Central Coast Regional Water Board adopts General Waste Discharge Requirements for Discharges from Irrigated Lands

CENTRAL COAST REGION – On April 15, 2021, the Central Coast Regional Water Quality Control Board adopted General Waste Discharge Requirements for Discharges from Irrigated Lands (Ag Order 4.0), and a resolution certifying the Final Environmental Impact Report for Ag Order 4.0.

The requirements in Ag Order 4.0 protect human health, protect and restore the beneficial uses of surface and groundwater, and achieve water quality objectives specified in the Central Coast Basin Plan by minimizing nitrogen discharges to groundwater, minimizing nutrient, pesticide and sediment discharges to surface water. The order also requires the protection of riparian and wetland habitat.

Irrigated agriculture is a significant cultural characteristic and economic driver in the Central Coast. Its Mediterranean climate facilitates multiple cropping cycles per year, sometimes up to 3 to 4 crops grown per acre per year, of high-value crops like lettuce, broccoli, spinach, cauliflower, and strawberries that require significant fertilizer nitrogen, herbicide, pesticide and other agrichemical inputs. The multiple cropping cycles per year of these crops result in multiple applications of agricultural inputs that cause well documented severe and widespread impacts to surface and groundwater quality, and impairment of drinking water, surface water and riparian habitat beneficial uses.

Groundwater and drinking water nitrate impacts associated with fertilizer nitrogen discharges are particularly significant and problematic in the Central Coast because it is a groundwater-dependent region, relying on groundwater for approximately 90 percent of its water supply. Unsafe drinking water severely and disproportionately impacts disadvantaged communities within and surrounding agricultural areas, and high nitrate concentrations in groundwater increases water costs to all users, including those connected to public water systems.

“The Board devoted an unprecedented amount of time to considering input from a broad range of stakeholders over the last several years and unanimously adopted an order that balances various competing interests while establishing clear objectives and requirements by which to evaluate measurable progress,” said Dr. Jean-Pierre Wolff, chair of the Central Coast Water Board. “The Board intends to approach Ag Order 4.0 implementation from an adaptive management perspective, using annual updates during public meetings to inform potential order modifications as may be required to improve implementation effectiveness.”

Ag Order 4.0 includes incentives for the use of compost, organic fertilizers, and cover crops to improve soil health, increase moisture retention and carbon and nitrate sequestration, and it includes incentives to utilize nitrate in irrigation water to reduce fertilizer-nitrogen application and mine groundwater nitrogen from aquifers. Ag Order 4.0 also includes provisions and incentives for growers and technical service providers to form or join third-party programs to provide compliance assistance to growers. Growers may choose to comply with certain Ag Order 4.0 requirements on an individual basis or via membership in a third-party program.

Ag Order 4.0 process documents are available on the Central Coast Water Board’s Irrigated Lands Program – Agricultural Order Renewal 4.0 website. The final approved order will be posted to the Central Coast Water Board’s Adopted Orders, Permits, Resolutions, and Settlements website in the next several weeks.

The Central Coast Water Board is a California state agency responsible for protecting and restoring water quality in a 300-mile-long coastal region, from southern San Mateo and Santa Clara counties to the northern part of Ventura County.