Field Trip to the Sacramento-San Joaquin Delta
|AGU > Meetings > Fall '02 > Activities >||AGU 2002 Fall Meeting|
To be led by James O. Sickman and Anke Mueller-Solger, California Department of Water Resources, Sacramento
The Sacramento San Joaquin Delta is the freshwater portion of the San Francisco estuary. It is the most critical junction for water in California. Two major rivers, the Sacramento and San Joaquin provide the majority of water inputs to the Delta from which two-thirds of Californians receive a portion of their drinking water. The extensive agricultural lands of California's Central Valley receive most of their water from the Delta and its tributaries.
The Delta covers approximately 2300 km2, and prior to 1850, was a vast freshwater-tidal estuary dominated by stands of great bulrush or tule (Scirpus, lacustris) and reeds (Phragmites, communis) and teamed with wildlife. By 1930, 1800 km2 of the Delta estuary had been converted to agricultural use and only small remnants of the native marsh still exist today. Decades of agricultural use have caused rapid subsidence of Delta islands. Lands that were once near or above sea level in the mid-1800s are now 20 feet below mean sea level. However, even today, the distinctive estuary ecosystem supports more than 750 species of fish, animals, and birds, including waterfowl migrating on the Pacific Flyway. It supplies and sustains fisheries, wildlife refuges, and 40,000 acres of critical wetlands in addition to being a recreation area for 12 million visitors per year.
To address historical water and ecosystem problems in the Delta, a cooperative effort among the public and state and federal agencies with management and regulatory responsibility in the Bay-Delta system was begun in 1994. The CALFED Bay-Delta Program seeks to develop and implement a long-term comprehensive plan that will restore ecological health and improve water management for beneficial uses of the Bay-Delta System. The program's major objectives are:
Our field trip will visit important management, restoration and wildlife sites in the Delta and will offer participants a unique opportunity to gain greater understanding of one of the most important estuaries in the United States.
Date: 11 December
0730 hr: Board bus at Moscone Center
0900 hr: Arrive at Suisun Marsh: Presentation by DWR scientists on Marsh, with time for wildlife viewing and visit to Salinity Control Gates.
Suisun Marsh is the largest contiguous brackish water marsh remaining on the west coast of North America. It is a critical part of the San Francisco Bay-Delta estuary ecosystem. The Marsh encompasses more than 10% of California's remaining natural wetlands and serves as the resting and feeding ground for thousands of waterfowl migrating on the Pacific Flyway. In addition, the Marsh provides essential habitat for more than 221 bird species, 45 animal species, 16 different reptilian and amphibian species, and more than 40 fish species. The Marsh supports 80% of the state's commercial salmon fishery by providing important tidal rearing areas for juvenile fish. Two hundred and thirty miles of levees within the Marsh provide critical protection of the drinking water for 22 million people by preventing salt water intrusion into the Delta.
1030 hr: Depart Suisun
1115 hr: Arrive Twitchell Island: Tour of Delta agricultural landscape and presentation by USGS/DWR scientists on artificial wetland program and other ongoing research/management programs.
Twitchell Island was purchased by the Department of Water Resources. The island is still extensively farmed, but parts of the island have been used for research on wetland restoration and organic carbon management. The peat soils on Twitchell Island have been gradually lost over the 20th century due to agricultural practices and much of the island is below sea level. The island is currently being considered as an in-Delta water storage reservoir.
1230 hr: Depart Twitchell Island
1245 hr: Arrive at Bouldin Island Marina: Break for lunch
1345 hr: Depart Bouldin Island
1445 hr: Arrive at John E. Skinner Delta Fish Protective Facility for tour and discussion of fisheries issues in the Delta.
The State Water Project and the Central Valley Project export water out of the San Francisco Bay Delta for urban and agricultural use in California. When water is exported, fish become entrained into the diversion. Since 1957, the U.S. Bureau of Reclamation (USBR) has salvaged fish at the Tracy Fish Collection Facility (TFCF). The Department of Fish and Game's Fish Facilities Unit, in cooperation with DWR, began salvaging fish at the Skinner Delta Fish Protective Facility (SDFPF) in 1968. The salvaged fish are trucked daily and released at several sites in the western Delta. The schedule of fish hauling is dependent on salvage rates, debris loading, and special-status-species procedures. Salvage of fish at both facilities is conducted 24 hours a day, seven days a week at regular intervals.
1600 hr: Leave fish facility and return to San Francisco
1730 hr: Arrive at Moscone Center