Regional Water Quality Control Board Research Articles

Developing agricultural pest management strategies with reduced-risks to surface water: An economic case study of California's Central Coast region

Pesticides are critical for protecting agricultural crops, but the off-site transport of these materials via spray drift and runoff poses risks to surface waters and aquatic life. California's Central Coast region is a major agricultural hub in the United States characterized by year-round production and intensive use of pesticides and other chemical inputs. As a result, the quality of many waterbodies in the region has been degraded. A recent regulatory program enacted by the Central Coast Regional Water Quality Control Board set new pesticide limits for waterways and imposed enhanced enforcement mechanisms to help ensure that water quality targets are met by specific dates. This regulatory program, however, does not mandate specific changes to pest management programs. In this study, we evaluate the economic, environmental, and pest management impacts of adopting two alternative pest management programs with reduced risks to surface water: 1) replacing currently used insecticide active ingredients (AIs) that pose the greatest risk to surface water with lower-risk alternatives and 2) converting conventional arthropod pest management programs to organic ones. We utilize pesticide use and toxicity data from California's Department of Pesticide Regulation to develop our baseline and two alternative scenarios. We focus on three crop groups (cole crops, lettuce and strawberry) due to their economic importance to the Central Coast and use of high-risk AIs. For Scenario 1, we estimate that implementing the alternative program in the years 2017–2019 would have reduced annual net returns on average by $90.26 – $190.54/ha, depending on the crop. Increased material costs accounted for the greatest share of this effect (71.9%–95.6%). In contrast, Scenario 2 would have reduced annual net returns on average by $5,628.12 – $18,708.28/ha during the study period, with yield loss accounting for the greatest share (92.8–97.9%). Both alternative programs would have reduced the associated toxic units by at least 98.1% compared to the baseline scenario. Our analysis provides important guidance for policymakers and agricultural producers looking to achieve environmental protection goals while minimizing economic impacts.

US and international per- and polyfluoroalkyl substances surface water quality criteria: A review of the status, challenges, and implications for use in chemical management and risk assessment.

Regulation of per- and polyfluorinated substances (PFAS) in surface water is a work-in-progress with relatively few criteria promulgated in the United States and internationally. Surface water quality criteria (SWQC) or screening values derived for perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) by Australia, Canada, the European Union (EU), and four US states (Florida, Michigan, Minnesota, and Wisconsin), and the San Francisco Bay Regional Water Quality Control Board (SFB RWQCB; California) were compared. Across these eight jurisdictions, promulgated numeric criteria for the same compound and receptor span over five orders of magnitude as a result of different approaches and data interpretations. Human health criteria for PFOS range from 0.0047 to 600 ng/L depending on route of exposure (e.g., fish consumption or drinking water) and are lower than most ecological criteria for protection of aquatic and wildlife receptors. Data gaps and uncertainty in chronic toxicity and bioaccumulation of PFOS and PFOA, as well as the use of conservative assumptions regarding intake and exposure, have resulted in some criteria falling at or below ambient background concentrations and current analytical detection limits (around 1 ng/L for commercial laboratories). Some jurisdictions (e.g., Australia, Canada) have deemed uncertainty in quantifying water-fish bioaccumulation too great and set fish tissue action levels in lieu of water criteria. Current dynamics associated with the emerging and evolving science of PFAS toxicity, exposure, and environmental fate (i.e., data gaps and uncertainty), as well as the continuous release of scientific updates, pose a challenge to setting regulatory limits. Integr Environ Assess Manag 2024;20:36-58. © 2023 AECOM Technical Services, Inc and The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Tertiary butyl alcohol plumes in southern california groundwater from leaking underground storage tank sites

