For decades, the Sacramento-San Joaquin Delta has been the focal point for a wide variety of water-related issues, generating more investigations than any other waterway system in California. It is the hub from which two-thirds of the State's population and millions of acres of agricultural land receive part or all of their supplies. The Delta provides habitat for many species of fish, birds, mammals, and plants while also supporting extensive farming and recreational activities. Many different interests have a vital stake in the Delta: farmers, fish and wildlife groups, environmentalists, boaters, people involved with shipping and navigation, and the people and industries that receive water from the Delta and the State's two largest export systems, the State Water Project and Central Valley Project.
At the middle of the last century, the Delta, an area of nearly 750,000 acres, was mostly a tidal marsh, part of an interconnected estuary system that included the Suisun Marsh and San Francisco Bay. Until reclaimed by levees, the Delta was a great inland lake during the flood season; when the flood waters receded, the network of sloughs and channels reappeared throughout the marsh. The Delta receives runoff from over 40 percent of the State's land area, including flows from the Sacramento, San Joaquin, Mokelumne, Cosumnes, and Calaveras rivers, and their tributaries.
The Delta channels were first surveyed in 1841 and again in 1849 by Lt. Commander Cadwalader Ringgold of the U.S. Navy. These surveys helped open up the Delta and upstream communities to increased trade with the San Francisco Bay area. Already experiencing a population boom because of the Gold Rush, Delta and northern California communities expanded even more as travel to the area became easier and less expensive.
The development of today's Delta began in late 1850 when the Swamp Land Act conveyed ownership of all swamp and overflow land, including Delta marshes, from the federal government to the State. Proceeds from the State's sale of swamplands were to go toward reclaiming them. In 1861, the State legislature created the Board of Swamp and Overflowed Land Commissioners to manage reclamation projects. In 1866, the board's authority was transferred to county boards of supervisors.
Developers first thought levees about 4 feet high and 12 feet wide at the bottom would protect Delta lands from tides and river overflow. In the 1870s, small-scale reclamation projects were started on Rough and Ready Island and Roberts Island, but the peat soils showed their weakness as levee material. The peat soils would sink, blow away when dry, and develop deep cracks and fissures throughout the levee system. In the late 1870s, developers realized that hand- and horse-powered labor could not maintain the reclaimed Delta islands. Steam-powered dredges were brought in to move large volumes of alluvial soils from the river channels; the alluvial soils were needed to construct the large levees we see today. These dredges were capable of moving material at about half the cost of hand labor. After World War I, the number of operating dredges decreased greatly, as nearly all Delta marshland had been reclaimed.
Today the Delta is comprised of about 500,000 acres of rich farmland, much of which is now below sea level (see Figure 10-1), is interlaced with hundreds of miles of waterways, and relies on more than 1,000 miles of levees for protection against flooding. The interiors of some of the islands are as much as 25 feet below sea level because of the continuing loss of peat soil. Soil loss comes primarily from oxidation, compaction, and wind erosion (see Figure 10-2).
Water exports from the Delta began in 1940 after the Contra Costa Canal, a unit of the CVP, was completed. Beginning in 1951, water was exported at the CVP's Tracy Pumping Plant, supplying the Delta-Mendota Canal. The SWP began delivery of water through the South Bay Aqueduct in 1962 (through an interim connection to the CVP's Delta-Mendota Canal). The SWP then continued deliveries by pumping from the South Delta in 1967 (supplying the California Aqueduct) and from the North Delta beginning in late 1987 (supplying the North Bay Aqueduct). Export water is either uncontrolled winter runoff or is released from CVP and SWP reservoirs into the Sacramento River system north of the Delta.
To facilitate movement of Sacramento River water to pumping facilities in the South Delta, the U.S. Bureau of Reclamation completed the Delta Cross Channel in 1951. This channel connects the Sacramento River to Snodgrass Slough and the Mokelumne River system. The flow from the Sacramento River is controlled by two 60-foot gates at the Sacramento River near Walnut Grove. Downstream from the Delta Cross Channel, Georgiana Slough also connects the Sacramento River to the Mokelumne River system, moving Sacramento River water into the Central Delta.
This chapter briefly describes Delta flows, outlines key Delta issues, profiles the Delta water resources management and planning process, and presents the options presently being discussed. Some specific issues are discussed more thoroughly in context with other statewide water supply concerns in other chapters of this report. (For example, water quality concerns are discussed in Chapter 5, Water Quality.) Readers are encouraged to refer to the other chapters cited throughout this discussion.
Most Delta issues are centered around the way water moves into, through, and out of the Delta. Fresh water flows in the Delta are typically much less than those caused by tides. Twice a day Pacific Ocean tides move into and out of the Delta (see Figure 10-3). The average incoming and outgoing Delta tidal flow is about 170,000 cubic feet per second. This is in contrast to the currently permitted combined SWP and CVP export capability of about 11,000 cfs.
The average calculated Delta outflow, water that flows through the Delta past Chipps Island to San Francisco Bay, is about 30,000 cfs or about 21 maf per year. The magnitude of this flow depends on Delta inflow, export, and depletions of channel water within the Delta. During the summer months of critically dry years, Delta outflow can be as low as 3,000 cfs. Fresh water moves into the Delta from three major sources: the Sacramento River, the San Joaquin River, and eastside streams. The Sacramento River (including the Yolo Bypass) contributes about 77 percent of the fresh water flows, the San Joaquin River contributes roughly 15 percent, and streams on the east side and the Mokelumne River provide the remainder. Salty water moves into the Delta with the tides, from Suisun and Honker bays in the west. Direct Delta exports are made by the CVP, the SWP, and the City of Vallejo. Channel depletions occur due to crop irrigation, evaporation, and channel seepage in the Delta (see Figure 10-4).
