Water Quality Assessment of the Condition of California Coastal Waters and Wadeable Streams: Clean Water Act Section 305b Report 2006
California State Water Resources Control Board (SWRCB) | July 25th, 2006
One of the first steps in managing our environmental resources is to determine their current condition by answering the key question, “What is the overall condition of California’s surface waters?” Often-raised questions relating to the condition of our waters include, “Is the water safe to drink?” “Are the waters safe to swim?” “Are the fish safe to eat?” “Is aquatic life healthy?”
The condition assessments presented in this report focus on two waterbody types: coastal bays and estuaries and wadeable perennial streams. The assessments in this report focus on the question “Is aquatic life healthy?” The “aquatic life” use designation in California’s water quality control plans refers to the beneficial uses of waters that support either warm-water or cold-water ecosystems, including fish, wildlife, invertebrates, vegetation, and other components of aquatic ecosystems. While historical assessments of water quality have primarily focused on describing chemical water quality, this report includes assessments based on biological indicators when available.
This report includes assessments of the condition of coastal bays and estuaries and wadeable perennial streams statewide based on data collected through the Environmental Monitoring and Assessment Program led by the U.S. Environmental Protection Agency (U.S. EPA). These statewide assessments represent the state’s initial attempt to make broad statistical estimates of the conditions of these waterbody types. It establishes baselines against which to compare future assessments. All the statewide assessments based on Environmental Monitoring and Assessment Program datasets have known levels of certainty. These confidence intervals are not included in this report but are available in the technical reports cited. The statewide assessments rely on data from a survey design that generates statistically defensible, unbiased assessments of the conditions of these waterbody types. As such, they did not specifically focus on areas of high impact. Other sampling, which has targeted such areas have shown toxicity and elevated chemical levels in some areas. In addition, only a limited set of indicators were used for the assessments. These indicators are specified in each section.
The federal Clean Water Act’s Section 305b requires each state to report on the quality condition of its waters. The California State Water Board submits its water quality condition assessment report biennially to the U.S. Environmental Protection Agency (U.S. EPA). The reports submitted by states serve as the basis for U.S. EPA’s National Water Quality Inventory Report to Congress.
The Inventory Report is the primary report for the public about the condition of the nation’s waters. The report is also used to inform water quality management decisions, including the allocation of certain Clean Water Act funds among states. However, key reviews of national and state monitoring and assessment efforts suggest that the National Water Quality Inventory Report does not accurately portray water quality conditions, that the monitoring done by states does not always allow for valid assessments of water quality condition in unmonitored waters, and that a consistent approach to monitoring and data collection is needed to support core water programs (U.S. Government Accounting Office, 2000; National Research Council, 2001). As a result, the information provided on the status and trends of waters at statewide and at national scales may be inadequate to support decision making.
The water quality condition assessment reports submitted thus far by California have been based on a regional approach to reporting. The approach corresponds to the structure of the nine California Regional Water Boards and provides essential information for specific waterbodies. However, the assessments cannot be successfully integrated into an accurate statewide report because regions use a variety of assessment approaches and do not always apply criteria consistently. Also, due to limited resources, monitoring has generally focused on problem identification. Clean waters were less likely to be targeted for monitoring, and assessments were based on data with a bias towards sites that were likely sampled due to suspected problems. Furthermore, assessments could not be extrapolated to unmonitored waterbodies or those with insufficient data.
That there is no current way to develop a valid national picture of water quality condition speaks both to the monitoring and assessment challenges faced by states as well as the need for improved assessment tools. The California Water Boards have actively taken steps to meet these challenges. The Surface Water Ambient Monitoring Program’s (SWAMP) comprehensive monitoring and assessment strategy describes some of these steps (A comprehensive monitoring and assessment strategy to protect and restore California’s water quality. Surface Water Ambient Monitoring Program. 2005. [http://www.waterboards.ca.gov/swamp/reports.html]).
As part of the strategy, SWAMP has partnered with U.S. EPA on large-scale monitoring efforts through the Environmental Monitoring and Assessment Program. The Environmental Monitoring and Assessment Program October 2006 Clean Water Act Section 305b Report 2006: California Water Quality Condition Assessment Report effort relies on a statistical monitoring approach that allows assessments of the condition of waters to be extrapolated to unmonitored areas.
For 2006, U.S. EPA has agreed that California can use a different format to submit and meet its Clean Water Act Section 305b reporting requirements. This report would include assessments based on an evaluation of California data collected under U.S. EPA’s Environmental Monitoring and Assessment Program. The assessments apply to two waterbody types: (1) coastal bays and estuaries and (2) wadeable perennial streams. “Wadeable” streams are streams, creeks, and small rivers that are shallow enough to sample without boats.
The assessments focus on one beneficial use (aquatic life use) and are based on a limited suite of key indicators. Specifically, the report had to include sections summarizing:
• Statewide assessments of coastal bays and estuaries based on California data collected as part of the Environmental Monitoring and Assessment Program for Coastal Waters.
• Statewide assessments of wadeable perennial streams based on aquatic invertebrate data collected in California as part of the Environmental Monitoring and Assessment Program for Inland Surface Waters.
• Assessments of northern and southern coastal California’s wadeable perennial streams based on aquatic invertebrate data collected in these areas as part of the Environmental Monitoring and Assessment Program for Inland Surface Waters.
When available, assessments from large-scale regional monitoring efforts such as the Regional Monitoring Program for San Francisco Bay, the Central Coast Long-Term Environmental Assessment Network, the Southern California Bight Project, and the Surface Water Ambient Monitoring Program have been included.
Specifically, more detailed assessments of the San Francisco Bay, the Central Coast, and the Southern California Bight areas are included as part of the coastal waters assessment. More detailed assessments of the Santa Clara River Watershed in Southern California and waters in the Central Coast region are included as part of the wadeable perennial streams assessment. Brief summaries of the Regional Water Boards’ surface water ambient monitoring programs are included in the final section of this report.