Tertiary butyl alcohol in the groundwater was evaluated using closed leaking underground storage tank sites in Southern California between 2016 and 2019. Tertiary butyl alcohol is not regulated and lacks a maximum contaminant level in California. The current level of 12 µg per liter in drinking water (notification level) is advisory and not enforceable. As high as 88% of sites during 2018–2019 fiscal year were closed with tertiary butyl alcohol higher than its notification level in groundwater. Twenty-five percent of the time, the maximum tertiary butyl alcohol concentrations in the groundwater at closure were higher than 2,300 µg per liter during 2016–2017, 7,600 µg per liter during 2017–2018, and 4,400 µg per liter during 2018–2019, respectively. The plume length of the maximum tertiary butyl alcohol increased from 649 feet in 2016 to 1,128 feet in 2019. Considering the proximity of drinking water wells to the leaking underground storage tank sites in California, this points to an increase risk of impact on the drinking water resources. Tertiary butyl alcohol remained above 12 µg/L in a substantial percentage (70% in 2016–1017, 72% in 2017–2018, and 88% in 2018–2019) of sites. Site closure practices at Los Angeles Regional Water Quality Control Board should be more stringent toward tertiary butyl alcohol contamination. Despite documented health hazards, tertiary butyl alcohol has not received sufficient attention from government agencies. The toxicological evaluation of tertiary butyl alcohol indicates significant human health concerns. Based upon the toxicological evidence, an MCL should be considered for tertiary butyl alcohol in drinking water.

Evaluation of tertiary butyl alcohol (TBA) impact on groundwater: application to California

Leaking underground storage tanks can contaminate the groundwater. Since the 1980s, California leaking underground storage tanks have released millions of gallons of petroleum containing tertiary butyl alcohol into the subsurface. This compound was banned in early 2000 due to human health concerns. The United States Environmental Protection Agency considers tertiary butyl alcohol an animal carcinogen and a potential human carcinogen. California has not established a maximum contaminant level for tertiary butyl alcohol. (1) Based on the documented health hazards, a maximum contaminant level should be developed for tertiary butyl alcohol in California. (2) The California Water Resources Control Board’s “Low Threat Closure Policy”, which is a tool to evaluate closure of leaking underground storage tank sites, does not require regulators to consider tertiary butyl alcohol contamination in soil or groundwater in their closure review. This practice should be revisited based upon tertiary butyl alcohol’s toxicity data, its biotransformation from methyl tertiary butyl ether, and its stability in the environment. This review summarizes toxicity, sources, and environmental transformation of tertiary butyl alcohol, aims to raise awareness regarding the magnitude of the tertiary butyl alcohol problem in groundwater, and urges California regulators to develop more stringent protocols for tertiary butyl alcohol treatment. The nine Regional Water Quality Control Boards regulate and oversee cleanup at leaking underground storage tank sites in California. This study will directly impact Regional Water Quality Control Boards regulatory practices and will help provide a framework for developing monitoring and cleanup strategy for tertiary butyl alcohol around the world.

Water storage and irrigation practices for cannabis drive seasonal patterns of water extraction and use in Northern California

There is growing concern over the impacts of cannabis farms on the environment and water resources in particular, yet data on cultivation practices and water use patterns have been limited. Estimates of water use for cannabis cultivation have previously relied on extrapolated values of plant water demand, which do not account for differences in cultivation practices, variation across the growing season, or the role of water storage in altering seasonal extraction patterns. The current study uses data reported by enrollees in California's North Coast Regional Water Quality Control Board Cannabis Program to model how variation in cultivation practices and the use of stored water affect the timing and amount of water extracted from the environment. We found that the supplemental use of stored water resulted in a seasonal pattern of water extraction (water withdrawals from the environment) that was distinct from water demand (water applied to plants). Although water input to storage in the off-season months (November through March) reduced water extraction in the growing season (April through October), farms generally did not have sufficient storage to completely forbear from surface water extraction during the growing season. The most important predictors of storage sufficiency were type of storage infrastructure, type of water source, and farm size, with the likelihood of sufficiency decreasing with increasing cultivation area. As of 2019, state cannabis regulations require forbearance from surface water diversions from April through October. To comply, farms relying on surface water must either develop storage, reduce water demand, or seek alternative water sources, such as groundwater. Our findings indicate that water extraction from farms using groundwater wells generally occurs during the summer dry season and highlight the need to assess their potential impacts to connected surface water in streams. Finally, given that the current study was based on data exclusively from permitted cannabis farms, additional data from unpermitted operations would enhance our overall understanding of cannabis water-use practices and consequences for the environment.

