects on communities.

216 CDM Smith, 2295 Gateway Oaks Dr. Suite 240, Sacramento, CA 95833. [email protected] 217 CDM Smith, 2295 Gateway Oaks Dr. Suite 240, Sacramento, CA 95833, [email protected]

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WORKING TOGETHER WITH MINIMUM BUDGET TO BREACH A HIGH-HAZARD DAM

Stephen L. Whiteside, P.E.218

Emily Davenport219 Jose Maria Guzman, P.E.220

ABSTRACT The Freedom Park Dam (formerly known as Gung Lake Dam) was originally classified as a Category II dam by the Georgia Safe Dams Program. As a result of Hurricane Jeanne in September 2004, the dam was overtopped and had considerable erosion. Subsequently, the Safe Dams Program performed dam-break analyses that indicated 3.5 feet of flooding above the finished floor elevation of a tire and service center 0.11 mile downstream. Based on these results, the Safe Dams Program reclassified the dam as Category I and instructed the city to either 1) upgrade the dam so that it is in compliance with dam safety rules, 2) breach the dam, or 3) remove or flood-proof the hazards downstream. Due to the lack of data and identified deficiencies, a detailed investigation and extensive rehabilitation of the dam or complete replacement of the dam would be required to bring the dam into compliance. Due to the high cost of either option, the city decided to breach the dam. CDM Smith performed a focused geotechnical investigation at the proposed breach location. Detailed hydrologic/hydraulic analyses were also performed to develop the required breach geometry to limit water levels upstream of the remaining embankment section during flood events as well as to reduce the potential for downstream impacts due to the loss of lake storage after the breach. Even the breach option presented a challenge to the city, because the plan called for a detailed design, construction bid, breach and final de-certification– with a potential construction cost of more than $350,000. During an inspection by the Safe Dams Program, a void was observed adjacent to the spillway training wall. CDM Smith found that the void extended beneath a large portion of the spillway slab. As a result, the city and Safe Dams Program agreed that an emergency breach should be performed. The city took the initiative to construct the breach with their skilled in-house staff that could operate heavy machinery and complete the work with input from the engineer of record. CDM Smith prepared a conceptual breach document to guide the breach and provided assistance during the breach construction, which was completed in October 2011 for a construction cost less than $90,000. The final breach was successful and allowed the city to remove the Category I classification from this dam with minimal cost. 218 CDM Smith, 5400 Glenwood Avenue, Suite 300, Raleigh, NC 27612, 919.325.3556, [email protected]. 219 City of Valdosta – Engineering Department, 300 N. Lee Street, P.O. Box 1125, Valdosta, GA 31603, 229.259.3530, [email protected]. 220 CDM Smith, 8381 Dix Ellis Trail, Suite 400, Jacksonville, FL 32256, 904.527.6702, [email protected].

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PINE CREEK DAM — PHASE V INVESTIGATION

Kathryn A. White, P.E221

ABSTRACT

Several investigations have been performed to identify potential voids surrounding the conduit and to provide information for analysis and remediation measures at Pine Creek Dam. This paper focuses primarily on the Phase V Investigation task order. This paper is a continuation of previous investigations described in a paper submitted and presented during the 2012 USSD Dam Safety Conference by author. Background information and potential concerns with the dam, summary of geotechnical investigations that lead to the Phase V investigation task order, description of the investigation methods and field activities, and discussion of the results and conclusions drawn from the investigation are provided.

221 Kathryn A. White, P.E., 1645 S. 101st East Avenue, Tulsa, OK, 74128, (918) 669-7651, [email protected]

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REDUCING SEEPAGE INTO INTER-GALLERY DRAINS WITHIN THE NARROWS DAM INTAKE STRUCTURE

Stefan Schadinger222

Mark J. Gross223 Michael McCaffrey224

Paul F. Shiers225 Christopher Godwin226

ABSTRACT

Narrows Dam is located on the Yadkin River near Badin, North Carolina, and is one of four developments which comprise the Yadkin Project owned and operated by Alcoa Power Generating Inc. (APGI). It is a concrete gravity structure approximately 200 feet high. Seepage into the intake inter-gallery drains (intake drains) has been a concern over the years with an increasing trend since the 1990s. Past visual inspections and evaluations have confirmed that almost all seepage was coming directly from these intake drains. In 1986 a cement grouting program in the piers between bays had limited success because high seepage rates made placement and containment of the grout difficult. However, the grouting reduced seepage into the intake drains from upstream of the intake gates. In 2007, seepage significantly reduced within minutes of dewatering two of the four units, indicating a short and direct path from the intake area to the intake drains. In addition, internal inspections of the intakes revealed cross-flow from adjacent units through open joints. In 2008, divers patched the surface of the joints in the transition area in Unit 3 resulting in a decrease in seepage. In addition, seepage data and a dewatered inspection since the patching, indicate the patching remains mostly effective. However, total seepage from the intake drains remains significant. The paper discusses two approaches to reduce seepage through the intake drains based on the assessment of the historical repairs and current analysis of the intake transition areas. Approach 1 is a drill and grout repair of the pier between bays, whereas Approach 2 is a surface patching and surface grouting repair of the joints. The technical aspects of each approach are discussed including the use of hydrophilic grout.

222 Lead Engineer, Parsons Brinckerhoff, 75 Arlington St., Boston, MA 02116, (617) 960-4976, [email protected] 223 Technical Manager, Alcoa Power Generating Inc., Yadkin Division, P.O. Box 576, Badin, NC 28009, (704) 422-5774, [email protected] 224 Principal Engineer, Parsons Brinckerhoff, 75 Arlington St., Boston, MA 02116, (617) 960-5041, [email protected] 225 Vice President, Parsons Brinckerhoff, 75 Arlington St., Boston, MA 02116, (617) 960-4990, [email protected] 226 Civil Engineer, Parsons Brinckerhoff, 75 Arlington St., Boston, MA 02116, (617) 960-5025, [email protected]

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EARLY CONTRACTOR INVOLVEMENT: CASE STUDIES FOR REDUCING COSTS, COMPRESSING SCHEDULES,

AND IMPROVING PROJECTS

Del A. Shannon, P.E.227 John F. Bowen228

ABSTRACT

The last decade has witnessed the continued closure of the gap between planning, design and construction. Nowhere has this been more evident than in the dams, water resources and hydropower markets where the complexity of projects, schedule demands, limited budgets, and permitting requirements are forcing owners, regulators, stakeholders and builders to move closer and closer together. Historically, these elements have frequently been viewed as competing with each other and requiring the safeguarding of their individual interests. This separation often creates friction between parties; friction that has, in turn, fashioned detrimental imbalances that threaten to dramatically alter the overall intent of the project. A basic requirement for everyone in our modern society is clean water and reliable power, and the ongoing maintenance of systems and projects that provide these elements, as well as the development of new projects to meet existing and future demand of these resources, must balance a wide range of impacts in order to meet these requirements. Early Contractor Involvement, a broad term that identifies involving constructors in the planning and design aspects of civil engineering projects, has become an effective tool in meeting these requirements. This paper will provide several case studies where including the constructor in the planning and design phases has provided considerable benefit to the overall project, including reducing project costs, compressing schedules, creating a collaborative work environment, and effectively addressing regulator and stakeholder issues and concerns. Further, this paper will show how Early Contractor Involvement can be implemented and accomplished in a variety of contractual vehicles, from proposals to design/build arrangements to hard bid. Case study projects will include: Pine Brook Dam, Boulder, Colorado Genesee Dam, Kittredge, Colorado Wyaralong Dam, Beaudesert, Queensland, Australia Cabresto Dam, Questa, New Mexico

