Through Coastkeeper’s research, agricultural runoff from nurseries was identified as a contributor of poor water quality in Orange County streams, with the highest unit loading of pollutants in runoff per acre. Runoff from wholesale nurseries contains high levels of sediment, nutrients, pesticides and bacteria that have an adverse effect on the receiving waters. These pollutant discharges can be reduced or eliminated with the use of Best Management Practices (BMPs). Unfortunately, missing or poorly implemented BMPs commonly result in over-watering, improper storage, overuse of fertilizers and agricultural chemicals, and/or poor site design.
A Cooperative Project
In order to address this situation, Orange County Coastkeeper initiated the Orange County Nurseries Water Quality Improvement Project in 2007. In a collaborative effort, Coastkeeper and the U.C. Cooperative Extension (UCCE) worked with nursery operators to reduce pollution from local nursery operations and selected large agricultural operations. Along the way, Coastkeeper collected water samples to identify pollution issues, and measure improvements over time.
What Did We Do?
This project had two major components: (1) water quality monitoring and (2) best management practice (BMP) education and outreach.
- The Parameters tested: temperature, pH, conductivity, total suspended solids (TSS), ammonia nitrogen, nitrate, nitrogen, orthophosphate, organophosphate, and pyrethroid pesticides.
- The Result? Most parameters exceeded their project action limits throughout the project (based on Basin Plan standards or EPA guidelines). Dry season monitoring of enrolled nurseries saw reductions in the following pollutant concentration: TSS, ammonia-nitrogen, orthophosphate, E. coli bacteria, and pesticide chlorphyrifos. During wet season monitoring, both enrolled and non-enrolled nurseries saw reductions in ammonia and nitrate loads, and increases in pesticides malathion, bifenthrin, and permethrin as well as total coliform and enterococcus bacteria.
Education and Outreach: UCCE performed 64 on-site consultations with wholesale nursery operators from 2006-2009. After the initial consultation, UCCE made BMP recommendations to nursery operators not correctly implementing all the BMPs that could be employed at their location.
- How was it done? ”Best Management Practices: A Water Quality Field Guide for Nurseries” was developed as a joint project by the University of California Cooperative Extension, Orange County Coastkeeper, Orange County Farm Bureau, and Southern California Edison. This guide was given to nursery operators, and used to inventory the BMPs in use by project wholesale nurseries.
- Results? By distributing the Field Guide, giving free consultations and hosting public workshops, this project educated local nursery operators in how they can prevent water pollution at their sites. Unfortunately, the State’s fiscal crisis led to a Stop Work order, which was issued for this project in December 2008. Therefore, no final BMP consultations were performed by UCCE to determine if the recommended BMPs were implemented by the nursery operators or BMPs inventoried during the initial consultation were still in use.
Did the Project make a difference?
The effectiveness of the BMP training was documented through water quality monitoring throughout the project. During dry weather monitoring, enrolled nurseries had higher water quality improvements than non-enrolled nurseries.
This project provided valuable data to the State and Regional Water Boards, fully characteristizing pollutant loading from nurseries in Orange County. The data also showed increases in pesticide levels during storm events from 2007-2009, which informs the Water Boards on the expanding use of these pollutants.
Our data has shown high levels of pollutants discharged from nursery operations, while at the same time these nurseries are exempt from water quality regulations. Coastkeeper will continue to demand stronger statewide standards to improve the water quality of agricultural runoff. We hope that BMP program will serve as a model for future oureach projects to nurseries across the state.
- Final Report: Orange County Nurseries Water Quality Improvement Project, 2009 (3mb, pdf)
- “Best Management Practices: A Water Quality Field Guide for Nurseries,” Southern California Edition (2mb, pdf)