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21st Century Dam Design —

Advances and Adaptations

31st Annual USSD Conference

San Diego, California, April 11-15, 2011

On the CoverArtist's rendition of San Vicente Dam after completion of the dam raise project to increase local storage and provide

a more flexible conveyance system for use during emergencies such as earthquakes that could curtail the region’s

imported water supplies. The existing 220-foot-high dam, owned by the City of San Diego, will be raised by 117

feet to increase reservoir storage capacity by 152,000 acre-feet. The project will be the tallest dam raise in the

United States and tallest roller compacted concrete dam raise in the world.

The information contained in this publication regarding commercial projects or firms may not be used for

advertising or promotional purposes and may not be construed as an endorsement of any product or

from by the United States Society on Dams. USSD accepts no responsibility for the statements made

or the opinions expressed in this publication.

Copyright © 2011 U.S. Society on Dams

Printed in the United States of America

Library of Congress Control Number: 2011924673

ISBN 978-1-884575-52-5

U.S. Society on Dams

1616 Seventeenth Street, #483

Denver, CO 80202

Telephone: 303-628-5430

Fax: 303-628-5431

E-mail: stephens@ussdams.org

Internet: www.ussdams.org

U.S. Society on Dams

Vision

To be the nation's leading organization of professionals dedicated to advancing the role of dams

for the benefit of society.

Mission — USSD is dedicated to:

• Advancing the knowledge of dam engineering, construction, planning, operation,

performance, rehabilitation, decommissioning, maintenance, security and safety;

• Fostering dam technology for socially, environmentally and financially sustainable water

resources systems;

• Providing public awareness of the role of dams in the management of the nation's water

resources;

• Enhancing practices to meet current and future challenges on dams; and

• Representing the United States as an active member of the International Commission on

Large Dams (ICOLD).

Managing Unexpected Endangered Species Issues 29

MANAGING UNEXPECTED ENDANGERED SPECIES ISSUES ON BID-READY PROJECTS

Anita M. Hayworth, Ph.D.1

Mary Putnam2 Douglas Gettinger3 Jeffrey D. Priest4 Paul M. Lemons5

ABSTRACT

Dam construction and subsequent reservoir inundation may affect sensitive plants and wildlife, thus requiring rigorous environmental permitting. Even with permits in hand, routine surveys may result in the unexpected discovery of sensitive species during project implementation. For dam construction projects, delays or work stoppages to allow for agency consultation and issuance of amended permits are problematic and potentially expensive. The San Vicente Dam Raise (SVDR) Project entails construction activity with habitat impacts. Initial surveys indicated three federally listed endangered species were present. A Biological Opinion for these species was issued as part of the Endangered Species Act Section 7 consultation between the U.S. Fish & Wildlife Service (USFWS) and the U.S. Army Corps of Engineers (Corps). However, during preconstruction surveys, a species not addressed with the permits, the federally listed endangered Quino Checkerspot Butterfly (Euphydryas editha quino) was unexpectedly observed on site. To avoid delays and address the species, the Water Authority and its consultant (Dudek) requested informal consultation with the agencies. Biologists were mobilized and Dudek used a USFWS model to estimate “occupied Quino Checkerspot Butterfly habitat”. The Water Authority team worked quickly and cooperatively with the agencies to conduct a site visit, prepare graphics, provide the model results, and prepare documents for use in permit amendments. Based on this information, impacts were calculated, mitigation was negotiated, and the amended Corps Section 404 permit and Biological Opinion were issued. The formal consultation process was completed in less than three weeks and resulted in no change in the project schedule.