Watering the Emerald Triangle: Irrigation sources used by cannabis cultivators in Northern California

Water use by cannabis cultivators represents an emerging threat to surface flows in Northern California's sensitive watersheds. To date, however, no data has been available to formally assess where cannabis sites source their water. This study analyzed data from annual reports, covering the year 2017, submitted by 901 cannabis cultivators enrolled in the Cannabis Waste Discharge Regulatory Program administered by the North Coast Regional Water Quality Control Board. The analysis identified cannabis cultivators' most common sources for water extraction, monthly patterns for each water source and differences between sites compliant and not compliant with the cannabis program. The most commonly reported source of water was wells (58% of sites), with most extraction from wells occurring during the growing season (April through October). Surface water diversions (22% of sites) and spring diversions (16% of sites) were the most common sources after wells, with extractions from these sources distributed much more evenly across the year. Although nearly one-third of noncompliant sites (33%) used wells, this source was more than twice as frequently reported among compliant sites (68%), indicating that wells may become increasingly common as more sites become part of the regulated cannabis industry.

UC-industry-agency partnerships influence and help implement dairy water quality policy

For 50 years, UC Agriculture and Natural Resources (UC ANR) has contributed to dairy water quality policy in California and helped, with partner organizations, to implement it in the dairy industry. When conditional waivers for waste discharge requirements expired in 2003, UC ANR shared research and best professional practices as regional water quality control boards developed new orders. UC ANR academics then worked with water quality control boards' staff and dairy industry representatives to develop feasible, staged implementation plans. Collaboratively, more than 50 hours of workshop curriculum were developed and disseminated, helping dairy producers to accept scientifically sound management practices that are more protective of groundwater. Research by UC ANR to better understand system dynamics, nitrogen management and practices to minimize the impact of manure application on groundwater quality continues, as does a program in environmental stewardship.

Development of treatment media for advanced stormwater treatment at an industrial site

Abstract The Santa Susana Field Laboratory (SSFL) occupies about 2,850 acres and is located in Ventura County, California. The site is jointly owned by the Boeing Company and the federal government (the National Aeronautics and Space Administration administers the federal portion of the property). Much of the site was historically used as a rocket engine testing and energy research facility from 1949 to 1998. The site stormwater discharges are permitted by the Los Angeles Regional Water Quality Control Board through an individual industrial NPDES permit that includes numeric effluent limits for a wide range of constituents, including dioxins and metals. A large portion of the site uses distributed source stormwater controls with natural treatment systems utilizing chemically active media. As part of this approach, extensive research was conducted to develop a robust media for use in these controls to meet the discharge objectives. This paper describes the development of the media and its characteristics.

Central Coast growers' trust in water quality regulatory process needs rebuilding

Growing evidence of agricultural water pollution in California's Central Coast even after the implementation of tough water quality regulations has increased the pressure on regional stakeholders. Previous research has shown that collaborative relationships between growers and regulators can motivate growers to make management decisions that benefit the environment. However, informal evidence suggested trust might have been eroding between growers and the Central Coast Regional Water Quality Control Board (CCRWQCB, the regulator) since 2004, the year the first legislation went into effect. Using a survey conducted in 2015, interviews and in-depth document review, this study assesses growers' trust of and communication with other agricultural groups and water quality regulatory agencies, specifically CCRWQCB. Survey results were compared to results of the same survey sent out in 2006. Results corroborate other research — growers' trust of most regional agricultural groups was closely correlated with frequency of communication. However, growers' trust of CCRWQCB did not correspond to the relatively high contact frequency and had declined since 2006. The literature on rebuilding trust suggests ways forward for CCRWQCB.

Changing patterns in water toxicity associated with current use pesticides in three California agriculture regions.