Today, minimum fresh water Delta outflow is maintained by releases from upstream storage reservoirs of the SWP and CVP. This outflow establishes a hydraulic barrier to prevent ocean water from intruding deep into the Delta and affecting municipal and agricultural water supplies. The hydraulic barrier, where fresh water gradually mixes with ocean water, is generally maintained near Chipps Island. During flood flows, the hydraulic barrier moves out into the Bay.
The expression reverse flow characterizes a Delta flow problem that stems from the lack of capacity in certain channels leading to the export pumps (see Figure 10-5). CVP and SWP water supply exports are obtained from uncontrolled Delta inflows (when available) and from upstream reservoir releases when Delta inflow is low. Most of these uncontrolled flows and releases enter the Delta via the Sacramento River and then flow by various routes to the export pumps in the southern Delta. Some of these flows are drawn to the SWP and CVP pumps through interior Delta channels, facilitated by the CVP's Delta Cross Channel and a natural connection through Georgiana Slough. In some situations, these interior channels do not have enough capacity to meet Delta demands for agriculture and the demands of the pumps in the southern Delta.
The remaining water from the Sacramento River needed to meet pumping demand flows down the Sacramento River to Three-mile Slough and the western end of Sherman Island and up the San Joaquin River towards the pumps. When freshwater outflow is relatively low, water in the western Delta is brackish because fresh water from the Sacramento River mixes with saltier ocean water entering as tidal inflow from the San Francisco Bay. This water can be drawn upstream (reverse flow) into the San Joaquin River and other channels by pumping plant operations when San Joaquin River flow is low and pumping is high. The massive amount of water driven in and out of the Delta by tidal action dwarfs the actual fresh water outflow and considerably complicates the reverse flow issue. Prolonged reverse flow can deteriorate water quality in the interior Delta and at the export pumps and harm fisheries.
Currently, during operational periods of reverse flow, more water than is needed for export must be released from project reservoirs to help repel intruding sea water, maintain required water quality in the Delta, and meet export quality standards. This incremental release of water from the reservoirs is termed carriage water. Carriage water is a function of Delta export, South Delta inflow, tidal cycle, and operation of the Delta Cross Channel gates. If the Delta Cross Channel gates are closed when pumping rates are high and the Delta is under controlled conditions, more water must be released to repel salinity intrusion.
Summarized here are Bay/Delta fish and wildlife issues that are discussed in more detail in Chapter 8, Environmental Water Use. Chapter 12, Water Supply and Demand Balance, presents a range of hypothetical environmental water requirements that could provide additional Delta outflow, with the intent of improving reliability of supply for environmental protection of aquatic species in the Delta. Water diversions and their relationship to fish in the Delta are discussed here.
Delta fish are affected by a number of physical and biological problems including: inflow that is reduced by upstream uses, upstream diversions that bypass the Delta, direct diversions from the Delta itself, and changes to the food chain from the introduction of nonnative aquatic species, toxics, and legal and illegal harvest. Direct diversions include those by power plants and industries in the western Delta; 1,800 local agricultural diversions; the North Bay Aqueduct, serving the northern Bay area; the Contra Costa Canal, serving the eastern San Francisco Bay Region; and the southern Delta diversions by the CVP and the SWP, which serve the southern Bay Area, the San Joaquin Valley, and Southern California.
Fish screens and protection facilities have been constructed for the North Bay Aqueduct, the CVP's Tracy Pumping Plant, and the SWP's H.O. Banks Delta Pumping Plant. Water rights Decision 1485 mandates that the CVP and SWP exports be curtailed during certain months to protect fish and that flows be maintained for protecting the Delta environment. Concern about entrainment losses due to Delta agricultural diversions has also resulted in fish screening requirements being established in the Fish and Game Code. In April 1992, DWR implemented a three-year Delta Agricultural Diversion Evaluation Program, with the objectives of developing reliable data about entrainment, determining the susceptibility of various fish species, and testing the effectiveness of experimental fish screens. (See the Agricultural Diversion Screening section later in this chapter.) Other protections include screens and special mitigation measures for the Pacific Gas and Electric Company's power plant diversions in the western Delta. Even with these measures, the need for a better understanding of the aquatic environment and more protection is evident, because some Delta fish are continuing to decline.
The general decline of several fish, the Delta smelt and winter-run salmon in particular, has generated much concern and has ultimately resulted in both cited species being listed under the federal Endangered Species Act. Two other species, the longfin smelt and the splittail, have also been petitioned for listing. The listing of species has considerably curtailed SWP and CVP diversions from the Delta, making those supplies less reliable and more uncertain for urban and agricultural users.
Local Delta water use is protected by a number of measures, such as the Delta Protection Act, the Watershed Protection Law, and water rights. DWR negotiated additional agreements to provide protection in connection with specific local problems.
The most pressing problem in the north Delta area is repeated and extensive flooding of the leveed tracts and islands. Levee failures have become common and there have been 14 levee breaks in the north Delta since 1980. Flooding problems are not limited to the north Delta. There have been 17 levee breaks since 1980 throughout the Delta. Both the limited channel capacities and the inadequate, deteriorating nonproject, or local, levees contribute to this critical problem.
Factors that affect South Delta water levels and water availability at some local diversion points are natural tidal fluctuations, San Joaquin River inflow, local agricultural diversions and returns, inadequate channel capacities, and SWP and CVP operations. Poor San Joaquin River water quality combined with local agricultural drainage returns, aggravated by poor water circulation, has affected channel water quality, particularly in shallow, stagnant, or dead-end channels. Channels that are too shallow and narrow also restrict flow and the volume of water available for export pumping. Recently, DWR entered into an agreement with the South Delta Water Agency and the USBR to develop long-term solutions for the SDWA's water problems.