INTRODUCTION

Dam construction and reservoir inundation impacts native habitats, which may affect sensitive plants and wildlife, thus requiring rigorous environmental permitting. Even 1Senior Biologist/Senior Project Manager, Dudek, 605 Third Street, Encinitas, CA 92024, ahayworth@dudek.com 2 Project Manager, San Diego County Water Authority, 4677 Overland Avenue, San Diego, CA 92123, mputnam@sdcwa.org 3Restoration Specialist, Dudek, 605 Third Street, Encinitas, CA 92024, dgettinger@dudek.com 4 Biologist, Dudek, 605 Third Street, Encinitas, CA 92024, jpriest@dudek.com 5 Biologist, Dudek, 605 Third Street, Encinitas, CA 92024, plemons@dudek.com

21st Century Dam Design — Advances and Adaptations 30

with permits in hand, routine surveys may result in the unexpected discovery of sensitive species during project implementation. For example, discovery of the federally listed endangered Dehli Sands Flower-Loving Fly (Rhaphiomidas terminatus abdominalis) at a 218-acre San Bernardino County commercial development was stalled when the fly was detected during surveys of the site (Flores 2002). The commercial project had been in the various stages of permitting for years, had initiated construction at one point and then the detection of the species halted all construction. For dam construction projects, delays or work stoppages to allow for agency consultation and issuance of amended permits are problematic and potentially expensive. The San Diego County Water Authority (Water Authority) is currently building the San Vicente Dam Raise (SVDR) using roller compacted concrete (RCC). San Vicente Dam is located near the unincorporated town of Lakeside in San Diego County, California (Figures 1 and 2). The SVDR Project combines two separate projects into a single construction project, which raises San Vicente Dam by 117 feet above the existing height of 220 feet for a total dam height of 337 feet. The Water Authority’s Emergency Storage Project (ESP) is a large-scale, multi-location storage project that was approved in 1996 and has been completed with the exception of the SVDR Project, which is the fourth and final phase of ESP implementation. The SVDR Project portion of the ESP is a 54-foot dam raise that will increase storage capacity by 52,100 acre-feet. A separate Carry Over Storage Project (CSP) was approved in 2008, which will increase the reservoir storage capacity by an additional 100,000 acre-feet. This increased storage capacity is part of a regional strategy by the Water Authority to improve service supply and reliability to its San Diego regional customers, particularly in times of drought. The CSP raises the dam 63 feet beyond the previously approved and permitted ESP dam raise, for an overall dam height increase of 117 feet, which would result in a total increase in the existing reservoir storage capacity of approximately 152,100 acre-feet. The combined CSP/ESP dam raise projects are being constructed as a single concurrent dam raise for cost and logistical purposes. Implementation of the SVDR Project entails three main phases: (1) drawdown of the water level at San Vicente Reservoir to allow for dam construction; (2) quarry excavation and raised-dam construction (with appurtenant facilities); and (3) refilling of the reservoir. The drawdown of the water level was completed in 2009 and the dam raise work is now under construction. The Water Authority estimates that the dam construction will take approximately three years, and the refilling period will be approximately three to five years, depending on the availability of imported water and local watershed precipitation inflows. The dam raise will be accomplished using RCC placed against the downstream side and above the existing concrete gravity dam. In addition to raising the

Managing Unexpected Endangered Species Issues 31

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Managing Unexpected Endangered Species Issues 33

existing dam, the SVDR Project will require the construction of a saddle dam located to the west of the main dam to prevent the heightened water level from spilling over a topographic low-point in the reservoir rim; relocation of the City’s existing San Vicente Marina that will be inundated by the raised water level; relocation of the marina access road to connect with the new marina; construction of a new inlet/outlet facility; and installation of a bypass pipeline extending from the new saddle dam to the First Aqueduct Diversion Structure. The project will also require temporary staging areas located on City-owned property downstream of the existing dam and within the marina expansion area.