227 Design Manager, ASI Constructors, Inc., 1850 E. Platteville Blvd, Pueblo West, Colorado, 81007, 791-647-2821; [email protected] 228 President, ASI Constructors, Inc., 1850 E. Platteville Blvd, Pueblo West, Colorado, 81007, 791-647-2821; [email protected]

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THE BID PROCESS — CLOSING THE COMMUNICATION GAP BETWEEN ENGINEER AND CONTRACTOR

Mark Landis, PG, PE229

Page Riley, PE230

ABSTRACT

In the traditional design-bid-build process, the engineer prepares bid documents including drawings and specifications, and usually with the assistance of the owner, contractual language known as the “Front End Documents”. The engineer also provides access to data reports prepared during the design process, such as the geotechnical investigations. Armed with this usually massive quantity of information, the bidding contractor is expected to prepare an informed, competitive bid in a short period of time. The additional constraints imposed by lump sum bid items often require the contractor to make leaps of faith without complete information. The authors represent both sides of this coin and present their perspectives on how the engineer perceives the contractor needs versus what the contractor perceives is needed to make an informed bid. Communication gaps can lead to a reduction in the number of active bidders and/or bids that are too high or too low. If bids are too high, the information was probably not portrayed correctly and the contractor had to account for the uncertainty. If too low, tensions likely result from the start of the job, with the potential for taking shortcuts during construction, and increasing the risk of a lengthy claims process following the project. Opportunities for closing the communication gap include the bid documents themselves, the pre-bid meeting, the site visit, the formal written Q&A process, and appropriate bid period selection based on project complexity and competing bid schedules.

229 Mark E. Landis, PG, PE, Schnabel Engineering, 11-A Oak Branch, Greensboro, NC 27407; 336-274-9456; email: [email protected] 230 Page Riley, PE, Philips and Jordan, Inc, 2100 Fairfax Road, Ste. 101D, Greensboro, NC 27407; 336-478-0265; email: [email protected]

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DEVELOPMENT AND FIELD TESTING OF A PRESSURE SENSING GROUT PACKER

David Paul, P.E.231

Jeffrey Schaefer, Ph.D., P.E.232 Brook Brosi, P.G.233 Patrick Carr, P.E.234

Chad Conti235

ABSTRACT When grouting for critical projects, it is important to understand what pressures are being applied to the ground in each stage. This is important for both the evaluation of the grouting effectiveness as well as limiting the potential to damage the structure. Currently in general practice, there is only a gauge at the top of the hole to measure the line pressure. In order to determine the pressure at the stage under consideration, a suite of calculations must be performed. These calculations require an estimate of the dynamic line losses from the gauge to the bottom of the packer, the pressure increase from the weight of the grout below the gauge, and an estimate of the groundwater pressure at the stage elevation. With so many variables involved there is a high level of uncertainty in the actual effective grout pressure being exerted in the ground. Schaefer et al. (2011) challenged the grouting community to read the pressure at the packer. This paper accepts that challenge. In early 2012, a modification to a Corps dam grouting contract was issued to measure the pressure at the packer. The Contractor, The Judy Company, Inc., was able to successfully measure the pressure in the formation over 1,000 times with minor durability issues. Surface checks of the gauge confirmed the downhole-gauge read correctly. USACE hopes to phase in this requirement for dam and levee pressure-grouting and water-pressure-testing, with the intent that this will be a future contractual requirement for this type of work.

231 Civil Engineer, U.S. Army Corps of Engineers, Risk Management Center, 12300 W. Dakota Ave Suite 230, Lakewood, CO 80228, [email protected], Phone 720-289-9042. 232 Geotechnical Engineer, U.S. Army Corps of Engineers, Risk Management Center, PO Box 59, Louisville, KY 40202, [email protected], Phone 502-315-6452. 233 Geologist, U.S. Army Corps of Engineers, Nashville District, 100 Power Plant Road, Jamestown, KY 42629, [email protected], Phone 270-343-6067. 234 President, The Judy Company, 8334 Ruby Ave, Kansas City, KS 66111, [email protected], Phone 913-422-5088. 235 Geologist, GEI Consultants, 400 Unicorn Park Drive, Woburn, MA 01801, [email protected], Phone 781-721-4119.

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MCCLURE PENSTOCK REPLACEMENT PROJECT — FROM FAILURE TO RECONSTRUCTION

Whitney Hansen, PE236

William Forsmark, PE237 Robert Meyers238

ABSTRACT

In 2007, the nearly 90-year old existing penstock ruptured at the McClure Hydroelectric facility, located in Marquette, Michigan. The 7-foot diameter part concrete-encased wood stave penstock and part buried steel penstock conveyed water 2.5 miles with about 400 feet of vertical drop from the dam to the 8-megawatt powerhouse. Barr Engineering Co. performed a replacement alternatives study and developed the detailed design for full replacement of the penstock with spiral weld steel (SWS) pipe, after nearly 2 years of studies and discussion with FERC on the life-cycle of the existing penstock. The unique aspects of the project include a remote work site, environmental constraints, new surge protection, embankment stability during construction, railroad and trout stream crossing, and an extensive alternatives evaluation. Barr performed detailed design for the steel penstock, a new pressure/vacuum relief system, and thrust blocks to prevent pipe movement along alignment. The new penstock tied in to the existing concrete intake structure, surge tank and powerhouse, slip-lined through an existing concrete encasement underneath a railroad, and extended above ground at two aerial crossings over protected wetlands. Barr also provided detailed site work and erosion control design along with existing penstock demolition and abandonment. The project required detailed geotechnical design for the earth-embankment dam, including evaluation of seepage and slope stability for embankment excavations, design of temporary shoring for excavation associated with the penstock replacement, settlement and movement predictions, movement-monitoring systems, and design of pipe subgrade and fill. Barr developed a detailed startup and commissioning plan and was onsite throughout construction and commissioning. During startup and commissioning, pressure transducers were installed in the penstock to correlate actual penstock pressures with design pressures. Many lessons were learned throughout design and construction. A few of these issues are listed and described, along with recommendations for future projects.

236 Barr Engineering Co., 4700 W 77th St Minneapolis, MN 55435, 953-832-2931, [email protected]. 237 Barr Engineering Co., 4700 W 77th St. Minneapolis, MN 55435, 952-832-2843, [email protected]. 238 Upper Peninsula Power Company, 500 N. Washington St. Ishpeming, MI, 49849, 906-485-2419, [email protected].

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LAKE TOWNSEND DAM REPLACEMENT — CHALLENGES IN BUILDING A NEW DAM AT THE TOE OF AN OLD DAM UNDER FULL RESERVOIR HEAD

Robert Cannon, PG239

Tillman Marshall, PE240 Greg Paxson, PE241

Frederic Snider, PG242 Melinda King, PE243

ABSTRACT

Due to aggressive ASR degradation, the existing gated ogee spillway of the Lake Townsend Dam required a complete replacement. As the dam impounds the primary water supply for the City of Greensboro, NC, construction of the new labyrinth spillway, diversion of flood flows during construction, and demolition of the old dam all had to be completed under full reservoir head. This requirement posed unique challenges in both design and construction. Due to space constraints imposed by extensive wetlands immediately downstream of the dam, the new labyrinth spillway was to be constructed immediately at the toe of the existing ogee spillway, using the old dam as the upstream cofferdam. Unsuitable floodplain soils in the new dam foundation required over 30 feet of excavation and removal of 1/3 of the downstream face of the existing southern embankment to provide adequate layback. An extensive program of excavation dewatering and instrumentation was required, as was a complex, sequenced diversion scheme to maintain the ability to pass flood flows in excess of 10,000 cfs through the construction area at all times. Wet borrow area soils coupled with a very wet spring and summer construction season necessitated chemical drying of the soils prior to compaction. A unique application of cement-modified soils as backfill for the entire labyrinth foundation was successfully implemented and provided both cost and time savings to the construction process. The new dam was completed and commissioned in late 2011 and instrumentation data to date indicates it meets or exceeds specified performance requirements.