DWR negotiated several long-term agreements with various local entities to protect their use of water from adverse project impacts. To protect agricultural uses, contracts were executed with the North Delta Water Agency and the East Contra Costa Irrigation District. To protect municipal uses, contracts were negotiated with the Contra Costa Water District and the City of Antioch. Industries near Antioch and Pittsburg use offshore water for processing. DWR signed two contracts (in 1987 and 1991) with Gaylord Container Corporation. DWR occasionally pays for providing substitute water through the Contra Costa Canal when offshore water quality falls below the industries' requirements.
A Delta Protection Commission was established by the Delta Protection Act of 1992 for management of land resources within the Delta. The commission is to develop a long-term resource management plan for the Delta "Primary Zone." As stated in the Act, the goals of this regional plan are to "protect, maintain, and where possible, enhance and restore the overall quality of the Delta environment, including, but not limited to, agriculture, wildlife habitat, and recreational activities." The Act acknowledges that agricultural land within the Delta is of significant value as open space and habitat for waterfowl using the Pacific Flyway. The regional plan is to protect agricultural land within the Primary Zone from the intrusion of nonagricultural uses.
Water quality control in California is regulated by the State Water Resources Control Board. From California's water supply perspective, perhaps the most important of the State's 16 water quality basin plans funded under California's Clean Water Bond Act of 1970 is the one for the Sacramento-San Joaquin Delta. The 1975 Basin Plan provided for protection of the Delta's varied beneficial water uses through a set of water quality objectives. These water quality objectives were similar to requirements in Decision 1379 by the SWRCB, a decision pertaining to water rights for the SWP and CVP.
In August 1978, the SWRCB adopted the Water Quality Control Plan for the Sacramento-San Joaquin Delta and the Suisun Marsh (the Delta Plan) and the corresponding water right Decision 1485, subsequent to D-1379 (1971). Both documents amended water quality standards relating to salinity control and fish and wildlife protection in the San Francisco Bay-Delta estuary in the 1975 Basin Plan. D-1485 standards are generally based on the degree of protection that municipal, industrial, agricultural, and fish and wildlife uses would otherwise have experienced, had the SWP and CVP not been built. D-1485 standards required that the SWP and CVP make operational decisions to maintain Delta water quality and to meet Delta fresh-water outflow within specified limits. About 5 maf of Delta outflow is required in an average year to meet D-1485 salinity standards.
To help implement these water quality standards, D-1485 mandated an extensive monitoring program. It also called for special studies to provide critical data about major concerns in the Delta and Suisun Marsh for which information was insufficient. D-1485 included water quality standards for Suisun Marsh as well as for the Delta, requiring DWR and the USBR to develop a plan for the marsh that would ensure meeting long-term standards for full protection by October 1984 (later extended to October 1988).
Recognizing that the complexities of project operations and water quality conditions would change over time, the SWRCB also specified that the Delta water right permit hearings would be reopened, depending upon changing conditions in the Bay/Delta region and the availability of new evidence on beneficial uses of water.
The following brief discussions of the Racanelli Decision and the SWRCB Bay-Delta Proceedings are repeated from Chapter 2, Institutional Framework. These issues are vitally important to the Delta and have institutional implications.
Lawsuits by various interests challenged Decision 1485, and the decision was overturned by the trial court in 1984. Unlike its predecessor, D-1379, whose standards had been judicially stayed, D-1485 remained in effect. In 1986, the appellate court in the Racanelli Decision (named after Judge Racanelli who wrote the opinion) broadly interpreted the SWRCB's authority and obligation to establish water quality objectives and its authority to set water rights permit terms and conditions that provide reasonable protection of beneficial uses of Delta water and of San Francisco Bay. The court stated that SWRCB needed to separate its water quality planning and water rights functions. SWRCB needs to maintain a "global perspective" in identifying beneficial uses to be protected (not limited to water rights) and in allocating responsibility for implementing water quality objectives (not just to the SWP and CVP, nor only through the Board's own water rights processes). The court recognized the SWRCB's authority to look to all water rights holders to implement water quality standards and advised the Board to consider the effects of all Delta and upstream water users in setting and implementing water quality standards in the Delta, as well as those of the SWP and the CVP.
Hearings to adopt a water quality control plan and water rights decision for the Bay-Delta estuary began in July 1987. Their purpose was to develop a San Francisco Bay/Sacramento-San Joaquin Delta water quality control plan and to consider public interest issues related to Delta water rights, including implementation of water quality objectives. During the first phase of the proceedings, State and federal agencies, including DWR, public interest groups, and agricultural and urban water purveyors provided many expert witnesses to testify on a variety of issues pertaining to the reasonable and beneficial uses of the estuary's water. This phase took place over six months, and generated volumes of transcripts and exhibits.
The SWRCB released a draft Water Quality Control Plan for Salinity and Pollutant Policy Document in November 1988. However, the draft water quality control plan, a significant departure from the 1978 plan, generated considerable controversy throughout the State. The Pollutant Policy Document was subsequently adopted in June 1990.
In January 1989, the SWRCB decided to significantly amend the draft plan and redesign the hearing process. The water quality phase was to continue, an additional scoping phase would follow, and issues related to flow were to be addressed in the final water rights phase. Concurrently, DWR and other agencies offered to hold a series of workshops to address the technical concerns raised by the draft plan. These workshops were open to the public and benefited all parties involved by facilitating a thorough discussion of technical issues. After many workshops and revisions to the water quality control plan, the SWRCB adopted a final plan in May 1991. The federal EPA rejected this plan in September 1991.
