Central Valley Project Improvement Act of 1992, 1993 CVP Operations

The 1993-94 water year is the first year of dedicated water use for fish and wildlife under the CVPIA (Title 34 of Public Law 102-575). Operations for 1993 dedicated 800,000 acre-feet, of which up to 400,000 is for the benefit of the Delta smelt. The 1993 prescribed measures include the following:

Sacramento and American River Basins

• At least an 8,000-cubic-foot-per-second pulse flow from Keswick Dam for a five-day period in late April to assist downstream migration of juvenile fall-run chinook and help provide the pulse flow needed in the Delta for Delta smelt and striped bass.
  
  
• At least 4,000-cfs releases from Keswick Dam to the Sacramento River from October through March, and at least 1,750 cfs from Nimbus Dam to the American River from October through February. These are to eliminate flow fluctuations for the spawning, incubation, and rearing of fall-run and late fall-run chinook salmon and steelhead trout.
  
  
• Close the Delta Cross Channel gates during May to reduce entrainment of downstream migrating fall-run chinook salmon, striped bass eggs and larvae, and other Delta species.

Stanislaus and San Joaquin River Basins

• Two pulse flows from New Melones Reservoir of at least 1,500 cfs: (1) from April 24 to May 16 primarily to help move fall-run chinook salmon smolts downstream and past the Delta pumps, secondarily to benefit Delta smelt; and (2) from May 20 to June 2 primarily to aid Delta smelt, secondarily to benefit striped bass and fall-run chinook salmon.
  
  
• A pulse flow of 1,000 to 2,000 cfs below New Melones Reservoir for a 7- to 14-day period in fall 1993 to attract upstream migrating fall-run chinook salmon.
  
  
• A base flow release of at least 300 cfs from New Melones Reservoir to the Stanislaus River from October through March to improve spawning and rearing conditions for fall-run chinook salmon.
  
  
• A carryover of 100,000 to 115,000 acre-feet in New Melones Reservoir beyond spring of 1994 for improved water temperatures and as a contingency against drought.

The Delta

• No reverse flow in the western Delta in May and June, maximum reverse flow of 1,000 cfs in July, and maximum reverse flow of 2,000 cfs in August, December, and January, specifically to benefit Delta smelt.
  
  
• A springtime pulse flow of about 4,500 cfs on the San Joaquin River side of the Delta. (Stanislaus River pulses and releases from other tributaries described above should provide this flow.)
  
  
• A pulse flow of at least 18,000 cfs from about April 20 to May 4 in the Sacramento River side of the Delta at Freeport. (The Keswick Dam pulse described above should contribute greatly to this.) From April 20 through May 30, the 14-day running average flow at Freeport should be at least 13,000 cfs, with daily minimums of at least 9,000 cfs.
  
  
• Base flows at Chipps Island between 14,000 and 7,700 cfs from May through July.
  
  
• Pumping reductions to 1,500 cfs (federal and State combined) from April 26 to May 16 (during the San Joaquin River pulse flows). Increased pumping to 4,000 cfs for the remainder of May, and 5,000 cfs for the month of June.

  The prescribed Delta measures will benefit outmigrating salmonids, striped bass, and Delta smelt, as well as other migratory and resident estuarine species.

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