Preserving San Joaquin Valley's Westside Production with Integrated On-Farm Drainage Management

By Judith Redmond
(Judith Redmond is a partner in Fully Belly Farm near Guinda and president of CAFF’s board of directors.)

California’s water future depends on choices that are being made now. This is especially true because water policies that helped us to become the agricultural and economic giant that we are today are not up to the challenges of the twenty first century. An important bill sponsored by CAFF (SB 1372) is pointing the way to better water management for farms in the San Joaquin Valley.

Decades ago, the construction of the giant State Water Project and the federally funded Central Valley Project, and the subsequent cultivation of vast stretches of the Central Valley, put agriculture, particularly on the west side of the San Joaquin Valley, on a collision course with its own irrigation practices. Once the water was delivered, the challenge then became what to do with the leftover irrigation drainage water.

Several hundred thousand acres on the west side of the San Joaquin Valley have severe drainage problems, to the extent that the long-term productivity of the land is in question. The soil is naturally high in salt and selenium, and even “fresh” irrigation water contains salt that build up in soil over time. Farmers use irrigation water to leach unwanted salt from around crop roots, but leaching also threatens the high groundwater table. Despite their best efforts, farmers are fighting a losing battle: salt buildup from heavy irrigation is making the west side farmland less productive.

Until the mid-1980s, when we discovered that drainage water contained toxic levels of selenium that led to bird deaths and deformities, giant ponds like the Kesterson Reservoir held farm runoff. Kesterson inspired a state law, the Toxic Pits Control Act that heavily regulates agricultural and industrial ponds containing toxic contaminants. Today farmers typically discharge their salt- and selenium-laden runoff into rivers and streams, which eventually lead to the San Joaquin River, or they spread the drainage water onto fallow land to percolate into the soil – and often the groundwater. Both practices are polluting and unsustainable.

Irrigation water is not only used to grow crops, but also to leach unwanted salts from around crop roots. These salts and minerals are present naturally in the soils, but also come dissolved in the irrigation water itself. If the salts are allowed to build up, many crops will simply not grow. Often, especially on the west side of the San Joaquin Valley, irrigation water draining from farm fields carries salts and naturally occurring selenium leached from the soil. Buildup of these salts and minerals can create huge environmental problems when the farm drainage gets into groundwater or rivers. When wildlife is exposed, it too has been harmed.

Clearly the runoff from these farm fields should be managed in order to reduce the spread of pesticides, fertilizers, salts, selenium and other agricultural byproducts. CAFF’s work to spread biological farming practices has a big role in reducing the use of farm chemicals at the source, but the buildup of salts and minerals in irrigated soil remains a problem that exists around the world.

CAFF is sponsoring SB 1372 (Machado) to make it easier for farmers to use an alternative approach, called Integrated On-Farm Drainage Management (IFDM), to manage their drainage water without harming the environment while also preserving the productivity of their land for the future. The program was developed over the past 17 years by CAFF member and Department of Water Resources scientist Vashek Cervinka and innovative farmers like John Diener, a family farmer in Five Points. IFDM involves capturing and reusing the irrigation water on sequentially more salt tolerant crops. The water is used several times, each time on a smaller field and on crops that are productive even when irrigated with saltier water. By the end of the process, the salts have become quite concentrated and the water is applied in a thin sheet onto a small area of land called a solar evaporator. There is no standing water and the only remaining residue is salt! The environmental and agricultural benefits are many. Salt and selenium are contained without being discharged into rivers and streams or into groundwater. Without standing water, birds are not threatened. And IFDM actually reduces overall water use by about 25 percent and restores degraded land by removing salt and selenium from the soil.

So why is SB 1372 needed? Ironically, this environmentally superior drainage management system falls under the Toxic Pits Control Act, costing farmers up to $150 per acre to comply with its regulations. Under CAFF’s SB 1372, an IFDM system would be certified by the Regional Water Quality Control Board to ensure that the farmer was protecting streams, groundwater, birds and other wildlife. Annual inspections and soil and water monitoring would be required. Once certified, an IFDM farmer would be exempt from the Toxic Pits Control Act.