With the adoption of the Water Quality Control Plan, the SWRCB began the EIR scoping phase and held several workshops during 1991 to receive testimony regarding planning activities, facilities development, negotiated settlements, and flow objectives. The goal was to adopt an EIR and a water right decision by the end of 1992.
In response to the Governor's April 1992 water policy statement, SWRCB decided to proceed with a process to establish interim Bay-Delta standards to provide immediate protection for fish and wildlife. Water right hearings were conducted from July through August 1992, and draft interim standards (proposed Water Right Decision 1630) were released for public review in December 1992. Concurrently, under the broad authority of the Endangered Species Act, the federal regulatory process was proceeding toward development of Delta standards and upstream measures applicable to the CVP and SWP for the protection of the threatened winter-run chinook salmon. In February 1993, the National Marine Fisheries Service issued a long-term biological opinion governing operations of the CVP and SWP with Delta environmental regulations that in certain months were more restrictive than SWRCB's proposed measures. On March 1, 1993, the U.S. Fish and Wildlife Service officially listed the Delta smelt as a threatened species and shortly thereafter indicated that further restrictions of CVP and SWP operations would be required.
In April 1993, the Governor asked the SWRCB to withdraw its proposed Decision 1630 and instead, to focus efforts on establishing permanent standards for protection of the Delta since recent federal actions had effectively pre-empted State interim standards and provided interim protection for the Bay-Delta environment. On December 15, 1993, EPA announced its proposed standards for the estuary in place of SWRCB water quality standards EPA had rejected in 1991; USFWS proposed to list the Sacramento splittail as a threatened species; and NMFS announced its decision to change the status of winter-run salmon from threatened to endangered.
In April 1994, the SWRCB began a series of workshops to review Delta protection standards adopted in its 1991 Water Quality Control Plan for Salinity and to examine proposed federal EPA standards issued in December 1993. These processes seek to involve both SWRCB and EPA and are intended to establish a mutually acceptable draft SWRCB Delta regulatory plan scheduled for release in December 1994. The plan will be developed in accordance with the Triennial Review requirements of the Clean Water Act.
Water quality of the Sacramento-San Joaquin Delta is generally satisfactory for agriculture. However, the quality of the Delta water could potentially pose problems to the municipal water purveyors charged with treating the water to meet anticipated federal standards for trihalomethanes and new standards for other disinfection byproducts. More stringent standards could force many water purveyors to spend billions of dollars for additional treatment.
Precursors of trihalomethane (THM) formation include naturally occurring dissolved organic matter and bromides. Dissolved organic matter is present in Delta drainage water primarily as a result of the decomposition of plants, such as the decayed Delta marsh lands. Bromide is present in sea water and is introduced into the Delta when fresh water is mixed with ocean water by tidal action. The degree to which saline water penetrates into the Delta is a function of the interaction of the high and low tides, fresh-water outflow, Delta export, diversions from the Delta channels, and atmospheric conditions.
Because THMs can potentially cause cancer, the EPA in 1979 set the standard for trihalomethanes in treated drinking water at 0.10 milligram per liter or 100 parts per billion. One ppb would be the equivalent to two drops in a large backyard swimming pool (25,000 gallons).
It will be difficult or perhaps impossible with existing facilities for water utilities to achieve compliance with stricter standards for THMs. Urban purveyors of Delta water, who serve two-thirds of the State's population, will be forced to redesign their existing water treatment facilities or limit Delta exports when water quality is not suitable unless a solution is found to improve the quality of export water for urban purveyors. Water quality considerations are presented in more detail in Chapter 5.
The reliability of Delta water supplies, in terms of water quality, could be affected by levee failures caused by poor levee maintenance, levee instability, high water, or earthquakes. Protection of certain islands in the western Delta is particularly important because water quality can be degraded by intrusion of brackish water. Large volumes of brackish water could rush into the Delta and deteriorate Delta water quality if a levee were to fail. Permanent flooding of western Delta islands could increase the upstream movement of ocean salts, requiring projects upstream of the Delta to provide more outflow to repel the salt and maintain water quality in the Delta and at the pumps.
The levees act as the only barriers between low-lying land and water in the Delta. Behind these earthen walls lie about half a million acres of agricultural land and wildlife habitat; many small communities; and numerous roads, railroad lines, and utilities. Delta islands, which commonly lie 10 to 15 feet below sea level and are composed in part of highly organic (peat) soils, are constantly in danger of further land subsidence and seepage. The original levees were constructed to heights of about 4 feet and founded on the soft, organic Delta soils. Due to continued subsidence of the levees and island interiors, it is necessary to continually add material to maintain freeboard and structural stability. Over the last century, many of the levees have significantly increased in size and now average between 15 and 25 feet high. The increasing levee height has meant an increased threat of failure which requires increasing maintenance and repair costs just to prevent further deterioration of levee conditions. The Delta Flood Protection Act enacted in 1988 (see below) has provided the impetus toward levee improvement rather than just maintaining the status quo.
Delta levees are classified as either project or nonproject levees. Project levees are part of the federal flood control project. Mostly found along the Sacramento and San Joaquin rivers, they are generally maintained to Army Corps of Engineers standards and provide dependable protection. Nonproject, or local, levees (three-fourths of the Delta levees) are those constructed and maintained to varying degrees by island landowners or local reclamation districts. Most of these levees have not been brought up to federal standards and are less stable, thereby increasing the chances of flooding.
The Delta Levee Subventions Program, originally known as the "Way Bill" program, began in 1973. The bill authorized funding for levee maintenance and rehabilitation costs, with up to 50-percent reimbursement to local agencies. The funding for these reclamation projects has grown from $200,000 annually in the 1970s to $2 million annually in the 1980s, with a 50-percent reimbursement rate to local districts.