Regulation of agriculture irrigation water discharges in California, USA, is assessed and controlled by its 9 Regional Water Quality Control Boards under the jurisdiction of the California State Water Resources Control Board. Each Regional Water Board has developed programs to control pesticides in runoff as part of the waste discharge requirements implemented through each region's Irrigated Lands Regulatory Program. The present study assessed how pesticide use patterns differ in the Imperial (Imperial County) and the Salinas and Santa Maria (Monterey County) valleys, which host 3 of California's prime agriculture areas. Surface-water toxicity associated with current use pesticides was monitored at several sites in these areas in 2014 and 2015, and results were linked to changes in pesticide use patterns in these areas. Pesticide use patterns appeared to coincide with differences in the way agriculture programs were implemented by the 2 respective Regional Water Quality Control Boards, and these programs differed in the 2 Water Board Regions. Different pesticide use patterns affected the occurrence of pesticides in agriculture runoff, and this influenced toxicity test results. Greater detection frequency and higher concentrations of the organophosphate pesticide chlorpyrifos were detected in agriculture runoff in Imperial County compared to Monterey County, likely due to more rigorous monitoring requirements for growers using this pesticide in Monterey County. Monterey County agriculture runoff contained toxic concentrations of pyrethroid and neonicotinoid pesticides, which impacted amphipods (Hyalella azteca) and midge larvae (Chironomus dilutus) in toxicity tests. Study results illustrate how monitoring strategies need to evolve as regulatory actions affect change in pesticide use and demonstrate the importance of using toxicity test indicator species appropriate for the suite of contaminants in runoff in order to accurately assess environmental risk. Integr Environ Assess Manag 2018;14:270-281. © 2017 SETAC.

An integrated vegetated ditch system reduces chlorpyrifos loading in agricultural runoff.

Agricultural runoff containing toxic concentrations of the organophosphate pesticide chlorpyrifos has led to impaired water body listings and total maximum daily load restrictions in California's central coast watersheds. Chlorpyrifos use is now tightly regulated by the Central Coast Regional Water Quality Control Board. This study evaluated treatments designed to reduce chlorpyrifos in agricultural runoff. Initial trials evaluated the efficacy of 3 different drainage ditch installations individually: compost filters, granulated activated carbon (GAC) filters, and native grasses in a vegetated ditch. Treatments were compared to bare ditch controls, and experiments were conducted with simulated runoff spiked with chlorpyrifos at a 1.9 L/s flow rate. Chlorpyrifos concentrations and toxicity to Ceriodaphnia dubia were measured at the input and output of the system. Input concentrations of chlorpyrifos ranged from 858 ng/L to 2840 ng/L. Carbon filters and vegetation provided the greatest load reduction of chlorpyrifos (99% and 90%, respectively). Toxicity was completely removed in only one of the carbon filter trials. A second set of trials evaluated an integrated approach combining all 3 treatments. Three trials were conducted each at 3.2 L/s and 6.3 L/s flow rates at input concentrations ranging from 282 ng/L to 973 ng/L. Chlorpyrifos loadings were reduced by an average of 98% at the low flow rate and 94% at the high flow rate. Final chlorpyrifos concentrations ranged from nondetect (<50 ng/L) to 82 ng/L. Toxicity to C. dubia was eliminated in 3 of 6 integrated trials. Modeling of the ditch and its components informed design alterations that are intended to eventually remove up to 100% of pesticides and sediment. Future work includes investigating the adsorption capacity of GAC, costs associated with GAC disposal, and real-world field trials to further reduce model uncertainties and confirm design optimization. Trials with more water-soluble pesticides such as neonicotinoids are also recommended. Integr Environ Assess Manag 2017;13:423-430. © 2016 SETAC.

Relative toxicity of bifenthrin to Hyalella azteca in 10 day versus 28 day exposures.

