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FINAL Supplemental EIS/EIR

Acquisition of Additional Water for Meeting the San Joaquin River Agreement Flow Objectives, 2000 – 2010

3. PROJECT AREA AND SCOPE OF ANALYSIS

This chapter presents a general description of the physical environment of the Project Area and vicinity. The existing condition of resources (which sets the baseline against which the Proposed Action is evaluated) and the environmental consequences and mitigation measures are described by resource in Chapters 4 through 14.

3.1 GENERAL DESCRIPTION OF PROJECT AREA AND WILLING SELLERS

As described in Section 2.2.1, the immediate Project Area is comprised of portions of the Stanislaus, Tuolumne, and Merced rivers and the San Joaquin River from Vernalis to its confluence with the Merced River. These are the primary rivers that would be affected by the supplemental water. The points of release occur at two reservoirs: New Don Pedro Reservoir on the Tuolumne River and Lake McClure on the Merced River. These rivers and related storage and conveyance facilities are located between the community of Vernalis in the north and the city of Merced in the southeast.

3.1.1 Project Area and Vicinity

As described in the Meeting Flow Objectives for the San Joaquin River Agreement, 1999-2010, Final Environmental Impact Statement and Environmental Impact Report (Final EIS/EIR, Reclamation 1999), inflows from the Merced, Tuolumne, and Stanislaus rivers historically contribute more than 60 percent of the flows in the San Joaquin River, as measured at Vernalis. The San Joaquin River enters the Delta at Vernalis, which is widely used as a monitoring point for Delta inflows and standards. The U.S. Geological Survey has operated a gaging station on the San Joaquin River near the community of Vernalis (Station 11303500) since 1922 (CALFED 1998).

The rivers in the Project Area are highly managed due to extensive water supply, hydroelectric, and flood control projects. As a result, the aquatic resources have undergone significant changes. Of concern is the protection and enhancement of important species, such as chinook salmon, and the adjacent riparian habitat which supports numerous plants and animals including some rare, threatened, and endangered species. Fall-run Chinook salmon inhabit the three tributaries to the San Joaquin River during spawning and development stages of their life cycle. The ecological health of the Project Area rivers in the San Joaquin River Basin is important to the health of the Bay-Delta Estuary.

Land uses within the Project Area are primarily open space, agriculture, and recreation. Agricultural lands are often adjacent to the river corridors. The two reservoirs in the Project Area are used for a variety of purposes: water supply (domestic as well as irrigation), regulation of river flows including flood control, hydroelectric power generation, and recreation. Recreation activities at Project Area reservoirs and rivers include boating, fishing, swimming, picnicking, camping, hunting, and wildlife observation.

The affected environment described in the following chapters cover not only the immediate area of direct Project impact but also the Project Area vicinity and adjacent areas that could potentially experience indirect impacts, such as the larger San Joaquin River Basin and the Bay-Delta Estuary. Definition of the larger area, such as the San Joaquin River Region, varies depending on the source of information. Groundwater in the basin is used for municipal, industrial, and agricultural purposes. Cultural resources in the San Joaquin River Region have been documented from the excavation of reservoirs and other sites to reveal numerous prehistoric resource locations. Agriculture and mining activities characterize historic resources.

The water supply for supplemental flows for Vernalis Adaptive Management Plan is to be provided by the process as identified in the San Joaquin River Agreement (SJRA) and reported in Section 2.2. Members of the San Joaquin River Group Authority (SJRGA) who may be providing water stored in their respective reservoirs for release to the San Joaquin River system include Modesto Irrigation District (MID), Turlock Irrigation District (TID), and Merced Irrigation District (Merced ID). The service areas of these districts are shown on Figure 3.1-1 of the Final EIS/EIR. Annual surface water and groundwater use by the SJRCA’s willing sellers is shown in Table 3-1. Each willing seller is introduced in the following sections.

Table 3-1
Surface and Groundwater Use by Willing Sellers (acre-feet per year)

Notes:

¹ The operations of TID, MID and Merced ID are supported by a variety of water rights, including pre-1914 appropriations and riparian rights in addition to post-1914 licenses issued by the State Water Resources Control Board. Absent an adjudication, it is not possible to identify the maximum amount of water available. However, The MID/TID water diversion varies between 900,000 and 1,100,000 acre-feet per year.