Seventeen islands have been partially or completely flooded since 1980, costing roughly $100 million for property recovery and repairs. As a result of floods in 1986, the Delta Flood Protection Act (Senate Bill 34) was enacted in 1988. Through the Act, funding for the Delta Subventions Program increased up to $6 million a year and allowed up to 75-percent reimbursement to the local agencies for their levee work. Another $6 million is directed toward implementing special flood control projects. Recent activities include planning and designing major levee rehabilitation projects for Twitchell Island and New Hope Tract; repair of threatened levee sites on Sherman Island, Twitchell Island, Bethel Island, and Webb Tract; and other special projects and studies to determine the causes of Delta land subsidence.
The levees are also potentially threatened by earthquake activity. Several active faults-the Antioch, Greenville, and Coast Range Sierra Nevada Boundary Zone faults-are west of the Delta and are capable of delivering moderate to heavy shaking. There has been continuous concern about the potential for liquefaction of the levees and of the foundation materials on some islands. There is no record of a levee failure resulting from earthquake shaking; however, many experts believe that the levee system has not really been tested by substantial earthquake shaking. Several studies indicate there will probably be levee damage or failure induced by earthquake shaking within the next 30 years. Further investigations will better define the expected performance of the levees during earthquakes.
Because of its importance to the state- wide water supply, the Sacramento-San Joaquin Delta is the most studied body of water in the State. No one in California disputes the need to improve water transfer efficiency, min-imize land subsidence and flooding, and improve conditions for fish and wildlife. The issue is not whether the Delta should be fixed, but rather how the Delta problems should be resolved.
Planning for Delta improvements to address sea water intrusion into the Delta has been under way since the late 1800s. Ocean salinity intrusion into the Delta was first noted in 1841, long before any upstream water development was in place. Planning began with an 1874 report by the U.S. Army Corps of Engineers suggesting use of Sacramento Valley water to irrigate both the Sacramento and San Joaquin valleys. That report was followed by a comprehensive State plan for water development issued in 1919 by Col. Robert B. Marshall, a topographer with the U.S. Geological Survey. Our present State water system includes many of Marshall's ideas. Reviewing the plan in 1926, the California Water Resources Association commented:
. . .whatever plan the Department of Public Works may recommend, [it] must. . .make some feasible and satisfactory recommendation covering the extremely grave problem of salt water encroachment in the Delta. . . . This is one of the most vital considerations before the people of California today . . . .
Since then, there have been numerous studies for controlling salinity intrusion and improving the water resources management of the Delta for the benefit of all Californians.
Four broad concepts have been studied for the Delta. These are:
During the last 50 years a variety of proposals modifying or combining all these concepts have been suggested to improve Delta conditions and to allow for beneficial use of Delta water supplies.
Physical barriers to separate salt and fresh water were predominant in early studies. During the 1940s and 1950s salt water barriers at numerous sites on the Bay and Delta system were again studied in detail. However, it was recognized that barriers in the San Francisco Bay system would not be functionally feasible and that further barrier consideration should be limited to, or upstream from, the Chipps Island site at the outlet of the Delta. Installation of barriers in major channels such as the one adjacent to Chipps Island would change the flow regime, change the location and area of the tidal mixing zone, affect the food chain in the Delta, and be an obstacle for shipping and migratory fish passing through the Delta.
Hydraulic barriers were also studied in early planning stages to repel salinity intrusion in the Delta. The thrust of hydraulic barrier studies was that water transfer through existing Delta channels for local use and export could be accompanied by water releases from upstream reservoirs to control salinity by outflow from the Delta. This was the basis of the proposals adopted for current SWP and CVP operations.
Through-Delta facilities were first studied in the late 1950s and were proposed by DWR in 1960 as the single-purpose Delta Water Project (later referred to as the Waterway Control Plan). This alternative proposed such actions as enlarging Delta channels, closing channels, and constructing siphons, as well as moderate releases of water from upstream storage reservoirs for salinity control to improve movement of Sacramento River water to pumps in the South Delta. A similar concept was formulated in a plan proposed by DWR in 1983 under "Alternatives for Delta Water Transfer." The most recent through-Delta facility proposal is the North Delta Program, which addresses North Delta flooding issues in addition to improving conveyance capacity of North Delta channels to reduce reverse flow and salinity intrusion.
Isolated facilities would convey water around the Delta for local supply and export through a hydraulically isolated channel. Delta salinity control would be accomplished by a hydraulic barrier maintained by releases from upstream storage reservoirs. This concept was formulated in a plan proposed by the Interagency Delta Committee in 1965 as the Peripheral Canal. A statute that would have authorized this and many other additions to the SWP was rejected by the voters in 1982.
Competing needs and various governmental agencies with different jurisdictional claims on the Delta have made today's Delta planning process more complex than ever. The Delta lies within five counties and is subject to various State and federal regulations. Consequently, Delta planning programs usually provide forums for many diverse interests and often generate much controversy. The challenge of Delta planning is to create a planning strategy that can balance the diverse and often conflicting interests.
Today, the decision-making process is slow and complicated by an intricate web of institutional constraints and the number of parties involved. This has made resolution of Delta problems a divided and sometimes disjointed process. Thus far, no consensus has been reached. Local, regional, State, and federal agencies, as well as environmental and economic concerns, all play a role in the Delta planning and decision-making process. Delta management decisions are made at every level of government. DWR is just one component in this complex puzzle. The trend, in recent years, has been toward more involvement of federal regulatory agencies in Delta water management planning.