MATERIALS AND METHODS The environmental study area for this project’s biological resources impacts includes the reservoir’s future increased inundation level and construction areas necessary for project implementation. The study area also includes an approximately 114-foot drinking water supply buffer zone surrounding the raised high-water level, creating a net study area extending 880 feet past the current reservoir high-water level. The study area for biological resources includes all of the various project components, including staging areas, a quarry site near the existing marina, access roads including a new marina access road, and temporary structures. A new marina will result in additional impacts to native vegetation communities and will be constructed west of the existing marina. The quarry footprint that is not inundated or otherwise occupied by the new marina facilities will be reseeded with native plant species after aggregate extraction and production. Within the proposed reservoir and construction inundation area of the SVDR Project are a number of native vegetation communities, as well as numerous native wildlife species and species of special status. Vegetation communities and land covers located within the project footprint include: open water, unvegetated channel, freshwater marsh, southern coast live oak riparian forest, southern cottonwood-willow riparian forest, mulefat scrub, southern willow scrub, coastal sage scrub, chaparral, non-native grassland, coast live oak woodland, eucalyptus woodland, disturbed habitat, and urban/developed lands. Initial project surveys indicated three federally listed threatened or endangered species (Coastal California Gnatcatcher [Polioptila californica californica], Least Bell’s Vireo [Vireo bellii pusillus], and Arroyo Toad [Anaxyrus californicus]) were present in the project area. A Biological Opinion for these species was issued as part of the Endangered Species Act Section 7 consultation between the USFWS and Corps. The Quino Checkerspot Butterfly is a federally listed endangered species (Figure 3). Currently, the distribution of the butterfly is limited to western Riverside County, southern San Diego County, and northern Baja California. This species is associated with open habitats supporting its larval host plants, including sage scrub, open chaparral, native grasslands, forblands, and vernal pools, of which, some of these habitats are located within the project area. The primary larval food plant for this species is Dot-Seed Plantain (Plantago erecta), a small annual plant that grows up to about 4 inches tall during the winter and spring. Field observations and laboratory studies indicate that other host plants may be used, including Common Owl’s Clover (Castilleja exserta ssp.

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Managing Unexpected Endangered Species Issues 35

exserta), Southern Chinese Houses (Collinsia concolor), and Bird’s Beak (Cordylanthus rigidus). The Quino Checkerspot Butterfly is generally found at sites where high densities of these host plants occur (USFWS 2002a). Threats limiting the distribution of this species include loss of habitat to development and degradation of habitat. Due to the potential for the endangered Quino Checkerspot Butterfly to be present within the project components, preconstruction surveys were conducted for the species within the areas anticipated to be impacted during the 2009 calendar year. While the butterfly was previously known to occur within the region, it was not identified within the project footprint during the environmental surveys conducted for both the CSP and ESP projects; therefore, the Biological Opinion issued by the USFWS for the projects did not address impacts to this species. There were approximately 140 acres of potential Quino Checkerspot Butterfly habitat, including coastal sage scrub and southern mixed chaparral, within the areas anticipated to be impacted during 2009.

Focused Quino Checkerspot Butterfly surveys were conducted by Dudek biologists following the USFWS survey protocol, which requires that the surveyors have federal take permits to conduct the surveys (USFWS 2002a, 2002b). The surveys included 10 visits within a 6-week period between March 4 and April 6, 2009. The survey methods consisted of slowly walking roughly parallel transects throughout all potential habitat within the survey area (i.e., all areas that are not excluded per the survey protocol, generally including sage scrub, open chaparral, grasslands, open or sparsely vegetated areas, hilltops, ridgelines, rocky outcrops, trails, and dirt roads). Survey routes were arranged to thoroughly cover the survey area at a rate of no more than 10 to 15 acres per hour. Mapping of Quino Checkerspot Butterfly host plant species was conducted on March 1 and April 3, 2009, by Dudek biologists. All patches of host plant species were recorded using Global Positioning System (GPS). The species name, patch size, and estimated number of plants were recorded for each patch.

RESULTS A single, adult Quino Checkerspot Butterfly was observed during the focused survey (Figure 4). The butterfly was observed on a ridgeline in the southwest corner of the site, and was observed flying and sunning on bare ground, rock, and deerweed. The habitat is this area is a form of disturbed, previously cut coastal sage scrub that is best characterized as monotypic stands of deerweed with scattered laurel sumac. The dominant shrub was deerweed with approximately 40% to 60% bare ground.

