Restoration of Hetch Hetchy Valley and San Francisco's Water Supply Q

Restoration of Hetch Hetchy Valley and San Francisco’s Water Supply Spreck Rosekrans Executive Director, Restore Hetch Hetchy Q: After restoration, where will San Francisco gets is water? A: From the Tuolumne River, just as it does now. Summary The San Francisco regional water system currently receives 85% of its supply from the Tuolumne River watershed. San Francisco stores its Tuolumne River supplies in four reservoirs - Hetch Hetchy, Cherry, Eleanor and Don Pedro. Hetch Hetchy and Eleanor Reservoir lie within Yosemite National Park, while Cherry and Don Pedro Reservoirs are outside the park. Figure 1 shows San Francisco’s facilities in the Tuolumne watershed. With modifications to pipelines in the Tuolumne watershed, restoration could occur with San Francisco being able to retain almost all its Tuolumne derived supplies. Only modest new supplies would be required to ensure no loss in water system reliability.1 This report addresses only the most commonly asked question by restoration skeptics: Where would the water come from? Restoration would also require increased water treatment costs and replacement of about 350 gigawatt-hours per year of hydropower production – issues not addressed herein. Restoration of Hetch Hetchy Valley and San Francisco’s Water Supply This approach would allow full deliveries of Tuolumne supplies in most years, but in the driest one out of five years there would be a shortage of about 60,000 acre-feet – about 20% of the San Francisco Regional Water System’s overall system supply. While a plethora of specific options for replacing 60,000 acre-feet of water in dry years is available, no particular alternative is singled out herein. The identification, development and implementation of a particular alternative is the purview of San Francisco and its Bay Area customers as they are best suited, given proper incentive, to determine what is the best option for their system. Nevertheless, any of the following four specific options could comprise a specific water supply alternative (with sufficient incentives for the cooperating districts): Enlarge Los Vaqueros Reservoir in Contra Costa County by 360,000 acre-feet or more and improve interconnections between the Contra Costa Water District, the East Bay Municipal Utility District and the San Francisco Regional Water System. Bank 360,000 acre-feet or more of groundwater with the Semitropic Water Storage District in Kern County, and connect San Francisco’s aqueduct to the California Aqueduct. Purchase 60,000 acre-feet of supply in dry years from the Turlock, Modesto or Oakdale Irrigation Districts. The Districts could use the funds received to recharge and improve the management of local groundwater supplies. Recycle 60,000 acre-feet of supply annually at Bay Area wastewater plants. Note that over the last 25 years other California urban agencies have developed more than 1,000,000 acre-feet of dry year supply – more than 18 times the amount of water required to restore Hetch Hetchy Valley - through a combination of surface storage, groundwater storage, water purchases and water recycling programs2. Most of this supply has been developed in response to requirements that these agencies improve the environmental performance of their water systems. Presently, San Francisco simply lacks the political will to make the system modifications necessary to return the Hetch Hetchy Valley in Yosemite National Park to the American people. Water supply effects of other aquatic restoration programs in California Water development has been critically important in semi-arid California, for supporting both its growing population and its world-class agricultural industry. In some instances, however, the impact on aquatic environments has been found to be unacceptable and significant modifications to the operations of some water delivery systems have been required. Since 1992, California water agencies have modified their water systems to better protect some of the state’s most renowned rivers and wetlands, as well as the fish and wildlife they support. None of these changes have been easy and some have been particularly controversial, but in large part improvements in the use, storage and delivery of water have been beneficial to California’s natural heritage. 