Among the agencies regulating water use from the Sacramento-San Joaquin river
system are:
State Water Resources Control Board
U.S. National Marine Fisheries Service
California Department of Fish and Game
U.S. Environmental Protection Agency
U.S. Fish and Wildlife Service
U.S. Army Corps of Engineers
These agencies exercise regulatory control and enforce statutes that include the State and federal endangered species acts, the federal Clean Water Act, and water rights. These laws are discussed in Chapter 2, The Institutional Framework for Water Management in California. How these laws affect Delta planning and the agencies involved are discussed here.
Virtually anything that can be done to resolve Delta problems will require permits from a number of agencies. Potential permits required for Delta program implementation are shown in Table 10-1. The environmental documentation process, regulatory permits, and compliance with requirements of the endangered species acts are the most important components of the decision-making process. The following sections discuss the environmental review process, regulatory permits, and the endangered species acts as they relate to Delta planning. Figure 10-6 is a flow chart showing the interrelationships of these three components in the Delta decision-making process.
Environmental Review Process. Both the National Environmental Policy Act and the California Environmental Quality Act require decision makers to document and consider the environmental impacts of their actions and encourage public participation in the decision-making process. Both CEQA and NEPA processes start with a formal public notice announcing to the public and concerned agencies that the planning and environmental documentation process has begun and that public input is sought. Public scoping meetings are held to solicit public input in determining the scope of the environmental document. A draft environmental document is then prepared and released for public review and comments. The draft document includes a comprehensive evaluation of alternatives and their impacts along with potential mitigation measures. Successful completion of the environmental documentation process depends on an agency's ability to adequately evaluate and address public comments and to build consensus and support for the action. Environmental interests, water users, and local entities in the Delta all have a great interest in any major decisions made for the Delta. For any Delta water planning decision to be acceptable, it should protect Delta islands from flooding, ensure a reliable water supply of suitable quality for Delta water users, and guarantee environmental protection for fish and wildlife.
Regulatory Permits. Implementation of a comprehensive program for the Delta requires a number of permits, including permits under Section 404 of the federal Clean Water Act and Section 10 of the Rivers and Harbors Act. These two permits are administered by the U.S. Army Corps of Engineers. Section 404 regulates the discharge of dredged and fill materials into waters of the United States. Issuance of 404 permits requires EPA approval and coordination with USFWS. A Section 10 permit (Section 10 of the Rivers and Harbors Act) is required for obstruction of any navigable water including construction of dams or barriers. The Section 404 (b)(1) guidelines promulgated by the EPA state, "No discharge of dredged or fill materials shall be permitted if there is a practicable alternative to the proposed discharge which would have less adverse impact on the aquatic ecosystem, so long as the alternative does not have other significant adverse environmental consequences." Any Delta program must comply with these guidelines by going through a comprehensive alternative analysis to determine the "least environmentally damaging practicable alternative." The alternative analysis along with environmental impacts analyses of the proposed action can be formulated within the framework of environmental documentation required by NEPA.
Endangered Species Acts. Requirements of the federal Endangered Species Act and the California Endangered Species Act have altered and now greatly affect water resources planning in the Delta. Two species, the winter-run chinook salmon and Delta smelt, were listed under the federal and State acts. These listings have changed the decision-making process for the Delta. In accordance with the ESA, a biological assessment should be prepared for any federal actions or permit applications in the Delta which may have impacts on listed and proposed species. The assessment contains information concerning listed and proposed species as well as material relating to the impacts of the proposed project on listed species. The biological assessment is used to determine whether formal consultation is required for the proposed action affecting the critical habitat or the species. Formal consultation is required if the listed species or their critical habitat are adversely affected by an action.
Based on the biological assessment, a biological opinion is prepared by either the USFWS or NMFS depending on the species. NMFS is responsible for ocean and anadromous species, while USFWS is the authority for inland species. The appropriate agency then determines whether the action is likely to jeopardize the continued existence of listed species or result in the destruction or adverse modification of critical habitat. If the action would jeopardize the continued existence of the species, the opinion contains a reasonable and prudent alternative to avoid jeopardy. An incidental-take statement is issued when there may be a taking of a listed species incidental to the action that does not jeopardize the listed species' continued existence or critical habitat. For the projects that may have an impact on the listed species, but do not require any federal actions, a Section 10 (Section 10 of the ESA) incidental-take permit is required.
When a Delta decision is determined to affect species listed under both FESA and CESA, a State lead agency engages in a consultation with DFG. DFG also participates in the federal consultation process to ensure that the federal biological opinion findings are consistent with the State findings. In most cases, DFG would adopt the federal biological opinion.
The U.S. EPA role in the Delta is as follows:
The federal government is playing a much greater role in determining what is ultimately to be done in the Delta than it has in the past. The Delta is an estuary and a navigable waterway subject to a number of significant federal laws because it includes wetlands and valuable anadromous fisheries. Any physical solution to Delta problems will require regulatory permits under Section 404 of the Clean Water Act and the endangered species acts. Over the years, activities necessary to obtain permits have evolved into complex and time-intensive processes.
Planning for the Delta generates controversy and promotes public and political debates. Actions by regulatory agencies are not isolated from these debates, and Delta planners recognize this complex relationship in formulating management strategies for the Delta. Such strategies require extensive coordination, cooperation, consultation, negotiation, and consensus between federal, State, and local entities. Building consensus for an action plan that would balance those interests and concerns of local entities requires extensive negotiations among agencies. The interrelationships between the environmental documentation process, permitting process, and endangered species actions are complex and continually changing. Delta planners are trying to find their way through an ever-changing maze of regulatory constraints surrounding the decision-making process in the Delta.
The options discussed briefly here present some of the alternatives that are currently being evaluated or could be evaluated in the future. Protection of fish and wildlife and the ultimate Delta solution will determine the feasibility of several water supply programs. The following programs are intended to show the range of options being discussed by interest groups and water planners at this time.