239 Robert Cannon, Schnabel Engineering, Greensboro, NC; email: [email protected] 240 Tillman Marshall, Schnabel Engineering, Greensboro, NC; email:[email protected] 241 Greg Paxson, Schnabel Engineering, West Chester, PA; email gpaxson@ schnabel-eng.com 242 Frederic Snider, Schnabel Engineering, Greensboro, NC; email: [email protected] 243 Melinda King, Dept of Water Resources, City of Greensboro, NC; [email protected]

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SEISMIC REMEDIATION DESIGN AND CONSTRUCTION OF KEY-BLOCK: MORMON ISLAND AUXILIARY DAM

M. Jonathan Harris, P.E.244

Michael J. Romansky, P.E.245

ABSTRACT Mormon Island Auxiliary Dam (MIAD) has been assessed as having high seismic risks according to Reclamation dam safety public protection guidelines. A key-block with overlay has been designed to reduce risk of failure of the dam due to foundation liquefaction and subsequent deformation of the structure. A unique solution for construction of a key-block downstream of the dam was designed based on: site conditions, the Folsom Project dam safety modification schedule, environmental and community impacts, cost, and dam safety risks. The excavate and replace method using a structural wall system was used to construct the key-block. The key-block was constructed in cells, thus minimizing dam safety risks during construction while maintaining full reservoir conditions. The design and construction of the key-block provided a method in which the uncertainty of strength parameters used in design was minimized by means of visual documentation, data collection and testing during and after construction.

244 Civil Engineer, Geotechnical Engineer, Bureau of Reclamation, P.O. Box 25007, 86-68313, Denver, CO 80225, [email protected] 245 Civil Engineer, Geotechnical Engineer, Bureau of Reclamation, P.O. Box 25007, 86-68313, Denver, CO 80225, [email protected]

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GEOTECHNICAL CONCERNS IN ADDRESSING SEEPAGE AT A ROCK-FILLED, WOOD-FACED DAM

John C. Stoessel, P.E.246

John Wilkes, P.E.247 Craig McElfresh248

ABSTRACT

Saddlebag Dam, a rock filled, wood faced dam located in the eastern High Sierra Nevada Mountains, was experiencing increasing seepage at the downstream toe of the dam. This trend had been observed for about ten years and state and federal regulators were concerned about the increasing magnitude of toe seepage. Southern California Edison (SCE) suspected that the increasing leakage was originating from two locations. First, the deteriorated redwood facing was a likely source, as other SCE dams with similar redwood facing had been observed to have seepage between the boards. Secondly, a sinkhole that had been repaired 40 years earlier was a potential source. Since SCE was planning to install a geomembrane liner over the redwood face, it was not necessary to confirm seepage by dye testing. However, because the sinkhole was a possible source and would not be affected by the geomembrane liner, dye tests were performed and the results confirmed that water was being drawn into the sinkhole and traveling to the downstream toe. With the reservoir drained to install the geomembrane liner, a plan was developed to conduct a more permanent repair to the sinkhole. This plan included excavation of the sinkhole down to bedrock, sealing the bedrock foundation with a bentonite slurry mix, pouring a concrete cap, and replacing and compacting native earth. Results of this work will be observed in the spring of 2013, when the reservoir is filled.

246 Southern California Edison Company, 300 N. Lone Hill Ave., San Dimas, CA 91773, [email protected] 247 Carpi USA, Inc., 4370 Starkey Rd., Suite 4D, Roanoke, VA 24014, [email protected] 248 MCS Construction, Inc., 2873 Larkin, Clovis, CA 93612, [email protected]

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CONCRETE PLACEMENT AND REHABILITATION AT THE HANNAWA DEVELOPMENT

Bryce Mochrie249

Lee Talbot250 Kevin Finn251

ABSTRACT

Originally built as a paper mill, the Hannawa Falls Hydroelectric Project is an 8 MW development near Potsdam, NY, located on the Raquette River. Hannawa was constructed in 1899, and has undergone a number of modifications to upgrade the facilities to provide electric generation. The project consists of a 38 ft high dam, a 2,700 ft long intake canal, masonry and concrete intake structures, a powerhouse with two horizontal Francis units, and a masonry wall lined tailrace canal. The structures have somewhat deteriorated over the 114 year lifespan of the project. Brookfield Renewable Energy Group raised concerns over the safety of the structure in 2011, based on cracking observed within the powerhouse and continued movement of the powerhouse walls. The progressive movement of the downstream wall had caused the internal crane, with one rail integral to the downstream wall of the powerhouse, to be almost completely decommissioned. An engineering inspection of the development confirmed that the downstream powerhouse wall was in the most severely deteriorated state. The approximately 150 ft long, 60 ft high wall required complete replacement. A temporary cofferdam was constructed across the tailrace to allow for dewatering and access to the open basement below the powerhouse. Atypical to powerhouse structures, the basement of Hannawa Falls was open to the discharge water. The rehabilitation effort included filling the basement with lean concrete to increase the first floor capacity. After installing new steel framing inside the powerhouse, hydraulic jacking was used to remove the roof loads from the downstream wall and transfer them to the new framing. The masonry wall was subsequently demolished and replaced with a sheet metal siding system. This paper presents the engineering effort related to designing the rehabilitation effort of an aged structure, with limited as-built documentation, as well as presenting the results of the construction effort.

249 Bryce Mochrie, Senior Principal Engineer, Parsons Brinckerhoff, 75 Arlington St. Boston, MA 02116, (617) 960-4971, [email protected] 250 Lee Talbot, Project Engineer, Brookfield Renewable Energy Group, New York East Regional Operating Center, 399 Big Bay Road Queensbury, NY 12804, (518) 743-2001, [email protected] 251 Kevin Finn, Engineer, Parsons Brinckerhoff, 75 Arlington St. Boston, MA 02116, (617) 960-5031, [email protected]

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DEVELOPING GREAT HYDROELECTRIC PROJECTS IN A CHALLENGING SOCIAL AND ECONOMICAL ENVIRONMENT: LA

ROMAINE COMPLEX, SITUATED IN NORTHERN QUEBEC, CANADA

Vlad Alicescu252 Jean-Pierre Tournier253

Pierre Vannobel254

ABSTRACT

Hydro-Québec is developing the Hydroelectric Complex of La Romaine, situated on the North shore of the St Lawrence River, in Quebec, Canada. The $6,5 billion project consists in building 4 generating stations with a total installed power of 1550 MW and an output of 8,0 TWh. The clean and renewable electricity produced in the four power plants of the Complex will help to avoid new emissions of gas with greenhouse effect in North America with approximately 3 million tons of CO2, if that energy would have been generated with natural gas and with about 7,5 million tons of CO2, if coal would have been used for the same purposes. The Environmental Assessment Report was presented to the provincial and federal governments in January, 2008 and the formal environmental assessment process was completed by May 2009. Environmental studies and measures carried out before, during and after construction will cost over $300 million altogether. The erection of the Complex started with the $2,4 billion Romaine 2 facility, and 2012 is showing good overall progress of the construction works.

