Presentations

Extensive agricultural groundwater and fertilizer use began in the arid, mild climate of the Salinas Valley, Monterey County, California in the late 1940s. A transformation occurred from dry crop farming and dairies in the early 1900s, to sugar beets, then later to the current multibillion dollar industry that utililizes high tech irrigation practices to grow, among other crops, coastal cool-season vegetables and strawberries. As a result of this agricultural productivity and sustainability, the Salinas Valley has emerged as the Salad Bowl of the world. This title can be attributed to the multiple generations of family farmers who, through their own innovation and good business practices coupled with advancements and implementation of new technology, have achieved economic viability in Monterey County as a 3.8 billion dollar industry in 2007. The Monterey County Flood Control and Water Conservation District (District) was created from a California Legislative Act in 1947 and charged to monitor flood and coastal seawater intrusion. The District name was later changed in 1990 to Monterey County Water Resources Agency. Seawater intrusion has been monitored in coastal aquifers since 1944. The historical, 1944-2007, Pressure 180-Foot Aquifer intrusion front, 500 mg/L chloride contour, is represented in Figure 1. The District, with financing from the Monterey County taxpayers, built two reservoirs in the late 1950s and early 1960s in the Salinas Basin. The primary benefits of the reservoirs were for flood control in the Salinas Valley, and to halt intrusion through conservation releases to the Salinas River for recharging the multiple Pressure Aquifers for maintaining water levels at or above sea level. Later, in the 1980s, after extensive long-term groundwater monitoring and in a drought situation, it was concluded that groundwater used both for agriculture and urban/domestic use continued to be impaired in the coastal area by high chloride from seawater intrusion, and, in the entire Salinas Valley, by elevated nitrate. Water quality monitoring data analysis and groundwater investigations concluded that nitrate sources included confined animal operations, septic systems, and commercial fertilizer. The Salinas Valley utilizes 95 percent groundwater for all water uses, which caused concern for long-term impacts to drinking water. Well construction integrity was also found to have a bearing on aquifer water quality. See Table 1 for results of the 2007 nitrate monitoring effort in the Salinas Valley indicating that many wells are over the Primary Drinking Standard for nitrate (as NO3).This paper presents four components of agricultural groundwater sustainability to inform others of 50 years of challenges and more to come in the Salinas Valley. Progression and productivity of agriculture in the Salinas Valley over multiple generations; impacts of urban and agricultural land use on groundwater quality, water levels, and extractions; successful measures taken by agricultural land owners and well operators, water resource managers, outreach and education cooperative partners, and regulators in the Salinas Valley Basin; discussion of what constitutes success to sustain agriculture and improve groundwater quality and quantity in the Salinas Valley; and how that success is measured by water resource managers, cooperative outreach partners, and regulators.