Many watersheds in the Central Valley region of California are listed as impaired due to pyrethroid-associated sediment toxicity. The Central Valley Regional Water Quality Control Board is developing numeric sediment quality criteria for pyrethroids, beginning with bifenthrin. Criteria are being developed using existing data, along with data from 10 d and 28 d toxicity tests with Hyalella azteca conducted as part of the current study. A single range-finder and 2 definitive tests were conducted for each test duration. Median lethal concentrations (LC50s), as well as LC20s and inhibition concentrations (IC20s) were calculated based on measured whole sediment bifenthrin concentrations and interstitial water concentrations. Sediment LC50s were also corrected for organic C content. Average LC50s were not significantly different in 10 d versus 28 d tests with H. azteca: 9.1 and 9.6 ng/g bifenthrin for 10 d and 28 d tests, respectively. Average LC20 values were also similar with concentrations at 7.1 and 7.0 for 10 d and 28 d tests, respectively. Bifenthrin inhibition concentrations (IC20s) based on amphipod growth were variable, particularly in the 28 d tests, where a clear dose-response relationship was observed in only 1 of the definitive experiments. Average amphipod growth IC20s were 3.9 and 9.0 ng/g for 10 d and 28 d tests, respectively. Amphipod growth calculated as biomass resulted in IC20s of 4.1 and 6.3 ng/g for the 10 d and 28 d tests, respectively. Lack of a clear growth effect in the longer term test may be related to the lack of food adjustment to account for amphipod mortality in whole sediment exposures. The average C-corrected LC50s were 1.03 and 1.09 μg/g OC for the 10 d and 28 d tests, respectively. Interstitial water LC50s were determined as the measured dissolved concentration of bifenthrin relative to interstitial water dissolved organic carbon. The average LC50s for dissolved interstitial water bifenthrin were 4.23 and 4.28 ng/L for the 10 d and 28 d tests, respectively. In addition, a set of 10 d and 28 d tests were conducted at 15 °C to assess the relative toxicity of bifenthrin at a lower temperature than the standard 23 °C test temperature. These results showed that bifenthrin was more toxic at the lower temperature, with LC50s of 5.1 and 3.4 ng/g bifenthrin in 10 d and 28 d tests, respectively. Amphipod growth at 15 °C after a 28 d exposure resulted in the lowest effect concentration of all experiments conducted (IC20 = 0.61 ng/g). This article discusses how bifenthrin dose-response data from 10 d and 28 d exposures inform development of sediment quality criteria for this pesticide for California Central Valley watersheds.

Comparison of advanced water purification operations and performance for San Diego’s demonstration facility

The City of San Diego (City) evaluated the option of indirect potable reuse with reservoir augmentation (IPR/RA), as a way to reduce dependence on imported water. The City’s concurrent Recycled Water Study evaluated ways to increase recycling, while reducing flows to the Point Loma Wastewater Treatment Plant (Point Loma). A 68 megaliters per day (MLD) capacity full scale advanced water purification facility (full scale facility) has been proposed to supply this water from the North City Water Reclamation Plant (North City). If reservoir augmentation is pursued, purified water would be blended with existing raw water supplies within San Vicente Reservoir and pass through an existing potable water treatment plant before use in the City’s drinking water supply (). As part of the City’s reservoir augmentation program, they commissioned a 3·8 MLD demonstration scale advanced water purification facility (demonstration facility) to verify consistent achievement of water quality criteria, facilitate public support, and aid in optimization of the proposed treatment processes. In June 2011, CDM Smith and team member MWH began a 12-month testing period followed by a 9-month operation period to determine the effectiveness of a three-step treatment process, including membrane filtration, through microfiltration (MF) and ultrafiltration (UF), reverse osmosis (RO), and ultraviolet light (UV) with advanced oxidation. The major objectives of the testing program included: demonstrate to the California Department of Public Health (now the State Water Resource Control Board Division of Drinking Water) and the Regional Water Quality Control Board (RWQCB) that the proposed advanced water purification (AWP) technology will produce a final product water quality that meets public health and surface water augmentation criteria; evaluate nutrient removal performance of the baseline AWP process train; implement a monitoring plan for Constituents of Emerging Concern (CECs) tailored to North City tertiary water characteristics and current recommendations of the State Water Resources Control Board; demonstrate integrity monitoring techniques and performance reliability measures for the AWP process train, which can be implemented at the full scale facility; and monitor and collect operational performance and maintenance requirements of the AWP equipment. This paper focuses on the membrane filtration and RO systems, evaluating the design criteria and operating performance, while comparing the performance of parallel treatment trains operating with different equipment and operating conditions.

DDT, chlordane, toxaphene and PCB residues in Newport Bay and Watershed: assessment of hazard to wildlife and human health.

DDT, chlordane, toxaphene and the PCBs are persistent organochlorines that are still found in aquatic environments of Newport Bay and Watershed (Orange County, California), decades after their use was discontinued. Under the Clean Water Act, organochlorines are regulated by a total maximum daily load (TMDL) to achieve levels that protect wildlife and human health. Stakeholders in the Newport Bay Watershed and an Independent Advisory Panel (IAP) requested by the Regional Board and administered by Orange County have questioned the quality of the science used to establish TMDL targets by US EPA Region IX and the Santa Ana Regional Water Quality Control Board. This review brings together a number of technical reports written by stakeholder consultants that address the scientific basis for the organochlorine TMDLs for Newport Bay and Watershed.