252 P.Eng., MScA, MBA, Planning of Development Projects, Hydro-Québec, 75, Boul. René Lévesque O, Montréal, Québec, Canada H2Z 1A4, [email protected], [email protected] 253 P.Eng., PhD, Expertise HEP, Hydro-Québec, 800, boul. De Maisonneuve East, Montréal, Québec, Canada H2L 4M8, [email protected] 254 P.Eng., M. Eng., Geotechnical specialist, Romaine 2 Facility, Des Murailles Camp, Havre St-Pierre Québec, Canada G0G 1P0, [email protected]

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REDUCE RISK OF COFFERDAM FAILURE WITH RCC — A HISTORICAL PERSPECTIVE

Daniel L. Johnson, P.E.255

Kenneth D. Hansen, P.E.256

ABSTRACT

Cofferdams are used on nearly all new dam construction projects and on many dam rehabilitation projects. Cofferdam design typically involves agreed upon criteria that is a balance between performance and cost, requiring an evaluation of risk specific to a site. Many cofferdams have failed during construction of dam projects, mainly by having the design flood exceeded. Cofferdam construction material selection depends on many factors, specific to each dam construction project and site conditions. To reduce the impact to a construction project, many designers are considering cofferdams capable of being overtopped, without failure. The overtopping may impact the construction activities and completed works, but without failure the impact to construction cost and schedule can be reduced. Here is where roller compacted concrete (RCC) is an alternative, mainly due to its erosion resistance. An historical perspective on the many applications of RCC in cofferdams, as well as performance, is the subject of this paper.

255 Daniel L. Johnson, P.E., Vice President, Tetra Tech, Inc., 350 Indiana Street, #500, Golden, Colorado 80401, 720-881-5845, [email protected] 256 Kenneth D. Hansen, P.E., Consulting Engineer, 6050 Greenwood Plaza Blvd., Suite 100, Greenwood Village, Colorado 80111, 303-695-6500, [email protected]

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ROCK ANCHORS FOR DAMS: A FIVE-YEAR UPDATE

Donald A. Bruce, Ph.D, C.Eng. 257 John S. Wolfhope, P.E. 258

Jesse D. Wullenwaber, P.E. 259

ABSTRACT During the period 2004-2006, Bruce and Wolfhope were Co-Principal Investigators on the National Research Program on Rock Anchors for Dams. Several publications resulted, dealing with aspects of over 400 case histories. Since that time, a significant number of additional anchoring projects have been undertaken, including some of the largest projects of their type. This paper updates the previous survey published in 2007, and describes the newer trends and developments of the last few years. The impact of the revised Post-Tensioning Institute’s (PTI) Recommendations (2004) on practice is also explored and recent developments in drilling and anchoring techniques and capabilities are described.

257President, Geosystems, L.P., P.O. Box 237, Venetia, PA 15367, (724) 942-0570, [email protected] 258Principal, Freese and Nichols, Inc., 10814 Jollyville Road, Building 4, Suite 100 Austin, TX 78759, (512) 451-7955, [email protected] 259Project Engineer, Schnabel Engineering, LLC, 1380 Wilmington Pike, Suite 100, West Chester, PA 19382 (610) 696-6066, [email protected]

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REHABILITATION OF TEMPORARY COMPOSITE DAMS — CASE STUDY: MARED SOIL-SHEET PILE DAM

Saber Alidadi260

Masoud Hakami261

ABSTRACT

Flow rate of Karun river, which is the longest and largest river in Iran, decreased from 600 m3/s to 100 m3/s in average, due to the drought in early 2008. This reduction caused water from Persian Gulf to advance farup-river and reach araw water supply basin and increase water electrical conductivity (EC) to 5,000 μmoh/cm. A temporary dam constructed from soil-sheet pile was installed to prevent salty water progress to the water supply location. Heavy rain fall and flooding with a flow rate of 1000 m3/s destroyed one-third of the dam in November 2008 and therefore, the lives of nearly 300,000 people were in danger due to water shortcoming. In this paper a new and innovative method for repairing the aforementioned dam is presented considering constraints such as type of dam destruction, limited time and cost, and other operating limitations. In this method, the damaged section of the dam was restored by composite geo-box piles. The piles were installed in two rows against the water to create a corridor and then the corridor was filled with soil geo-boxes. Based on the seepage and overturning analysis, and considering implementation conditions, the geometry of proposed method was selected. After successful implementation of the plan, the dam was restored and consequently the EC of the water was reduced to 1,800 μmoh/cm and raw water quality improved significantly in less than 2 months with minimum cost. It was finally realized that the soil erosion inside the cells was reduced; the bed was stabilized and its integrity over the dynamic loads was sustained. Therefore, it can be said that there is a significant uniformity between the fixed part and the existing structure of the dam. It can be concluded that this method of rehabilitation is an innovative and fast method to fix the damaged dams with minimum cost.

260 MSc. Geotechnical Engineering, Khuzestan Water & Power Authority, Department of Dam and Powerplant Development, Ahwaz, Iran. Phone:00989166141235, email:[email protected] 261 Khuzestan Water & Power Authority, Department of Dam and Powerplant Development, Ahwaz, Iran. Phone:00989166177933, email:[email protected]

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ROV SONAR INSPECTION OF A POWER TUNNEL

Florijon Dhimitri262 Richard Glenn263 Michael Sabad264 Olga Zabawa265

ABSTRACT

A condition inspection was performed for a 26-foot-diameter 2300-foot-long power tunnel that conveys water from a dam controlled reservoir to a powerhouse of the Calderwood Development, utilizing available technology as a way to mitigate safety risks and alleviate cost. The purpose of the inspection was to observe the condition of previously observed defects inside the tunnel, and identify any new defects that could impact tunnel performance and integrity. The tunnel was excavated in a steep rock mountainside during the construction of the dam and lined with concrete to provide a smooth water passage. Previous engineering inspections of this tunnel were performed at 10 year intervals with a team of engineers and inspectors making a walk-through visual inspection of the dewatered tunnel. This has been a generally accepted method of inspecting the tunnel in the past. The risks to the safety of inspectors inside a dewatered tunnel as well as the risks to the tunnel lining due to the stress of being dewatered are better understood now, and an alternative that could provide a quality inspection without these risks was sought. In a continuing effort to increase employee and contractor safety, and in light of more stringent safety standards for employers over the years, Remotely Operated Vehicle (ROV) technology was chosen to eliminate the personnel safety and tunnel risks altogether, while still ensuring and even improving the quality and cost effectiveness of the inspection. This paper focuses on the risks mitigated and cost benefit of this inspection method. A discussion of the ROV equipment, methods and findings are also presented herein.

262 Florijon Dhimitri, Engineer 1, Parsons Brinckerhoff, 75 Arlington Street, Boston, MA 02116, (617) 960- 4847, [email protected]. 263 Richard Glenn, President, Glenn Underwater Services, Inc., 6401 Carmel Road Suite 209, Charlotte, NC 29226, (704) 540-9777, [email protected]. 264 Michael Sabad, APGI, Tapoco Division, 300 North Hall Road, MS-T1521, Alcoa, Tennessee 37701, (865) 977-2218, [email protected]. 265 Olga Zabawa, Lead Engineer, Parsons Brinckerhoff, 75 Arlington Street, Boston, MA 02116, (617) 960- 5023, [email protected].