Interim South Delta Water Management Program. DWR recently evaluated the South, North, and West Delta programs to improve conditions in the Delta. The Interim South Delta Water Management Program is an important part of any water banking program and was implemented in response to an October 1986 agreement among DWR, USBR, and the South Delta Water Agency. The program also addresses the need to increase the operational flexibility and reliability of the SWP, including Los Banos Grandes, a south-of-the-Delta offstream storage project authorized in 1984. In the SDWA agreement, all three parties committed to developing mutually acceptable, long-term solutions to the water supply problems of local water users within SDWA.
The Interim South Delta Preferred Alternative consists of constructing interim facilities that include an additional SWP intake structure at Clifton Court Forebay, limited channel dredging, four flow-control structures, and a permit allowing the SWP to increase its existing pumping capacity. These facilities are intended to provide for operational flexibility to improve SWP water supply capability, reduce fishery impacts (particularly on San Joaquin River salmon populations), and improve water levels and circulation for local agricultural diverters.
A new multigate intake structure is proposed for the northeastern corner of the existing Clifton Court Forebay near the confluence of Old River and the Victoria and North canals as shown on Figure 10-7. This additional intake structure would be operated according to tidal water elevations to increase peak flow into the forebay. It would increase average daily diversion into the forebay and allow pumping at the H.O. Banks Delta Pumping Plant to the maximum design capacity of 10,300 cfs. Some channel dredging would be required to assure that channel scouring does not occur. This dredging would be in Old River north of the forebay.
Three of the four flow-control structures are proposed to control water levels, circulation, and the flow in the South Delta channels. The structures would be tidally operated during the irrigation season. Operations would retain flood tide flows in South Delta channels for a longer period of time to raise water levels. During other times of the year these control structures would be opened and would not affect local hydrology. The fourth, a control structure on Old River near the San Joaquin River, would be operated in the fall and spring to help salmon migrating in the San Joaquin River. During other times of the year this structure would not alter flows. The Interim South Delta Water Management Program could augment SWP supplies by about 60,000 af per year.
North Delta Program. Limited channel capacity in the north Delta has contributed to two major problems: reverse flow in the San Joaquin River, a consequence of SWP and CVP exports from the Delta, and repeated flooding of local leveed tracts. A proposed solution to both problems is dredging and widening of various interior Delta channels to allow more unrestricted flows. A primary focus of the North Delta Program is improving the connection to the Sacramento River, thereby sharply reducing reverse flow.
For flood control, the biggest problem in the north Delta is the bottleneck caused by the narrow channels of the Mokelumne River. Its channels are too small to handle high water flows. Repeated flooding of leveed tracts is a threat to more than 2,000 people, their homes, and thousands of acres of valuable farmlands.
The intent of the North Delta program is to allow greater flood flows to pass safely, while lowering flood levels throughout the area by dredging and building new setback levees. The new levees would provide greater protection for Thornton, Walnut Grove, Tyler Island, New Hope Tract, and other Delta lands.
Increased channel capacity and less or no reverse flow would create a more efficient means of transferring water through the north and central Delta, thus providing additional water supply for SWP users. Another benefit to increased channel capacity and reduced reverse flow is better water quality.
The winter-run 1993 biological opinion requires that the Delta Cross Channel be closed from February 1 through April 30 each year to reduce entrainment of winter-run chinook salmon into the Central Delta. Closing Delta cross channel gates increases reverse flow, thus curtailing SWP and CVP exports. Similar concerns would need to be addressed and resolved if North Delta facilities were in place.
West Delta Program. DWR is implementing a unique land use management program that could effectively control subsidence and soil erosion on Sherman and Twitchell islands, while also providing significant wildlife and waterfowl habitat. DWR and DFG have jointly developed the Wildlife Management Plan for Sherman and Twitchell islands to accomplish this objective. This plan is designed to benefit wildlife species that occupy wetland, upland, and riparian habitat, and provide recreational opportunities for hunting and wildlife viewing. Property acquired and habitat developed through DWR's contribution will be available for use as mitigation for impacts associated with ongoing DWR Delta water management programs.
This plan would significantly reduce subsidence by minimizing oxidation and erosion of the peat soils on the islands. This would be accomplished by replacing present agricultural cultivation practices with land use management practices designed to stabilize the soil. Such practices range from minimizing tillage to establishing wetland habitat.
Altering land use practices on Sherman and Twitchell islands could provide up to 13,600 acres of managed wildlife and waterfowl habitat and responds directly to the underlying need for additional wetlands in the Delta, as expressed in national and State policies for wetlands enhancement and expansion.
Agricultural Diversion Screening. Entrainment losses due to agricultural diversions in the Delta may be a substantial source of mortality for the early life stages of some Delta fish species. However, little is known about the extent of these losses or the factors affecting them. Due to concerns about water diversions and impacts on fishery resources, DWR implemented a three-year Delta Agricultural Diversion Evaluation Program in April 1992. The objectives of the program are to develop reliable data about entrainment of various fish species, determine the effects of entrainment on the species' life stages, describe the species susceptibility to agricultural diversions during the irrigation season, and compare the obtained data with information about abundance and life stages of the same species living in adjacent channels. The 1992 pilot study focused on refining sampling techniques and assessing the suitability of four diversion sites (Twitchell Island, Bacon Island, McDonald Tract, and Naglee Burk Tract). The McDonald Tract tested the effectiveness of an experimental fish screen installed on the siphon intake for the Central Delta Water Agency Fish Screen Test Project. The screen was effective in reducing entrainment of larvae 4 to 5 millimeters and larger. However, the effects of the screen impingement on the larvae are not known. Generally, larval fish are usually more abundant than juveniles or older fish due simply to the natural mortality rate of a population before they reach these later stages.