Medications and treatment practices used on California dairies

During the December, 2010, Central Valley Regional Water Quality Control Board (RB5) board meeting, requests were made for more stringent permit requirements for dairy operations. The dairy industry proposed that UC-Davis complete a study of pharmaceutical use on California dairies in order to generate current and objective data with which to inform the permit development process. To obtain the data required, a survey of practicing dairy veterinarians was conducted to provide a point of reference for evaluating pharmaceutical use specific to California dairies.

Implementation of Best Management Practices to Reduce Agricultural Total Maximum Daily Loads in the Calleguas Creek and Santa Clara River Watersheds: A Case Study of Water Contaminant Mitigation in California

Agriculture is a major industry in California, with cool-season crops grown along the state’s coasts, warm-season crops grown in the hot deserts, and many temperate crops grown in the state’s valleys. In coastal communities such as Ventura County, the Calleguas Creek and the Santa Clara River watersheds have 50,000 and 60,000 irrigated acres of farm crops, respectively. These watersheds are considered impaired by nutrients, salts, pesticides, and other agricultural contaminants. Mitigation of chemical and sediment runoff through grower-implemented best management practices (BMPs) is therefore one of the highest priorities in the Los Angeles Regional Water Quality Control Board Basin Plan. A 3-year project was designed to assist Ventura County growers in meeting regional water quality objectives. The University of California Cooperative Extension Ventura County and the University of California, Riverside, collaborated with the Ventura County Resource Conservation District and the Ventura County Agricultural Irrigated Lands Group (VCAILG) to address three project goals: increase grower and landowner understanding of local agricultural water quality issues; identify gaps or deficiencies in current management practices in agricultural operations; and reduce the contribution of nutrients, pesticides, and other pollutants to impaired water bodies. To achieve these goals, 469 surveys of agricultural water quality management practices were collected to assess the extent of current adoption of BMPs. Over 160 growers who farm more than 14,000 acres that drain into Calleguas Creek and 7,000 acres that drain into the Santa Clara River watersheds were assisted. Using the survey, growers developed site-specific farm water quality plans and received on-farm recommendations for BMPs. Additionally, 12 water quality educational programs, “including demonstrations of successful BMPs,” were developed and more than 2500 copies of 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. The project resulted in improved understanding, by growers and landowners, of water quality issues and significantly increased the implementation of appropriate on-farm BMPs to protect water quality. Nearly 100 new BMPs primarily aimed at managing erosion, sediment movement, and irrigation runoff were identified and documented through annual reassessments for more than 8000 acres draining into Calleguas Creek. 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.

Survey of dairy housing and manure management practices in California

In 2007, a descriptive survey was mailed to all dairies in Glenn (G) and Tulare (T) Counties to identify current and future opportunities of manure management practices on California dairies. The purpose was to provide baseline information for development of outreach curriculum and a decision support tool to quantify potential benefits of various N management options on dairy farms. Such baseline information is valuable to staff regulating dairy facilities (e.g., San Joaquin Valley Unified Air Pollution Control District and Central Valley Regional Water Quality Control Board), dairy trade association representatives, and technology vendors. Response rates for each county were similar at 29.7% (n=19; G) and 26.7% (n=88; T). Mean milking herd size averaged 570 (range 50 to 3,000) cows in G and 1,800 (range 196 to 9,286) cows in T. Survey data are reported by location due to differences between counties in herd size, housing facilities, and climate. Freestalls are common housing facilities (63.2%, G; 38.6%, T) and separated solids and corral scrapings are commonly used as bedding in freestalls (81.8% G and 79.4% T). The most common methods of manure collection were flushing and scraping (18.8%, G; 44.7%, T), only flushing (43.8%, G; 34.1%, T), or only scraping daily or less frequently than daily (37.5%, G; 20.0%, T). Most dairy farms in G (63.2%) and T (70.5%) used some method of separating solids from liquids. However, mechanical separation systems alone were used by 5.3% G and 11.4% T of dairy farms. Storage or treatment ponds were found on 95.9% of dairies. Respondents identified existing manure management practices and did not indicate any new technologies were in use or being considered for manure management. Survey results were used to describe the 2 predominant manure management pathways of manure collection, storage, treatment, and utilization. Survey results will be used to develop and disseminate targeted information on manure treatment technologies, and on-farm evaluation of implemented technologies related to anaerobic digesters, solid liquid separation, and pond additives.