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LIBBY DAM HEMISPHERICAL BULKHEAD INSPECTION A 30-STORY DESCENT TO A DAM INSPECTION

Kenwarjit S. Dosanjh, P.E.266

Travis L. Ford, P.E.267 Samuel M. Planck, P.E.268 Joshua J. Erickson, P.E.269 Michael T. Likavec, P.E.270

Greg Mayer271

ABSTRACT

The U.S. Army Corps of Engineer’s 422 foot tall Libby Dam is located on the Kootenai River upstream of Libby, Montana. The dam has eight penstocks but the generators in Penstocks #6, #7 and #8 have never been installed. The original construction included hemispherical bulkheads (giant, 20-foot diameter, steel 1/2-balls) in the penstocks for “temporary” closure. In 2008 HDR inspected the downstream sides of the bulkheads via rope-access by ascending approximately 200 feet up the inclined penstocks with the aide of magnetic anchors. One of the more surprising finds was the word ALMOST spray painted in 3-foot tall letters on Bulkhead #8; presumably in reference to “almost” installing the generating units. In 2010 HDR was tasked with inspecting the upstream side of the bulkheads; the side normally 100 feet to 300 feet underwater. The first step in the project was designing and fabricating a temporary drain system that was light enough to be installed on-rope and in a confined space environment, yet strong enough to withstand a possible 300 feet of head. The inspection of the bulkheads took place over two mobilizations in June, 2011. The draining of Penstock #7 and #8 proceeded smoothly; Penstock #6 did not. The first person to make the 300-foot rope descent into the bulkhead reported that it was still 1/2 full of water and there was a non-plan standpipe present preventing further draining. Three days of draining, unclogging, and creative reconfigurations of the draining system followed before the bulkhead was able to be prepared for inspection.

266 Civil Engineer, HDR Engineering Inc., 2365 Iron Point Road Suite 300, Folsom, CA 95630, [email protected] 267 Civil Engineer, HDR Engineering Inc. 2365 Iron Point Road Suite 300, Folsom, CA 95630, [email protected] 268 Section Manager – Dams and Hydraulics Structures, HDR Engineering Inc. 2365 Iron Point Road Suite 300, Folsom, CA 95630, [email protected] 269 Mechanical Engineer, USACE – Seattle District, 17877 MT HWY 37, Libby, MT 59923, [email protected] 270 Bridge Safety and Hydraulic Steel Structures Program Manager, USACE – Seattle District, PO Box 3755, Seattle, WA 98124-3755, [email protected] 271 Rope Access Safety Lead, Ropeworks/Mistras Group, Inc. 8587 White Fir Street, Suite A3, Reno, NV 89523, [email protected]

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PERFORMANCE EVALUATION OF UPSTREAM SLOPE PROTECTION DURING RESERVOIR DRAWDOWN

Donald J. Montgomery, P.E.272

Christine T. Weber, P.E.273 Terrence E. Arnold, P.E.274

ABSTRACT

The Peace River Reservoir #2 project is an off-channel water supply reservoir with a fully encircling embankment located in southwest Florida. With a 4-mile long embankment constructed largely out of clean to slightly silty sand, soil-cement was selected as an efficient, economical construction material for the erosion protection on the interior face of the embankment for this project. The design of the soil-cement slope protection involved balancing the requirements for wave loading and run-up on the slope with constructible dimension and weight to resist potential hydrostatic load imbalances. A geosynthetic drainage system was designed and constructed to promote a balance between reservoir water levels and excess pore water pressure that could potentially be generated beneath the soil-cement face during reservoir operation. The drainage system includes geosynthetic strip drains located at various elevations along the slope with drain outlets extending through the soil-cement. The facility has been in operation for about three years and operation has included multiple fill/drawdown cycles. The pore pressures beneath the soil-cement facing are monitored by a system of vibrating wire piezometers. Results of the monitoring have been compared to analytical transient seepage modeling coupled with slope stability analysis. This paper describes the results of the field monitoring and performance of the slope protection and provides a comparison with the coupled transient seepage-stability analysis for relatively closely spaced time-steps.

272 Supervising Engineer, MWH Americas, Inc, 1801 California Street, Suite 2900, Denver, CO 80202, [email protected] 273 Senior Engineer, MWH Americas, Inc. 1801 California Street, Suite 2900, Denver, CO 80202, [email protected] 274 Principal Engineer, MWH Americas, Inc. 1801 California Street, Suite 2900, Denver, CO 80202, [email protected]

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EARLY WARNING SYSTEM AT CREEKSIDE DAMS — PUTTING IT TO THE TEST

Laura LaRiviere, P.E.275 Brian Boswell, P.E.276

ABSTRACT

Creekside Potable Water Reservoir (PWR) is a 370 acre-foot HDPE lined water supply reservoir located near Canyonville, Oregon. The Dam for the PWR, referred to as Dam#1, was constructed in 2006 by the Cow Creek Band of the Umpqua Tribe of Indians. An interstate highway, truck stop, and casino directly downstream of the earthfill dam made it necessary to install an early warning system (EWS) to provide advanced warning of a potential uncontrolled release at the dam that may require notification or evacuation of businesses and residents, or closure of the highway downstream. In 2007 an Irrigation Water Reservoir (IWR) was constructed by the Tribe. There are two dams - the main and auxiliary dams, known as Dam #1 and #2, associated with the IWR. When the IWR was constructed in 2007 immediately upstream of the PWR , an EWS was also installed. For all dams, the EWS monitors vibrating wire piezometers, reservoir level sensors, and collected seepage amounts. The EWS at the PWR also monitors for water located beneath the reservoir liner. Instrumentation readings are recorded and displayed on a password protected website that can be monitored from any computer connected to the internet. In the winter of 2007 during the first fill of the PWR, the reservoir experienced a liner failure causing increased flow rates out of the outlet works. Data from the EWS allowed the owner’s engineering team to conclude that the dam had indeed experienced a failure of the liner and not an embankment failure or slide gate malfunction. Continually increasing flow rates from the outlet works forced the owner to drain the reservoir and make repairs. This paper will highlight the EWS and data recording capabilities, the role they played during the 2007 liner failure, and how they have provided robust dam safety monitoring of the Creekside dams.

275 Water Resources Engineer, Kleinfelder, 611 Corporate Circle, Suite C, Golden, CO 80401, [email protected] 276 Project Engineer, Umpqua Indian Utility Cooperative, 130 Creekside Drive, Canyonville, OR 97417, [email protected]

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DAM SAFETY TRAINING FOR DAM OPERATING PERSONNEL

Jay N. Stateler277

ABSTRACT In recent years, tremendous strides forward have been made with respect to developing methods and procedures for determining appropriate dam safety monitoring programs. “Performance Parameters” work by the Bureau of Reclamation (BOR) in the mid-1990’s, and the Potential Failure Mode Analysis (PFMA) methodology instituted by the Federal Energy Regulatory Commission (FERC) shortly thereafter, provide a logical, rational approach for defining dam safety monitoring programs. The current challenge is to effectively institute the well-defined dam safety monitoring programs, particularly in the area of efficiently providing appropriate training for dam operating personnel. Since many of the key monitoring parameters associated with a dam’s potential failure modes can only be detected by visual inspections (e.g. new seepage areas, new sinkholes, new cracks, etc.), the routine visual inspections performed by dam operating personnel are vital to a successful dam safety monitoring program. Consequently, training performed to ensure the effectiveness of the monitoring efforts, particularly the visual monitoring, is very important. While many dams now have had a PFMA, the majority have not. Providing appropriate monitoring programs and associated training regarding those programs presents special challenges. Using “presumptive” potential failures, visual inspection checklists based on “presumptive” failure modes, and performing onsite dam operator training based on these tools can go a long way towards having an effective, efficient (though not ideal) routine dam safety monitoring program. A concise document that highlights key information about the dam, the “presumptive” potential failure modes, and the routine dam safety monitoring program, can be a useful tool for achieving cost-efficient, yet effective, dam operator training. Examples and templates for these documents, as well as visual inspection checklists, are included at the end of this paper.

