Appendix D 

Folsom DS/FDR Biological Assessment 


Folsom Dam Safety and Flood 

Damage Reduction Action 

Biological Assessment 

U.S. Department of the Interior 

Bureau of Reclamation 
Folsom DS/FDR Action – Biological Assessment 

Folsom Dam Safety and Flood 

Damage Reduction Action 

Biological Assessment 

prepared by: 

ENTRIX, Inc. 

590 Ygnacio Valley Road Suite 200 

Walnut Creek, California 94596 

U.S. Department of the Interior 

Bureau of Reclamation 

i
Folsom DS/FDR Action – Biological Assessment 

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TABLE OF CONTENTS 

Table of Contents ...................................................................................................................................................3

1.0 INTRODUCTION....................................................................................................................................1

1.1 Project History ..................................................................................................................................1

1.2 Folsom DS/FDR Action Description ................................................................................................1

1.2.1 Construction...............................................................................................................................1

1.2.2 Operations..................................................................................................................................2

1.2.3 Cumulative Impacts ...................................................................................................................3

1.3 Summary of Consultation to Date.....................................................................................................4

2.0 ENVIRONMENTAL SETTING..............................................................................................................6

3.0 FEDERALLY PROTECTED SPECIES..................................................................................................7

3.1 Plants.................................................................................................................................................7

3.1.1 El Dorado Bedstraw...................................................................................................................7

3.1.2 Layne’s Butterweed ...................................................................................................................8

3.2 Invertebrates......................................................................................................................................8

3.2.1 Vernal Pool Fairy Shrimp ..........................................................................................................8

3.2.2 Vernal Pool Tadpole Shrimp .....................................................................................................9

3.2.3 Valley Elderberry Longhorn Beetle.........................................................................................11

3.3 Amphibians.....................................................................................................................................12

3.3.1 California Red-Legged Frog ....................................................................................................12

3.4 Reptiles ...........................................................................................................................................14

3.4.1 Giant Garter Snake...................................................................................................................14

3.5 Birds................................................................................................................................................15

3.5.1 Bald Eagle................................................................................................................................15

4.0 Analysis of Effects and Proposed Avoidance and Minimization Measures...........................................17

4.1 El Dorado Bedstraw........................................................................................................................17

4.2 Layne’s Butterweed ........................................................................................................................18

4.3 Vernal Pool Fairy Shrimp ...............................................................................................................18

4.4 Vernal Pool Tadpole Shrimp...........................................................................................................20

4.5 Valley Elderberry Longhorn Beetle ................................................................................................21

4.6 California Red-Legged Frog ...........................................................................................................22

4.7 Giant Garter Snake..........................................................................................................................23

4.8 Bald Eagle.......................................................................................................................................23

5.0 DETERMINATION OF EFFECTS .......................................................................................................25

6.0 REFERENCES.......................................................................................................................................26

Appendix A. Federally Listed, Proposed, and Candidate Species Potentially Present in the 

Vicinity of the Proposed Action 

Appendix B. Elderberry Mitigation 

Appendix C. U.S. Fish and Wildlife Service Species Lists for Project Quadrangles 

Appendix D. White Paper: A Brief Synthesis on Mercury in the Environment
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ACRONYMS AND ABBREVIATIONS 

BA biological assessment 

CESA California Endangered Species Act 

CNDDB California Natural Diversity Database 

Corps United States Army Corps of Engineers 

CRLF California red-legged frog 

DWR Department of Water Resources 

ESA Federal Endangered Species Act 

Folsom DS/FDR Action Folsom Dam Safety and Flood Damage Reduction Action 

MIAD Mormon Island Auxiliary Dam 

OHWM Ordinary high water mark 

Reclamation United States Bureau of Reclamation 

Reclamation Board State Reclamation Board 

SAFCA Sacramento Area Flood Control Agency 

USFWS United States Fish and Wildlife Service 

VELB valley elderberry longhorn beetle 
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1.0 INTRODUCTION 

The proposed Folsom Dam Safety/Flood Damage Reduction (DS/FDR) Action reflects a 

cooperative effort by the U.S. Department of the Interior, Bureau of Reclamation 

(Reclamation) and the U.S. Army Corps of Engineers (Corps), as well as the Corps’ nonfederal sponsors, the State Reclamation Board (Reclamation Board)/Department of Water 

Resources (DWR) and the Sacramento Area Flood Control Agency (SAFCA). The Folsom 

DS/FDR Action is intended to implement Reclamation’s dam safety and security obligations 

and the Corps’ flood damage reduction objectives at Folsom Dam and appurtenant facilities. 

These facilities impound waters of the American River forming Folsom Reservoir and are 

collectively referred within this document as the Folsom Facility (Folsom Facility). 

The Folsom DS/FDR Action responds to certain objectives of each of the aforementioned 

agencies. Reclamation's Safety of Dams Program objectives focus on reducing the risk of 

failure under hydrologic (flood), seismic (earthquake), and static (seepage) loads. Folsom 

Dam has been designated as a National Critical Infrastructure Facility and any compromise 

of the facility could result in grave property damage and loss of life. Reclamation's Security 

Program objectives are being upgraded to protect public safety by securing Folsom Dam, the 

appurtenant structures, and other Reclamation facilities, including the Folsom power plant. 

The Corps' flood damage reduction objective is to improve the annual recurrence level of 

flood protection provided to the lower American River corridor. Similarly, SAFCA and 

DWR seek to improve the level of flood protection for the Sacramento region. Reclamation 

is the lead agency for this action and is the responsible party for all of the environmental 

mitigation associated with the Safety of Dams construction, and construction of the auxiliary 

spillway and six submerged tainter gates. 

The Folsom DS/FDR study area includes the area surrounding the Folsom Facility. The 

Folsom Facility falls within the borders of Placer, Sacramento, and El Dorado Counties, in 

the State of California. The study area primarily consists of federally-owned lands that are 

currently leased to and managed by the California Department of Parks and Recreation. The 

Folsom DS/FDR Action footprint associated with this assessment is composed of areas that 

may be potentially affected by the Folsom DS/FDR Action in the vicinity of Folsom 

Reservoir including: potential dike construction zones, potential borrow areas, potential 

contractor use areas, existing haul roads and proposed haul roads. A depiction of the Folsom 

DS/FDR Action footprint and vicinity is provided in Figure 1-1. 

1.1 Project History 

The Folsom Dam and associated facilities were constructed by the Corps, with construction 

completed in 1956. Currently, the Bureau of Reclamation manages Folsom Reservoir, while
Folsom DS/FDR Action – Biological Assessment 

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the majority of the surrounding lands are managed by the State of California’s Parks and 

Recreation Department. 

During initial construction of Folsom Dam and immediately upon completion of 

construction, major storm and flood events occurred on the American River which were 

precursor events to an event which occurred in February 1986. At that time, a series of major 

storms occurred in the Sacramento region that brought approximately 10 inches of rain over a 

period of 11 days, and exposed deficiencies in the flood control system of the region. Dam 

operators at Folsom and Nimbus Dams were required to release approximately 130,000 cfs, 

which is 15,000 cfs more than the downstream levees were designed to accommodate at a 

sustained flow rate. Water levels rose well above the designated freeboard of the 

downstream levees. Although major failure of the dam and levees did not occur, questions 

arose about the level of protection the structures could actually provide. 

Also in the 1980s, seismic concerns were identified at Mormon Island Auxiliary Dam 

(MIAD) by the Corps and Reclamation. The Corps and Reclamation jointly determined that 

liquefaction of the foundation and the subsequent failure of MIAD could occur during 

seismic (earthquake) activity. A phased structural modification program was rapidly 

undertaken in the early 1990s by Reclamation when reservoir levels were lower than normal 

as result of drought. The modifications partially reduced the risk of seismically induced 

liquefaction. 

In 2000, Reclamation identified the potential need for additional dam safety modifications to 

address other hydrologic, seismic and static risks. Hydrologic risk is characterized as the risk 

of any or all of the 11 earthen embankment dams and dikes being overtopped during a 

Probable Maximum Flood (PMF) event leading to rapid uncontrollable erosion and failure. 

In addition to the seismic concerns at MIAD, it was also determined that modifications 

would be required to prevent the main dam from sliding along the dam rock foundation 

contact and as the deformation of main dam pier and gate elements leading to the 

displacement and/or failure of the structures, resulting in an uncontrollable breach. 

Additionally, it was determined that modifications would be required to reduce the static risk 

of potential seepage paths developing undetected within select earthen embankment dams 

and dikes leading also to uncontrolled erosion and subsequent failure. 

1.2 Folsom DS/FDR Action Description 

1.2.1 Construction 

The Folsom DS/FDR Action includes several elements that, when combined, meet all of 

Reclamation’s Safety of Dams needs, as well as the Corp’s Flood Damage Reduction needs. 

These elements include modifications to the Main Dam, the stilling basin, the Left and Right 
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Wing Dams, the auxiliary spillway, the Mormon Island Auxiliary Dam (MIAD) and Dikes 1 

through 8, as well as several construction use areas. Construction details are described in the 

project description supplied the Service on February 22, 2007. 

The original project description and consultation letter included a description of the Corps’ 

proposed 3.5-ft dam raise alternative and the impacts associate with the construction of that 

feature. Reclamation is not including that feature or the potential impacts of constructing 

that feature in this consultation due to the uncertainty of whether or not the raise is needed to 

meet project goals. If the raise is not needed to meet the FDR goals of the project, or the 

benefits of the raise do not justify the costs, then the feature will not be constructed. The 

Corps will not make a final decision on the raise alternative when more detailed design 

information is available. Supplemental environmental compliance documentation will be 

completed as necessary. 

1.2.2 Operations 

When the Folsom DS/FDR Action is completed, Folsom Dam will have four methods of 

discharging flows from the reservoir: three power penstocks, eight flood control outlets, 

tainter/radial spillway gates set near the main spillway crest (five service and three 

emergency), and six submerged tainter gates in the proposed auxiliary spillway. To ensure 

adequate tailwater, the three emergency spillway gates may not be used unless the total 

outflow from the dam exceeds 240,000 cfs. This restriction makes the emergency gates 

unusable for normal flood control purposes and limits the use of the gates to dam safety 

outflows. 

In general, utilization of these features in conjunction with the auxiliary spillway would 

allow the objective release of 115,000 cfs to be achieved sooner in a flood event, and would 

reduce peak flows for large, infrequent hydrologic events. A maximum flood release of 

160,000 cfs, which is the emergency downstream channel capacity, would be made through 

the auxiliary spillway when necessary, based on observed and anticipated reservoir inflows. 

After construction of the auxiliary spillway, emergency releases of 160,000 cfs or above 

would not be made any sooner during the event than would occur under existing conditions. 

Variations in releases utilizing project features would not be any larger than those allowed 

under the existing conditions. These larger, earlier flows would conserve flood storage 

space. 

It is anticipated that a revised Water Control Manual, and the supporting environmental 

compliance coordination and documentation would be completed at least one year prior to 

completion of construction of the project. However, if this does not occur, the project 

features would be operated under existing operating criteria. Under this scenario, the same 

amount of water would ultimately be released with and without the project features (due to 

operational constraints), but operators would have the ability to release more water sooner in 

a hydrologic event. 
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The full flood damage reduction benefits of the JFP auxiliary spillway would not be fully 

realized until revision of the Water Control Manual and optimization of the operation of the 

JFP spillway is in place. 

