DISSEMINATION OF SELF-ASSESSMENT QUESTIONNAIRES

To gather information about BMP use in the Calleguas Creek and Santa Clara watersheds, a survey of water quality management practices for agriculture was developed and distributed to growers in Ventura County at the beginning of 2009 by the VCAILG. VCAILG is a voluntary program consisting of growers and landowners. This group is managed under the Farm Bureau of Ventura County but is funded through annual assessments to its members. The role of VCAILG is to hire consultants who will establish water-monitoring sites, collect and submit runoff water samples to independent laboratories for analyses, and report results to the appropriate state water agencies (Farm Bureau of Ventura County, 2013). The survey included questions regarding 100 individual BMPs, which were classified into the following categories: sediment and erosion management, irrigation management, pest management, nutrient management, salinity management and leaching, and property management (Ventura County Agriculture Irrigated Lands Group, 2008). Surveys were mailed to landowners within VCAILG’s first-tier priority and second-tier priority drainage areas on Mar. 2009 and Oct. 2009, respectively. These priority drainage areas were classified as first, second, or third tier based on the total number of benchmark exceedances, the number of classes of pollutants, the number of total maximum daily loads effective at the drainage point, and the percentage of agricultural acreage enrolled in the VCAILG. Drainages included in the first priority area were Oxnard Central Ditch (Oxnard Coastal watershed), La Vista Drain (Calleguas Creek watershed), and Todd Barranca and Piru Creek (Santa Clara River watershed) (Figs. 1 and 2). Drainages included in the second priority area were Mugu Lagoon, Revolon Slough, and Calleguas Creek (Calleguas Creek watershed) (Fig. 1).

Four hundred twenty-nine surveys that described management practices on the irrigated land were completed and returned. BMPs were evaluated for the constituents that produced water quality benchmark exceedances during VCAILG monitoring in 2007 and 2008. Monitoring data collected by VCAILG to characterize conditions in Calleguas Creek before project implementation indicated that most exceedances of water quality benchmarks were the result of nitrate, organochlorine (forms of DDT, chlordane, and toxaphene), and organophosphorus pesticides (diazinon and chlorpyrifos) as well as salts at some sites (Ventura County Agriculture Irrigated Lands Group, 2010). Results of the surveys (2009 benchmark data) indicate that growers implemented new BMPs after Jan. 2008 in all of the priority drainages areas where exceedances occurred; however, some BMP categories had not been implemented for specific targeted constituents at this time. BMPs designed for sediment/erosion management and salinity/leaching management were less widely implemented in the priority drainages than BMPs designed for management of irrigation, pests, nutrients, and property. Property management was the most prevalent BMP category in use in the priority drainages with an overall average use of 98% for each priority constituent (nitrogen, organochlorine, and organophosphorus pesticides) across the second-tier priority areas (Table 1).

Table 1.

Percentage of acreage within the Calleguas Creek and Santa Clara watersheds where best management practices (BMPs) were implemented to mitigate benchmark exceedances of nitrate, organochlorine, and organophosphorus pesticides (n = 429 surveys) in 2009 (Ventura County Agriculture Irrigated Lands Group, 2010).^z

View Table

DOCUMENTATION OF BEST MANAGEMENT PRACTICES

Between 1 May 2009 and 31 Mar. 2012, 161 farmers and landowners farming 14,287 acres draining to the Calleguas Creek watershed and 7,304 acres draining to the Santa Clara River watershed were assisted with on-site farm water quality management planning (Table 2). Based on site conditions such as topography, microclimate, and crop type, various types of BMPs were suggested during these consultations. Most recommendations included sediment and erosion management practices and irrigation management practices. During the 3-year project period, newly implemented BMPs were documented on 53 properties in the Calleguas Creek watershed, representing over 9800 acres (Table 3). This acreage represents 18% of the estimated agricultural acreage in the watershed (the total acreage of Calleguas Creek watershed is 219,520 acres with an estimated 25% in agricultural land use). Various BMPs were implemented with irrigation management being implemented in all stream reaches (Table 4). Some growers expressed that more efficient irrigation management during the dry season would result in reduced runoff, because most runoff during the dry season results from improper irrigation. Growers on level terrain close to sea level often installed tile drains and pumps to reduce water levels on their fields, so improved irrigation management would minimize additional tile drain pumping. Sediment and erosion management was also frequently implemented by growers.

Table 2.

Number of acres impacted with on-site water quality management plans in the Calleguas Creek and Santa Clara River watersheds from May 2009 to Mar. 2012 based on surveys conducted with growers and landowners during this time period.^z

View Table

Table 3.

Number of properties and total acreage in which best management practices were implemented between May 2009 and Mar. 2012 based on surveys conducted with growers and landowners during this time period.^z

View Table

Table 4.

Total acreage in each of the Calleguas Creek watershed stream reaches in which best management practices (BMPs) were implemented from May 2009 to Mar. 2012 based on surveys conducted with growers and landowners during this time period.^z

View Table

EDUCATION AND OUTREACH

Twelve educational programs were developed and conducted. These programs included classroom lectures and demonstrations and tours of farms showcasing successful BMP implementation. Meetings were open to growers in all Ventura County watersheds as well as growers in other counties. The educational programs were also used by VCAILG members and farmers from other agricultural areas to obtain “Ag Waiver” credits. Each workshop included a survey to assess whether the information presented was useful in implementing BMPs. Additionally, more than 2500 copies of several educational materials published by the University of California, the Resource Conservation District, and the Natural Resources Conservation Service of the U.S. Department of Agriculture were distributed at on-farm visits, workshops, and other grower events to enhance adoption of BMPs.

Over 55% of meeting attendees completed program evaluations when averaged for all 12 workshops. Over 90% of these attendees rated the workshops and tours as “informative,” the highest rating of the choices provided. At eight workshops conducted between May 2009 and June 2011, attendees were asked whether participating in a previous educational program resulted in implementation of a BMP; over 55% of respondents indicated this was the case. Irrigation and property management BMPs were among the most widely adopted after attending an education meeting. Beginning in June 2011, attendees were asked about planned BMP implementation as a result of attending the meeting being evaluated. Approximately 75% of respondents indicated they would adopt new BMPs in the next 5 years, particularly for irrigation, erosion, and pest management. The results of program evaluations highlight the importance of educational workshops and tours. Not only were these meetings rated highly by growers, property managers, and other affiliates, but attendance also led to immediate implementation of BMPs as well as future plans for further BMP adoption.

CONCLUSIONS

This 3-year, collaborative project resulted in improved understanding, by growers and landowners, of water quality issues and significantly increased the implementation of appropriate BMPs to protect water quality. Nearly 100 new BMPs, primarily aimed at managing erosion, sediment movement, and irrigation runoff in more than 8000 acres draining into Calleguas Creek, were identified and documented. A total of 518 people attended the educational programs, and over 90% of participants who completed evaluations rated the programs highly. In the final year of the project, 75% of attendees indicated they plan to implement new BMPs within the next 5 years, especially in the areas of irrigation, erosion, and pest management.