US Army Corps of Engineers
BUILDING STRONG®
Folsom Dam
Water Control Manual Update
Public Workshop November 18, 2014
9:00 am - Noon
Location: 1020 11th Street, Sacramento
CSAC Conference Center, 2nd Floor
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Welcome and Introductions
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Purpose of Manual Update
Revise operation rules for Folsom Dam to
reduce flood risk based on capabilities of
Folsom Joint Federal Project (JFP)
Reflect operational capabilities created by
improved weather forecasts
Potentially reduce volume of flood control
reservation in Folsom Reservoir at any
particular time by comparison to operations
that have been in effect since 1995
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Objectives of Manual Update
Pass the Probable Maximum Flood while maintaining 3 feet of
freeboard below top of dam to stay within dam safety
constraints of U.S. Department of Interior, Bureau of
Reclamation.
Control a 1/100 annual chance flow (“100-year flood”) to a
maximum release of 115,000 cubic feet per second as criteria
set by Sacramento Area Flood Control Agency to support
Federal Emergency Management Agency levee accreditation
along American River.
Control a 1/200 annual chance flow (“200-year flood”) as
defined by criteria set by State of California (State) Department
of Water Resources to a maximum release of 160,000 cubic
feet per second, when taking into account all authorized
modifications within American River Watershed.
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Purpose of Today’s Workshop
Review and receive input on flood
operation alternatives that U.S. Army
Corps of Engineers (USACE) is currently
evaluating; and
Receive input on other flood operation
alternatives that possibly should be
evaluated
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Joint Federal Project
Time Lapse Video
http://youtu.be/tYXsPEwMZeQ?l
ist=UUnFQ8FQ-
6bx9yYCH8YmnB2g
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JFP Increased Release Capability
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10/01/14 JN
Existing and JFP Outlets
Main Dam
569 115K cfs – with JFP
283 115K cfs - existing
967 Main Dam
stilling basin floor
JFP Flood space
(KAF)
0
400
600
Top of flood pool
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Water Control Manual
Water Control Plan
►Objectives
►Constraints
►Key diagrams
• Emergency Spillway Release Diagram
• Water Control Diagram
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Primer on
Water Control Diagrams
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Storage Zones
Seasonal flood space
Dam
Top of conservation
Conservation
pool
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Water Control Diagram Example
Seasonal Variation
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct
1,000
800
600
400
200
Storage
(KAF)
Flood space
400
0
Flood space
(KAF)
Top of conservation
Storage
Conservation pool
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Water Control Diagram Example
Seasonal Variation + Variable Space
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct
1,000
800
600
400
200
Storage
(KAF)
Flood space
Storage
400
600
0
Flood space
(KAF)
Top of conservation
Conservation pool
Variable space
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We Will Cover: Existing
►USACE 400 + Basin Wetness
►BOR-SAFCA 400/670 + Upstream Storage
Alternatives (400/600 with JFP)
►1 – Upstream Storage Credit
►2 – Upstream Storage Credit + Basin Wetness
►3a – Upstream Storage Credit + Runoff Forecast
►3b – Integrated Inflow Forecast
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WATER CONTROL DIAGRAMS
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Water Control Diagram
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct
400
600
670
1,000
800
600
400
200
0
Storage
(KAF)
Flood Space
(KAF)
Existing (USACE) 400 KAF Flood Space
+ Basin Wetness
Existing (BOR-SAFCA) 400/670 KAF Flood Space
+ Upstream Storage Credit
Alternative 1 400/600 KAF Flood Space
+ Upstream Storage Credit
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Water Year 1997 Simulation
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Water Control Diagram
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct
400
600
1,000
800
600
400
200
0
Storage
(KAF)
Flood Space
(KAF)
Existing (USACE) 400 KAF flood space
+ basin wetness
Alternative 1 400/600 KAF flood space
+ upstream storage credit
Alternatives 2, 3a, 3b 400/600 KAF flood space
2 upstream storage + basin wetness
3a us storage + runoff forecast .
