5.0 IMPACT ASSESSMENT METHODOLGY

5.0 IMPACT ASSESSMENT METHODOLGY

Chapter 5.0 Impact Assessment Methodology

5.0-1

5.0 Impact Assessment Methodology

5.1 Water Rights Context

This chapter identifies and discusses the specific impact assessment methodologies,

modeling tools, evaluation frameworks and baseline assumptions used in the preparation

of the EIR. It provides the framework upon which the potential environmental review is

assessed in the following chapters. EDWPA‟s obligation under CEQA to disclose and

analyze the direct and reasonably foreseeable indirect environmental effects of the

proposed project presents a challenge. As explained in earlier chapters, the proposed

project seeks the assignment of portions of State-filed water rights applications that, if

approved by SWRCB, would give EDWPA a 1927 water rights priority date. Among the

benefits of the seniority associated with that date is the fact that California water law and

conditions in existing water rights permits for junior downstream appropriators, where

necessary due to drought conditions or regulatory constraints, require the junior

appropriators to reduce or forego their diversions before EDWPA would be required to

curtail its diversions.

Thus, EDWPA could not be made, on its own, to reduce its diversions in order to ensure

the enforcement of Delta or lower American regulatory standards or environmental

conditions deemed minimally acceptable. Rather, that burden would more likely fall on

more junior appropriators downstream on the American River or elsewhere within the

CVP/SWP including the Sacramento River, San Joaquin River, their tributaries, and

Delta. Where a potential or actual adverse environmental outcome requires some water

user to reduce its diversion, the burden will generally fall on those more junior

appropriators where the adverse environmental effect would not occur but for their

incremental diversions above and beyond those of senior water right holders.

One important source of legal authority for assisting the SWRCB in sorting out how

junior, downstream appropriators within the American River watershed may have to

adjust their activities in response to the proposed project is the 1958 water rights decision

known as D-893. In that decision, the State Water Rights Board (predecessor to the

SWRCB) conditioned the water rights of the USBR and the City so as to make them

subordinate to the paramount rights for the use of water originating within the American

River watershed within El Dorado County (In the Matter of Applications 12140, et al. by

the City of Sacramento and other applicants, to appropriate waters of the American River

and its tributaries. (1958) Decision 893 (“D-893”).)

The State Water Rights Board, referring to El Dorado County and other upstream

applicants, prefaced its conditioning of the consumptive right permits of USBR and the

City of Sacramento as follows:


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Protection is afforded these [El Dorado] applicants and other

potential users within upstream sub-area of the American River

watershed by terms to be inserted in permits to divert at points

below them to the effect that diversions under those permits are

and shall remain subject to reduction in the event of appropriation

for use within the watersheds that lie above the diversion works

relating to those permits.

(D-893, slip copy, at pp. 58-59.)

The SWRCB has enforced similar permit conditions protecting paramount rights against

other permit holders in the past, requiring water right holders to abstain from their prior

diversion in favor of the diversions of those in a position of paramountcy. (See In re the

Applications 24578, 24579 to Appropriate from the Underflow of the Santa Ynez River

(1978) D-1486; In the Matter of Application 22423 of the Solvang Municipal Utility

District to Appropriate Underflow from the Santa Ynez River (1969) D-1338; In the

Matter of Applications 11331, 11332, 11761, 11762, 11989 (1958) D-886.) This

precedent suggests that, in the future, a similar approach may be used within the

American River watershed.

Despite the relatively predictable manner in which this legal and regulatory system

allocates the benefits and burdens among senior water rights and junior water rights

holders, the impact assessment methodology used in this EIR nevertheless fully addresses

and analyzes the diversion-related effects of the proposed project as though it represents a

new, direct depletion of water from the existing hydrological system. This approach is

legally conservative in the sense that it errs on the side of possibly overstating, rather than

understating, the actual environmental effects of the project, and is intended to comply

with the letter and the expansive spirit of CEQA, which favors the full disclosure of all

possible adverse environmental effects of projects.

Accordingly, an evaluation of the potential impacts of such new water depletion is a kind

of worst case analysis, assuming a new net depletion of up to 40,000 AFA. Even so, the

analysis will provide a very useful source of information for the SWRCB as it faces

ongoing challenges regarding how to protect important beneficial uses of various kinds

throughout the Sacramento-American River system.

Impact analysis for diversion-related effects was performed at the project-level. Project-

level detailed analyses focused on the potential impacts of diverting the new water right

water at three potential points of diversion; 1) EID‟s existing intake to their El Dorado

Hills Water Treatment Plant on Folsom Reservoir, 2) the White Rock Penstock, and 3)

the American River Pump Station on the North Fork of the American River through an


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exchange. These potential points of diversion have been discussed and described in

detail in Chapter 3.0 Project Description, and Chapter 4.0 Alternatives.

Under the project-level analyses, potential hydrologic changes in the various waterbodies

and waterways affected by the project were evaluated. These affected waterbodies

included those within the Upper American River basin, as well as those downstream

within the CVP/SWP. Given the coordinated nature of the CVP/SWP, any diversion

project in a CVP reservoir or from watercourses feeding into it has the potential to affect

downstream reservoirs and watercourses of the CVP/SWP and the Delta. Hydrologic

modeling was undertaken to quantitatively determine the extent and frequency of any

such changes in the hydrologic regime of the CVP/SWP and local area waterways. This

modeling output was then used as the basis upon which impact analyses for all water-

related resources were preformed.

The primary impact analyses for the EIR, therefore, focused on the hydrological effects

of the proposed project on potentially affected waterbodies and waterways including

those of the local area and broader CVP/SWP, including the Delta.

Alternatively, program-level analyses addressed more generally, the future potential

impacts to resources that were non-diversion related. The non-diversion related impacts

included two categories.

First, new diversion, conveyance, and possibly new treatment facilities and related

infrastructure would be required in the future to take this new water supply. The full

details, timing, and commitments for such infrastructure, however, is not currently

known. No design specifications, siting plans, or corridor alignments are currently

available. However, because of the potential necessity for the future construction of such

facilities, the potential impacts of such facilities (including their construction), to the

extent known, are disclosed and discussed generally at the program-level.

Second, the resources within the water service areas or intended Places of Use were also

assessed at the program-level. This included the various facilities, activities, land uses

and other potentially affected resources within the proposed Places of Use including the

Favorable Areas, as defined in the project description. These facilities and activities are

typically assumed as part of ongoing development activities within urban and rural areas.

Such activities, land uses and resources have already been analyzed in the adopted El

Dorado County General Plan Update and EIR, which this EIR relies upon. A detailed

analysis of those activities, land uses, and resources is not repeated in this EIR.

As noted previously in Chapter 1.0 (Introduction), given the proposed project as

described, there will likely be future CEQA documents that will be required and prepared

to divert, convey, and/or treat and deliver this new water supply. These projects will

result from local agencies (e.g., EID, GDPUD, El Dorado County, etc.) making use of the


5.0-4

new water made available under this project. These facility projects, however, are future

actions that, currently, have not been proposed and do not have detailed information from

which to undertake specific analyses. This current EIR is intended to provide the

hydrologic, project-level analyses that would support future facility projects, thus

avoiding any need for reassessment of instream hydrologic effects for those projects.

The potential resources and issues addressed in this EIR were identified through a

combination of known issues coupled with public involvement through project scoping.

In addition to two formal scoping meetings conducted during the public review and

comment period on the NOP/Initial Study, informal sessions with various stakeholder

groups and public trust resource agencies were conducted by EDWPA. These

discussions and input helped shape the scope of the EIR.

5.2 Diversion-Related Impact Evaluation

As noted, the diversion-related impact assessment relied upon a hydrologic impact

framework to generate quantitative data with which to evaluate potential impacts to

water-related resources. Such potential impacts were evaluated by comparing the

existing hydrologic condition (or Base Condition) with that of the simulated system after

implementation of the proposed project and alternatives (i.e., diversion of the new water

right). Two mass-balance hydrologic reservoir routing models were used: the ResSim

model for the upper American River basin and the CALSIM II model for CVP/SWP

reservoirs and waterways.

