Status of California’s Wadeable Perennial Streams (2000-2007)

The Surface Water Ambient Monitoring Program’s (SWAMP) Perennial Streams Assessment (PSA) surveys measure the ability of California’s perennial wadeable streams (some 85,000 km) to support aquatic life. PSA surveys found half (50%) of the wadeable perennial stream length in California to be in relatively good biological condition, while about 22% is in very degraded biological condition. The statewide distribution of good, degraded and very degraded sites shows that most high quality streams in good biological condition are located in the mountainous regions of the state. Streams with the most degraded biology tend to be found in low-lying agricultural and urban areas in the central valley and parts of the coast.