3b integrated inflow forecast .
.
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Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct
400
600
1,000
800
600
400
200
0
Storage
(KAF)
Flood Space
(KAF)
Alternative 2 - 400/600 KAF Variable Flood Space
(Upstream Storage + Basin Wetness)
Max
Upstream
Storage
Credit
Max
Basin
Wetness
Credit
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Forecast Alternatives 3a and 3b
Incorporate inflow forecast, and
uncertainty about that forecast, into
release decision logic.
Release schedule specifies minimum
release required based on current storage
and forecasted inflow.
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Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct
400
600
1,000
800
600
400
200
0
Storage
(KAF)
Flood Space
(KAF)
Alternative 3a - 400/600 KAF Variable Flood Space
(Upstream Storage + Unimpaired Runoff Forecast)
Max
Upstream
Storage
Credit
Unimpaired
Runoff
Forecast
Release
Schedule Forecast
3 to 5-
Day
Storage
Hydrograph
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Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct
400
600
1,000
800
600
400
200
0
Storage
(KAF)
Flood Space
(KAF)
Alternative 3b - 400/600 KAF Variable Flood Space
(Integrated Inflow Forecast)
Storage
Hydrograph
Release
Schedule Forecast
1-Day
3-Day
5-Day
Integrated
Inflow
Forecast
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Status
Completed Models
►Existing USACE
►Existing BOR-SAFCA
►Alternative 1
Under Development
►Alternative 2
►Alternatives 3a and 3b
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More Detailed Look
Integrated Inflow Forecast
Alternative 3b
400/600 KAF Variable Flood Space
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Overview
1. American River Characteristics
2. Meteorology and Hydrology
3. Winter Flood Example
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Floodway
Typical American River Cross Section
8k
25k
115k 160k
40k – 50k
Not to scale 30
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Meteorology and Hydrology
November 25, 2012 – 1 Day AR & QPF
Forecasts
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Meteorology and Hydrology
November 25, 2012 – 3 Day AR & QPF
Forecasts
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Meteorology and Hydrology
November 25, 2012 – 5 Day AR & QPF
Forecasts
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General Objectives
1. Readily store in Variable Space based on hydrologic conditions
2. Evacuate an increment of storage prior to main storm event by making prudent release decisions based on forecast confidence
3. Initial Release decisions based on a Forecast/Storage based framework
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Conceptual Design Approach
1. Structured Elements
► Communication and Certainty
2. Decisions Tied to Release Thresholds
► Notification and Operational Coordination
3. Forecast-Informed Release
► Modest Releases in Advance of Major Events
4. Anticipate Forecast Dynamics
► Appropriate Flood Risk and Forecast
Uncertainty
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More
Aggressive
Release
Prudent Storm Release Actions
Significant Forecast Information (Days)
1 4 2 3 5
Reserv
oir S
tora
ge M
etr
ic
(Volu
me)
Less
Aggressive
Release
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Shasta Flood Control Diagram
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Release Schedule
Applies to Rising Limb
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Pe
rce
nt
Req
uir
ed
Flo
od
Co
ntr
ol S
pa
ce
Use
d
Actual and Forecasted Inflow Volume
Release not specified
Inflow to Release
Threshold Inflow to Release
Threshold
Inflow to Release Threshold
Inflow to Release Threshold
Inflow to Release
Threshold
Inflow to Release
Threshold
Small Inflow Volume Medium Inflow Volume Large Inflow Volume