Two species of Quino Checkerspot Butterfly larval host plants were observed on the site during focused surveys: Dot-Seed Plantain (Plantago erecta; PE) and Common Owl’s-Clover (Castilleja exserta ssp. exserta; Ce). Occurrences of the two larval host plants throughout the survey area are shown on Figure 4. Potential adult butterfly

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Managing Unexpected Endangered Species Issues 37

nectar plants (Mattoni et al. 1997; USFWS 2002a, 2002b, 2003) noted during the surveys also were recorded within the project area. The observation of the butterfly, in combination with the presence of suitable host plant for Quino larvae and suitable nectar plants for the adults resulted in the conclusion that the project area, although not originally thought to be occupied, was indeed occupied by the federally listed endangered butterfly species.

Since previous surveys were negative, the Quino Checkerspot Butterfly was not included in the Biological Opinion, which allowed for take of federally listed endangered or threatened species. Unfortunately, the pre-construction surveys were conducted after the project was out for bid and the butterfly was discovered the day after bids were opened. Surveys could not be conducted earlier due to specific survey protocols that require the surveys to be done during the flight season, which changes each year based on specific weather-related conditions. Because of the importance of the project, any delay in contract award would not have been acceptable. A model to determine and define occupied Quino Checkerspot Butterfly habitat was prepared as directed by the USFWS. The model was based on the location of the adult butterfly observation, the distance that the butterfly has been documented to travel, and the location of suitable patches of the host plants of the larvae of the species. The distance used to create the model included a radius of 200 meters from the location of the adult and suitably sized patches of the main host plant (Dot-Seed Plantain), and 100 meters from the locations of the suitable-sized patches of the secondary host plant (Common Owl’s-Clover) (Figure 5). Previously graded or disturbed areas, existing structures and open water areas within the reservoir were designated as non-suitable habitat. GIS was used to prepare the model of occupied Quino Checkerspot Butterfly habitat with an overly of project footprint components. Direct impacts were quantified that may occur to the Quino Checkerspot Butterfly as a result of the loss of modeled occupied habitat. Based on the project design, a total of 10.34 acres of occupied butterfly habitat will be permanently impacted by the construction of the marina access road. A total of up to 9.48 acres of occupied Quino Checkerspot Butterfly habitat may be temporarily impacted by the rock removal associated with the construction of the new marina access road (Figure 6).

DISCUSSION To expedite permit amendments, the Water Authority and its environmental consultant (Dudek) immediately requested informal consultation with the agencies. Additional biological field crews were mobilized and Dudek used a USFWS computer model to estimate “occupied Quino habitat.” The Water Authority team worked quickly and cooperatively with the agencies to conduct a site inspection, prepare graphics, provide the Quino model results, and “ghost write” documents for use in preparing permit amendments. Based on this information, impacts were calculated, mitigation was negotiated, and the amended Corps’ Section 404 permit and Biological Opinion were issued.

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Managing Unexpected Endangered Species Issues 39

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The Corps and the Water Authority proposed measures to avoid or otherwise minimize the incidental take of the Quino Checkerspot Butterfly. Implementation of these measures is intended to mitigate project-related biological impacts to the butterfly to below a level of significance and in so doing, result in no project delays. The following measures were proposed:

• Debiting of coastal sage scrub mitigation credits equivalent to 10.34 acres of occupied Quino Checkerspot Butterfly habitat at the San Miguel Conservation Bank owned and operated by the Water Authority, at a 1:1 mitigation ratio;

• Restoration to original, pre-project condition of up to 9.48 acres of rock removal

area in conjunction with the construction of the marina access road; actual temporary disturbance areas will be mapped immediately after the rock removal activity is deemed complete and actual temporary impact acreages will be provided to the USFWS. Applicant will reserve 18.96 acres of Quino Checkerspot Butterfly occupied coastal sage scrub habitat at the San Miguel Conservation Bank as mitigation for rock removal activity impacts that are not restored to their pre-project impact or biologically superior condition within three growing seasons after the rock removal impacts are deemed complete. Applicant will prepare a restoration and monitoring plan within 90 days of the issuance of a Notice to Proceed for project construction that includes the rock removal activity, and submit the plan to the Corps and USFWS. The Quino Checkerspot Butterfly occupied habitat that is disturbed within the rock removal area will be revegetated with a seed mixture reflective of the plant species composition documented for butterfly habitat in the area.