Recognizing the complexity of the Delta decision-making process, the Governor provided specific direction and guidance to correct the current "broken" condition of the Delta in his 1992 statewide water policy speech. He established the Bay-Delta Oversight Council to help guide the planning and decision-making process. BDOC is to define objectives, evaluate criteria, and formulate alternatives for the Delta. The council is composed of concerned private citizens from throughout California. BDOC will evaluate all reasonable options to solve complex Delta problems as part of this process. However, any recommended long-term solution must be practical, scientifically sound, improve protection for the Bay-Delta estuary, and provide for more reliable water supplies. The following are some of the programs that could be investigated for a long-term solution to Delta problems.
Isolated Facility. The isolated facility consists of constructing an isolated canal from near Hood on the Sacramento River to Clifton Court Forebay (with a fish screen near Hood), siphons, and the capability to release water to Delta channels to improve water circulation in Delta channels (see Figure 10-8). This option can improve water quality for urban and agricultural water users. It would eliminate reverse flow in the Delta and improve water quality and flow in the Delta by releasing water to South Delta channels. Because the intake gate of this facility would be upstream of much of the Delta along the Sacramento River, it would significantly reduce bromide and agricultural drainage impacts on water delivered to urban water purveyors. Possible collateral measures to improve water quality at the intake gate would be to divert major Sacramento Valley agricultural drainage and Sacramento Regional Treatment Plant effluent to the Yolo Bypass. This option would also reduce the effects of CVP and SWP export facilities on fish by eliminating predation in Clifton Court Forebay, improving fish migration by closing the Delta cross channel gates, and by eliminating reverse flow.
The Dual Water Transfer Facility. The dual water transfer facility would also consist of an isolated canal, with fish screens near Hood, to transfer SWP water from Hood on the Sacramento River to Clifton Court Forebay on the same alignment as the above isolated facility, except it that would be smaller. This facility would provide better quality water for urban water agencies, but its full potential, in this regard, could only be realized by separating urban from agricultural supplies using existing facilities and constructing new conveyance facilities south of the Delta. The Delta cross channel gates would remain operational. Pumping for SWP and CVP exports from the South Delta would continue, but at a lower rate and when high flows are available. Dual water transfer would allow for release of water to South Delta channels to improve water supply and circulation in the South Delta channels. This facility would provide some benefits to fisheries, but benefits would not be as great as with an isolated facility.
Sierra Source. The Sierra source option consists of a new channel transferring water directly from the Feather and Sacramento rivers, bypassing the Delta, and delivering water directly to Clifton Court Forebay and the federal export facilities in the South Delta. This option would reduce THM precursors, provide high quality water for export, and have the same fish benefit as an isolated facility. In addition, it would eliminate direct diversion along the Sacramento River and provide for a free-flowing river from Keswick through the Delta. A more detailed description of this option can be found in Chapter 11 under Westside Sacramento Valley Project.
Delta Agricultural Drainage Management. This management action would collect all or a major part of the agricultural drainage from Delta islands and discharge the drainage to another location or treat it to reduce THM precursors at Delta pumps. This management program improves Delta water quality for urban use by reducing organic THM precursors; however, bromide precursors will still be present in the water. Drainage water collection and disposal could be a major undertaking that may be costly for the benefit gained from the program.
Delta Storage. Storage of unregulated flood flows in and around the Delta has been the subject of several studies in recent years. DWR studied Los Vaqueros Reservoir in the early 1980s to evaluate the feasibility of augmenting SWP supplies with the construction of a 1-maf storage facility on Kellogg Creek in Contra Costa County. This project has been further studied by Contra Costa Water District to provide water supply reliability to the district; see Chapter 11 for a more detailed description.
In the late 1980s, a unique wetlands management and water storage project for the Sacramento-San Joaquin Delta was proposed by a land development company. The proposed project, Delta Wetlands, would convert land use on Bouldin, Webb, Holland, and Bacon islands from agricultural use to water storage and managed wetlands. Two islands, Bacon Island and Webb Tract, would be managed primarily for water storage. The stored water would be pumped from the islands to the Delta channels for sale to participating water purveyors. The other two islands, Bouldin Island and Holland Tract, would be operated primarily for wildlife benefits, which would provide an opportunity to develop new habitat for endangered species. Because the wetlands would be in a wet or semi-moist condition year-round, invertebrate food for wildlife would be more abundant. Also, nesting opportunities on Bouldin Island and Holland Tract would be greatly enhanced.
The Delta Wetlands project proposes to convert surplus wet year Delta flows to a new source of central Delta water, which would be used later in the year when demand exists (see Figure 10-9). The proposed water supply storage capacity of the project is about 230,000 af. Water rights applications have been filed for this project. The lead agencies are the SWRCB for California and the Corps of Engineers for the federal government. A Draft EIR/EIS was released on December 26, 1990. A redraft of the document is anticipated to be available in 1994.
The Delta is the hub of California's water supply infrastructure. It is the source from which two-thirds of the State's population and millions of acres of agricultural land receive part or all of their water supplies. The Delta provides valuable habitat and migration corridors for many species, including winter-run salmon and delta smelt, which are listed under the State and federal Endangered Species acts. Key problems in the Delta must be addressed before several other Level I options can progress to help California meet its water supply needs to the year 2020.
The Governor's water policy statement of April 1992 specifically called for
taking interim actions in the Delta, such as improvements in the South Delta
that will help restore the environment and improve water supply in the short-term,
while starting the CEQA/NEPA processes to address and develop long-term solutions
to Delta problems. State and federal agencies must work together to resolve
these complex issues and move toward long-term solutions.
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