Ecological Condition Assessments of California’s Perennial Wadeable Streams: Highlights from the Surface Water Ambient Monitoring Program’s Perennial Streams Assessment (PSA ) (2000-2007)

Since 2000, California has conducted three successive probability surveys of its perennial streams and rivers, each with a focus on biological endpoints. These surveys are now combined and are managed collectively by the Surface Water Ambient Monitoring Program (SWAMP) under its Perennial Streams Assessment (PSA) program.

In 2010, SWAMP’s Perennial Streams Assessment (PSA) conducted the State Water Board’s eleventh continuous year of probability monitoring of perennial, wadeable streams. To date, the program has collected biological data (invertebrates, algae) and associated chemical and habitat data from approximately 850 probabilistic sites statewide. These surveys have produced a wealth of data that can and should be used to inform many decisions made by California’s water resource agencies. For example, the  assessments in the 2006 California Water Quality Assessment Report (Clean Water Act Section 305(b) Report) were based in large part on data from these surveys.  Data from these surveys were also used in the development of the 2010 Integrated Report.

This report highlights some of the most significant results from the first eight years of PSA and demonstrates some ways that these data can go beyond 305(b) and 303(d) applications to improve California’s water quality programs. The results presented in this summary represent just a fraction of the potential uses of data generated by these ongoing surveys. As the data  et becomes more robust, it will continue to support multiple uses for years to come.

This report is organized around four questions that were used to frame management objectives for the State Water Board’s Non-Point Source Program (NPS), a major partner in PSA’s development:

1. What is the condition of California’s streams?
2. Is stream condition changing over time?
3. What is the relative condition of streams draining agricultural, urban and forested regions?
4. Which stressors have the strongest associations with biological condition?

Future SWAMP reports will highlight the application of PSA data to various State Water Board water quality programs, including links to regional monitoring objectives.