1.2.3 Cumulative Impacts 

The USFWS expressed concern about the potential effects of the project on listed aquatic 

species, chiefly over sediment containing mercury being mobilized during construction. The 

Folsom DS/FDR Action has the greatest potential to affect aquatic species through the effects 

of dredging fine sediments from the bottom of Folsom Reservoir during construction of the 

JFP spillway. Additional impacts could occur through enlargement of the stilling basin at the 

base of the auxiliary spillway. The principal concern associated with the dredging and 

excavation of the JFP spillway and the stilling basin is the potential for fine sediment and 

associated mercury to be released from Folsom Reservoir. 

Most project elements (construction of the auxiliary spillway approach, staging and site 

development areas, security upgrades) would occur in the dry. As they are occurring in out 

of water areas, they would have the potential to affect the aquatic environment of Folsom 

Reservoir only through the incidental discharge of sediment or toxic substances into the 

reservoir. If such a discharge did occur it would be extremely small and would not have the 

potential to affect the Lower American River, as it would have to pass through both Folsom 

Reservoir and Lake Natomas before reaching the Lower American River. 

To minimize the effects of re-suspending fine sediments outside of the immediate 

construction area, the construction area would be isolated from the rest of Folsom Reservoir, 

including the normal outlet structure, using silt curtains, sheet piles and other sediment 

minimization devices and practices. Fine sediments would be dredged and removed to upland 

storage locations prior to blasting and excavation of the underlying bedrock. This work 

would occur when the reservoir is not likely to spill. These mechanisms and practices are 

expected to contain all fine sediments and associated mercury within Folsom Reservoir, and 

most of this would be contained within the construction area. Any mercury that was released 

from Folsom Reservoir would enter Lake Natomas, which would act as a large settling basin. 

Transit time for sediments through Lake Natomas has been estimated to be approximately 3 

days, indicating the low velocities within Lake Natomas and the ample opportunity for 

settling this would allow. 

Should suspended sediments and associated mercury enter Lake Natomas and the Lower 

American River, only a small portion (0.8 to 2.5 percent, Domagalski 2001, Domagalski et 

al. 2000) likely could be methylated. Rates of methyl mercury production depend not only on 

the abundance of inorganic mercury but also on a complex assortment of environmental 

variables which affect the activities and species composition of anaerobic bacteria and the 

availability of the inorganic mercury for methylation (HSDB 2003, Beckvar et al. 1996, EPA 

1997). These factors include temperature, dissolved organic carbon, salinity, acidity (pH), 

availability of wetlands and other anoxic environments, oxidation-reduction conditions, and 

the form and concentration of sulfur in water and sediments (Beckvar et al. 1996, EPA 1997). 
Folsom DS/FDR Action – Biological Assessment 

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Elemental and inorganic mercury can be converted to organic mercury by anaerobic bacteria. 

Within the project area and downstream waters, methylation rates are likely to be low, as 

relatively little of the total mercury concentration is readily available for transformation, the 

waters are not acidic, and there are few areas providing the anaerobic conditions that promote 

methylation. 

It is expected that very little fine sediment and associated mercury is likely to be transported 

from the project area to the Lower American River below Lake Natomas. Most sediment is 

expected to remain within Folsom Reservoir and any sediment that is discharged from the 

reservoir would be expected to settle out in Lake Natomas. It typically takes three days, 

under normal conditions for a release to make it to the Lower American River from Folsom 

Dam. Therefore these activities would not affect listed species in the Lower American River, 

the Sacramento River, or further out in the system. 

The project description is currently being updated to reflect the information that was 

developed for this document. As soon as a draft is available with the updates, it will be 

provided to the USFWS. 

Appendix D provides more technical information on mercury. 

1.3 Summary of Consultation to Date 

Other projects proposed in the immediate vicinity of the Folsom DS/FDR Action include the 

Folsom Bridge project, Common Features, the Auburn Folsom road widening project, the 

Reliable Water Supply Pipeline for Roseville, Folsom, and San Juan Water Districts, and the 

Sacramento Municipal Utility District Transmission Line Project. The Folsom Dam Road 

Closure and the Folsom Historic District Traffic Calming Program are not likely to affect 

biological resources and are not included in this evaluation. 

In January 1996, the Corps submitted the final Biological Data Report for the American 

River Watershed Project to the U.S. Fish and Wildlife Service (FWS). This report addressed 

four project alternatives. In May 1996, the FWS provided a biological and conference 

opinion (file number 1-1-96-F-28) on the effects of the Corps’ Detention Dam Plan on the 

delta smelt, delta smelt critical habitat, Sacramento splittail, valley elderberry longhorn 

beetle, and giant garter snake. In the Water Resources Development Act (WRDA) of 1996, 

Congress authorized construction of the Common Features Project, which consisted of 

features common to three of the alternatives. After reviewing detailed project designs the 

Corps subsequently reinitiated formal consultation and received a Biological Opinion for the 

American River Common Features Project on July 7, 1999 (file number 1-1-99-F-0078). A 

supplemental biological assessment prepared by the Corps for modifications to this project 

covered only the fish species. 

For the Folsom Dam Raise project, the Corps provided a Biological Assessment that 

concluded project effects would only have impacts to the valley elderberry longhorn beetle 
Folsom DS/FDR Action – Biological Assessment 

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and to certain fish species that are not present in the project footprint for the Folsom DS/FDR 

Action (Corps 2001). A Biological Opinion was received in December 2004 and amended in 

May 2005. 

The DEIS/EIR for the Folsom Bridge project (Corps 2006) found there would be no adverse 

effects to California red-legged frog, the giant garter snake, the vernal pool fairy shrimp, or 

the vernal pool tadpole shrimp from any of the alternatives evaluated for that project because 

“...no suitable habitat for special-status reptiles, amphibians, or invertebrates was noted 

during the wetland delineation for the proposed project” (Corps 2006). The DEIS/EIR for 

the Folsom Bridge project did identify potential effects to the bald eagle if this species were 

present during construction. This document also provided mitigation measures to reduce any 

potential effects. 

The Sacramento Municipal Utility District Transmission Line Project will result in limited 

impacts to native vegetation. Construction activities will primarily take place in areas 

already affected either by the Folsom Bridge Project or the Folsom DS/FDR Action. 

Additional impacts to native vegetation in the Folsom DS/FDR Action area are not expected 

from this project. Construction activities for the Reliable Water Supply Project for the City 

of Roseville, City of Folsom, the San Juan Water District project and the Sacramento 

Municipal Utility District Transmission Line Project would be implemented concurrently 

with, and generally within the footprint of, construction activities implemented for the 

Folsom DS/FDR Action. Therefore, they would not contribute appreciably to additional 

direct or indirect impacts. There is currently no known starting date for the Reliable Water 

Supply Project, however, it is anticipated that construction will be initiated at some point 

during the 18 year construction period for the Folsom DS/FDR action. 

USFWS is participating in the Folsom DS/FDR Action pursuant to the ESA and FWCA. 

Reclamation is consulting with USFWS for preparation of this Biological Assessment and a 

Coordination Action Report. 
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2.0 ENVIRONMENTAL SETTING 

The Folsom DS/FDR Action footprint is located within the American River watershed and 

would affect lands around Folsom Reservoir that are impounded by Folsom Dam or are 

adjacent to the retention area. Folsom Reservoir is located at the western edge of the Sierra 

Nevada foothills, adjacent to the Central Valley. This region is characterized by rolling hills 

and upland plateaus, dissected by major river canyons. The climate is characterized by cool, 

wet winters and hot, dry summers. 

Upland communities within the Folsom DS/FDR Action area include interior live oak 

woodland, blue oak woodland and savanna, California annual grassland and a few small 

areas with chaparral shrubs, sometimes associated with oak woodland. Riparian, aquatic and 

seasonally wet areas include cottonwood-willow riparian, freshwater marsh, and seasonal 

wetlands. Developed areas within the Folsom DS/FDR Action area include dams and dikes, 

the facilities associated with the main dam, and campgrounds, day-use areas and boat 

launches that are State Park facilities. Areas devoid of vegetation include portions of the 

reservoir shoreline fluctuation zone and barren areas where previous construction has taken 

place. 
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3.0 FEDERALLY PROTECTED SPECIES 

A list of special status species with potential to occur in the Folsom DS/FDR Action area was 

compiled through a series of literature, website and database sources. This search included a 

review of California Department of Fish and Game’s (CDFG) California Natural Diversity 

Database (CNDDB) (CDFG 2005a) and the U.S. Fish and Wildlife Service (USFWS) 

Sacramento District website (USFWS 2006). Both the CNDDB and the USFWS website 

were queried by 7.5-minute quadrangle. The list of Folsom DS/FDR Action quadrangles 

(quads) included Folsom and Clarksville, Rocklin, and Pilot Hill. The list from the USFWS 

list is provided in Appendix C. Additional species were included in the analysis based on 

known distribution, habitat requirements, and/or incidental sightings. Other literature 

sources including Zeiner et al. (1988, 1990a, 1990b) the California Wildlife Habitat 

Relationship (CWHR) database (CDFG 2000), and others are referenced as appropriate. 

Eight federally-protected species were identified as potentially occurring in the Folsom 

DS/FDR Action area: two plants, three invertebrates, one amphibian, one reptile, and one 

bird. These species are El Dorado bedstraw (Galium californicum ssp. sierrae), Layne’s 

butterweed (Senecio layneae), vernal pool fairy shrimp (Branchinecta lynchi), California 

vernal pool tadpole shrimp (Lepidurus packardi), valley elderberry longhorn beetle 

(Desmocerus californicus dimorphus), California red-legged frog (Rana aurora draytonii), 

giant garter snake (Thamnophis gigas), and bald eagle (Haliaeetus leucocephalus). Two bird 

species that were formerly protected under the federal Endangered Species Act (ESA) may 

occur in the Folsom DS/FDR Action area. The American peregrine falcon (Falco peregrinus 

anatum) was de-listed in 1999 (Federal Register 1999) and the Aleutian Canada goose 

(Branta canadensis leucopareia) was de-listed in 2001 (Federal Register 2001). Since these 

species have been de-listed for more than five years, they are not discussed further in this 

document. 

3.1 Plants 

3.1.1 El Dorado Bedstraw 

The El Dorado bedstraw (Galium californicum ssp. sierrae) is federally listed as endangered 

(Federal Register 1996b), is state-listed as rare, and is a California Native Plant Society 

(CNPS) List 1B species. 

Natural History 

This bedstraw is a perennial herb that blooms from May to June. A member of the 

Rubiaceae family, this species is only found in El Dorado County. The El Dorado bedstraw 

is found within chaparral, cismontane woodland, lower montane and coniferous forest 

habitats and gabbroic soils in an elevation range from 100 to 585 meters (CNPS 2001). 
Folsom DS/FDR Action – Biological Assessment 

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Status within the Folsom DS/FDR Action Area 

It is unlikely that El Dorado bedstraw occurs in the primary Folsom DS/FDR Action area 

based on the small extent of chaparral and the absence of coniferous forest. However, the 

Folsom DS/FDR Action area is in the lower extent of the elevation range for this species, and 

cismontane woodland is present. Therefore, there is a small probability that this species 

would be present. Habitat for this species may be present in areas around the reservoir that 

fall within the project action area. 