• Incorporation of all mitigation measures outlined in the project documents

including the Mitigation Monitoring and Reporting Program (MMRP; April 2008) and the conservation measures included in the Biological Opinion (October 2008) and Biological Assessment (August 2008).

Based on the model developed by the Water Authority and Dudek and the negotiation with the USFWS, the conclusion regarding the potential take of the federally listed endangered species was as follows: (1) The SVDR Project may result in take of the Quino Checkerspot Buttefly as a result of permanent and temporary removal of modeled occupied butterfly habitat; (2) Permanent impacts would total 10.34 acres of occupied habitat; (3) Temporary impacts may total up to 9.48 acres of occupied habitat; and (4) Potential impacts to the Quino Checkerspot Butterfly resulting from the SVDR Project would not impact the continued existence of this species.

CONCLUSION By implementing the SVDR Project monitoring and mitigation programs and the conservation measures outlined in the Biological Opinion, it was concluded that the project will not adversely affect the continued existence of the Quino Checkerspot

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Butterfly. The project was authorized to incidentally take up to 10.34 acres permanently and 9.48 acres temporarily of occupied Quino Checkerspot Butterfly habitat. To ensure that projects are expedited, the Water Authority maintains service contracts with the Corps and USFWS. As a result of the unexpected discovery of a single endangered butterfly, the expedited formal consultation process was completed in less than three weeks and resulted in no change in the project schedule. Typically, the amendment process takes several months, but by immediately addressing agency concerns and preparing the model as well as written documents that the agencies could use in their permits, the process was drastically shortened. Also, agency service contracts provided staff funding to prioritize and expedite development of a solution for an unexpected, and untimely, endangered species issue.

REFERENCES

Flores, J. Emilio. 2002. “Endangered Fly Stalls Some California Projects.” The New York Times. Accessed October 11, 2010: http://www.nytimes.com/2002/12/01/us/endangered-fly-stalls-some-california-projects.html. Jones & Stokes. 2008. Final Biological Assessment Carryover Storage and San Vicente Dam Raise Project. August 2008. Mattoni, R., G. Pratt, T. Longcore, J. Emmel, and J. George. 1997. The endangered Quino checkerspot butterfly, Euphydryas editha quino (Lepidoptera: Nymphalidae). J. Res. Lep. 34:99–118. San Diego County Water Authority and U.S. Army Corps of Engineers. 2008. Final Environmental Impact Report/Environmental Impact Statement for the Carryover Storage and San Vicente Dam Raise Project. April 2008. San Diego County Water Authority. 2008. Final Environmental Impact Report/Environmental Impact Statement for the Carryover Storage and San Vicente Dam Raise Project. Mitigation Monitoring and Reporting Program. April 2008. TAIC (Technology Associates). 2008. Biological Resources Technical Report, Carryover Storage and San Vicente Dam Raise Project. April 2008. USFWS (U.S. Fish & Wildlife Service). 2002a. Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for the Quino Checkerspot Butterfly (Euphydryas editha quino); Final Rule. Federal Register, 67(72). USFWS. 2002b. Quino Checkerspot Butterfly (Euphydryas editha quino) Survey Protocol Information. Carlsbad, Califorinia. February 2002. 8 pp.

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USFWS. 2003. Quino Checkerspot Butterfly Recovery Plan.

USFWS. 2008. Biological Opinion. San Diego County Water Authority Carryover Storage and San Vicente Dam Raise Project, San Diego County, California. 2008B0061-2008F0732. October 28, 2008