2 Restoration of Hetch Hetchy Valley and San Francisco’s Water Supply Table 1 below provides a list of five distinct instances in which water has been redistributed back to the environment, and compares the amounts of these supplies with the amount that would be required to restore Hetch Hetchy Valley in Yosemite National Park. Water agencies throughout California have made significant modifications to their systems in order to improve environmental performance with respect to California’s rivers, wetlands and the Bay Delta. These volumes of rededicated water are far in excess of that which would be required to restore Hetch Hetchy Valley in Yosemite National Park. Table 1: Annual Water Volumes Rededicated for Environmental Uses Since 1992 (acre-feet) Average Critically Environmental Reoperation of all Dry years Years San Joaquin Valley Wetlands (1992): Water supply exported from the Delta redirected from agricultural use to wetlands for the benefit 250,000 200,000 of waterfowl. Mono Lake (1994): Water diversions to Los Angeles reduced in order to restore the water level of Mono Lake for the benefit of 46,000 30,000 waterfowl. Bay-Delta Accord (1994-1995): State Water Board ratifies agreement to improve springtime Delta outflow and protect estuarine fish. Deliveries of water exported from the Delta are 316,000 430,000 reduced to San Joaquin Valley farms as well as to cities in northern and southern California. Trinity River Restoration Plan (2000): Diversions from the Trinity River are reduced to improve salmon and steelhead populations, 83,000 155,000 reducing water supplies delivered to Central Valley farms. Delta Endangered Species Act rulings (2008): Regulations governing the flows of Old and Middle River in the Delta to protect salmon and Delta smelt result in reduced export deliveries to San 980,000 572,000 Joaquin Valley farms as well as to cities in northern and southern California. Hetch Hetchy Valley in Yosemite National Park (20XX): Proposal to restore this once iconic valley would diminish delivery of 12,000 60,000 Tuolumne River water supplies to San Francisco Bay Area. Since 1992, more than 1,500,000 acre-feet of water have been redirected for environmental purposes. Affected agencies have responded by developing new surface and groundwater storage, recycling water, investing in efficiency (especially drip irrigation), and participating in an increased number of market transactions. 3 Restoration of Hetch Hetchy Valley and San Francisco’s Water Supply San Francisco’s water system as it exists today It’s important to realize that San Francisco’s water system includes nine reservoirs - five in the Bay Area, and four in the Tuolumne watershed. The five Bay Area reservoirs principally hold runoff from local watersheds and provide about 15% of the total supply of San Francisco’s system. The location and sizes of these reservoirs are shown in Figure 2 and Table 2 respectively. San Francisco owns and operates Table 2: Principle Tuolumne River and three “upcountry” reservoirs in the SFPUC Reservoirs Tuolumne watershed - Cherry, (acre-feet) Eleanor and Hetch Hetchy. These facilities, along with several pipelines and powerhouses, were Bay Area authorized by the federal Raker Act Pilarcitos 3,000 in 1913 – the one time in American San Andreas 19,000 history that a city was allowed to San Antonio 51,000 build significant infrastructure in a Crystal Springs 69,000 national park. Calaveras 97,000 Upper Tuolumne The fourth, and largest reservoir, is Eleanor Don Pedro - owned and operated by 27,000 the Turlock and Modesto Irrigation Cherry 273,000 Districts. Don Pedro is almost 6 Hetch Hetchy 360,000 times as large as Hetch Hetchy Lower Tuolumne Reservoir, and one third of its Don Pedro (SF Water Bank) 634,000 storage is dedicated to a water Don Pedro (MID/TID portion) 1,395,000 “bank” for San Francisco – a SFPUC Total 1,533,000 4 Restoration of Hetch Hetchy Valley and San Francisco’s Water Supply privilege for which San Francisco paid half the cost of Don Pedro’s construction. San Francisco does not presently draw water directly from Don Pedro, nor is it permitted to do so under its “fourth agreement” with Turlock and Modesto, but the water bank provides functional storage as it allows San Francisco to divert river flows upstream that would otherwise belong to the districts. Together the Bay Area and Tuolumne Some, but not all, restoration alternatives would components of San Francisco’s water system provide about 265,000,000 involve San Francisco’s direct use of its Don Pedro gallons of water per day. Roughly 1/3 water bank – something not presently permitted by of this water is delivered to customers the Turlock and Modesto Irrigation Districts. It is within the City and County of San Restore Hetch Hetchy’s view that a restoration plan Francisco. The remaining two thirds is can be developed that provides the Districts’ with delivered to customers in San Mateo assurances that their rights and water supplies will be County and parts of Alameda and Santa protected if they allow San Francisco direct access to Clara Counties. Don Pedro Reservoir on occasion, despite their Diverting Tuolumne Supplies current reluctance to do so. without Hetch Hetchy Reservoir First and foremost, San Francisco would continue diverting from the Tuolumne River into its Mountain Tunnel at Early Intake when there is sufficient river flow – typically in winter, spring and early summer. This is the present point where Tuolumne supplies are diverted below Hetch Hetchy Reservoir. During the dry months of the year, San Francisco would divert water that is stored in either Don Pedro or Cherry Reservoirs. To make these diversions possible, one or more new interties from other Tuolumne River reservoirs to San Francisco’s existing conveyance system are necessary.

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