No critical habitat has been determined or proposed for El Dorado bedstraw. The upper end 

of the South Fork arm of Folsom Reservoir lies within the Salmon Falls section of the Pine 

Hills Preserve. This area was identified as Priority 1 land in the recovery plan that includes 

El Dorado bedstraw (USFWS 2002b). 

3.1.2 Layne’s Butterweed 

Layne’s butterweed (Senecio layneae) is federally listed as threatened (Federal Register 

1996b), is state listed as rare, and is a CNPS List 1B species. 

Natural History 

This butterweed is a perennial herb that blooms from April to May in chaparral and 

cismontane woodland habitats on serpentinite, gabbroic, or rocky soils. A member of the 

Asteraceae family, the Layne’s butterweed is found in El Dorado, Tuolumne and Yuba 

Counties. Habitat areas fall within 200 to 1,000 meters in elevation (CNPS 2001). 

Status within the Folsom DS/FDR Action Area 

Layne’s butterweed is not likely to occur in the Folsom DS/FDR Action area based on the 

limited extent of chaparral and the lack of serpentinite soils. Habitat for this species may be 

present in areas around the reservoir that fall within the project action area. 

No critical habitat has been determined or proposed for Layne’s butterweed. The upper end 

of the South Fork arm of Folsom Reservoir lies within the Salmon Falls section of the Pine 

Hills Preserve. This area was identified as Priority 1 land in the recovery plan that includes 

Layne’s butterweed (USFWS 2002b). 

3.2 Invertebrates 

3.2.1 Vernal Pool Fairy Shrimp 

Vernal pool fairy shrimp (Branchinecta lynchi) was federally listed as threatened in 1994 

(Federal Register 1994). Critical habitat has been designated for this species, but includes no 

land in the Folsom DS/FDR Action area (Federal Register 2003). 
Folsom DS/FDR Action – Biological Assessment 

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Natural History 

This species is restricted to seasonal vernal pools (Eng, et al. 1990; Federal Register 1994). 

Water quality is one of the most important factors in habitat suitability of vernal pool fairy 

shrimp. They prefer cool-water pools that have low dissolved solids, conductivity, alkalinity 

and chloride (Eriksen and Belk 1999, Federal Register 1994). This fairy shrimp is found 

primarily in the Central Valley and the foothills of the Sierra Nevada in northern California 

from 10 to 290 meters in elevation (Eng et al. 1990, Eriksen and Belk 1999, Federal Register 

1994). 

Surveys conducted by Sugnet and Associates (1993) listed 178 records of this species 

representing 32 populations out of 3092 “discrete locations” containing potential habitat 

(Federal Register 1994). The geographic distribution of this species ranges from Stillwater 

Plain in Shasta County through the Central Valley to Pixley in Tulare County. They also 

occur along the coast range from Northern Solano County to Pinnacles in San Benito County 

(Federal Register 1994). 

Fairy shrimp are adapted for survival in water bodies that are transient and their cysts 

(protected eggs) can withstand long dry periods. They require cool waters early in the rainy 

season for hatching and are highly susceptible to contaminants. Dispersal of cysts is thought 

to occur by animal vectors, including grazing animals or waterfowl. 

Status within the Folsom DS/FDR Action Area 

Evidence of seasonal ponding was observed in August surveys east of MIAD, at locations 

that may be included in the Folsom DS/FDR Action as contractor use areas. A total of 0.04 

acre (1,842 square feet) of seasonal wetlands has been mapped at these locations. Vernal 

pool fairy shrimp have been observed less than one mile away from the Folsom DS/FDR 

Action area (David Murth pers. obs., as cited in LSA 2003). Although the seasonal pools 

within the study area contain less water than is typical for this species’ habitat, the close 

proximity of the Folsom DS/FDR Action area to a known occurrence provides at least a low 

potential for this species to occur. 

3.2.2 Vernal Pool Tadpole Shrimp 

The vernal pool tadpole shrimp (Lepidurus packardi) is federally listed as endangered 

(Federal Register 1994). Critical habitat has been designated for this species, but includes no 

land in the Folsom DS/FDR Action area (Federal Register 2003). 

Natural History 

This species is a small crustacean found in ephemeral freshwater pools. The vernal pool 

tadpole shrimp is known from 18 populations in the Central Valley, ranging from east of 

Redding in Shasta County south to San Luis National Wildlife Refuge in Merced County. 

They inhabit vernal pools ranging in size from five square meters (54 square feet) to 36 

hectares (89 acres). Water contained in occupied pools can range from clear to highly turbid 

and often has low conductivity, total dissolved solids, and alkalinity (Federal Register 1994, 
Folsom DS/FDR Action – Biological Assessment 

10

Eng et al. 1990). Temperatures in pools where this tadpole shrimp have been found to vary 

from three to 23°C (Gallagher 1996). Vernal pool formations occur in grass-bottomed 

swales of grasslands, in old alluvial soils underlain by hardpan or in mud bottomed pools 

(Federal Register 1994). Pools with cobblely hardpan bottoms also serve as habitat 

(Gallagher 1996). Gallagher (1996) found that the depth, volume, and duration of inundation 

of a pool were important for the presence of this tadpole shrimp in vernal pools when 

compared to the needs of other branchiopods. Vernal pool tadpole shrimp needs deeper and 

longer-lasting pools if they are to persist over a rainy season in which both wet and dry 

periods occur. 

This species is relatively long lived when compared to the life histories of similar 

branchiopods. Sexually mature adults are often present within three to six weeks after pools 

begin inundating and remain reproductive until pools dry up in late spring or early summer. 

A female may lay up to six clutches in a single season totaling up to 861 eggs. These eggs 

are “glued” to plant matter and sediment particles where some percentage will immediately 

hatch while others will remain in the soil to hatch during later rainy seasons (Federal Register 

1994). 

Status within the Folsom DS/FDR Action Area 

Because of the high probability of the occurrence of VELB in the Folsom DS/FDR Action 

area, protocol surveys were conducted by both ENTRIX and USFWS. Surveys for VELB 

record the number of elderberry shrubs, their stem diameters, and the presence and number of 

exit holes formed by VELB as they exit the branch. Certain elderberry shrubs had previously 

been identified for mitigation for the Folsom Bridge Project and the Corps’ originally 

proposed Folsom Dam Modification Project. These plants are not included in the following 

counts. The surveys for VELB resulted in the recording of 140 elderberry shrubs within the 

Folsom DS/FDR Action area or 100 feet of this area. The 116 plants that are within the 

Action area will be adversely affected. The 24 plants in the 100-foot buffer area would be 

indirectly affected by dust or other construction-related consequences. However, 

Reclamation is proposing to transplant the shrubs that are within the 100-foot buffer area, so 

these will also be directly affected. Of the 140 shrubs, 127 will be transplanted and 13 are 

considered non-transplantable. Shrubs were identified as non-transplantable either due to 

their location or because they are growing in ground that they cannot be extracted from in a 

transplantable condition, such as boulders. 

Compensation for indirect effects from other projects has already been provided for certain 

of these shrubs. In the one to three inches diameter category, 258 stems were recorded. In 

the greater than 3 to 5 inches diameter category, 159 stems were recorded. In the greater 

than 5 inches diameter category, 197 stems were recorded. Stem diameters (recorded near 

ground level) ranged from less than one inch to over eight inches. Elderberry shrubs for 

which heights were recorded ranged in height from three to twenty-seven feet, with an 

average height of approximately ten feet. Exit holes, both new and old, were observed 

during the survey. 
Folsom DS/FDR Action – Biological Assessment 

11

3.2.3 Valley Elderberry Longhorn Beetle 

Because of the high probability of the occurrence of VELB in the Folsom DS/FDR Action 

area, protocol surveys were conducted by both ENTRIX and USFWS. Surveys for VELB 

record the number of elderberry shrubs, their stem diameters, and the presence and number of 

exit holes formed by VELB as they exit the branch. Certain elderberry shrubs had previously 

been identified for mitigation for the Folsom Bridge Project and the Corps’ originally 

proposed Folsom Dam Modification Project. These plants are not included in the following 

counts. The surveys for VELB resulted in the recording of 140 elderberry shrubs within the 

Folsom DS/FDR Action area or 100 feet of this area. The 116 plants that are within the 

Action area will be adversely affected. The 24 plants in the 100-foot buffer area would be 

indirectly affected by dust or other construction-related consequences. However, 

Reclamation is proposing to transplant the shrubs that are within the 100-foot buffer area, so 

these will also be directly affected. Of the 140 shrubs, 127 will be transplanted and 13 are 

considered non-transplantable. Shrubs were identified as non-transplantable either due to 

their location or because they are growing in ground that they cannot be extracted from in a 

transplantable condition, such as boulders. 

Compensation for indirect effects from other projects has already been provided for certain 

of these shrubs. In the one to three inches diameter category, 258 stems were recorded. In 

the greater than 3 to 5 inches diameter category, 159 stems were recorded. In the greater 

than 5 inches diameter category, 197 stems were recorded. Stem diameters (recorded near 

ground level) ranged from less than one inch to over eight inches. Elderberry shrubs for 

which heights were recorded ranged in height from three to twenty-seven feet, with an 

average height of approximately ten feet. Exit holes, both new and old, were observed 

during the survey. 

Natural History 

This species is associated with various species of elderberry (Sambucus spp.). While the 

beetle historically ranged throughout the Central Valley, recent surveys suggest the beetle is 

now restricted to scattered localities along the Sacramento, American, San Joaquin, Kings, 

Kaweah, and Tule rivers and their tributaries. 

This species generally occurs in savanna areas and along waterways and in floodplains that 

support remnant stands of riparian vegetation containing elderberry shrubs. In order to serve 

as habitat, elderberry stems must be greater than 1.0 inches in diameter at ground level 

(DBH). In a comprehensive 1991 survey conducted by the USFWS, 50 percent of exit holes 

were found on branches between 2-4 inches in diameter. Occasional exit holes were found 

on branches thinner than 1.5 inches in diameter and no exit holes were found on branches 

measuring less than 0.6 inches in diameter. Most exit holes are found in mature, healthy and 

unstressed plants (USFWS 1991). 

Both larvae and adult VELB feed on elderberry shrubs. Females mate and lay eggs in 

crevices in the elderberry bark. As larvae hatch they bore into the tree where they feed 

internally on the pith of the trunk and larger branches where they may stay up to two years. 
Folsom DS/FDR Action – Biological Assessment 

12

VELB larvae chew an exit hole in the elderberry trunk, through which the adult beetle later 

exits the plant (CDFG 2003). Larvae then pupate and emerge as adult beetles. Adults are 

active between March and June when they will feed externally on elderberry flowers and 

foliage and mate (USFWS 2006a). 

Status within the Folsom DS/FDR Action Area 

The Folsom DS/FDR Action area includes blue elderberry (Sambucus mexicana), the 

obligate host of the VELB. Exit holes have been observed in the elderberry shrubs in the 

Folsom DS/FDR Action area. Therefore this species is assumed to occur within the Folsom 

DS/FDR Action area. 

