Implementation of Best Management Practices to Reduce Agricultural Total Maximum Daily Loads (TMDLs) In the Calleguas Creek and Santa Clara River Watersheds

Section 303(d) of the U. S. Clean Water Act requires each state to identify water bodies that do not meet water quality standards and are not addressed by existing pollution control programs. Several stream reaches of the Calleguas Creek and the Santa Clara River Watersheds, located in Ventura County, California, have been included on the State 303(d) list due to impairments that include benchmark exceedances of nutrients and agricultural pesticides. To control and regulate irrigation and storm water runoff from agricultural lands and to protect water quality in this area, the Los Angeles Regional Water Quality Control Board adopted a Conditional Waiver of Waste Discharge Requirements for Discharges from Irrigated Lands. The current Conditional Waiver for this region was adopted in October 2010 and lasts for five years. The program requires either individual land managers or “Discharger Groups” of managers to monitor water drained from irrigated lands, to implement Best Management Practices (BMPs), and to complete 8 hours of farm water quality education. To assist growers in complying with Conditional Waiver requirements, we are collaborating with the Ventura County Farm Bureau and Resource Conservation District, as well as with the Agricultural Irrigated Lands Group, in a program established to control nonpoint source pollution, funded by the State Water Resources Control Board. Our program includes the dissemination of a self-assessment questionnaire to help growers identify runoff mitigation practices and to develop site and crop-specific farm water quality plans. This questionnaire is also used to document irrigation, pest, nutrient, and sediment and erosion BMPs implemented in targeted stream reaches of each watershed to mitigate runoff.  We have also designed educational workshops with farm tours and demonstrations of effective BMPs for nurseries, orchards, strawberries, and vegetable crops. In addition, we have compiled and developed instructional materials and resources on water quality, which are disseminated at educational meetings and during on-site farm visits. To date, over 400 questionnaires, 50 on-farm visits and nine educational meetings have been completed, to facilitate implementation of BMPs to reduce total maximum daily loads (TMDLs) of agricultural pollutants in the Calleguas Creek and Santa Clara River Watersheds.