Delta Water Quality

The Delta watershed extends nearly 500 miles from the Cascade Range in the north to the Tehachapi Mountains in the south, and is bounded by the Sierra Mountain Range to the east and the Coast Range to the west. The watershed includes the largest estuary on the west coast of North and South America and the only inland Delta in the world: the Sacramento-San Joaquin Delta. Nearly half of the surface water in California starts as rain or snow and flows downstream through the Delta and out to the Pacific Ocean through the Golden Gate Strait.

Good water quality is vital to key uses of water such as drinking water, fish and wildlife, agriculture, and recreational activities. Delta waterways are impaired by multiple pollutants including salinity, pathogens, pesticides, metals, mercury, nutrients, and invasive species. Many different entities monitor and work to improve water quality in the Delta.

Water Quality Monitoring

Water quality monitoring provides information about the physical, chemical, and biological characteristics and health of a water body. Monitoring data is combined to understand current conditions in the watershed, screen for potential pollution problems, and inform adaptive management decisions and best management practices or identify data gaps.

Stone Lake National Wildlife Refuge

The Delta Conservancy is collaborating with the Stone Lakes National Wildlife Refuge (web link) to coordinate water quality monitoring. The Refuge contains over 1,000 acres of managed permanent and seasonal wetlands and provides vital habitat for migratory birds and resident plants and wildlife. Good water quality is essential to the health of the plants and wildlife that use Refuge waters, and to ensure continued opportunities for recreation related to wildlife viewing. The goal of this monitoring effort is to determine the current water quality conditions and trends in water quality, to then make scientifically-based watershed management decisions.

Implementation of Best Management Practices

Many water quality problems can be addressed through Best Management Practices (BMPs). BMPs are techniques, measures, or structural controls that can be implemented to protect, restore, or improve water quality before runoff reaches the main water system.

Wetland habitat in the Cosumnes River Preserve.
Cosumnes River Preserve