Because of the high probability of the occurrence of VELB in the Folsom DS/FDR Action 

area, protocol surveys were conducted by both ENTRIX and USFWS. Surveys for VELB 

record the number of elderberry shrubs, their stem diameters, and the presence and number of 

exit holes formed by VELB as they exit the branch. Specific elderberry shrubs had 

previously been identified for mitigation for the Folsom Bridge Project and the Corps’ 

originally proposed Folsom Dam Modification Project. These plants are not included in the 

following counts. The surveys for VELB resulted in the recording of 137 elderberry shrubs 

within the Folsom DS/FDR Action area or 100 feet of this area. The 117 plants that are 

within the Action area will be adversely affected. The 20 plants in the 100-foot buffer area 

would be indirectly affected by dust or other construction-related consequences. However, 

Reclamation is proposing to transplant the shrubs that are within the 100-foot buffer area, so 

these will also be directly affected. Of the 137 shrubs, 124 will be transplanted and 13 are 

considered non-transplantable. Shrubs were identified as non-transplantable either due to 

their location or because they are growing in ground that they cannot be extracted from in a 

transplantable condition, such as boulders. 

Compensation for indirect effects from other projects has already been provided for certain 

of these shrubs. In the one to three inches diameter category, 258 stems were recorded. In 

the greater than 3 to 5 inches diameter category, 150 stems were recorded. In the greater 

than 5 inches diameter category, 195 stems were recorded. Stem diameters (recorded near 

ground level) ranged from less than one inch to over eight inches. Elderberry shrubs for 

which heights were recorded ranged in height from three to twenty-seven feet, with an 

average height of approximately ten feet. Exit holes, both new and old, were observed 

during the survey. 

3.3 Amphibians 

3.3.1 California Red-Legged Frog 

The California red-legged frog (Rana aurora draytonii) is federally listed as threatened 

(Federal Register 1996a) and is a California species of special concern. Critical habitat was 
Folsom DS/FDR Action – Biological Assessment 

13

designated in 2001 (Federal Register 2001). However, on November 6, 2002, the U.S. 

District Court for the District of Columbia entered a consent decree, vacating the critical 

habitat designation (except Units 5 and 31) and remanding the designation to the USFWS to 

conduct an economic analysis. The USFWS released a recovery plan in 2002 (USFWS 

2002a). Critical habitat was again proposed on November 3, 2005 (Federal Register 2005b), 

and the final rule was published on April 16, 2006 (Federal Register 2006a). No critical 

habitat is within the Folsom DS/FDR Action area. 

Natural History 

Historically, the California red-legged frog occurred in coastal mountains from Marin County 

south to northern Baja California, and along the floor and foothills of the Central Valley from 

about Shasta County south to Kern County (Jennings et al. 1992). Currently, this subspecies 

generally only occurs in the coastal portions of its historic range; it is apparently extirpated 

from the valley and foothills and in most of southern California south of Ventura County. 

California red-legged frogs are usually associated with aquatic habitats, such as creeks, 

streams and ponds, and occur primarily in areas having pools approximately 3 feet deep, with 

adjacent dense emergent or riparian vegetation (Jennings and Hayes 1988). California redlegged frogs generally seem to stay near aquatic habitats, however, they are known to travel 

large distances seasonally within their local aquatic and terrestrial habitats (Jennings and 

Hayes 1994). Adults move between breeding and foraging habitats in spring and summer 

(Jennings and Hayes 1994). A few records exist that may indicate that they move into 

terrestrial riparian thickets during the fall (Jennings and Hayes 1994). During high water, 

this species are rarely observed (Jennings and Hayes 1994). Some individuals have been 

observed concealed in pockets or small mammal burrows beneath banks stabilized by 

shrubby riparian growth during periods of high water (Jennings and Hayes 1994), however 

much of the spatial ecology of this species is poorly understood. 

California red-legged frogs breed from November to March. Egg masses are attached to 

emergent vegetation (Jennings and Hayes 1994) and hatch within fourteen days. 

Metamorphosis generally occurs between July and September. Postmetamorphs grow 

rapidly; males can reach sexual maturity by their second year after metamorphosis and 

females by their third year. Both sexes may not reproduce until three or four years after 

metamorphosis (Jennings and Hayes 1994). 

Status within the Folsom DS/FDR Action Area 

Within the Folsom DS/FDR Action area, perennial and intermittent creeks and Folsom 

Reservoir may provide marginally suitable habitat for this species. This species has been 

extirpated from this portion of the foothills. While red-legged frogs have been discovered in 

Calaveras County in 2003, creeks within the Folsom DS/FDR Action area are occupied by 

bullfrogs and fish, and therefore, likely preclude the reestablishment of California red-legged 

frogs here. According to CNDDB, a juvenile California red-legged frog was observed along 

a small drainage adjacent to Fitch Way on the east side of the reservoir approximately one 
Folsom DS/FDR Action – Biological Assessment 

14

mile up the South Fork American River arm. Despite the proximity on this occurrence to the 

area, vegetation surveys have failed to discover suitable vegetation to support red-legged 

frogs. Therefore, it is unlikely that this species occurs within the Folsom DS/FDR Action 

area. 

3.4 Reptiles 

3.4.1 Giant Garter Snake 

The giant garter snake (Thamnophis gigas) is federally listed as threatened (Federal Register 

1993) and is stated-listed as threatened under the California Endangered Species Act 

(CESA). No critical habitat has been designated for the giant garter snake, but a draft 

recovery plan for this snake has been written (USFWS 1999a). The Folsom DS/FDR Action 

area lies within the Midvalley Recovery Unit defined in this recovery plan. 

Natural History 

This species historically ranged in the Sacramento and San Joaquin valleys from Butte 

County in the north to Kern County in the south (Rossman et al. 1996). Its current range is 

much reduced, and it is apparently extirpated south of northern Fresno Co. (Bury 1971, 

Rossman et al. 1996). 

Habitat requirements consist of adequate water during the snake's active season (early-spring 

through mid-fall) to provide food and cover. Emergent herbaceous wetland vegetation, such 

as cattails and bulrushes, serve as cover and foraging habitat during the active season; grassy 

banks and openings in waterside vegetation for basking; and uplands for cover and refuge 

from flood waters during the snake's dormant season in the winter (Hansen 1988). Giant 

garter snakes are absent from larger rivers and other water bodies that support introduced 

populations of large, predatory fish, and from wetlands with sand, gravel, or rock substrates 

(Hansen 1980, Rossman and Stewart 1987, Brode 1988, Hansen 1988). 

The giant garter snake inhabits marshes, sloughs, ponds, small lakes, low-gradient streams, 

and other waterways and agricultural wetlands, such as irrigation and drainage canals and 

rice fields. Giant garter snakes feed on small fishes, tadpoles, and frogs (Fitch 1941, Hansen 

1980, Hansen 1988). Giant garter snakes are found in small mammal burrows and other soil 

crevices above prevailing flood elevations throughout their winter dormancy period 

(November to mid-March). They typically select burrows with sunny aspects along south 

and west facing slopes. Upon emergence, males immediately begin searching for mates. 

The breeding season is March and April, and females give birth to live young from late July 

through early September (Hansen and Hansen 1990). Brood size is variable, ranging from 10 

to 46 young (Hansen and Hansen 1990). Young immediately scatter into dense cover and 

absorb their yolk sacs, after which they begin feeding on their own. Sexual maturity is 

achieved by age three in males and age five for females. 
Folsom DS/FDR Action – Biological Assessment 

15

Status within the Folsom DS/FDR Action Area 

It is unlikely that the seasonal wetlands in the Folsom DS/FDR Action area hold water 

throughout the summer and into the fall. Intermittent and perennial creeks flowing into 

Folsom Reservoir could potentially support giant garter snakes. Potential habitat exists 

within the vicinity of the Folsom DS/FDR Action area, and individuals may be found within 

Folsom DS/FDR Action boundaries, it is unlikely that a viable population occurs within the 

Folsom DS/FDR Action area. In addition, this species has not been recorded from within the 

Folsom DS/FDR Action area. Occurrence records for this species are markedly west and 

south of the Folsom DS/FDR Action area. 

3.5 Birds 

3.5.1 Bald Eagle 

The bald eagle (Haliaeetus leucocephalus) was formerly federally listed as endangered under 

the Endangered Species List of 1967 (32 FR 4001). In 1995, the bald eagle was downlisted 

to threatened (Federal Register 1995) and later was proposed for delisting as recovered in 

1999 (Federal Register 1999). In 2006, USFWS re-opened the public comment period on the 

proposed delisting (Federal Register 2006b). At this time, the bald eagle remains federally 

listed as threatened, is listed as California Endangered under CESA and is a California fully 

protected species. No critical habitat has been designated for the bald eagle. Bald eagle 

populations in California were addressed in the recovery plan for the Pacific states of the 

lower 48 coterminous states (USFWS 1986). 

Natural History 

Bald eagles occur throughout North America north of northern Mexico. Breeding 

populations of bald eagles are generally found along coastal regions and major river and 

reservoir systems where there are tall trees or cliffs appropriate for nests. Suitable roost sites 

consisting of large sturdy trees with an open structure that allows access to perch; and 

feeding areas that include open water such as rivers, lakes, or the ocean, often where there 

are trees, cliffs, or large objects on which to perch (Harris 2002). During migration they may 

be found widely throughout their range. They winter primarily in coastal estuaries and river 

systems, and at large lakes and reservoirs that retain ice-free areas with many birds often 

gathering where there are concentrated food resources. In Alaska, thousands of bald eagles 

migrate each fall to take advantage of salmon runs (USFWS 2004a). 

Nesting habitat for bald eagles in California and the Pacific northwest is typically within 

multi-storied, uneven-aged coniferous forest stands with at least some large tress and a 

relatively open canopy cover of between 20 to 60 percent (Lehman 1979; Anthony and Isaacs 

1981). Nest trees are typically among the largest live trees in the area, often over 100 feet 

tall, and with a deformed top and large open branches in the top half of the tree. Nest site 

selection is also influenced by topography, distance to water, and distance from disturbance 
Folsom DS/FDR Action – Biological Assessment 

16

(Lehman et al. 1980, Grubb et al. 1992). In California, 73 percent of the nest sites are within 

0.5 mile of a body of water, and 89 percent are within 1 mile; no nests are known to be over 

2 miles from water (Lehman et al. 1980). Perch trees are also needed by bald eagles for 

roosting and foraging. These trees typically provide an unobstructed view of the surrounding 

area and associated water body, and are often prominently located on the topography 

(USFWS 1986). Snag trees with exposed lateral limbs, or trees with dead tops, are often 

present in nesting territories and are used for perching or as points of access to and from the 

nest. Such trees also provide vantage points from which territories can be guarded and 

defended. Winter roost sites provide protection from inclement weather conditions and are 

characterized by more favorable microclimate conditions. These communal winter roosts 

can be at great distances from food sources (USFWS 1986). 

Status within the Folsom DS/FDR Action Area 

Bald eagles likely occur within the Folsom DS/FDR Action area as migrant and over 

wintering animals. There is potential for occurrence as breeding birds within the Folsom 

DS/FDR Action area based on the availability of adequate nesting sites and foraging habitat. 