The upper American River basin Base Condition is based on and consistent with the

conditions established in the FERC Relicensing Settlement Agreement for the Upper

American River Project (UARP) and Chili Bar project between Sacramento Municipal

Utility District (SMUD), Pacific Gas & Electric (PG&E), and various governmental and

non-governmental agencies and individuals (SMUD et al, 2007). The use of this differs

from the normal practice of treating existing conditions, as they existed at the time of the

Notice of Preparation, as the “baseline” for purposes of impact analysis (see CEQA

Guidelines, § 15125, subd. (a)). The UARP and Chili Bar project relicensing conditions

were included in the Base Condition for the upper American River basin because this

approach is more conservative for purposes of assessing the significance of impacts

(tending to overstate, instead of understate, impacts) and because the UARP and the Chili

Bar project will be operating under the terms of the Relicensing Settlement Agreement

prior to the implementation of the proposed project. To use language from CEQA case

law, the baseline chosen here is “the actual environment upon which the project will

operate.” (Environmental Planning and Information Council v. County of El Dorado

(1982) 131 Cal.App.3d 350, 354.) For this reason, the approach taken here finds

abundant support in that case law.


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Resource evaluations were broken into two categories: Diversion-related Impacts, and

Indirect or Non-Diversion related Impacts.

Diversion-related impacts could potentially affect the following resources:

Water Supply

Hydropower Generation

Flood Control

Fisheries

Water Quality

Riparian and Riverine Resources

5.2.1 Upper Basin Modeling – HEC-ResSim

HEC-ResSim (Version 3.0.1), a public domain software package developed by the

Hydrologic Engineering Center of the U.S. Army Corps of Engineers (HEC) as a

decision support tool for reservoir regulators, was used for numerical computer modeling

to evaluate the impacts of the proposed project .

Features of ResSim include:

A map-based schematic development environment;

A complex reservoir element that can include multiple dams and outlets;

An operations scheme that can define the reservoir's operating goals and

constraints in terms of pool zones and zone dependent rules;

A set of operation rule types that include release requirements and constraints,

downstream control requirements and constraints, pool elevation or inflow rate-

of-change limits, hydropower requirements, and induced surcharge (emergency

gate operation);

Operation of multiple reservoirs for a common downstream control, including

storage balancing;

Alternative builder to allow for a wide range of "what if" analysis;

Computation time-steps from 15 minutes to 1 day;

Summary Reports and a Release Decision Report; and,

HEC-DSS (a scientific database system developed by HEC) for storage of input

and output data.


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As a starting point, this analysis used an existing ResSim model (Hughes, 2007), jointly

developed by the California Department of Fish & Game (CDFG) and U.S. Forest

Service, as part of SMUD‟s UARP FERC relicensing process. This model is based on the

conditions established in the Relicensing Settlement Agreement for the UARP and Chili

Bar project between SMUD, Pacific Gas & Electric (PG&E), and various governmental

and non-governmental agencies and individuals (SMUD et al, 2007).

Following the CDFG model, the period extending from Water Year (WY) 1975 through

WY 1999 was selected as the study period because of the availability of observed data

and unimpaired flow estimates for this period. Alternate scenarios were created to reflect

the various possible withdrawal cases under the proposed water rights. The model was

used to verify the environmental boundary conditions associated with EDWPA‟s

proposed diversion and provide a means of determining the potential impact to the

reservoirs and watercourses in the project area, relative to those established in the

Settlement Agreement.

5.2.1.1 Approach

The existing ResSim model, with modifications to reflect the diversion at the White Rock

Penstock, was used to generate the time-series for comparison. Since this analysis is

based on a pre-existing model, detailed background information on the model

construction is not provided here. Such information may be found in the supporting

document for the Settlement Agreement ResSim model published by California

Department of Fish & Game (Hughes, 2007). Copies of this document are available for

review at the offices of the El Dorado County Water Agency located at 3932 Ponderosa

Road, Suite 200, Shingle Springs, CA 95682.

The objective of the model is to evaluate the impacts of the proposed EDWPA diversions

on the reservoirs and watercourses in the project area. Modifications were made to the

model to incorporate the proposed diversion and are described in Section Model

Modifications. The evaluation of the impacts of the diversion was possible through a

comparison of the Base Condition (i.e., Settlement Agreement ) with four possible

diversion scenarios (described in Section Diversion Scenarios) using various metrics such

as power generation, rafting flows, reservoir storage, and lake levels (described in

Section Parameters Used for Comparison of Alternatives). Computational limitations of

the model are discussed in Model Computational Limitations. Finally, the period of

evaluation for the results is presented in "Period of Evaluation".

5.2.1.2 Model Modifications

The ResSim model contains a Base Case, which reflects the Relicensing Settlement

Agreement and four proposed diversion scenarios. These different diversion scenarios are

summarized in Table 5.2.1-1. In all scenarios, the total annual diversion has a monthly


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distribution in accordance with the Monthly Water Need Schedule information shown in

Tables 5.2.1-2 and 5.2.1-3.

The following modifications were made to the ResSim model to reflect the diversion

from the White Rock Penstock in physical and operational terms:

Diverted Outlet

A Diverted Outlet was added at Slab Creek Reservoir (identified as EDWPA Diversion)

to describe water diverted just prior to the White Rock Powerhouse.

Table 5.2.1-1

Summary of Model Simulations

Name of Simulation

Location of Diversion

White Rock

Powerhouse

Penstock

Folsom Reservoir

American River

Pump Station

(future)

Base Condition - - -

Proposed Project B 40,000 - -

Proposed Project C 30,000 - 10,000

Reduced Project

Alternative B-2 20,000 - -

Reduced Project

Alternative C-2 15,000 - 5,000

Note: All values are in Acre-Feet and reflect annual diversions. Monthly distribution is shown in Table 5.2.1-2.

Operation of Slab Creek Reservoir

The operation of Slab Creek Reservoir in the Base Scenario model (formerly ResLevel2

from DFG model) is governed by the operation set RecFlow-6. Copies of this set were

made to retain all other parameters, and the copies were then modified to create four new

operation sets, each of which reflects one of the four scenarios being studied. These

operation sets are labeled:

Proposed Project B

Proposed Project C

Reduced Project Alternative B-2

Reduced Project Alternative C-2

Note: These labels were used for modeling identification purposes and are not the CEQA

proposed project and alternatives. The relationship between the modeling nomenclature

and the CEQA proposed project and alternatives is provided in Table 5.2.7-1.


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Table 5.2.1-2

Monthly Diversions at White Rock Penstock

Monthly

Distribution %

Model Simulation

10% 5% 4% 4% 4% 4% 4% 8% 13% 16% 16% 12% 100%

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Total

Proposed

Project B

Monthly

Volume

(AF)

4,000 2,000 1,600 1,600 1,600 1,600 1,600 3,200 5,200 6,400 6,400 4,800

40,000

Average

flow (cfs) 65 34 26 26 29 26 27 52 87 104 107 78

Proposed

Project C

Monthly

Volume

(AF)

3,000 1,500 1,200 1,200 1,200 1,200 1,200 2,400 3,900 4,800 4,800 3,600

30,000

Average

flow (cfs) 49 25 20 20 22 20 20 39 66 78 78 59

Reduced

Project

Alt. B-2

Monthly

Volume

(AF)

2,000 1,000 800 800 800 800 800 1,600 2,600 3,200 3,200 2,400

20,000

Average

flow (cfs) 33 17 13 13 14 13 13 26 44 52 52 39

Reduced

Project

Alt. C-2

Monthly

Volume

(AF)

1,500 750 600 600 600 600 600 1,200 1,950 2,400 2,400 1,800

15,000

Average

flow (cfs) 24 13 10 10 11 10 10 20 33 39 39 29

Note: Scenarios with no diversion at White Rock are not shown here.


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Table 5.2.1-3

Monthly Diversions at Folsom Reservoir

Monthly

Distribution %

Model Simulation

10% 5% 4% 4% 4% 4% 4% 8% 13% 16% 16% 12% 100%

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Total

Proposed

Project A

Monthly

Volume

(AF)

3,000 1,500 1,200 1,200 1,200 1,200 1,200 2,400 3,900 4,800 4,800 3,600

30,000

Average

flow (cfs) 49 25 20 20 22 20 20 39 66 79 79 59

Proposed

Project D

Monthly

Volume

(AF)

4,000 2,000 1,600 1,600 1,600 1,600 1,600 3,200 5,200 6,400 6,400 4,800

40,000

Average

flow (cfs) 65 34 26 26 29 27 27 52 87 104 104 78

Reduced

Project

Alt. A-2

Monthly

Volume

(AF)

1,500 750 600 600 600 600 600 1,200 1,950 2,400 2,400 1,800

15,000

Average

flow (cfs) 24 13 10 10 11 10 10 20 33 39 39 29

Reduced

Project

Alt. D-2

Monthly

Volume

(AF)

2,000 1,000 800 800 800 800 800 1,600 2,600 3,200 3,200 2,400

20,000

Average

flow (cfs) 33 17 13 13 14 13 13 26 44 52 52 39

Note: Scenarios with no diversion at Folsom Reservoir are not shown here.