² TID usage based on 25-year average (1973-1997).

³ Merced ID average annual diversion since completion of New Exchequer Dam, 1968-2000.

⁴ Groundwater use is by district.

⁵ In 1993, Merced ID implemented new groundwater management practices. Since 1993 the average annual groundwater pumped has been 10,000 acre-feet. During the consecutive Critical years of 1988-1992 the average annual groundwater pumped was 78,000 acre-feet. For the period of 1978-1987, the average annual groundwater pumped was 27,000 acre-feet, with a range from 22,000 to 35,000 acre-feet. The maximum groundwater pumped in a single year was 180,000 acre-feet in 1976.

3.1.2 Willing Sellers on the Tuolumne River

3.1.2.1 Modesto Irrigation District

Organized in 1887, MID is located in Stanislaus County on the east side of the San Joaquin Valley. MID encompasses a 108,000-acre service area and supplies surface water, groundwater, and electrical service to agricultural (64,000 irrigated acres) and municipal users including the cities of Waterford, Empire, Modesto, and Salida. The primary economy in MID is agriculture and agricultural-related businesses, and the primary crops are trees (primarily almond), vines, grain, row, and pasture. The average farm size is 20 acres, and approximately 3,200 farms are within MID (MID 1996). MID has pre-1914 and post-1914 water rights.

3.1.2.2 Turlock Irrigation District

Organized in 1887, TID is located on the east side of the San Joaquin Valley, and it encompasses portions of Stanislaus and Merced counties. TID’s service area covers 272,000 acres and includes the cities of Turlock, Ceres, Hughson, part of Modesto, and the unincorporated communities of Keyes, Denair, Hickman, Delhi, and Hilmar. Over the past 25 years, TID has provided on average 498,000 acre-feet of water to irrigators for 149,000 acres. The primary agricultural crops grown in TID include almonds, tomatoes, walnuts, peaches, grapes, and melons (Stanislaus County General Plan 1994). TID also generates hydroelectricity within its service area. TID has a firm supply of developed surface water and operates surface diversions from the Tuolumne River. TID jointly operates the New Don Pedro Reservoir with MID. Surface water accounts for about 81 percent of the total delivery for irrigation (TID 1997).

3.1.3 Willing Sellers on the Merced River

3.1.3.1 Merced Irrigation District

Organized in 1919, the Merced ID is located on the east side of the San Joaquin Valley in Merced County. Merced has a firm supply of developed surface water and operates surface diversions from the Merced River. More than 140,000 acres are located within Merced ID’s boundaries, of which approximately 70 percent are irrigated with Merced ID water (Merced ID 1998). Merced ID uses surface and groundwater to supply approximately 522,000 acre-feet per year to irrigation customers. Surface water accounts for about 95 percent of the total delivery (Van Camp, pers. comm., 1998). Agricultural crops grown within the Merced ID service area include almonds (nearly 12,000 acres), corn (nearly 10,000 acres), alfalfa and cotton (nearly 8,000 acres each) (Merced ID 1998).

3.2 SCOPE OF ANALYSIS

This document is a Supplemental EIS/EIR (SEIS/EIR) covering minor additions to the project addressed in the Final EIS/EIR (Reclamation 1999). As explained in Chapter 2, the Proposed Project is the provision of additional or "supplemental" water for the Spring Pulse Flow above the amount evaluated in the previous EIS/EIR. As noted in the Final EIS/EIR (p. 2-5): "If achieving the double-step requires more than the 110,000 acre-feet of supplemental water, additional water from willing sellers on the San Joaquin, Stanislaus, Tuolumne, and Merced rivers (approximately 50,000 acre-feet) may be acquired by the U.S. Bureau of Reclamation (Reclamation) for the Spring Pulse Flow period, and it would require additional [National Environmental Policy Act/California Environmental Quality Act] NEPA/CEQA analysis." Hydrologic events since release of the Final EIS/EIR required additional documentation in 1999 and in 2000, although the additional water was not needed in 2000.