Successful nesting has not yet been recorded at Folsom Reservoir. Based on anecdotal 

observations, a pair of immature eagles was noticed engaging in possible breeding behavior 

in early spring 2006. By March 2006, the eagles had left the Folsom DS/FDR Action area 

without any sign of successful breeding (SPR pers. comm.). 
Folsom DS/FDR Action – Biological Assessment 

17

4.0 Analysis of Effects and Proposed Avoidance and Minimization 

Measures 

The effects for the action alternatives were estimated based on the following conditions 

pertaining to Folsom DS/FDR Action implementation: 

• Excavation activities at borrow sites upstream of Folsom Dam would occur when sites 

are dry. Indirect effects to aquatic habitats may occur at these sites during the rainy 

season following excavation activities. 

• Borrow sites upstream of Folsom Dam would be utilized to their maximum extent. Sites 

would be excavated to an approximate depth of 30 feet between the shoreline and the 

400-foot contour and the reservoir rim. Upon completion of borrow excavation activities, 

borrow areas would be sloped or restored to accommodate recreational foot traffic. 

• Implementation of a spill prevention plan would reduce the risk of fuel or oil spills from 

construction and transportation equipment. 

• The implementation of BMPs would control soil erosion due to construction activities, 

and minimize potential construction-related effects on water quality. 

• A revised Water Control Manual, and the supporting environmental compliance 

coordination and documentation are expected to be completed at least one year prior to 

completion of construction of the Folsom DS/FDR Action. However, if this does not 

occur, the Folsom DS/FDR Action features would still be operated under existing 

operating criteria. Under this scenario, the same amount of water would ultimately be 

released with and without the Folsom DS/FDR Action features (due to operational 

constraints), but operators would have the ability to release more water sooner in a 

hydrologic event. The full flood damage reduction benefits of the spillway would not be 

fully realized until revision of the Water Control Manual and optimization of operation of 

the spillway is in place. 

4.1 El Dorado Bedstraw 

Analysis of Effects 

Construction Related Effects 

The El Dorado bedstraw is not likely to occur within the Folsom DS/FDR Action area. 

Therefore, no adverse effects to this species have been identified with the construction of any 

Folsom DS/FDR Action features, and no mitigation measures are proposed. 

Operational Related Effects 
Folsom DS/FDR Action – Biological Assessment 

18

The potential impacts from an increase in the reservoirs temporary storage capacity to this 

species were all associated with the 3.5-ft raise. There will not be any operations-related 

impacts to this species under the current project description. 

4.2 Layne’s Butterweed 

Analysis of Effects 

Construction Related Effects 

Layne’s butterweed is not likely to occur within the Folsom DS/FDR Action area. Therefore, 

no adverse effects to this species have been identified with the construction of any Folsom 

DS/FDR Action features, and no mitigation measures are proposed. 

Operational Related Effects 

The potential impacts from an increase in the reservoirs temporary storage capacity to this 

species were all associated with the 3.5-ft raise. There will not be any operations-related 

impacts to this species under the current project description. 

4.3 Vernal Pool Fairy Shrimp 

Analysis of Effects 

Construction Related Effects 

Evidence of seasonal ponding was observed in surveys in the vicinity of Dike 2 and southeast 

of MIAD, at locations that may be included in the Folsom DS/FDR Action as contractor use 

areas. A total of 0.03 acres of seasonal wetlands has been mapped at these locations. These 

seasonal ponds would likely be affected either directly (filling of habitat) or indirectly (water 

quality degradation, localized erosion, human intrusion, etc). 

The sites in question are currently being surveyed for vernal pool fairy shrimp and vernal 

pool tadpole shrimp by a USFWS-approved biologist implementing proper survey protocols. 

The first survey, conducted during a dry period, was negative for the presence of either listed 

branchiopod species. Reclamation will conduct another survey for the listed branchiopods in 

wet conditions in early 2007. The USFWS will be provided with the survey data once each 

survey is complete. 

If it is determined that this species is absent from the project footprint after the dry and wet 

season surveys, Folsom DS/FDR Action related effects to this species would not occur and 

therefore no avoidance and minimization measures would be necessary. If this species is 
Folsom DS/FDR Action – Biological Assessment 

19

found, measures detailed in the following section would be implemented to reduce adverse 

effects to this species. 

Operational Related Effects 

The potential impacts from an increase in the reservoirs temporary storage capacity to this 

species were all associated with the 3.5-ft raise. There will not be any operations-related 

impacts to this species under the current project description. 

Proposed Avoidance and Minimization Measures 

The following avoidance and minimization measures are based on an existing USFWS 

Programmatic Consultation and Biological Opinion (USFWS 1996) and are subject to 

Section 7 consultation and USFWS approval. Avoidance and minimization measures may be 

adjusted at the direction of the USFWS. 

Potential habitat for the vernal pool fairy shrimp that may be affected by construction 

activities for the Folsom DS/FDR Action has previously been altered by dam and dike 

construction for the Folsom Reservoir and does not represent undisturbed natural habitat. 

For habitat that is directly or indirectly affected, vernal pool credits would be dedicated 

within a USFWS-approved ecosystem preservation bank. Based on USFWS evaluation of 

conservation values of the affected habitat, seasonal pool habitat may be preserved on the 

Folsom DS/FDR Action site or on another non-bank site as approved by the USFWS. 

For habitat that is directly affected, vernal pool creation credits would be dedicated within a 

USFWS-approved habitat mitigation bank. Based on USFWS evaluation of site-specific 

conservation values of the affected habitat, vernal pool habitat would be created and 

monitored on the Folsom DS/FDR Action site or on another non-bank site as approved by the 

USFWS. 

Vernal pool habitat and associated upland habitat used as on-site mitigation would be 

protected from adverse effects and managed in perpetuity with a Service approved 

conservation easement. 

If habitat is to be avoided, an approved biologist (monitor) would inspect constructionrelated activities to ensure that no unnecessary take or destruction of habitat occurs. The 

biologist would have the authority to stop activities that may result in such take or 

destruction until corrective measures have been taken. The biologist also would be required 

to report immediately any unauthorized effects to Reclamation and to the USFWS and the 

California Department of Fish and Game. 

Fencing would be maintained around any preserved seasonal pool habitat and a 250-foot 

wide buffer zone to prevent effects from vehicles and other construction-related activities. 

All on-site construction personnel would receive instruction regarding the presence of listed 

species and the importance of avoiding effects to these species and their habitat. 
Folsom DS/FDR Action – Biological Assessment 

20

4.4 Vernal Pool Tadpole Shrimp 

Analysis of Effects 

Construction Related Effects 

Evidence of seasonal ponding was observed in surveys in the vicinity of Dike 2 and southeast 

of MIAD, at locations that may be included in the Folsom DS/FDR Action as contractor use 

areas. A total of 0.03 acres of seasonal wetlands has been mapped at these locations. These 

seasonal ponds would likely be affected either directly (filling of habitat) or indirectly (water 

quality degradation, localized erosion, human intrusion, etc). 

The sites in question are currently being surveyed for vernal pool branchiopods by a 

USFWS-approved biologist implementing proper survey protocols. If this species is found to 

be absent, Folsom DS/FDR Action related effects to this species would not occur and 

therefore no avoidance and minimization measures would be necessary. If this species is 

found, the following measures are proposed to reduce adverse effects to this species. 

Operational Related Effects 

The potential impacts from an increase in the reservoirs temporary storage capacity to this 

species were all associated with the 3.5-ft raise. There will not be any operations-related 

impacts to this species under the current project description. 

Proposed Avoidance and Minimization Measures 

The following avoidance and minimization measures are based on an existing USFWS 

Programmatic Consultation and Biological Opinion (BO) and are subject to Section 7 

consultation and USFWS approval. Avoidance and minimization measures may be adjusted 

at the discretion of the USFWS. Potential habitat for California vernal pool tadpole shrimp 

that may be affected by construction activities for the Folsom DS/FDR Action has previously 

been altered by dam and dike construction for the Folsom Reservoir and does not represent 

undisturbed natural habitat. 

For habitat that is directly or indirectly affected, vernal pool credits would be dedicated 

within a USFWS-approved ecosystem preservation bank. Based on Service evaluation of 

conservation values of the affected habitat, seasonal pool habitat may be preserved on the 

Folsom DS/FDR Action site or on another non-bank site as approved by the USFWS. 

For habitat that is directly affected, vernal pool creation credits would be dedicated within a 

USFWS-approved habitat mitigation bank. Based on USFWS evaluation of site-specific 

conservation values of the affected habitat, seasonal pool habitat would be created and 

monitored on the Folsom DS/FDR Action site or on another non-bank site as approved by the 

USFWS. 
Folsom DS/FDR Action – Biological Assessment 

21

Vernal pool habitat and associated upland habitat used as on-site avoidance and minimization 

would be protected from adverse effects and managed in perpetuity with a Service approved 

conservation easement. 

If habitat is to be avoided, an approved biologist (monitor) would inspect constructionrelated activities to ensure that no unnecessary take or destruction of habitat occurs. The 

biologist would have the authority to stop activities that may result in such take or 

destruction until corrective measures have been taken. The biologist also would be required 

to report immediately any unauthorized effects to Reclamation and to the USFWS and the 

California Department of Fish and Game. 

Fencing would be maintained around any preserved vernal pool habitat and a 250-foot wide 

buffer zone to prevent effects from vehicles and other construction-related activity. 

All on-site construction personnel would receive instruction regarding the presence of 

protected species and the importance of avoiding effects to these species and their habitat. 

4.5 Valley Elderberry Longhorn Beetle 

Analysis of Effects 

Construction Related Effects 

Actions resulting in the loss of elderberry shrubs, the obligate host plant of the valley 

elderberry longhorn beetle (VELB), in the Folsom DS/FDR Action footprint may result in 

adverse effects to individual beetles, pupae, or larvae as well as loss of habitat. The 

following avoidance and minimization measures are summarized from the Conservation 

Guidelines for the Valley Elderberry Longhorn Beetle (USFWS, 1999). 

Within the boundaries of the Folsom DS/FDR Action, beetles inhabiting elderberry shrubs in 

areas of the proposed retrofit of the existing dikes and dams, proposed borrow areas or in 

proposed staging areas, contractor use areas, processing plant sites or along proposed haul 

routes would be directly affected by activities by removal of or direct impacts to elderberry 

shrubs or indirectly affected by dust. 

Operational Related Effects 

A revised Water Control Manual, and the supporting environmental compliance coordination 

and documentation are expected to be completed at least one year prior to completion of 

construction of the Folsom DS/FDR Action. However, if this does not occur, the Folsom 

DS/FDR Action features would be operated under existing operating criteria and no impacts 

to the valley elderberry longhorn beetle or its habitat would be expected. 
Folsom DS/FDR Action – Biological Assessment 

22

Proposed Avoidance and Minimization Measures 

The following avoidance and minimization measures are subject to and contingent upon a 

Section 7 consultation with the USFWS. 

Where possible complete avoidance in conjunction with the establishment and maintenance 

of a 100 foot buffer zone surrounding any elderberry plants containing stems measuring 1.0 

inches or greater in diameter. USFWS would be consulted before any disturbances within 

the buffer area are considered. 