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Power Generation

The ResSim model is not specifically designed as a tool to evaluate energy generation

impacts; however, the model does report energy generation with sufficient accuracy to be

used to evaluate the overall difference in generation between two alternatives (Hughes,

2007). Power generation is calculated separately for each Upper American River Project

and Chili Bar Project power plants. For evaluation, total generation for both SMUD‟s

Upper American River Project and PG&E‟s Chili Bar Project were evaluated.

Reservoir Storage

Annual inflows in the following reservoirs were evaluated for comparison:

Loon Lake Reservoir

Union Valley Reservoir

Ice House Reservoir

Camino Reservoir

Slab Creek Reservoir

Chili Bar Reservoir

Reservoir Levels

Water levels in the following reservoirs were evaluated for recreational resource impact

purposes:

Loon Lake Reservoir

Union Valley Reservoir

Ice House Reservoir

Camino Reservoir

Slab Creek Reservoir

Chili Bar Reservoir

Rafting Flows

Flows were evaluated in the following reaches of Silver Creek and South Fork (SF)

American River, which are popularly used for whitewater rafting:

Silver Creek above SF American River

SF American River below Slab Creek Reservoir

SF American River below Chili Bar Reservoir


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5.2.1.4 Model Computational Limitations

In order to preserve the nature of the model in its original form no attempt was made to

modify any preexisting model features unless they directly affected the proposed

EDWPA diversions. Wherever the original model simulation encountered numerical

instabilities, these were left unadjusted. When simulation runs were conducted on the

model in its original condition, it appeared that there were minor numerical instabilities

and the model was unable to converge on several instances when computing water levels

for Camino Reservoir. However, these instabilities did not affect the results. However,

after adding the EDWPA diversion at White Rock Penstock, the associated rules and

operation sets, and running the model over a continuous daily time series from WY 75

through WY 99, these instabilities were found to be amplified to the extent that the model

simulation would stall.

When ResSim is unable to converge on a solution after several passes, it automatically

refers to the "Look Back" time-series and picks a value for the particular time-step for

which it has been unable to converge. The model for this study is split in four

simulations representing sub-periods (WY 75-81, WY 82-88, WY 89-95, WY 95-99).

Each simulation (except the first one) was set to „look back‟ on the end result of the

previous simulation period for its starting conditions. There was no single continuous

Look back time-series for ResSim to refer to in case of a severe numerical instability.

Without a Look Back file when instabilities were found in the middle of a simulation

period, the model stalled.

To mitigate this situation, all four simulations were programmed to look back at an

artificial WY1975-1999 Look Back time-series, rather than just the end results of the

preceding time series. The disadvantage to this is that the starting condition of a

simulation period would not match the ending condition of the previous simulation. The

model, however, would quickly seek out appropriate values in a matter of a few time-

steps. Despite the numerical constraints described above, the model provides results that

can be effectively used for impact evaluation purposes since the environmental

assessments are based on comparisons between model simulation outputs. As a tool that

provides comparative data, the seeming limitations in model representation are equitable

(i.e., the same) across all simulations. Bias is eliminated when the comparative

confidence limits are identical across all model simulations.

5.2.1.5 Period of Evaluation

The model was run for the period from WY1975 through WY1999. For ease of

reporting and evaluation, only selected years have been presented in the results. These

years have been selected on the basis of the water year type (i.e., based on amount of


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rainfall) - the Hydrology Technical Report classified each month between WY 1975 and

WY 2001 as Critically Dry, Dry, Below Normal, Above Normal, and Wet.

WY 1977 was selected to represent a Critically Dry year, WY 1992 as Dry, WY 1990 as

Below Normal, and WY 1997 as a Wet year. However, in the study period of WY1975-

1999, there is no water year that showed unambiguous qualities in order to be represented

as an Above Normal Year. The current model runs have been programmed to „look back‟

at a single "Look Back" time-series. This time-series, which was part of the original

CDFG model, stops at the end of WY 1999. As a result, the latest version of the model

cannot be run past WY 1999. Finally, the Above Normal water year was omitted since

there was no year that provided a good representation within the dataset and values could

be inferred using the Below Normal and Wet data.

5.2.1.3 Modeling Simulations

Under each of these modeling simulations, eponymous new rules were created to reflect

the proposed diversions. These rules operate release from Slab Creek Reservoir through

the EDWPA Diversion (entity identified in the model as “Slab Creek Reservoir–EDWPA

Diversion”). Each of these rules contains Release Functions which reflect the monthly

flows shown in Table 5.2.1-2.

To avoid redundancy, only some of the EIR alternatives were modeled with ResSim. The

Base Condition and the maximum and minimum proposed diversions were modeled to

provide the appropriate environmental bracket. It is assumed that all other diversion

permutations would impart impacts that would fall within these boundary extremes. The

various modeling simulations to account for the various diversion scenarios considered

for this analysis are described below and previously summarized in Table 5.2.1-1. In all

simulations, the total annual diversion has a monthly distribution in accordance with the

Monthly Water Need Schedule summarized in Tables 5.2.1-2 and 5.2.1-3.

EDWPA Null

To ensure that no water is diverted to EDWPA Diversion under the Base Condition, a

rule called “EDWPA Null” was created under the operation set RecFlow-6 (which

operates the Base Condition). This rule restricts the diversion to zero throughout the

year.

Time-step

A time-step of one day was adopted for the model.

Base Condition

The Base Condition reflects conditions under the Settlement Agreement. The Settlement

Agreement has established various environmental thresholds (e.g., minimum instream


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flows, limits on tunnel diversions, provisions for geomorphic releases etc) which were

followed. This model simulation does not include any additional water diversions above

current conditions. The existing diversions are assumed to take place throughout the year

based on the monthly water need schedule that was developed for the project.

Proposed Project B

This model simulation supports a total annual diversion of 40,000 AF from the turnout on

White Rock Powerhouse Penstock. The diversions are assumed to take place throughout

the year based on the monthly water need schedule that was developed for the project.

Proposed Project C

This model simulation scenario supports a total annual diversion of 40,000 AF comprised

of 30,000 AF from the turnout on White Rock Powerhouse Penstock and 10,000 AF from

the American River Pump Station. The diversions are assumed to take place throughout


Reduced Project Alternative B-2

This model simulation supports a reduced total annual diversion of 20,000 AF from the

turnout on White Rock Powerhouse Penstock. The diversions are assumed to take place

throughout the year based on the monthly water need schedule that was developed for the

project.

Reduced Project Alternative C-2

This model simulation supports a reduced total annual diversion of 20,000 AF comprised

of 15,000 AF from the turnout on White Rock Powerhouse Penstock and 5,000 AF from

the American River Pump Station. The diversions are assumed to take place throughout


Parameters Used for Comparison of Alternatives

To quantitatively evaluate the potential impacts from each of the four model simulations,

relative to the Base Condition, it was necessary to identify parameters which could be

easily discredited for numerical comparison. The parameters chosen for comparison have

been described above.

5.2.2 CALSIM II

CALSIM II is a model jointly developed by the U.S. Bureau of Reclamation (USBR) and

the California Department of Water Resources (DWR) for planning studies relating to

CVP and SWP operations. The primary purpose of CALSIM II is to evaluate the water

supply reliability of the CVP and SWP at current or future levels of development (e.g.

2001, 2030), with and without various assumed future facilities, and with different modes


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of facility operations. An extensive model, CALSIM II simulates monthly operations of

the following water storage and conveyance facilities:

Trinity, Lewiston, and Whiskeytown reservoirs (CVP);

Spring Creek and Clear Creek tunnels (CVP);

Shasta and Keswick reservoirs (CVP);

Oroville Reservoir and the Thermalito Complex (SWP);

Folsom Reservoir and Lake Natoma (CVP);

New Melones Reservoir (CVP);

Millerton Lake (CVP);

C.W. Jones (CVP), Contra Costa (CVP) and Harvey O. Banks (SWP) pumping

plants; and

San Luis Reservoir (shared by CVP and SWP).