This SEIS/EIR is organized to address the same environmental resources covered in the Final EIS/EIR: surface water resources, groundwater resources, terrestrial resources, aquatic resources, land uses, cultural resources, recreation, energy resources, Indian Trust Assets, environmental justice, and cumulative effects. The Final EIS/EIR is incorporated into this document by reference. Key sections are summarized sufficiently to permit a reasonable analysis of impacts. Because the SJRA flow objectives were approved in 1999 and confirmed in the State Water Resources Control Board's (1999) Water Right Decision 1641, the SJRA is now part of the No Action/existing condition baseline used for the analysis of environmental impacts in this SEIS/EIR. However, the hydrologic analysis in Appendix A includes a non-SJRA setting.

Furthermore, the analysis herein is for a specific project: supplemental water provided from carry-over storage in two reservoirs, New Don Pedro and Lake McClure. In the absence of the Proposed Project, this water would be released at a future date as flood control releases and spills and/or as discretionary releases above the minimum flow requirement. The water from carry-over storage results from a combination of water years with the hydrologic condition that prompts a double-step target flow that would exceed the 110,000 acre-feet provided in the SJRA. As such, it does not represent water that would be available for sale, transfer, or use by current water users in the willing sellers' districts on an annual or ongoing basis. The environmental impact analysis does not speculate on alternative uses, because the Proposed Project/Action is not a project for management of excess water on an annual basis.

3.3 DETERMINATION OF IMPACT AND MITIGATION

The environmental consequences of the alternatives are classified into the following impact categories:

• Significant. Significant adverse environmental impacts are those that can be clearly identified as significant based on the criteria identified for each resource area. There is no mitigation available to reduce the impact too less than significant.
• Potentially Significant. Adverse impacts have been identified that have the potential to be significant. In the absence of sufficient information to determine that the potential impact is less than significant, the impact is treated as significant. Also, if the potentially significant impact cannot be mitigated to a less-than-significant level, then it is considered significant.
• Less Than Significant. This type of adverse impact is determined to be small or insignificant based on the criteria identified for each resource area. This type of environmental effect is usually short term or measurably small. It may or may not contribute to a cumulative impact over the long term.
• No Impact. Using the criteria for determining significance of impact, this category means that no adverse impact can be identified. There is no adverse physical change that can be determined based on available information.
• Beneficial. The environmental consequences are positive or otherwise beneficial to the resource. A beneficial impact may be further described as a significant beneficial impact when the magnitude of the positive effect is large.

This classification system is based on criteria contained in the CEQA Guidelines (OPR 1998) and others explained in the first section under each resource category. Both qualitative and quantitative thresholds of significance are used, consistent with Section 15064 of the CEQA Guidelines, depending on the resource and the availability of measurable standards. The NEPA criteria for significance listed in 40 CFR 1508.27 are broader and less stringent than the CEQA criteria. They are also incorporated in the CEQA criteria. For these reasons, identification of impacts as significant under CEQA will identify all impacts that would be significant under NEPA, and any required mitigation measures set forth to deal with CEQA significant impacts would also mitigate NEPA significant impacts.

Adverse and beneficial impacts can be direct (primary), indirect (secondary), short term, long term, and/or cumulative. Cumulative impacts are those created as a result of the combination of Proposed Project/Action together with other projects/actions causing related impacts. Cumulative as well as unavoidable impacts, irreversible commitments of resources, and the relationship between short-term uses and long-term productivity are described in Chapters 14 through 18 following the affected environment and impact evaluation sections for each resource area.

Mitigation measures to reduce significant adverse impacts to a less-than-significant level are specific, feasible actions that will improve or mollify adverse conditions. A mitigation measure is feasible if it can be accomplished in a successful manner within a reasonable period of time, taking into consideration economic, environmental, legal, social, and technological factors.

According to Section 15370 of the CEQA EIR Guidelines and Section 1508.20 of the CEQA regulations for implementation of NEPA, the term "mitigation" includes:

• Avoiding the impact altogether by not taking a certain action or parts of an action.
• Minimizing impacts by limiting the degree of magnitude of the action and its implementation.
• Rectifying the impact by repairing, rehabilitating, or restoring the impacted environment.
• Reducing or eliminating the impact over time by preservation and maintenance operations during the life of the action.
• Compensating for the impacts by replacing or providing substitute resources or environments.

Impacts that are less than significant or not significant (no impact) do not require mitigation. Impacts that are potentially significant that can be mitigated, and the feasible mitigation measures, are described in Chapter 21, Mitigation Monitoring Program.