Elderberry plants that cannot be avoided would be transplanted if technically feasible. All 

elderberry plants containing stems measuring 1.0 inches or greater in diameter would be 

transplanted to a USFWS-approved conservation area between November 1, 2007 and 

February 15, 2008. Data on the number of stems in each category and the corresponding 

mitigation needs are provided in Appendix B. 

Each elderberry stem measuring 1.0 inch or greater in diameter that is adversely affected 

would be compensated for in the conservation area, with elderberry seedlings or cuttings in 

accordance with the Service’s 1999 Guidelines. Stems that cannot be feasibly transplanted 

will be compensated at a ratio two-times the normal amount. A minimum survival rate of at 

least 60 percent of the elderberry plants would be maintained throughout the monitoring 

period. If survival drops below this level, additional seedlings would be planted. Stock for 

plantings would be obtained from local sources. 

Native plants associated with elderberry plants at the Folsom DS/FDR Action site or similar 

reference sites would be planted in accordance with the Service’s 1999 guidelines. A 

minimum survival rate of at least 60 percent of the associated native plants would be 

maintained throughout the monitoring period. If survival drops below this level, additional 

seedlings or cuttings would be planted. Only stock from local sources would be used, unless 

such stock is not available, per the Conservation Guidelines for the Valley Elderberry 

Longhorn Beetle (USFWS 1999b). 

4.6 California Red-Legged Frog 

Analysis of Effects 

Construction Related Effects 

The California red-legged frog is not likely to occur within the Folsom DS/FDR Action area. 

Therefore, no adverse effects to the California red-legged frog have been identified with the 

construction of any Folsom DS/FDR Action features, and no mitigation measures are 

proposed. The construction of new flood protection berms, if required, would be analyzed in 

a supplemental Biological Assessment. 
Folsom DS/FDR Action – Biological Assessment 

23

Operational Related Effects 

The potential impacts from an increase in the reservoirs temporary storage capacity to this 

species were all associated with the 3.5-ft raise. There will not be any operations-related 

impacts to this species under the current project description. 

Proposed Avoidance and Minimization Measures 

No mitigation measures have been proposed since there is little likelihood of the frog 

occurring within the footprint of the proposed work. Furthermore, habitat for the frog in the 

construction area is marginal at best. 

4.7 Giant Garter Snake 

Analysis of Effects 

Construction Related Effects 

Giant garter snakes are not likely to occur in the Folsom DS/FDR Action area. Therefore, no 

adverse effects to the giant garter snake due to construction of any Folsom DS/FDR Action 

features have been identified, and no mitigation measures are proposed. 

Operational Related Effects 

The potential impacts from an increase in the reservoirs temporary storage capacity to this 

species were all associated with the 3.5-ft raise. There will not be any operations-related 

impacts to this species under the current project description. 

Proposed Avoidance and Minimization Measures 

No mitigation measures have been proposed since there is little likelihood of the giant garter 

snake occurring within the footprint of the proposed work. 

4.8 Bald Eagle 

Analysis of Effects 

Construction Related Effects 

Wintering bald eagles occurring within or less than 0.5 miles from proposed dike 

construction zones, haul routes, and borrow sites could incur effects as a result of noise and 

human presence. Alteration of aquatic habitat could temporarily prevent bald eagles from 

foraging in areas adjacent to on-going construction-related activities. 

Construction activities, including earth moving, earthen dike retrofit, and haul route 

construction could result in permanent alteration of up to 95 acres of potential bald eagle 
Folsom DS/FDR Action – Biological Assessment 

24

wintering habitat. The avoidance and minimization measures detailed in the following 

section would reduce the effects to this species. 

Operational Effects 

The potential impacts from an increase in the reservoirs temporary storage capacity to this 

species were all associated with the 3.5-ft raise. There will not be any operations-related 

impacts to this species under the current project description. 

Proposed Avoidance and Minimization Measures 

Prior to the implementation of vegetation removal, a Service-approved biologist would 

conduct surveys to ensure no bald eagles are present within the area in which vegetation is to 

be removed. If no bald eagles are observed, then no further mitigation measures would be 

implemented. 

If bald eagles are present, vegetation removal would to be postponed until eagles vacate the 

area of their own volition. Eagles would not be disturbed in order to clear them from the 

area. 

If breeding bald eagles are found to be present within or less than 0.5 mile from the proposed 

Folsom DS/FDR Action boundaries, a 0.5-mile buffer would be established around the nest 

site. This buffer zone would not be entered for Folsom DS/FDR Action construction 

activities until the eagles have completed breeding activities and have vacated the area of 

their own volition. 
Folsom DS/FDR Action – Biological Assessment 

25

5.0 DETERMINATION OF EFFECTS 

Based on the above information and the data collected up to this point, and with 

implementation of the avoidance and minimization measures, this Biological Assessment 

concludes that the expected outcome is: 

• Implementation of construction activities for the Folsom DS/FDR Action will not 

adversely affect the El Dorado bedstraw or Layne’s butterweed. 

• Implementation of the Folsom DS/FDR Action, , may result in loss of individuals of the 

vernal pool fairy shrimp, but will not rise to the level of a population effect. 

• Implementation of the Folsom DS/FDR Action, may result in loss of individuals of 

California vernal pool tadpole shrimp, but will not rise to the level of a population effect. 

• Implementation of construction activities for the Folsom DS/FDR Action, will adversely 

affect the valley elderberry longhorn beetle. If it becomes necessary to utilize the 

increased capacity of the reservoir for emergency retention of floodwaters, Reclamation 

will re-initiate formal Section 7 consultation with the Service. 

• Implementation of construction activities for the Folsom DS/FDR Action will not 

adversely affect the California red-legged frog. Implementation of construction activities 

for the Folsom DS/FDR Action will not adversely affect the giant garter snake. 

• Implementation of the Folsom DS/FDR Action, will not adversely affect the bald eagle. 

• Implementation of the Folsom DS/FDR Action will not have adverse impacts from 

mercury to listed aquatic species. 

If additional surveys conducted prior to construction result in an indication that the above 

listed species will be adversely affected by the proposed action, Reclamation will 

immediately notify the appropriate agencies and reinitiate formal Section 7 consultation. 
Folsom DS/FDR Action – Biological Assessment 

26

6.0 REFERENCES 

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Folsom DS/FDR Action – Biological Assessment 

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status for one plant from the Central Sierran Foothills of California. October 18, 1996 

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federal list of endangered and threatened wildlife, and to remove the similarity of 

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list of endangered and threatened wildlife. March 20, 2001 (Volume 66, Number 54). 

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wildlife and plants; final designation of critical habitat for four vernal pool 

crustaceans and eleven vernal pool plants in California and southern Oregon . August 

6, 2003 (Volume 68, Number 151). 

Federal Register. 2004. 50 CFR Part 17, Page 47212-47248. Determination of threatened 

status for the California tiger salamander; and special rule exemption for existing 

routine ranching activities. August 4, 2004 (Volume 60, Number 149). 

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wildlife and plants; designation of critical habitat for the California tiger salamander, 

Central Population; final rule. August 23, 2005 (Volume 70, Number 162). 

Federal Register. 2005b. 50 CFR Part 17, Page 66905-67064. Endangered and threatened 

wildlife and plants; revised proposed designation of critical habitat for the California 

red-legged frog (Rana aurora draytonii); proposed rule. November 3, 2005 (Volume 

70, Number 212). 

Federal Register. 2006a. 50 CFR Part 17, Page 19243-19346. Designation of critical habitat 

for the California red-legged frog, and special rule exemption associated with final 

listing for existing routine ranching activities; Final Rule. April 13, 2006 (Volume 71, 

Number 71). 

Federal Register. 2006b. 50 CFR Part 17, Page 8238-8251. Endangered and threatened 

wildlife and plants; removing the bald eagle in the lower 48 states from the list of 

endangered and threatened wildlife. February 16, 2006(Volume 71, Number 32). 

Fitch, H. S. 1941. Geographic variation in garter snakes of the genus Thamnophis sirtalis in 

the Pacific coast region of North America. American Midland Naturalist, 26: 570-

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Gallagher, S. P. 1996. Seasonal occurrence and habitat characteristics of some vernal pool 

Branchiopoda in northern California, U.S.A. Journal of Crustacean Biology 16: 323-

329. 

Garrett, K. and J. Dunn. 1981. Birds of Southern California. Los Angeles, CA: Los Angeles 

Audubon Society. 

Grinnell, J., and A. H. Miller. 1944. The distribution of the birds of California. Pac. Coast 

Avifauna No. 27 

Grinnell, J. and T. I. Storer. 1924. Animal life in the Yosemite: an account of the mammals, 

birds, reptiles and amphibians in a cross-section of the Sierra Nevada. Berkeley, CA: 

University of California Press. 752pp. 

Grinnell, J., and A. H. Miller. 1944. The distribution of the birds of California. Pac. Coast 

Avifauna No. 27. 608pp. 

Grubb, T. G., W. W. Bowerman, J. P. Giesy, and G. A. Dawson. 1992. Responses of 

breeding bald eagles, Haliaeetus leucocephalus, to human activities in north-central 

Michigan. Canadian Field-Naturalist 106: 443-453. 

Hansen, G.E. 1988. Review of the status of giant garter snake (Thamnophis couchi gigas) 

and its supporting habitat during 1986-1987. Final report for the California 

Department of Fish and Game. (Standard Agreement No. C-2060.). Unpublished, 

31pp. 

Hansen, R. W. 1980. Western aquatic garter snakes in central California: An ecological and 

evolutionary perspective. Master's thesis, California State University, Fresno. 

Hansen, R. W. and G. E. Hansen. 1990. Thamnophis gigas (giant garter snake) reproduction. 

Herpetological Review. 21(4): 93-94. 

Harris, M. 2002. "Haliaeetus leucocephalus", Animal Diversity Web. Accessed April 11, 

2006 at 

http://animaldiversity.ummz.umich.edu/site/accounts/information/Haliaeetus_leucoce

phalus.html. 

Hickman, J. C. 1993. The Jepson manual: higher plants of California. Berkeley, CA: 

University of California Press. 

Holland, R. F. 1986. Preliminary descriptions of the terrestrial natural communities of 

California. Sacramento: California Department of Fish and Game. 
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Jennings, M. R., and M. P. Hayes. 1988. Habitat correlates of distribution of the California 

red-legged frog (Rana aurora draytonii) and the foothill yellow-legged frog (Rana

boylii): implications for management. In: Proceedings of the symposium on the 

management of amphibians, reptiles, and small mammals in North America. R. Sarzo, 

K.E. Severson, and D.R. Patton, (technical coordinators). U.S.D.A. Forest Service 

General Technical Report RM-166, pp. 144-158. 

Jennings, M. R., and M. P. Hayes. 1994. Amphibian and reptile species of Special Concern 

in California. California Department of Fish and Game, Rancho Cordova, CA. 

Jennings, M. R., M. P. Hayes, and D. C. Holland. 1992. A petition to the U.S. Fish and 

Wildlife Service to place the California red-legged frog (Rana aurora draytonii) and 

the western pond turtle (Clemmys marmorata) on the list of endangered and 

threatened wildlife and plants. 

Johnsgard, P. A. 1990. Hawks, eagles, and falcons of North America. Washington, D.C.: 

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Lehman, R. N., D. E. Craigie, P. L. Colins, and R. S. Griffen. 1980. An analysis of habitat 

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by Wilderness Research Institute, Arcata, CA., for U.S. Forest Service, Region 5. San 

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the California Department of Parks and Recreation and United States Bureau of 

Reclamation. April 2003. 

