Tuesday, November 6, 2007 - 2:35 PM
145-4
Sustainable Best Management Practices for Wetland Seasonal Drainage in Response to San Joaquin River Salinity and Boron TMDLs.
Managed seasonal wetlands in California’s San Joaquin Valley are an important national resource, providing over-wintering habitat to waterfowl in the Pacific Flyway. These wetlands are irrigated during the summer to closely mimic natural conditions prior to the construction of dams on the San Joaquin River and its major tributaries. Saline drainage from these wetlands negatively impacts San Joaquin River water quality providing pollutant loads that contribute to violations of numeric water quality objectives for salt and boron. The Grassland Water District, California Department of Fish and Game and Berkeley National Laboratory have a decade-long experiment to improve current understanding of salt balance on seasonally managed wetlands. This knowledge will be used to manipulate annual drawdown management practices in a manner that preserves optimal marsh habitat for migratory wildfowl, sustains hunting success while improving compliance with state water quality objectives. This paper describes the conceptual model behind this real-time water quality management initiative and the water quality monitoring, soil and biota data collection activities that are being used to ensure practices are sustainable. A pilot implementation project is underway which will compare the long term impact of this modified wetland hydrology on habitat health and productivity in six paired wetland cells – where each pair comprises one cell where traditional marsh management is practiced and a second which delays drawdown to a period of increased san Joaquin River assimilative capacity. Initial results will be discussed.
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