To varying degrees, CALSIM II nodes also define CVP/SWP conveyance

facilities including the Tehama-Colusa, Corning, Folsom-South, and Delta-

Mendota canals and the California Aqueduct. Other non-CVP/SWP reservoirs or

rivers tributary to the Delta also are modeled in CALSIM II, including:

New Don Pedro Reservoir;

Lake McClure; and

Eastman and Hensley lakes.

CALSIM II uses a mass balance approach to simulate the occurrence, regulation, and

movement of water from one river reach (computation point or node) to another within

monthly time steps. Various physical processes (e.g., surface water inflow or accretion,

flow from another node, groundwater accretion or depletion, and diversion) are simulated

or assumed at each node as necessary. Operational constraints, such as reservoir size,

seasonal storage limits, and minimum flow requirements, also are defined for each node.

Accordingly, flows are specified as a mean flow for the month, and reservoir storage

volumes are specified as end-of-month values. In addition, modeled X2 (2 parts per

thousand [ppt] near bottom salinity isohaline) locations are specified as end-of-month

locations, Delta outflows are specified as mean outflows for each month, and Delta

export-to-inflow (E/I) ratios are specified as mean ratios for each month.

The hydrologic period of record used by CALSIM II has recently been extended so that

today, the model can simulate system operations over an 82-year period. The model

assumes that facilities, land use, water supply contracts, and regulatory requirements are


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constant over this period, and represent a fixed level of development (e.g., 2001 or 2030).

The historical flow record from 1921 to 2003, adjusted for the influence of land use

change and upstream flow regulation, is used to represent the possible range of water

supply conditions that could conceivably occur. This is a reasonable assumption and one

that presumes that past hydrologic conditions are a good indicator of future hydrologic

conditions. As discussed later, this concept of stationarity in hydrologic conditions has

come under significant scrutiny in recent years, both temporally and spatially, with

climate change representing a key causal factor in this uncertainty (see Chapter 8 –

Climate Change).

The model simulates one month of operation at a time, with the simulation passing

sequentially from one month to the next, and from one year to the next. Each estimate

that the model makes regarding stream flow is the result of defined operational priorities

(e.g., delivery priorities to water right holders, and water contractors), physical

constraints (e.g., storage limitations, available pumping and channel capacities), and

regulatory constraints (flood control, minimum instream flow requirements, Delta

outflow requirements). Certain decisions, such as the definition of water year type, are

triggered once a year, and affect water delivery allocations and specific stream flow

requirements. Other decisions, such as specific Delta outflow requirements, vary from

month to month. CALSIM II output contains estimated flows and storage conditions at

each node for each month of the simulation period. Simulated flows are mean flows for

the month, reservoir storage volumes correspond to end-of month storage.

CALSIM II, together with associated environmental models (e.g., USBR‟s Trinity,

Shasta, Whiskeytown, Oroville, and Folsom Reservoir Water Temperature Models;

USBR‟s Trinity, Sacramento, Feather, and American (with Automated Temperature

Selection Procedure [ATSP]) River Water Temperature Models; USBR‟s Feather, and

Sacramento River Early Life Stage Chinook Salmon Mortality Models; the Long Term

Gen Model; and the General Purpose Output Generation Tool) provided the predictive

hydrology and environmental outputs necessary to determine potential water-related

resource impacts throughout the CVP/SWP as a result of the proposed action and

alternatives.

A more detailed discussion of CALSIM II and the modeling impact framework used in

this EIR is provided below (all modeling assumptions specific to the individual model

simulations are provided in Modeling Technical Memorandum, Appendix G).

5.2.2.1 CALSIM Utility

At the present time, CALSIM II is considered the best available tool for modeling the

integrated CVP and SWP and is the only system-wide hydrologic model being used by

USBR and DWR to conduct planning and impact analyses of potential projects. While


5.0-16

these agencies developed the model for project-related purposes (i.e., CVP/SWP actions),

the model has been employed for various other purposes with varying degrees of success.

These limitations are discussed in more detail later.

As the official model for California‟s two largest inter-regional projects with implications

for statewide and Central Valley water operations and planning, CALSIM II results are

often at the center of many technical and policy controversies. As such, CALSIM II, not

unlike its predecessors, PROSIM 2000 and PROSIM, warrants and, in fact, has received

considerable scrutiny from the water resources and environmental communities. The

range of issues raised has been diverse, and includes a variety of issues and perspectives

related to water supply reliability, environmental management and performance, water

demands, economics, documentation, changing hydrology and climate, software, and

regulatory compliance.

A primary intended use of CALSIM II is to estimate the impacts and benefits of large-

scale proposed projects and regulatory actions on the statewide system. Much of the

initial focus of system-wide modeling of this nature was intended to help determine

export quantities and timing. Current analyses using CALSIM II include, among others,

proposed CALFED storage projects, including In-Delta storage, North of Delta Off-

stream Storage (Sites Reservoir), expansion of Los Vaqueros and Shasta reservoirs,

storage in the Upper San Joaquin Basin, and conjunctive use both north and south of the

Delta. Of particular note, CALSIM II has also been used in the Biological Assessment

for the Long-Term Coordination of the CVP and SWP and in both Biological Opinions

on this action.

At the local level, many agencies also rely on CALSIM II results to estimate potential

impacts to the integrated system based on their own specific project actions. CALSIM II

has been used in the P.L.101-514 New CVP Water Service Contracts, Freeport Regional

Project, the Lower Yuba River Accord, the Sacramento Area Water Forum Lower

American River Flow Standard, and numerous Warren Act contracting actions, to name

but a few. Similar to the reliance on predecessor models, the use of CALSIM II and any

of its future revisions is anticipated to continue in the future.

5.2.2.2 CALSIM II Operation

The operations of CALSIM II have been described in numerous documents. The

following discussion is taken from DWR (2006, 2005, 2003a, 2003b); Ferreira et al.

(2005); Draper et al. (2004); and the Freeport Regional Water Project EIS/EIR (2003).

CALSIM II utilizes optimization techniques to route water through a watershed network

on a monthly time-step. A linear programming (LP)/mixed integer linear programming

(MILP) solver determines an optimal set of decisions for each time period given a set of

weights and system constraints. A key component for specification of the physical and


5.0-17

operational constraints is the WRESL language. The model user describes the physical

system (e.g., dams, reservoirs, channels, pumping plants, etc.), operational rules (e.g.,

flood-control diagrams, minimum flows, delivery requirements, etc.), and priorities for

allocating water to different uses in WRESL statements.

CALSIM II includes a hydrology developed jointly by USBR and DWR. Water

diversion requirements of purveyors (demands), natural stream accretions and depletions,

river basin inflows, irrigation efficiencies, return flows, non-recoverable losses, and

groundwater operation are components that make up the hydrology used in CALSIM II.

Sacramento Valley and tributary basin hydrology is developed using a process designed

to adjust the historical sequence of monthly stream flows to represent a sequence of flows

at either current or future levels of development. Adjustments to historic water supplies

are determined by imposing land use on historical meteorological and hydrologic

conditions. San Joaquin River basin hydrology is developed using fixed annual demands

and regression analysis to develop accretions and depletions. The resulting hydrology

represents the water supply available from Central Valley streams to the CVP and SWP

at an established level of development.

CALSIM II uses DWR‟s Artificial Neural Network (ANN) model to simulate the flow-

salinity relationships for the Delta. The ANN model correlates DSM2 model-generated

salinity at key locations in the Delta with Delta inflows, Delta exports, and Delta Cross

Channel operations. The ANN flow-salinity model estimates electrical conductivity at

the following four locations for the purpose of modeling Delta water quality standards:

Old River at Rock Slough, San Joaquin River at Jersey Point, Sacramento River at

Emmaton, and Sacramento River at Collinsville. In its estimates, the ANN model

considers antecedent conditions up to 148 days, and considers a “carriage-water” type of

effect associated with Delta exports.