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Forecast Based Release
Schedule
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Perc
en
t R
eq
uir
ed
Flo
od
Co
ntr
ol S
pace
Used
Actual and Forecasted Inflow Volume
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Perc
en
t R
eq
uir
ed
Flo
od
Co
ntr
ol S
pace
Used
Actual and Forecasted Inflow Volume
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Perc
en
t R
eq
uir
ed
Flo
od
Co
ntr
ol S
pace
Used
Actual and Forecasted Inflow Volume
Actual,
Forecast
24 – 48 hrs
Forecast
72 hrs
Forecast
120 hrs
Select
Maximum
Release Value
from Release
Decisions
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0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
12/31 1/1 1/2 1/3 1/4 1/5 1/6 1/7 1/8 1/9 1/10
Flo
w (
cfs
)
Date
Example Advance Release: Rising Limb
Inflow
Outflow
8,000 cfs
25,000 cfs
40,000 – 50,000 cfs
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0
100
200
300
400
500
600
700
800
900
1000
-
50,000
100,000
150,000
200,000
250,000
300,000
350,000
400,000
12/29 12/31 1/2 1/4 1/6 1/8 1/10 1/12 1/14 1/16 1/18 1/20 1/22 1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9
Sto
rage
(TA
F)
Flo
w (
cfs)
Date Time
1 in 100 Year Storm
Inflow (cfs)
Release (cfs)
Storage (TAF)
400
600
833 TAF
115 kcfs
25 kcfs 25 kcfs
343 TAF
BUILDING STRONG®
Benefits Applying Forecasts
Forecast Storm Reasonably Well
►Mobilize flood preparedness
►Prepare flood space
►Moderate releases downstream
►Reduce excessive scour/gravel mobilization
►Improve spring re-fill management
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Risks Applying Forecasts
Forecast Storm Imprecisely
►Volume Over Predicted
• Prepare greater flood space than
actually needed
►Volume Under Predicted
• Lost opportunity to moderate releases
downstream
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Incorporate Feedback
Pre-Storm Storage Condition
► Assess Fill Potential vs Basin Conditions
Further Evaluate Forecast Uncertainty
Iterative Refinement:
► Inflow Volume Thresholds
► Release Decision Smoothing
► Forecast Variability and Confidence
Further Refinement
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Questions/Comments
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JFP – WCM Integrated Master Schedule 13 Nov 14
47 47 BUILDING STRONG®
2014 2015 2016 2017
Jan-Mar Apr-Jun Jul-Sep Oct-Dec Jan-Mar Apr-Jun Jul-Sep Oct-Dec Jan-Mar Apr-Jun Jul-Sep Oct-Dec Jan-Mar Apr-Jun
ROD & Final
Report Signed
(30 Apr 17)
Eng Report Reviews
Alternatives Analysis
Draft Final Eng Rpt
Develop Draft Env. Documentation
Prepare Final EIS/EIR
135 Day Sec 7 Consultation
45 Day Public Rev. of Draft EIS/EIR
Complete Draft Engineering Rpt 2 (Oct 15)
End Draft EIS/EIR Public Review (Aug 16)
Complete Draft Engineering Rpt 1 (Dec 14)
Initial Partner Input (Aug 14)
Identify Recommended Alternative (Dec 15)
Biological Opinion Complete (Sep 16)
Complete Final IPR (Apr 16)
Develop J602 Model
Develop Wetness Alternative
Develop Combined Alternative
Develop Forecast Alternative
Dev. Exist. Conditions
Final EIS/EIR
Prepare Final Docs
Engr. Report 1
Alternatives Formulation
30 Day Public Review Final EIS/EIR
Alt. F
orm
ula
tion
Report
Develo
pm
ent
Revie
w
Biological Assessment
Final Part. Feedback ( Mar 15)
Complete J602 Model (Apr 14)
6 mo window
( Oct 14 – Mar 15)
JFP – WCM Integrated Master Schedule15 Nov 14
11/17/14 BCM
Critical Path
Non-Critical
Milestone-Scheduled
Milestone- Actual
Fixed Duration
Stakeholder Briefing (Nov 14)
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Discussion / Questions
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Stakeholder Input on Other
Possible Alternatives
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Summary Comments
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Closing Remarks