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Symposium and Workshop. B.G. Pendleton, ed. Nat. Wildl. Fed. Sci. Tech. Ser. No. 

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Mayer, K. E., and W. F. Laudenslayer. 1988. A guide to wildlife habitats of California. 

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3rd ed.628 pp. 

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State University (63): 1-25. 

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ecology. Norman, OK: University of Oklahoma Press. 332pp. 
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Sibley, D. A. 2001. The Sibley guide to bird life and behavior. New York: Alfred A. Knopf. 

Stebbins, R. C. 1951. Amphibians of western North America. Berkeley, CA: University of 

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and National Marine Fisheries Service from K. Hitch, U.S. Army Corps of Engineers. 

January 30, 2001. 

__________. 2006. Bridge American River Watershed Project post authorization decision 

document: Folsom dam raise - Folsom bridge draft supplemental environmental 

impact statement/environmental impact report. May, 2006. 

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Folsom Dam – Safety of Dams Corrective Action Study Scoping Report. Technical 

Service Center. Denver, Colorado. August 2005. 

U.S. Fish and Wildlife Service (USFWS). 1984. Recovery plan for the valley elderberry 

longhorn beetle. U.S. Fish and Wildlife Service, Portland, Oregon. 

__________. 1986. Pacific States bald eagle recovery plan. U.S. Fish and Wildlife Service, 

Portland, Oregon. 160 pp. 

__________. 1999a. Draft recovery plan for the giant garter snake (Thamnopsis gigas). U.S. 

Fish and Wildlife Service, Portland, Oregon. 

__________. 1999b. Conservation guidelines for the valley elderberry longhorn beetle. U.S. 

Department of the Interior, Fish and Wildlife Service. Sacramento. July 9, 1999. 

13 pp. 

__________. 2002a. Recovery plan for the California red-legged frog (Rana aurora 

draytonii). U.S. Fish and Wildlife Service, Portland, Oregon. 

__________. 2002b. Recovery plan for gabbro soil plants of the Central Sierra Nevada 

foothills. U.S. Fish and Wildlife Service, Portland, Oregon. 

__________. 2004. Bald eagle species description. Accessed April 11, 2006 at 

http//ecos.fws.gov/docs/life_histories/B008.html 
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__________. 2006. Federal endangered and threatened species that occur in or may be 

affected by projects in the counties and/or U.S.G.S. 7 1/2 minute quads for Folsom, 

Clarksville, Rocklin, Pilot Hill. U.S. Fish and Wildlife Service Sacramento District 

office database. Available at: http: 

//www.fws.gov/pacific/sacramento/es/spp_lists/auto_list_form.cfm. Accessed 

October 2006. 

__________. 2006a. Endangered Species Accounts. Available at: http: 

//www.fws.gov/sacramento/es/spp_info.htm. Accessed January 2006 

__________. 2006b. Endangered Species Program American peregrine falcon, Falco 

peregrinus anatum (Bonaparte). http: //www.fws.gov/endangered/i/b/sab22.html 

accessed: 1/20/06. 

Williams, D. F., H. H. Genoways, and J. K. Braun. 1993. Taxonomy. In: Biology of the 

Heteromyidae (H.H. Genoways and J.H. Brown eds.). Special Publication, The 

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wildlife Volume I amphibians and reptiles. Sacramento, CA: California Department 

of Fish and Game. 

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wildlife: Volume II. birds. Sacramento, CA: California Department of Fish and 

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wildlife: Volume III. mammals. Sacramento, CA: California Department of Fish and 

Game. 
Folsom DS/FDR Action – Biological Assessment 

APPENDIX A. FEDERALLY LISTED, PROPOSED, AND CANDIDATE SPECIES 

POTENTIALLY PRESENT IN THE VICINITY OF THE FOLSOM DS/FDR ACTION 
Folsom DS/FDR Action – Bio

Table A-1 

Federally Listed, Proposed, and Candidate Species Potentially Present in the Vicinity of the Folsom DS/

Name Status Habitat Poten

Plants Pine Hill ceanothus Ceanothus roderickii 

FE, CR 

CNPS 1B 

Chaparral and cismontane woodland with serpentinite or gabbroic soils. Elevation: 260-630 m. 

No. Project areelevation range

Pine Hill flannelbush Fremontodendron californicum ssp. decumbens

FE, CR 

CNPS 1B 

Chaparral and cismontane woodland with gabbroic or serpentinite soil. Also rocky areas. Elevation: 425-760 m. 

No. Project areelevation range

El Dorado bedstraw Galium californicum ssp. sierrae

FE, CR 

CNPS 1B 

Chaparral, cismontane woodland and lower montane coniferous forest with gabbroic soils. Elevations: 100-585 m. 

Unlikely. No suconiferous fore

Sacramento Orcutt grass Orcuttia viscida

FE, CE 

CNPS 1B 

Vernal pools. Elevation: 30-100 m. No. Suitable ha

the Project site

Layne’s butterweed Senecio layneae

FT, CR 

CNPS 1B 

Chaparral and cismontane woodland on serpentinite or gabbroic soils and/or rocky areas. Elevation: 200-1,000 m. 

Unlikely. No chsoil in project a

Invertebrates Vernal pool fairy shrimp Branchinecta lynchi

FT Endemic to the grasslands of the Central Valley, Central Coast 

mountains, and South Coast mountains, in rain-filled pools. Inhabit small, clear-water sandstone-depression pools and grassed swales, earth slumps, or basalt-flow depression pools. 

Possible. Have proximity to prhabitat exists 

Valley elderberry longhorn beetle Desmocerus californicus dimorphus 

FT Occurs only in the Central Valley of California, in association with 

blue elderberry (Sambucus mexicana). Prefers to lay eggs in elderberry stems 2-8 inches in diameter; some preference shown for “stressed” elderberry shrubs. 

Yes. Suitable hproject area. Obwithin project a
Folsom DS/FDR Action – Bio

Name Status Habitat Poten

Invertebrates (continued)vernal pool tadpole shrimp Lepidurus packardi

FE Vernal pools in the Central Valley. Unlikely. Poten

project area maenough 

Amphibians California tiger salamander Ambystoma californiense

FT 

CSC 

California endemic, a lowland species restricted to the grasslands and lowest foothill regions of Central and Northern California, which is where its breeding habitat (long-lasting rain pools) occurs. During dry-season, uses small mammal burrows as refuge, travelling up to 1.6 kilometers (km). 

No. Outside the the species. 

California red-legged frog Rana aurora draytonii 

FT 

CSC 

Lowlands and foothills in or near permanent sources of deep water with dense, shrubby or emergent riparian vegetation. Requires 11-20 weeks of permanent water for larval development and must have access to aestivation habitat. 

Possible. Howehabitat exists w

Reptiles Giant garter snake Thamnophis gigas 

FT 

CT 

Prefers freshwater marsh and low gradient streams. Has adapted to drainage canals and irrigation ditches. This is the most aquatic of the garter snakes in California. 

No. Although spresent at the Pwas not found dProject area. 

Birds Aleutian Canada goose Branta canadensis leucopareia 

FD1 (Wintering) Winters on lakes and inland prairies. Forages on natural 

pasture or that cultivated to grain; loafs on lakes, reservoirs, and ponds. 

Possible. Suitabproject area, altreported winter
Folsom DS/FDR Action – Bio

Name Status Habitat Poten

Birds (continued) American peregrine falcon Falco peregrinus anatum 

FD2

CE 

(Nesting) Near wetlands, lakes, rivers, or other water; on cliffs, banks, dunes, mounds; also, human-made structures. Nest consists of a scrape on a depression or ledge in an open site. 

Yes. Suitable nhabitat present 

Bald eagle Haliaeetus leucocephalus 

FT/FPD3

CE/CFP 

(Nesting and wintering) Ocean shore, lake margins, and rivers for both nesting and wintering. Most nests within 1 mile of water. Nests in large, old-growth, or dominant live tree with open branches, especially ponderosa pine. Roosts communally in winter. 

Yes. Suitable harea. 

Sources CDFG 2005a, CDFG 2005b, CDFG 2006a, CDFG 2006b, USFWS 2005a, Zeiner et al. 1988; 1990a; and 1990b. Codes 1 Delisted from federally threatened on 3/20/2001 2 Delisted from federally endangered on 8/25/1999 3 Proposed for federal delisting on 2/16/2006 

FE: federally listed as endangered FT = federally listed as threatened FD: federally delisted FPD: federally proposed for delisting CE: State of California Endangered CT: State of California Threatened CR: State of California Rare CFP: California Fully Protected CSC: California Species of Concern CNPS = California Native Plant Society  1b = rare, threatened or endangered in California and elsewhere 
Folsom DS/FDR Action – Biological Assessment 

APPENDIX B. ELDERBERRY MITIGATION 

Folsom DS/FDR Action – Biological Assessment 

Table B-1. Transplantable Elderberry Shrubs 

Location Stems 

(maximum 

diameter at 

ground level) 

Exit 

Hole on 

Shrub 

(Yes or 

No) 

Elderberry 

Seedling 

Ratio 

Associated 

Native Plant 

Ratio 

Number 

of Stems 

Counted 

Required 

Elderberry 

Plantings 

Required 

Associated 

Native Plant 

Plantings 

Dikes 1, 2, 3 

Non-Riparian 1-3” No 1:1 1:1 3 3 3 

Yes 2 :1 2:1 6 12 24 

Total 9 15 27 

Total Elderberry Shrubs (all shrubs assumed directly affected) 2 

Compensation Area required for transplants and seedlings 0.12 

Compensation Area Required for Additional Native Plantings 0.12 

Total 0.24 

Dikes 4 – 8, MIAD, Right Wing Dam, and Staging Areas 

Non-Riparian 1-3” No 1:1 1:1 77 77 77 

Yes 2 :1 2:1 58 116 232 

Non-Riparian 3-5” No 2:1 1:1 40 80 80 

Yes 4:1 2:1 22 88 176 

Non-Riparian >5” No 3:1 1:1 48 144 144 

Yes 6:1 2:1 21 126 252 

Riparian 1-3” No 2:1 1:1 2 4 4 

Yes 4:1 2:1 0 0 0 

Riparian 3-5” No 3:1 1:1 10 30 30 

Yes 6:1 2:1 0 0 0 

Riparian >5” No 4:1 1:1 10 40 40 

Yes 8:1 2:1 0 0 0 

Total 288 705 1035 

Total Elderberry Shrubs (all shrubs assumed directly affected) 63 

Compensation Area required for transplants and seedlings 5.83 

Compensation Area required for additional native plants 3.22 

Total 9.05 

Left Wing Dam (Auxiliary Spillway)