The delivery logic CALSIM II utilizes in determining deliveries to North-of-Delta and

South-of-Delta CVP and South-of-Delta SWP contractors uses runoff forecast

information that incorporates uncertainty and standardized rule curves (i.e., Water Supply

Index versus Demand Index Curve) to estimate the water available for delivery and

carryover storage. Updates of delivery levels occur monthly from January 1 through May

1 for the SWP and March 1 through May 1 for the CVP as water supply parameters

become more certain. The South-of Delta SWP delivery is determined based upon water

supply parameters and operational constraints. The CVP system wide delivery and

South-of-Delta delivery are determined similarly upon water supply parameters and

operational constraints with specific consideration for export constraints.

CALSIM II incorporates procedures for dynamic modeling of Section 3406(b) (2) of the

CVPIA and the Environmental Water Account (EWA), under the CALFED Framework


5.0-18

and Record of Decision (ROD). Per the October, 1999 Decision and the subsequent

February, 2002 Decision, CVPIA 3406(b)(2) accounting procedures are based on system

conditions under operations associated with SWRCB D-1485 and D-1641 regulatory

requirements. Similarly, the operating guidelines for selection of actions and allocation

of assets under the EWA are based on system conditions under operations associated with

SWRCB D-1641 regulatory requirements. This requires sequential layering of multiple

system requirements and simulations. CVPIA 3406(b) (2) allocates 800 TAF (600 TAF

in Shasta critical years) of CVP project water to targeted fish actions. The full amount

provides support for SWRCB D-1641 implementation. According to monthly

accounting, 3406(b) (2) actions are dynamically selected according to an action matrix.

Several actions in this matrix have defined reserve amounts that limit 3406(b) (2)

expenditures for lower priority actions early in the year such that the higher priority

actions can be met later in the year.

5.2.2.3 CALSIM II Simulations

The applicability of CALSIM II in environmental analyses is based on its ability to

provide comparative data results. This is an important point since CALSIM II, as with

most gross-scale, long time-step (monthly) hydrologic simulations, are appropriate for the

purposes upon which they were designed but not necessarily for other evolved and

evolving applications. While CALSIM II has, and continues to be used for

environmental analyses of specific project (or action) increments, its strength does not lie

in those types of applications. Nevertheless, with an integrated CVP/SWP and

coordinated operations throughout the many interconnecting watersheds, CALSIM II is a

useful and accepted tool to gauge system-wide hydrological changes resulting from a

particular action. Again, as noted, it does so within a comparative framework where, the

results of the with-project condition are compared against the baseline condition.

Accordingly, the results from a single simulation may not necessarily represent the exact

operations for a specific month or year, but should reflect long-term trends. Since

CALSIM II is not designed to accurately predict operations and flows, results from

individual months should be considered only in the context of overall trends and

averages. CALSIM II represents operational or regulatory thresholds through the use of

step functions. Due to CALSIM's dynamic responses to system conditions, slight

changes in model inputs or operations could trigger responses which may significantly

vary on an individual monthly basis between the Base Condition and “Project”

simulation. These dynamic responses, however, often average out over longer time

periods. It is these longer-term trends which are useful in determining potential effects of

larger diversion projects on the coordinated CVP/SWP.


5.0-19

5.2.2.4 CALSIM II Limitations

Regardless of the model, models only approximate natural phenomena. In fact, most

models are inherently inexact since the mathematical descriptions upon which they are

based are either imperfect and/or our understanding of the inherent processes (that we are

trying to simulate) is incomplete. It is well accepted that the mathematical parameters

used in models which are intended to represent real processes are often uncertain. This

uncertainty arises because these parameters are empirically determined and often attempt

to represent multiple processes. Additionally, the initial or starting conditions and/or the

boundary conditions in a model are often not well known. CALSIM II, despite its

powerful capabilities, remains a model and, as such, is subject to the same issues

regarding limitations as any other model.

As noted previously, CALSIM II is able to simulate the integrated CVP/SWP system

over the 83-year historical hydrology. In theory, such simulation allows model users to

assess the effects that certain actions would have had on the system had they been

implemented in any year of the historical record. The ability of the model to represent a

predictive indicator of the effect of certain actions into the future, however, largely

depends on the representative nature of the historical hydrology, relative to likely future

hydrology. This is a very important point. With growing concerns throughout the

scientific community, past hydrology, it is felt, may not be a good indicator of the

hydrological conditions one could expect in the future. A good example of this concern

is related to global climate change. While most water practitioners accept climate change

as an eventual reality and agree with its inevitability, the degree to which it will affect

specific resources and the temporal pattern of that effect say, over a season, is still largely

a subject of continuing debate. Water managers today have begun to consider global

climate change in earnest when planning for the future. Unfortunately, at the time

modeling for this proposed action was completed, CALSIM II was not well suited to

model perturbed hydrology or other future scenarios where non-stationarity in hydrologic

or meteorologic processes derived at the basin-scale are relevant. Physical experimental

designs where watershed processes under a variable hydrometeorologic regime are

evaluated have not been incorporated into CALSIM II. CALSIM II has not yet been

calibrated against physical snowmelt and altered runoff generating processes resulting

from possible climatic perturbations. Current CALSIM II work, however, is moving

towards improving those types of analyses.

CALSIM II also lacks detailed documentation regarding the known limitations and

weakness of the model. Without a clear understanding of the model‟s formulation, water

managers have been wary of applying it in a predictive (absolute) mode. A long-standing

issue is that error bars need to be specified for all CALSIM II output; this would be


5.0-20

especially applicable where the model was being used in predictive mode (Ferreira et al.,

2005).

From a temporal perspective, there is ongoing concern that CALSIM II‟s monthly time

step cannot accurately capture hydrologic variability and, thus, does not compute water

exports and export capacity accurately, both of which are significant factors in CVP/SWP

operations. CALSIM II‟s inability to capture within-month variations often results in

overestimates of the volume of water the projects can export from the Bay-Delta and

makes it seem easier to meet environmental standards than it is in real-time operations.

Many of the system‟s operations function, in fact, on a shorter time scale. CALSIM II

cannot represent them well given its current formulation. On the other hand, it is unclear

if reducing the time step would result in more accurate or more useful data results given

the additional data and assumptions that would be needed to characterize the system at

this finer temporal resolution. A daily time step might, in fact, worsen some problems

due to questions regarding the precise timing of short events (Ferreira et al., 2005).

CALSIM is also limited by its geographic coverage. For CALSIM II to be a truly State-

wide model, it needs to fully cover the Bay Area, Tulare Basin (including the Friant-Kern

and Madera canals, eastside San Joaquin reservoirs, and Millerton), Yuba River Basin

(for potential water transfer opportunities), Colorado River, Colorado River and Los

Angeles aqueducts, and all local Southern California projects. Coupled with a need for

greater geographic coverage, CALSIM II should also include management options

available in California at both the regional and local levels. Inter– and intra-agency water

transfers are now commonplace, as are other management options such as groundwater

banking (e.g., aquifer-storage-recovery), conjunctive use, desalination, and water

conservation. Accordingly, to effectively simulate the array of potential water operations

available within the State, CALSIM II needs to include a wider range of management

options, facilities, and regions. It is vital that those involved in the management of

California‟s water be able to analyze how local, regional, and state facilities and options

best go together. California does not currently have a model or modeling framework

capable of such integrated analysis, to parallel the kinds of integrated management

thinking being pursued at local, regional, and statewide levels (Ferreira et al., 2005).

CALSIM II is also currently lacking in its ability to perform hydropower computations,

which is an important component of the federal CVP system. This should ideally include

risk-based power capacity evaluation, and possibly incorporate the ISM (indexed

sequential hydrologic modeling) method that Reclamation has used for many years in

hydropower capacity analysis. Also, hydropower should not simply be an after-the-fact

calculation as it is with the use of the Long-Term Gen Model, but explicitly included in

the system objectives and incorporated into CALSIM II.


5.0-21

With respect to groundwater, CALSIM II is acknowledged as being significantly limited.

Groundwater is modeled as a series of inter-connected lumped-parameter basins.

Groundwater pumping, recharge from irrigation, stream-aquifer interaction and inter-

basin flow are calculated dynamically by the model. The purpose of the multi-cell

groundwater model is to better represent groundwater levels in the vicinity of the streams

to better estimate stream gains and losses to aquifers.