California's Rangeland Water Quality Management Plan: An Update

In late 1989, California’s Range Management Advisory Committee, made up of livestock industry and public members, identifi ed water quality as a priority issue. In 1990, California’s range livestock industry began to develop a program of voluntary compliance with the Federal Clean Water Act, federal and state coastal zone regulations, and California’s Porter-Cologne Act, which provides for regulation of water quality by the State Water Resources Control Board (SWRCB) and nine Regional Water Quality Control Boards.1 This livestock industry initiative led to development of the California Rangeland Water Quality Management Plan (CRWQMP) for nonfederal rangelands, which was approved by the SWRCB in 1995.2 The objectives of the CRWQMP were to conduct management activities that would prevent sediment, nutrients, pathogens, and water temperature from exceeding prescribed standards established by California’s Regional Water Quality Control Boards (RWQCB). The CRWQMP proposed that nonfederal rangeland owners and managers voluntarily develop a management strategy at the ranch and watershed level that would 1) determine impairment to benefi cial uses of water bodies in the ranch’s watershed and 2) assess the causes of impairments. The CRWQMP, developed in collaboration with regulatory agencies, state advisory committees, private consultants, the US Department of Agriculture Natural Resources Conservation Service (NRCS), and University of California Cooperative Extension (UCCE), provided for development and implementation of ranch water quality plans that address these two objectives on a voluntary basis.

REGULATION OF NUTRIENT MANAGEMENT IN VEGETABLE PRODUCTION: THE CALIFORNIA EXPERIENCE

More than 160,000 ha of cool-season vegetables are produced annually in the coastal valleys of central California. In these valleys vegetable production dominates the landscape, and since most fields produce two or more crops per year the mean annual fertilizer input is very high. Not surprisingly, environmentally problematic levels of soluble phosphorus in surface waters, and nitrate-nitrogen (NO 3 -N) in both surface- and groundwater, are common. The Central Coast Regional Water Quality Control Board (WQCB) is struggling to develop effective regulatory measures to improve water quality without damaging the viability and competitiveness of the commercial vegetable industry. Recognizing the dynamic nature of a system in which dozens of vegetable commodities are produced year around on a range of soils and in varying rotational schemes, the WQCB has been reluctant to impose numerical limits on fertilizer application, or to mandate the use of specific management practices. To date, regulatory efforts have been tied to the discharge of irrigation tailwater or storm runoff from agricultural land. In 2004 the WQCB granted a 5-year waiver from the requirement to obtain a permit for such discharge to all growers who agreed to: a) attend an extensive water quality training course; b) develop a written farm water quality protection plan outlining practices to be undertaken to reduce nutrient losses; and c) participate in a watershed-scale water quality monitoring program. In the initial years of this program the majority of vegetable growers met these requirements, yet the monitoring data have shown no substantive improvement in water quality parameters related to nutrients. The WQCB is currently planning additional grower educational activities to encourage wider adoption of efficient nutrient and irrigation management practices, and is considering additional grower requirements for extending the discharge waivers.

Developing Effective Stakeholder Based Total Maximum Daily Loads for Multiple Pollutants

Developing Effective Stakeholder Based Total Maximum Daily Loads for Multiple PollutantsLocated in Ventura County California, the Calleguas Creek Watershed (CCW), though relatively small in area, suffers from more water quality impairments than most California watersheds, as defined by the USEPA's 303(d) list. Local stakeholders, along with the Los Angeles Regional Water Quality Control Board (LARWQCB), began a watershed planning process over eight years ago to develop a better...Author(s)Chris MintonSourceProceedings of the Water Environment FederationSubjectArticlesDocument typeConference PaperPublisherWater Environment FederationPrint publication date Oct, 2007ISSN1938-6478SICI1938-6478(20071001)2007:5L.55;1-DOI10.2175/193864707786619297Volume / Issue2007 / 5Content sourceTMDLS ConferenceFirst / last page(s)55 - 63Copyright2007Word count79