277 Civil Engineer, Bureau of Reclamation, Denver, CO, [email protected]

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EFFICIENCY AND AUTOMATION: ARE AUTOMATED DATA ACQUISITION SYSTEMS MORE EFFICIENT THAN MANUAL METHODS?

Christopher J. Hill 278

ABSTRACT

In striving to do “more with less”, conventional wisdom is that implementing automated methods results in greater operating efficiency. This paper explores three case histories where automation was used to achieve certain dam safety monitoring objectives. The costs of achieving those objectives using traditional versus automated methods are compared. Automation is economical if relatively high data collection rates are required. If data collection intervals are long; say two weeks or more, then manual methods may be more cost-effective. If, however, the desired data is collected at higher frequencies, for example daily, then automated methods are more efficient. The economic evaluation that goes into determining the “break-even” point of efficiency is discussed. There are other things to be considered, however, besides economics. There are clear safety benefits to having “eyes on the dam” more frequently, as occurs when using manual methods. There are also legal precedents that suggest that because automated equipment is available and may provide some safety benefit, there may be a liability incurred by not using the available equipment if something does go wrong.

278 Team Manager, Safety of Dams Team, Metropolitan Water District of Southern California, [email protected]

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INVESTIGATIVE PROCEDURE FOR ASSESSING EARTH FISSURE RISK FOR DAMS AND LEVEES

Kenneth Fergason, PG 279

Michael Rucker, PE280 Michael Greenslade, PE 281

ABSTRACT

The depletion of groundwater resources in many deep alluvial basin aquifers in the Western U.S is causing ground subsidence. Ground subsidence can severely impact infrastructure and adversely impact infrastructure by changing the ground elevation, ground slope (grade) and through the development of ground cracks known as earth fissures that can erode into large gullies. Earth fissures have the potential to undermine the foundations of dams, levees, and other pertinent structures and cause system failure. Earth fissures that have been exposed to flowing water will most likely have observable surficial expressions such as ground cracking, piping holes, vegetative and tonal lineaments, and similar features, however uneroded earth fissures often do not have surficial expression. Subsequent to the performance of an evaluation of the overall subsidence experienced in the vicinity of a subsidence-impacted structure, a detailed investigation to search for earth fissures must be performed. Such an investigation must include investigative techniques capable of detecting earth fissures that do not have significant surficial expression. Utilizing the findings of subsidence investigation, additional investigative methods for earth fissure search include photogeological (lineament) analysis, assessment of the capability of near-surface soils to develop an earth fissure, assessment of the degree of ground disturbance, detailed site inspection, seismic refraction profiling for concealed earth fissures, and excavation and detailed logging of trenches.

279 AMEC Environment and Infrastructure, Inc., 4600 East Washington Street, Suite 600, Phoenix, AZ 85034, (602) 329-9714, [email protected] 280 AMEC Environment and Infrastructure, Inc., 4600 East Washington Street, Suite 600, Phoenix, AZ 85034, (602) 733-6000 [email protected] 281 Flood Control District of Maricopa County, 2801 West Durango Street, Phoenix, AZ 85009, (602) 506-4601, [email protected]

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INSAR AS A SUBSIDENCE CHARACTERIZATION TOOL FOR FLOOD CONTROL DAM STUDIES

Bibhuti B. Panda282

Michael L. Rucker283 Kenneth C. Fergason284

Michael D. Greenslade285

ABSTRACT Flood control dams, retention structures (FRS) and other infrastructure have been constructed in Arizona to protect agricultural lands in alluvial basin settings where irrigation waters were supplied by extensive groundwater pumping. Groundwater pumping commonly caused land subsidence while developments of infrastructure needed flood protection requirements which necessitated upgrading of FRS. The Arizona Department of Water Resources (ADWR) maintains an active program of acquisition, processing and disseminating subsidence information in active land subsidence areas within Arizona using satellite-based interferometry by repeat-pass synthetic aperture radar (InSAR). This remote sensing imaging provides unique information about active land subsidence over large areas based on multiple radar images (commonly about 100x100 km scenes) obtained from different time periods. The subsidence or deformation image known as interferogram can also reveal with proper interpretation some preliminary subsurface information about alluvial basin geometry, lithology and hydrology where active land subsidence is interpreted from interfergrams. However, utilizing interferometry is very a complex task that requires synthesis of available information to properly or best constrain an interpretation. A numerical model is developed to assimilate both InSAR and historic subsidence data for prediction of subsidence and earth fissure due to future groundwater decline. The interpreted InSAR data is used for the development of conceptual subsurface geologic model required for the numerical model. The example of prediction of future subsidence at two FRS dams utilizing numerical model is presented. Different time history subsidence plots interpreted from the InSAR analysis are presented to show the advance of subsidence with time.

282 Senior Geotechnical Engineer, AMEC Environment & Infrastructure, Inc., 4600 East Washington Street, Suite 600,Phoenix, Arizona 85034 ph. 602-733-6000, [email protected] 283 Senior Engineer, AMEC Environment & Infrastructure, Inc., 4600 East Washington Street, Suite 600,Phoenix, Arizona 85034 ph. 602-733-6000, [email protected] 284 Senior Geologist, AMEC Environment & Infrastructure, Inc., 4600 East Washington Street, Suite 600,Phoenix, Arizona 85034 ph. [email protected] 285 Michael D. Greenslade, PE, Flood Control District of Maricopa County, [email protected]

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CHARACTERIZATION OF SUBSIDENCE IMPACTING FLOOD CONTROL DAMS AND LEVEES

Michael Rucker, PE 286

Kenneth Fergason, PG287 Michael Greenslade, PE 288

Lawrence Hansen, PhD, PE289

ABSTRACT Historic and continuing land subsidence due to groundwater withdrawal has impacted several flood control structures (Flood Retarding Structures – “FRS”) or dams in Arizona, and may impact more FRS infrastructure in the future. Impacts include relative changes in crest elevation effecting flood storage geometry, capacity, and flood flow characteristics, and potential for development of earth fissures that could lead to piping erosion and catastrophic failure at an FRS. Effective subsidence risk assessment and mitigation requires understanding and quantification of historic subsidence, and estimation of potential future subsidence that could impact the FRS infrastructure. A primary subsidence mechanism is increasing effective stress due to groundwater level decline within saturated compressible basin alluvium. Ultimate subsidence magnitude at a given location is a function of change in effective stress, and compressible alluvium thickness and modulus. Modulus is typically a function of effective stress. Subsidence rates are assumed to largely be a function of rate of groundwater level decline, alluvium permeability or hydraulic conductivity and distance from groundwater level stress points (such as pumping wells). Basin alluvium and bedrock interface geometry, and changes and interfaces in basin alluvium lithology, profoundly influence subsidence patterns. Characterization includes collection and synthesis of historic survey and well data, surface geophysical methods for basin and bedrock characterization, and when available, synthetic aperture radar interferometry (InSAR) to document recent or current subsidence patterns. Utilizing a synthesis of this information, subsidence modeling matching documented historic subsidence and estimating potential future subsidence can be developed to assess potential impacts on FRS infrastructure.