In the Sacramento Valley, groundwater is explicitly modeled in CALSIM II using a

multiple-cell approach based on Drainage Service Area (DSA) boundaries. For the

Sacramento Valley, there are a total of 14 groundwater cells. Currently, no multi-cell

model has been developed for the San Joaquin Valley. Instead, stream-aquifer interaction

is estimated from historical stream gage data. These flows are fixed and are not

dynamically varied according to stream flows or groundwater elevation.

Groundwater availability from aquifers is poorly represented in the model. This results

from the fact that aquifers in the northern part of the state (Sacramento Valley) have not

been thoroughly investigated regarding their storage and recharge characteristics. Thus,

in the model, upper bounds on potential pumping from aquifers remain undefined.

Realistic upper bounds to pumping from any of the aquifers represented in the model

need to be developed and implemented. In addition, historical groundwater pumping is

used to estimate local groundwater sources in the model; however, the information on the

historical pumping is very limited, causing these pumping rates to be very uncertain.

Improved pumping information is required and an analysis of the effect of this

uncertainty on model results needs to be conducted. In general, the level of

representation of groundwater in CALSIM II is not optimal.

Finally, CALSIM II is still relatively new and many of today‟s water managers remain

unfamiliar with its full capabilities and limitations. The fact that CALSIM II is priority-

based rather than rule-based, adds to this uncertainty, since the model‟s structure and

logic differ significantly from previous models (e.g., DWRSIM and PROSIM). The

strengths and alleged weaknesses of CALSIM II are not only technical (software, data,

and methods), but also institutional in how this model has been developed and utilized.

Nevertheless, CALSIM II remains an important component of any overall integrated

approach to impact assessment for water projects operating within the framework of the

overall CVP/SWP system. Even with its limitations, the model represents the best

available hydrological tool for assessing the impacts of new water projects within that

overall system.

5.2.3 Water Temperature Modeling

USBR has developed water temperature models for the Trinity, Sacramento, Feather, and

American rivers. The models have both reservoir and river components to simulate water


5.0-22

temperatures in five major reservoirs (Trinity, Whiskeytown, Shasta, Oroville, and

Folsom); four downstream regulating reservoirs (Lewiston, Keswick, Thermalito, and

Natoma); and four main river systems (Trinity, Sacramento, Feather, and American).

The following sections provide additional detail regarding the reservoir and river

components of the water temperature models, respectively. Additional details regarding

USBR‟s water temperature models are well documented in the Central Valley Project

Improvement Act (CVPIA) Draft Programmatic EIS Technical Appendix, Volume Nine.

These water temperature models also are documented in the report titled: U.S. Bureau of

Reclamation Monthly Temperature Model Sacramento River Basin. The water

temperature information from these documents is hereby incorporated by reference and is

briefly summarized below. Copies of these documents are available for review at the

offices of the El Dorado County Water Agency located at 3932 Ponderosa Road, Suite

200, Shingle Springs, CA 95682.

5.2.3.1 USBR’s Reservoir Water Temperature Models

USBR‟s reservoir models simulate monthly water temperature profiles in five major

reservoirs: Trinity, Whiskeytown, Shasta, Oroville, and Folsom. The vertical water

temperature profile in each reservoir is simulated in one dimension using monthly

storage, inflow and outflow water temperatures and flow rates, evaporation, precipitation,

solar radiation, and average air temperature. The models also compute the water

temperatures of dam releases. Release water temperature control measures in reservoirs,

such as the penstock shutters in Folsom Reservoir and the temperature control device

(TCD) in Shasta Reservoir, are incorporated into the models.

Reservoir inflows, outflows, and end-of-month storage calculated by CALSIM II and

post-processing applications are input into the reservoir water temperature models.

Additional input data include meteorological information and monthly water temperature

targets that are used by the model to select the level from which reservoir releases are

drawn. Water TCDs, such as the outlet control device in Shasta Dam, the temperature

curtains in Whiskeytown Dam, and the penstock shutters in Folsom Dam, are

incorporated into the simulation. Model output includes reservoir water temperature

profiles and water temperatures of the reservoir releases. The reservoir release water

temperatures are then used in the downstream river water temperature models, as

described in the next section.

Automated Temperature Selection Procedure

The Automated Temperature Selection Procedure (ATSP), developed by HDR|SWRI,

works with the Folsom Reservoir temperature model to optimize the use of Folsom

Reservoir‟s cold water pool throughout the year for the benefit of downstream aquatic

resources. The procedure starts with multiple sets of monthly temperature targets on the


5.0-23

American River at Watt Avenue. These targets are designed to provide the optimum

biological benefit throughout the year to the downstream aquatic resources for varying

levels of cold water availability. The procedure selects a set of targets for each year and

runs the Folsom Reservoir temperature model for the period of record. The results are

then compared to the targets for each year to see if they were met. If the targets were

met, a new set with higher biological benefit is selected; if they are not met, a new set

with lower biological benefit is selected. Each year is treated independently, that is, each

year has its own set of targets based on the specific characteristics of that year that may

be different from any other year. The procedure continues until the selected targets each

year represent the highest level of biological benefit that can be met for that year.

EID Temperature Control Device

The Folsom Reservoir temperature model does not explicitly model any TCD on the EID

diversion; however the model does include a TCD on the main downstream release

outlets and at the Folsom Pump Station. The input for the Folsom Reservoir temperature

model is generated by a utility that reads flow data from the CALSIM II output and

prepares the inputs for the temperature model. To implement an EID TCD, under future

cumulative conditions, the CALSIM II output is copied and the EID diversion is added to

the flow of the Folsom Pump Station then set to 0 to create a “virtual” CALSIM II output

that can be read by the utility to generate the Folsom Reservoir Temperature model input.

The effect is that the Folsom Temperature model will now route the EID diversion

through the Folsom Pump Station TCD as an approximation of a TCD on the EID

diversion. The volume of the release to the American River is not changed and the water

balance is maintained at Folsom Reservoir.

5.2.3.2 USBR’s River Water Temperature Models

USBR‟s river water temperature models utilize the calculated temperatures of reservoir

releases, much of the same meteorological data used in the reservoir models, and

CALSIM II outputs for river flow rates, gains and water diversions. Mean monthly water

temperatures are calculated at multiple locations on the Sacramento, Feather, and

American rivers.

Reservoir release rates and water temperatures are the boundary conditions for the river

water temperature models. The river water temperature models compute water

temperatures at 52 locations on the Sacramento River from Keswick Dam to Freeport,

and at multiple locations on the Feather and American rivers. The river water

temperature models also calculate water temperatures within Lewiston, Keswick,

Thermalito, and Natoma reservoirs. The models are used to estimate water temperatures

in these reservoirs because they are relatively small bodies of water with short residence


5.0-24

times; thereby, on a monthly basis, the reservoirs act as if they have physical

characteristics approximating those of riverine environments.

5.2.4 Early Life Stage Salmon Mortality Modeling

USBR‟s Early Life Stage Chinook Salmon Mortality Models (Salmon Mortality Models)

uses water temperatures calculated for specific reaches of the Sacramento and Feather

rivers. These are used as inputs to estimate annual mortality rates of Chinook salmon

during specific early life stages. For the Sacramento River analyses, the model estimates

mortality for each of the four Chinook salmon runs: fall, late fall, winter, and spring. For

the Feather River analyses, the model1 produces estimates of only fall-run Chinook

salmon mortality. Since hydrologic conditions in the Yuba River are not characterized in

USBR‟s current Salmon Mortality Models, it is not possible to estimate changes in early

life stage mortality for Chinook salmon in the lower Yuba River using this modeling tool.

The Salmon Mortality Models produce a single estimate of early life stage Chinook

salmon mortality in each river for each year of the simulation. The overall salmon

mortality estimate consolidates estimates of mortality for three separate Chinook salmon

early life stages: (1) pre-spawned (in utero) eggs; (2) fertilized eggs; and (3) pre-

emergent fry. The mortality estimates are computed using output water temperatures

from USBR‟s water temperature models as inputs to the Salmon Mortality Models.

Thermal units (TUs), defined as the difference between river water temperatures and

32°F, are used by the Salmon Mortality Models to track life stage development, and are

accounted for on a daily basis. For example, incubating eggs exposed to 40°F water for

one day would experience 8 TUs. Fertilized eggs are assumed to hatch after exposure to

750 TUs. Fry are assumed to emerge from the gravel after being exposed to an additional

750 TUs following hatching.

Since the models are early life stage based, that is, they are limited to calculating

mortality during the early life stages; they do not evaluate potential impacts to later life

stages, such as recently emerged fry, juvenile out-migrants, smolts, or adults.

