A Problem Solving Approach to Nitrate Pollution on Franklin Creek

A collaboration between regulatory and monitoring program staff

Project Purpose:

To problem solve and monitor greenhouse management practices with regard to nitrate pollution improvement.

The Central Coast Ambient Monitoring Program (CCAMP) coastal confluence sites, located at the bottoms of our major watersheds, are used to track long-term water quality trends in streams and rivers entering the ocean. Several creeks in the Carpinteria area were “standouts” because of the very elevated levels of nitrate regularly present. Regulatory staff toured the area with Channelkeeper and determined that greenhouses were discharging wastewater to Santa Monica and Franklin Creeks in the Carpinteria Marsh watershed. Upstream sampling confirmed that greenhouses were likely contributing to nitrate pollution.

On August 20, 2001, a subcommittee of the Water Board conducted a public workshop in Carpinteria with greenhouse operators and others to discuss issues and solutions. The Water Board formed a Greenhouse Team and continued to work with growers and Channelkeeper toward problem solutions.

Project Results:

Greenhouse operators ceased discharging to surface waters per specific time schedules and plans. Many chose to internally recycle their wastewater, eliminating a direct discharge to the stream. Four years of data at the CCAMP coastal confluence monitoring station on Franklin Creek show significant declines in nitrate concentrations. Average concentrations have declined by almost 50%. The data show dramatic water quality improvement associated with the Water Board's use of problem-solving and teamwork with greenhouse operators and Channelkeeper. The Water Board intends to continue monitoring for additional water quality improvements in this area.

How Success Was Measured:

Success was measured by direct water quality improvements in nitrate concentrations.

Pictures:

Figure 1. Regression of mean nitrate concentrations (mg/L) over time at Franklin Creek (significant at 95% confidence level)

Contact:

Michael Higgins at:
mhiggins@waterboards.ca.gov, 805-542-4649

Karen Worcester at:
Karen.Worcester@waterboards.ca.gov, 805-549-3333