286 AMEC Environment and Infrastructure, Inc., 4600 East Washington Street, Suite 600, Phoenix, AZ 85034, (602) 733-6000, [email protected] 287 AMEC Environment and Infrastructure, Inc., 4600 East Washington Street, Suite 600, Phoenix, AZ 85034, (602) 329-9714, [email protected] 288 Flood Control District of Maricopa County, 2801 West Durango Street, Phoenix, AZ 85009, (602) 506-4601, [email protected] 289 AMEC Environment and Infrastructure, Inc., 4600 East Washington Street, Suite 600, Phoenix, AZ 85034, (602) 733-6000 [email protected]

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LABORATORY TESTING OF CRITICAL HYDRAULIC CONDITIONS FOR THE INITIATION OF PIPING

Mandie Swainston-Fleshman290

John Rice291

ABSTRACT

Seepage-related erosion (internal erosion) is one of the predominant mechanisms responsible for incidents and failures of dams and levees. Internal erosion can be classified into four general mechanisms: heave, piping, concentrated leak erosion, and suffusion. Current geotechnical engineering practice for the assessment of piping potential consists of comparing expected exit gradients with the critical gradient of the soil at the seepage exit point. This method was developed to model the heave mechanism and does not fully model the mechanisms associated with piping. The critical gradient is generally considered as the ratio of soil buoyant unit weight and the unit weight of water; suggesting that the critical gradient only depends on the void ratio and specific gravity of the solids. However, in the field and in research it has been observed that piping can initiate at average gradients much lower than unity due to concentrations in flow and non-vertical exit faces. Therefore, there is a need for deeper understanding of the granular scale mechanisms of the piping erosion process. This paper presents the results of a laboratory study to assess the effects that soil properties and exit face configurations have on the potential for initiation of piping and the piping mechanisms. Using a laboratory device designed and constructed specifically for this study, the critical gradients needed to initiate piping in a variety of sandy soils were measured to assess the effects parameters such as gradation, grain size, and grain shape have on the critical gradients. The tests are also used to observe the grain scale mechanisms of piping erosion initiation. The ultimate goal of the study is to develop an empirical, but mechanism-based, grain-scale model that can take into account the effects of converging flows, non-horizontal exit faces, and soil properties while assessing the potential for piping erosion to occur.

290 Mandie Swainston Fleshman, Graduate Assistant, UMC 4110 – CEE Department, Utah State University, Logan, Utah 84322, [email protected], 801-725-6949 291 Assistant Professor, Utah State University, [email protected], 435-797-8611

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CAN FERC’S RISK INFORMED DECISION MAKING (RIDM) SAVE YOU MONEY? YES!

A CASE STUDY OF ASHTON DAM, IDAHO

Frank L. Blackett, P.E.292 Justin F. Smith, P.E.293

Patrick J. Regan, P.E.294

ABSTRACT As the Federal Energy Regulatory Commission (FERC) continues to move forward in the development of their Risk Informed Decision Making (RIDM) process, some are asking about the economic impacts it will have on those regulated by the FERC. The current economic market typically results in engineering design and construction services being evaluated by the lowest bid and shortest schedule. This approach is typically considered to be the best business decision, and the most prudent approach to take. Unfortunately, this approach has the potential to introduce fatal flaws into the design, or result in significant delays during construction, which can then equate to significant cost overruns during construction when conditions are encountered that were not clearly understood during the design process. RIDM is intended to result in the most technically sound approach at a reasonable economic cost. A form of RIDM was used in the modification of Ashton Dam; a High Hazard potential dam completed in 1916 as a zoned earthen rockfill embankment, and modified with a RCC overlay built in 1991. The dam has long been in a meta-stable state, slowly progressing towards failure, as other similarly designed dams that failed. The total cost for design and construction actually increased and the construction schedule was lengthened after performing a risk analysis when issues were raised with the original conceptual design. One reason is that the Risk Analysis provided information and understanding that was not available during the conceptual design resulting in a modified design that provided the best fix for all the dam safety concerns. Additional modifications would have been required at a later date during construction at additional costs if the conceptual design had been constructed. Although the detailed risk analysis seemingly resulted in an increase in costs from the original modifications, cost savings were realized in the long run by determining the most economical and technically sound design to extend the life of project so the dam could continue to operate safely. This paper will discuss the concept of the RIDM approach for design and construction of dam modifications and specifics regarding the Ashton Dam.

292 Senior Civil Engineer, Federal Energy Regulatory Commission, Division of Dam Safety and Inspections, Portland Regional Office, 805 SW Broadway, Suite 550, Portland, OR 97205, 503-552-2718, [email protected] 293Civil Engineer, Federal Energy Regulatory Commission, Division of Dam Safety and Inspections, 888 First Street, NE, Washington DC, 20426, 202-502-6426, [email protected] 294 Senior RIDM, Federal Energy Regulatory Commission, Division of Dam Safety and Inspections, Portland Regional Office, 805 SW Broadway, Suite 550, Portland, OR 97205, 503-552-2741 [email protected]

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POTENTIAL FOR CRACKING AROUND OUTLET CONDUITS AND ITS IMPACT ON SEEPAGE SAFETY

Keith A. Ferguson, P.E.295

Mahdi Soudkhah, PhD, P.E.296 Elena Sossenkina, P.E.297

ABSTRACT Evaluating seepage conditions and potential failure modes, particularly around outlet conduits in dams is a difficult task and requires extensive experience and keen engineering insight and judgment. This paper continues the discussion (Ferguson, USSD, 2012) about investigating and evaluating potential seepage failure modes with a focus on dam penetrations. The 2012 paper presented theoretical aspects of seepage failure mode development, examined two case histories of large outlet conduits with identified seepage deficiencies, and provided considerations for investigation and monitoring programs. This paper presents the results of further evaluation of stress conditions around conduits and the related potential for hydraulic fracturing and cracking. Because of its configuration, the Lake Isabella Dam Borel Canal Outlet Conduit serves as a starting point for a parametric examination of several key issues affecting stress distributions including construction sequencing and configuration, foundation settlement, and embankment properties. Based on these parametric evaluations the potential for hydraulic fracturing and embankment cracking around outlet conduits and its impacts on seepage failure mode development is discussed.

295 National Practice Leader for Dams, Levees, and Hydraulic Structures, HDR Engineering, Inc., 303 East 17th Avenue, Suite 700, Denver, CO 80203-1256, [email protected], 303-764-1546. 296 Project Engineer, HDR Engineering, Inc., 303 East 17th Avenue, Suite 700, Denver, CO 80203-1256, [email protected], 303-764-1520. 297 National Technical Advisor for Risk Analysis, HDR Engineering, Inc., 303 East 17th Avenue, Suite 700, Denver, CO 80203-1256, [email protected], 303-764-1520

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ECONOMICAL AND RELIABLE SOLUTIONS FOR ARRESTING SURFICIAL SLOPE FAILURES IN EARTHEN DAMS

José Hernández298

Bhaskar C. S. Chittoori299 Minh Le300

Les Perrin301 Ken McCleskey302

Anand J. Puppala303

ABSTRACT Surficial slope failures induced by prolonged rainfall are common in many parts of the world. Several research studies have been conducted to understand the reasons for these failures and effectively restrict them. One such study is being performed by The University of Texas at Arlington (UTA) and supported by the U.S. Army Corps of Engineers Fort Worth District (SWF) at Grapevine Dam. For this research study, a testing area consisting of five sections (one control and four treated) was established at the dam site. The surface layer of the treated sections was stabilized with 20% compost, 4% lime with 0.30% polypropylene fibers, 8% lime with 0.15% polypropylene fibers, and 8% lime. Cost analysis was performed for each treatment method to assess the most viable solution economically. The initial costs were included in the analysis for each test section to ascertain the effects of the treatment methods. Numerical modeling studies using SLOPE/W were also carried out under a reliability framework to assess slope stability as well as understand the effectiveness of the treatment methods, and their results are presented in this paper. The purpose of the reliability analysis was to perform a complex risk evaluation based on statistical variation of the different parameters affecting the shallow failures in earthen dams. Stabilization methods are ranked in accordance with their performance from engineering, environmental and economic perspectives.