Additionally, the models do not directly consider factors other than water temperature

that may affect early life stage mortality, such as adult pre-spawn mortality, instream

flow fluctuations, redd superimposition, and predation.

1 For the purposes of improved technical accuracy and analytical rigor, simulated Chinook salmon early life stage

survival estimates specific to the Feather River are derived from a revised version of Reclamation‟s Salmon

Mortality Model (2004), which incorporates new data associated with: (1) temporal spawning and pre-spawning

distributions; and (2) mean daily water temperature data in the Feather River. Although the updated Feather River

information serving as input into the model deviates slightly from that which was used in Reclamation‟s OCAP BA,

both versions of the model are intended for planning purposes only, and thus should not be used as an indication of

actual real-time in-river conditions. Because a certain level of bias is inherently incorporated into these types of

planning models, such bias is uniformly distributed across all modeled simulations, including both the Project

Alternatives and the bases of comparison, regardless of which version of the model is utilized.


5.0-25

Since the Salmon Mortality Models operate on a daily time-step, a procedure is required

to convert the monthly water temperature output from the water temperature models into

daily water temperatures. The Salmon Mortality Models compute daily water

temperatures based on the assumption that average monthly water temperature occurs on

the 15th of each month, and interpolate daily values from mid-month to mid-month.

Output from the Salmon Mortality Models provide estimates of annual (rather than

monthly mean) losses of emergent fry from egg potential (i.e., all eggs brought to the

river by spawning adults)

5.2.5 Long-Term GEN Hydropower Model

The Long Term Gen Model is a CVP power model developed to estimate the CVP power

generation, capacity, and project use (i.e., CVP usage) based on the operations defined by

a CALSIM II simulation. Created using Microsoft‟s Excel spreadsheet with extensive

Visual Basic programming, the Long Term Gen Model computes monthly generation,

capacity, and project use (e.g., pumping power demand) for each CVP power facility for

each month of the CALSIM II simulation.

The Long Term Gen Model does not compute the energy requirement or loads at the EID

pumping plant directly. It does, however, compute the pumping power requirements for

the diversion at CALSIM Node 8, which represents several diversions from Folsom

Reservoir, including the EID diversion.

5.2.6 Historical Hydrology – Projected Application

The period of record used in the hydrologic modeling for this EIR extended for the water

years from 1921 through 2003 (82-years). The period of record for the water temperature

modeling extended from water years 1923 through 2003 (81-years). Similarly, early life

stage salmon mortality modeling also used an 81-year period of record. As discussed

previously, these periods, based on the historic hydrologic record, are deemed to be

representative of the natural variation in hydrology that is characteristic of California in

recent times. It includes dry-periods (1928-1934 and 1977), wet-periods (1986), and

variations in between. Extended drought, periods of high precipitation and resultant

runoff, as well as “normal” water years are included in this period of record.

5.2.7 ResSim and CALSIM II Model Simulations Used in this EIR

The proposed project, as defined, as well as the range of alternatives that were carried

forward for detailed analysis in the EIR was correlated with specific ResSim and

CALSIM II simulations (i.e., model runs). Each of the model runs are set out in Table

5.2.7-1 and 5.2.7-2 below.


5.0-26

Table 5.2.7-1

ResSim Model Runs

Correlated with the EIR Proposed Project and Alternatives

Model

Run

Corresponding Model

Simulation Label

Used in EIR

Details of Model Run

Base Condition

Run 1 Base Condition (0 AFA Total Increment)

Base Condition hydrology at 2005

Proposed Project Runs

Run 2 Proposed Project “B”

(40,000 AFA Total Increment)

Modeled as 40,000 AFA diversion at White Rock

Penstock

Run 3 Proposed Project “C”



Penstock (assumed 10,000 AFA diverted at

American River Pump Station)

Alternatives Runs

Run 4 Reduced Project

Alternative “B-2”



Penstock


Alternative “C-2”



Penstock (assumed 5,000 AFA diverted at American

River Pump Station)

Future Cumulative Runs

As there are no anticipated projects or changes in future diversions in the Upper

American River basin that have not already been included in the Settlement Agreement

and made part of the ResSim Base Condition. Accordingly, no ResSim Future

Cumulative Modeling runs were modeled.

Note: The “B” and “C” postscripts represent permutations of the proposed project from a ResSim modeling perspective since the

options for diversion, as defined by the project, are several. The proposed project includes the flexibility to divert all of the water at

the White Rock Penstock or, partition the diversions between Folsom Reservoir and the American River Pump Station.


5.0-27

Table 5.2.7-2

CALSIM II Model Runs

Correlated with the EIR Proposed Project and Alternatives

Model

Run

Corresponding Model

Simulation Label

Used in EIR

Details of Model Run

Base Condition

Run 1 Base Condition (0 AFA Total Increment)

Base Condition hydrology at 2005

Proposed Project Model Runs

Run 2 Proposed Project “A”


Modeled as 30,000 AFA direct depletion from

Folsom Reservoir; and, Modeled as 10,000 AFA less

inflow into Folsom Reservoir (assumed diverted at


Run 3 Proposed Project “B”

(40,000 AFA Total Increment) Modeled as 40,000

AFA less inflow into Folsom Reservoir (assumed

diverted at Whiterock Penstock)

Alternatives Model Runs


Alternative “A-2”







Alternative “B-2”


Modeled as 20,000 AFA less inflow into Folsom

Reservoir (assumed diverted at Whiterock Penstock)

Future Cumulative Model Runs

Run 6 Future Cumulative

Condition





Run 7

Future Cumulative

Condition without

Proposed Project “A”

Modeled without 30,000 AFA direct depletion from

Folsom Reservoir; and, Modeled without 10,000

AFA less inflow into Folsom Reservoir (assumed

diverted at American River Pump Station)

Note: The “A” and “B” postscripts represent permutations of the proposed project from a CALSIM modeling perspective since the options for diversion, as defined by the project, are several. The proposed project includes the flexibility to divert all of the water at

the Whiterock Penstock or, partition the diversions between Folsom Reservoir and the American River Pump Station.


5.0-28

The various modeling runs shown above covered hydrologically, the collective suite of

alternatives that were carried forward for analysis in the EIR. This is because the

alternatives, by definition, can only result in so many permutations of water withdrawal

(or depletion) from the system simulated by the mass balance comparative hydrology that

is captured by ResSim and CALSIM II.

As noted previously, the use of ResSim and CALSIM II modeling output is premised on

a comparative analysis between model runs. Model output is generated showing the

differences between model runs. Each pairing or coupling of model runs provides a level

of hydrologic evaluation that is then correlated to the specific alternatives under review.

ResSim

ResSim model run comparisons used in the EIR are as follows:

Run 1 versus Run 2 – Proposed Project “B” Simulation

Run 1 versus Run 3 – Proposed Project “C” Simulation

Run 1 versus Run 4 – Reduced Project Alternative “B-2” Simulation

Run 1 versus Run 5 – Reduced Project Alternative “C-2” Simulation

Run 1 versus Run 2 – Future Cumulative Condition Simulation

(Same as Proposed Project “B” Simulation)

As there are no anticipated projects or changes in future diversions in the Upper

American River basin that have not already been included in the Settlement Agreement

and made part of the ResSim Base Condition. Accordingly, no ResSim Future

Cumulative Modeling runs were modeled.

CALSIM II

CALSIM II model run comparisons used in the EIR are as follows:

Run 1 versus Run 2 – Proposed Project “A” Simulation

Run 1 versus Run 3 – Proposed Project “B” Simulation

Run 1 versus Run 4 – Reduced Project Alternative “A-2” Simulation

Run 1 versus Run 5 – Reduced Project Alternative “B-2” Simulation

Run 1 versus Run 6 – Future Cumulative Condition Simulation

Run 6 versus Run 7 – Proposed Project Increment under Future Cumulative

Condition


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Each model run represented a specific condition (e.g., Base Condition, proposed project,

etc.). For CEQA analytical purposes, model runs were compared against each other

depending on whether the proposed project or alternatives were being evaluated. The

following identifies which model run(s) were used, in which comparison, for each of the

proposed project and alternative evaluations for both ResSim and CALSIM II analyses.