Non-Riparian 1-3” No 1:1 1:1 58 58 58 

Yes 2 :1 2:1 2 4 8 

Non-Riparian 3-5” No 2:1 1:1 51 102 102 

Yes 4:1 2:1 8 32 64 

Non-Riparian >5” No 3:1 1:1 85 255 255 

Yes 6:1 2:1 4 24 48 

Riparian 1-3” No 2:1 1:1 3 6 6 

Yes 4:1 2:1 0 0 0 

Riparian 3-5” No 3:1 1:1 1 3 3 

Yes 6:1 2:1 0 0 0 

Riparian >5” No 4:1 1:1 3 12 12 

Yes 8:1 2:1 0 0 0 

Total 215 496 556 

Total Elderberry Shrubs (all shrubs assumed directly affected) 55 

Compensation Area required for transplants and seedlings 4.13 

Compensation Area required for additional native plants 0.50 

Total 4.63 

Total for All Areas 13.92 
Folsom DS/FDR Action – Biological Assessment 

Table B-2. Non-Transplantable Elderberry Shrubs 

Location Stems 

(maximum 

diameter at 

ground level) 

Exit 

Hole 

on 

Shrub 

(Yes 

or No) 

Elderberry 

Seedling 

Ratio 

Associated 

Native Plant 

Ratio 

Number 

of 

Stems 

Observe

d 

Required 

Elderberry 

Plantings 

Required 

Associated 

Native Plant 

Plantings 

Left Wing Dam (Auxiliary Spillway) 1

Non-Riparian 1-3” No 2:1 1:1 5 10 10 

Yes 4 :1 2:1 0 0 0 

Non-Riparian 3-5” No 4:1 1:1 4 16 16 

Yes 8:1 2:1 0 0 0 

Non-Riparian >5” No 6:1 1:1 7 42 42 

Yes 12:1 2:1 0 0 0 

Riparian 1-3” No 4:1 1:1 7 28 28 

Yes 8:1 2:1 0 0 0 

Riparian 3-5” No 6:1 1:1 0 0 0 

Yes 12:1 2:1 0 0 0 

Riparian >5” No 8:1 1:1 10 80 80 

Yes 16:1 2:1 0 0 0 

Total 33 176 176 

Total Elderberry Shrubs (all shrubs assumed directly affected) 11 

Compensation Area Required for Additional Seedlings and Native Plants 1.45 1

- compensation for indirect impacts to 9 under other projects 
Folsom DS/FDR Action – Biological Assessment 

APPENDIX C. U.S. FISH AND WILDLIFE SERVICE SPECIES LISTS FOR PROJECT 

QUADRANGLES 

Folsom DS/FDR Action – Biological Assessment 
Folsom DS/FDR Action – Biological Assessment 

APPENDIX A. FEDERALLY LISTED, PROPOSED, AND CANDIDATE SPECIES 

POTENTIALLY PRESENT IN THE VICINITY OF THE FOLSOM DS/FDR ACTION 
Folsom DS/FDR Action – Bio

Table A-1 

Federally Listed, Proposed, and Candidate Species Potentially Present in the Vicinity of the Folsom DS/

Name Status Habitat Poten

Plants Pine Hill ceanothus Ceanothus roderickii 

FE, CR 

CNPS 1B 

Chaparral and cismontane woodland with serpentinite or gabbroic soils. Elevation: 260-630 m. 

No. Project areelevation range

Pine Hill flannelbush Fremontodendron californicum ssp. decumbens

FE, CR 

CNPS 1B 

Chaparral and cismontane woodland with gabbroic or serpentinite soil. Also rocky areas. Elevation: 425-760 m. 

No. Project areelevation range

El Dorado bedstraw Galium californicum ssp. sierrae

FE, CR 

CNPS 1B 

Chaparral, cismontane woodland and lower montane coniferous forest with gabbroic soils. Elevations: 100-585 m. 

Unlikely. No suconiferous fore

Sacramento Orcutt grass Orcuttia viscida

FE, CE 

CNPS 1B 

Vernal pools. Elevation: 30-100 m. No. Suitable ha

the Project site

Layne’s butterweed Senecio layneae

FT, CR 

CNPS 1B 

Chaparral and cismontane woodland on serpentinite or gabbroic soils and/or rocky areas. Elevation: 200-1,000 m. 

Unlikely. No chsoil in project a

Invertebrates Vernal pool fairy shrimp Branchinecta lynchi

FT Endemic to the grasslands of the Central Valley, Central Coast 

mountains, and South Coast mountains, in rain-filled pools. Inhabit small, clear-water sandstone-depression pools and grassed swales, earth slumps, or basalt-flow depression pools. 

Possible. Have proximity to prhabitat exists 

Valley elderberry longhorn beetle Desmocerus californicus dimorphus 

FT Occurs only in the Central Valley of California, in association with 

blue elderberry (Sambucus mexicana). Prefers to lay eggs in elderberry stems 2-8 inches in diameter; some preference shown for “stressed” elderberry shrubs. 

Yes. Suitable hproject area. Obwithin project a
Folsom DS/FDR Action – Bio

Name Status Habitat Poten

Invertebrates (continued)vernal pool tadpole shrimp Lepidurus packardi

FE Vernal pools in the Central Valley. Unlikely. Poten

project area maenough 

Amphibians California tiger salamander Ambystoma californiense

FT 

CSC 

California endemic, a lowland species restricted to the grasslands and lowest foothill regions of Central and Northern California, which is where its breeding habitat (long-lasting rain pools) occurs. During dry-season, uses small mammal burrows as refuge, travelling up to 1.6 kilometers (km). 

No. Outside the the species. 

California red-legged frog Rana aurora draytonii 

FT 

CSC 

Lowlands and foothills in or near permanent sources of deep water with dense, shrubby or emergent riparian vegetation. Requires 11-20 weeks of permanent water for larval development and must have access to aestivation habitat. 

Possible. Howehabitat exists w

Reptiles Giant garter snake Thamnophis gigas 

FT 

CT 

Prefers freshwater marsh and low gradient streams. Has adapted to drainage canals and irrigation ditches. This is the most aquatic of the garter snakes in California. 

No. Although spresent at the Pwas not found dProject area. 

Birds Aleutian Canada goose Branta canadensis leucopareia 

FD1 (Wintering) Winters on lakes and inland prairies. Forages on natural 

pasture or that cultivated to grain; loafs on lakes, reservoirs, and ponds. 

Possible. Suitabproject area, altreported winter
Folsom DS/FDR Action – Bio

Name Status Habitat Poten

Birds (continued) American peregrine falcon Falco peregrinus anatum 

FD2

CE 

(Nesting) Near wetlands, lakes, rivers, or other water; on cliffs, banks, dunes, mounds; also, human-made structures. Nest consists of a scrape on a depression or ledge in an open site. 

Yes. Suitable nhabitat present 

Bald eagle Haliaeetus leucocephalus 

FT/FPD3

CE/CFP 

(Nesting and wintering) Ocean shore, lake margins, and rivers for both nesting and wintering. Most nests within 1 mile of water. Nests in large, old-growth, or dominant live tree with open branches, especially ponderosa pine. Roosts communally in winter. 

Yes. Suitable harea. 

Sources CDFG 2005a, CDFG 2005b, CDFG 2006a, CDFG 2006b, USFWS 2005a, Zeiner et al. 1988; 1990a; and 1990b. Codes 1 Delisted from federally threatened on 3/20/2001 2 Delisted from federally endangered on 8/25/1999 3 Proposed for federal delisting on 2/16/2006 

FE: federally listed as endangered FT = federally listed as threatened FD: federally delisted FPD: federally proposed for delisting CE: State of California Endangered CT: State of California Threatened CR: State of California Rare CFP: California Fully Protected CSC: California Species of Concern CNPS = California Native Plant Society  1b = rare, threatened or endangered in California and elsewhere 
APPENDIX B. ELDERBERRY MITIGATION 

Table B-1. Transplantable Elderberry Shrubs 

Location Stems 

(maximum 

diameter at 

ground level) 

Exit 

Hole on 

Shrub 

(Yes or 

No) 

Elderberry 

Seedling 

Ratio 

Associated 

Native Plant 

Ratio 

Number 

of Stems 

Counted 

Required 

Elderberry 

Plantings 

Required 

Associated 

Native Plant 

Plantings 

Dikes 4 – 8, MIAD, Right Wing Dam, and Staging Areas 

Non-Riparian 1-3” No 1:1 1:1 73* 73 73 

Yes 2 :1 2:1 77 154 308 

Non-Riparian 3-5” No 2:1 1:1 43 86 86 

Yes 4:1 2:1 26 104 208 

Non-Riparian >5” No 3:1 1:1 47 141 141 

Yes 6:1 2:1 30 180 360 

Riparian 1-3” No 2:1 1:1 2 4 4 

Yes 4:1 2:1 0 0 0 

Riparian 3-5” No 3:1 1:1 10 30 30 

Yes 6:1 2:1 0 0 0 

Riparian >5” No 4:1 1:1 10 40 40 

Yes 8:1 2:1 0 0 0 

Total 318 812 1250 

Total Elderberry Shrubs (all shrubs assumed directly affected) 72 

Compensation Area required for transplants and seedlings 6.71 

Compensation Area required for additional native plants (10/1800 ft2) 1.81 

Total 8.52 

Left Wing Dam (Auxiliary Spillway)

Non-Riparian 1-3” No 1:1 1:1 61 61 61 

Yes 2 :1 2:1 9 18 36 

Non-Riparian 3-5” No 2:1 1:1 49 98 98 

Yes 4:1 2:1 15 60 120 

Non-Riparian >5” No 3:1 1:1 79 237 237 

Yes 6:1 2:1 4 24 48 

Riparian 1-3” No 2:1 1:1 3 6 6 

Yes 4:1 2:1 0 0 0 

Riparian 3-5” No 3:1 1:1 1 3 3 

Yes 6:1 2:1 0 0 0 

Riparian >5” No 4:1 1:1 3 12 12 

Yes 8:1 2:1 0 0 0 

Total 224 519 519 

Total Elderberry Shrubs (all shrubs assumed directly affected) 54 

Compensation Area required for transplants and seedlings 4.29 

Compensation Area required for additional native plants (10/1800 ft2) 0.42 

Total 4.71 

Total for All Areas 13.23 

*4 stems added as compensation for shrub that was unreachable for measuring 
Table B-2. Non-Transplantable Elderberry Shrubs 

Location Stems 

(maximum 

diameter at 

ground level) 

Exit 

Hole 

on 

Shrub 

(Yes 

or No) 

Elderberry 

Seedling 

Ratio 

Associated 

Native Plant 

Ratio 

Number 

of 

Stems 

Observe

d 

Required 

Elderberry 

Plantings 

Required 

Associated 

Native Plant 

Plantings 

Left Wing Dam (Auxiliary Spillway) 1

Non-Riparian 1-3” No 2:1 1:1 17 34 34 

Yes 4 :1 2:1 0 0 0 

Non-Riparian 3-5” No 4:1 1:1 14 56 56 

Yes 8:1 2:1 0 0 0 

Non-Riparian >5” No 6:1 1:1 14 84 84 

Yes 12:1 2:1 0 0 0 

Riparian 1-3” No 4:1 1:1 16 64 64 

Yes 8:1 2:1 0 0 0 

Riparian 3-5” No 6:1 1:1 1 6 6 

Yes 12:1 2:1 0 0 0 

Riparian >5” No 8:1 1:1 10 80 80 

Yes 16:1 2:1 0 0 0 

Total 72 324 324 

Total Elderberry Shrubs (all shrubs assumed directly affected) 13 

Compensation Area Required for Additional Seedlings and Native Plants 2.68