298 Regional Geotechnical Engineer, USACE South Atlantic Division, Atlanta, GA, [email protected] 299 Faculty Associate-Research, Dept. of Civil Engineering, The University of Texas at Arlington, Arlington, TX, [email protected] 300 Graduate Research Assistant, Dept. of Civil Engineering, The University of Texas at Arlington, Arlington, TX, [email protected] 301 Chief-Geotechnical Section (Retired), USACE Fort Worth District, TX, [email protected] 302 Acting Chief-Geotechnical Section USACE Fort Worth District, TX, [email protected] 303 Distinguished Teaching Professor Dept. of Civil Engineering, The University of Texas at Arlington, Arlington, TX, [email protected]

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FIELD TESTING OF CRUSHED IGNIMBRITE FOR DAM FILTER MATERIAL

Lelio H. Mejia, PhD, P.E.304

ABSTRACT The performance of zoned embankment dams depends on the ability of filter and drain zones to prevent seepage erosion and piping of impervious materials, while providing adequate internal drainage. Because cracking of filter and drain zones might compromise their function, special care is typically exercised to build such zones of cohesionless materials that are unable to support cracks and that prevent the development of internal erosion pipes. Limited information is available on the cracking susceptibility of filter and drain materials manufactured by rock crushing. This paper presents a case history of field and laboratory testing of a crushed ignimbrite rock to evaluate its suitability as filter and drain material for the seismic retrofit of Matahina Dam to withstand foundation fault rupture. The paper presents the field and laboratory test results, and discusses key issues associated with the design of filters to mitigate the risk of dam cracking.

304 Principal Engineer, URS Corporation, 1333 Broadway, Oakland, CA 94612, [email protected].

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EVALUATION OF THE CENTRAL FILTER AT SADDLEBACK FLOOD RETARDING STRUCTURE

Dean B. Durkee, Ph.D., P.E.305

Sam Sherman, P.E.306 Frances Ackerman, P.E., P.G.307

ABSTRACT

The Saddleback Flood Retarding Structure (FRS) is a 5.1 mile long compacted earth-fill dam operated by the Flood Control District of Maricopa County (the District). The embankment has a maximum height of 21 ft and a storage capacity of 3,620-acre ft. The embankment was constructed with a 5-ft wide vertical central filter with strip drain outlets approximately every 400 ft. The filter was constructed concurrently with the embankment. The top of the constructed filter extends vertically to about 3ft to 5ft below the crest, varying along the length of the structure. Sections of the filter at the major drainages extend downward to about the foundation level. Numerous erosion holes and longitudinal cracks have been observed along the dam crest beginning approximately two years after construction was completed in 1982. Investigations, repairs, and inspection and monitoring of the structure have been ongoing; however the cause(s) of the erosion holes and cracking have not been definitively determined. Because the filter does not extend to the crest, leaving the upper portion of the embankment unprotected from possible flow and subsequent erosion through cracks that could develop through the embankment, the District identified the need to modify Saddleback FRS potential failure modes in the upper portion of the embankment, above the existing central filter. A preliminary design level geotechnical investigation focused on the upper portion of the embankment and also included minimal sampling and laboratory testing throughout the existing filter. Because several samples from the existing filter exhibited higher fines content than expected, a supplemental investigation and laboratory testing program was performed to improve the overall understanding of the condition and the anticipated performance of the existing filter. The results of the additional investigations indicated that the existing filter has excessive fines content does not meet current criteria its’ performance under reservoir loading was determined to be uncertain. The results also indicated that failure due to internal erosion through a crack propagating through the existing filter is a credible failure mode. The original objective of the Saddleback FRS Modifications Project was to extend the existing filter vertically to the crest. This would mitigate failure modes related to cracking and hole formation in the upper portion of the embankment above the central filter. However, this modification would not address the potential failure modes related to crack propagation through the existing filter or under the existing filter because the existing filter would be left in place. This paper presents the details of the investigation.

305 Gannett Fleming, Inc., Phoenix, AZ 602-553-8817, [email protected] 306 Flood Control Dist. of Maricopa County, Phoenix, AZ 602-506-3639, [email protected] 307 Gannett Fleming, Inc. Phoenix, AZ 602-506-8817, [email protected]

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DEVILS LAKE FLOOD RISK MANAGEMENT — GEOTECHNICAL ASPECTS DEVILS LAKE, NORTH DAKOTA

Paul D. Madison, P.E.308

Stephen L. McCaskie, P.E., G.E.309

ABSTRACT Since 1990, Devils Lake flooding has destroyed hundreds of homes and businesses and inundated thousands of acres of farmland. North Dakota and the U.S. government have spent more than $1 billion in flood mitigation and assistance. Covering over 325 square miles, Devils Lake lies within a 3,810 square mile closed basin with no natural outlet. Embankments have been constructed and roadways have been raised to “act” as dams, protecting people and resources from the lake, which has risen 54 feet since 1940. The embankments and roadways have been raised several times ahead of the rising lake level. The St. Paul District USACE and Bergmann-Hanson JV have completed dam safety analyses and designs for embankment and roadway segments totaling over 13 miles in length, including several pump stations and ancillary facilities. Design recommendations for the dam embankment improvements include constructing a zoned earth dam with a select impervious core and impervious fill; providing seepage control with sand / toe drains and berms; and a slurry cutoff wall where necessary. Constructability addressed excavation into existing embankments, and removal or abandonment of drainage structures, utilities and penetrations, while under head. Construction is underway in phases with sequencing critical to safely completing embankment improvements and pump station construction without compromising flood protection of the City of Devils Lake and surrounding areas. Geotechnical aspects are presented and designs, seepage and slope stability mitigation measures discussed. Construction observations and project performance are presented including means and methods adapted to meet disclosed subsurface and groundwater conditions.

308 Geotechnical Engineer, USACE St. Paul District, 180 5th St. East, Ste 700, St. Paul, MN 55101-1678, 651-290-5401; [email protected] 309 Geotechnical Engineer, Hanson Professional Services, 13801 Riverport Dr., Ste 300, Maryland Heights, MO 63043, 314-770-0467 X115; [email protected]

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EFFECT OF ANISOTROPIC PERMEABILITY ON PHREATIC LINE RECESSION IN HOMOGENEOUS EARTH DAMS UNDER RESERVOIR RAPID

DRAW DOWN

V. Rashidian310

ABSTRACT

Seepage is the continuous movement of water from the upstream face of the dam toward its downstream face. The upper surface of this stream of percolating water is known as the phreatic surface. The position of the phreatic surface influences the stability of the earth dam because of potential piping due to excessive exit gradient and sloughing due to the softening and weakening of the soil mass. Earth dams are usually supposed to have isotropic permeability in theoretical solutions but indeed, the method of placement and compaction in earth fills is such that stratifications are generally built into embankments. Generally tamping or sheep foot rollers are used to compact the fine grained earth fill materials in construction of an earth dam. As rollers compact the lifts of earth fill, the horizontal permeability tends to be larger than the vertical. Ratios of the horizontal permeability kx to the vertical permeability ky in compacted fills tend to be even larger than those of 2 to 10 in normally consolidated sedimentary clays. This stratifications force the seepage flow to move faster in horizontal direction. In this paper the effect of considering anisotropic permeability compared to isotropic one in phreatic line recession under steady-state and reservoir rapid draw down (transient) condition is investigated.

310 M.Sc student, Department of Civil Engineering, Imam Khomeini International University, Nouroozian Boulevard, Qazvin 34149-16818, Iran; E-mail: [email protected]; [email protected]

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United States Society on Dams

1616 Seventeenth Street, #483

Denver, Colorado 80202

Phone: 303-628-5430

Fax: 303-628-5431

E-mail: [email protected]

Internet: www.ussdams.org

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