Proposed Project

ResSim

Run 1 (Base Condition) versus Run 2 (Proposed Project "B")

Run 1 (Base Condition) versus Run 3 (Proposed Project "C")

CALSIM II

Run 1 (Base Condition) versus Run 2 (Proposed Project "A")


Alternative 1

(No modeling was undertaken - Impacts were inferred from the modeling output for

Alternative 2)

Alternative 2

ResSim

Run 1 (Base Condition) versus Run 4 (Reduced Project Alternative "B-2")

Run 1 (Base Condition) versus Run 5 (Reduced Project Alternative "C-2")

CALSIM II

Run 1 (Base Condition) versus Run 4 (Reduced Project Alternative "A-2")

Run 1 (Base Condition) versus Run 5 (Reduced Project Alternative "B-2")

Alternative 3

ResSim




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CALSIM II



Alternative 4

ResSim



CALSIM II



Alternative 8

ResSim



CALSIM II



5.2.8 Impact Thresholds – Frequency and Magnitude

CEQA defines a significant effect as a substantial, or potentially substantial, adverse

change in the environment (Public Resources Code § 21068). CEQA (Public Resources

Code § 21083(b)(1)) stipulates that a “significant effect on the environment” could occur

when “[a] proposed project has the potential to degrade the quality of the environment,

curtail the range of the environment, or to achieve short-term, to the disadvantage of

long-term, environmental goals.” Section 15065(a) of the Guidelines Implementing

CEQA (Guidelines Guidelines) directs that additional significant effects on the

environment be found where a “project has the potential to: . . . substantially reduce the

habitat of a fish or wildlife species; cause a fish or wildlife population to drop below self-

sustaining levels,; threaten to eliminate a plant or animal community; substantially


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reduce the number or restrict the range of an endangered, rare or threatened species; or

eliminate important examples of the major periods of California history or prehistory.”

The Guidelines implementing CEQA direct that scientific data and factual data form the

basis for significance determination. The impact discussion in each of the following

subchapters identifies the specific criteria for determining the significance of a particular

impact. The significance criteria are consistent with the intent of the Guidelines

implementing CEQA. The State CEQA Guidelines (§ 15382) recognize a significant

effect on the environment as:

“….substantial, or potentially substantial adverse change in any of the physical

conditions within the area affected by the project including land, air, water, minerals,

flora, fauna, ambient noise, and objects of historic or aesthetic significance. An

economic or social change by itself shall not be considered a significant effect on the

environment. A social or economic change related to a physical change may be

considered in determining whether the physical change is significant.”

Modeling data used to assess potential impacts to water-related resources provided the

opportunity to evaluate effects from both a temporal and severity perspective. The

historic hydrologic record (i.e., 83-years) provided the temporal basis for assessment; that

is, the monthly differences in hydrology between the baseline and the proposed project

(or alternatives) could be viewed over an 83-year period. A review of the entire period of

record facilitated the assessment of how frequent such incursions would be. In any

individual year, the quantitative comparison in modeling output between the baseline and

the proposed project (or alternatives) provided the severity or magnitude of effect. From

this perspective, both magnitude and frequency were important considerations in the

determination of impact significance, as defined by CEQA.

5.3 Non-Diversion-Related Impact Evaluation

As established under CEQA case law, potential secondary (or indirect) impacts

associated with a project are the result of activities and/or conditions in the natural or

man-made environment that would or could arise from full implementation of the

proposed project. These impacts are separate, and distinctive from the direct impacts of

the project. Such indirect effects have been ascribed the “but for” test, that is, their

increment of effect would not occur, but for, the current proposed project. Common

examples of indirect effects include increased traffic, reduced air quality, or increased

soil erosion.


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Indirect or non-diversion related impacts could potentially affect the following resources:

Land Use/Urban Development

Transportation/Traffic

Air Quality

Noise

Geology and Soils

Visual Resources

Terrestrial Resources

Recreational Resources (non-water related)

Cultural Resources (non-water related)

It is typical in water acquisition projects (e.g., new water entitlements), regardless of

type, that the potential indirect effects associated with delivering the water to the

proposed service areas (i.e., intended places of use) as well as the changed conditions

within those areas be addressed in the required CEQA document for the water

acquisition. This increased level of assessment is necessary because, as part of the whole

project (e.g., an important concept in CEQA), a water acquisition project per se, cannot

be limited to looking only at the direct effects (i.e., hydrological) of its action; it must

follow the water supply to its ultimate end user. An environmental analysis that does so

will adequately capture the potential effects of the project in its entirety.

The level of detail, however, with which such indirect effects can, and should be assessed

in water acquisition projects, varies depending on the project. In some projects, there is

ample information on the mechanisms by which a new water supply would be diverted,

conveyed, treated, and ultimately distributed to the end users. In some cases, actual

facility and linear footprints of the conveyance routes (that is, siting locations) are

available. More commonly, however, since water acquisition projects represent only the

first phase of a larger and longer-term water supply planning effort, these secondary

actions (i.e., facilities) are not well defined. In many cases, these secondary actions are

years and, in fact, sometimes as long as a decade or more away from funding, planning,

and environmental review, let alone construction and implementation. In those typical

situations, it is difficult and inappropriate, consistent with CEQA, to speculate on where

and how such infrastructure/facilities would be placed and operated.

As discussed previously, for this EIR, a project-level analysis of the new water

acquisition was performed; that is, a detailed evaluation of the hydrological effects of the


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new water right on all those waterbodies and watercourses potentially affected by the

proposed diversion withdrawals.

At a more general level, indirect or secondary impacts were evaluated and included those

resources categorized as being non-diversion related; that is, they are not part of the

hydrological system. Accordingly, while it is accepted that new diversion, conveyance,

and treatment facilities are not required to grant the new water rights sought by this

project, because of the potential for the future construction of such facilities, the potential

impacts of such facilities, to the extent known, were disclosed and discussed generally at

a program-level.

Using this context, the EIR addressed the areas between the proposed points of new

diversion and the existing service areas of EID and GDPUD, including those delineated

“Favorable Areas” that have been made a part of the proposed intended place of use.

Baseline information that exists today was reviewed and used to evaluate the potential

effects to these non-diversion related resources based on a generalized consideration of

typical construction-related activities for these types of facilities. Reference to existing

General Plan and other County policies, ordinances, and guidelines as well as State

and/or federal agency protocols that govern the practices (e.g., BMPs) of construction-

related activities were made, as appropriate. The EIR acknowledges and provide the

background for future site-specific projects if, or when new infrastructure are proposed;

the EIR also clearly acknowledges that such actions would require separate and

independent environmental reviews of the precise facility features and seek to obtain all

necessary associated permits (e.g., Streambed Alteration Agreement, Encroachment

Permit, Authority to Operate, etc.) at that time.

Accordingly, no linear footprints of facilities are presented for analysis in this EIR.

Moreover, no on-the-ground field surveys were conducted for this EIR.

Within the service areas, a wide range of non-diversion related resources (e.g., land use,

traffic, soils, recreation, utilities, etc.) were assessed, again at this more general level of

evaluation. This assessment included the various facilities, activities, land uses and other

potentially affected resources within the service areas that are typically part of ongoing

development activities within urban and rural areas and are typical of those found within

the EID and GDPUD service areas. Since the current project would be contributing to

these indirect effects, a generalized discussion is warranted.

It is important to note, however, that such activities, land uses, and resources have

already been fully analyzed in the adopted El Dorado County General Plan and EIR,

upon which this EIR relies. No adverse effects to in-county resources or activities would

occur as an indirect result of this current project that was not, or has not been already

examined in the El Dorado County General Plan and EIR, and ensuing amendments.


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This EIR, therefore, only summarizes and discuss those findings. The EIR does not

attempt to fully re-examine the precise impacts of growth on the environment anticipated

to occur as a result of future development County-wide or, even of this project. As noted,

this is because the physical environmental effects of urban development have already

been appropriately evaluated, across all resources, in the El Dorado County General Plan

and accompanying EIR and the various resource programs that have developed since the

adoption of the General Plan. The General Plan and accompanying EIR fulfilled its

requirements under CEQA and serves as the appropriate evaluation of and validation for

anticipated growth-related effects within the County.

Documents

5.0 IMPACT ASSESSMENT METHODOLGY