Alternative Water Supply Options for Nitrate Contamination in California's Tulare and Salinas Groundwater Basins

itrate is California's most ubiquitous groundwater contaminant and has significant potential to harm human health. The Tulare Lake Basin and Salinas Valley were chosen as pilot study areas to study the population susceptible to nitrate contamination in groundwater, and identify the available short-term and long-term alternative water supply options. Farming practices on agricultural lands and dairies in these basins produce high levels of nitrate. The population served by the groundwater have a high risk of exposure to nitrate, and often cannot afford treatment or alternative water supply options. These factors combine to make the Tulare Lake Basin and Salinas Valley highly susceptible to health effects from nitrate in drinking water. This thesis estimates the population potentially susceptible to consuming nitrate in groundwater and examines the alternative water supply options available for each system type. The economic and financial costs are estimated for each water supply option and a least cost analysis is performed for the entire basin susceptible population.;Approximately 766,000 people in California's Tulare Lake Basin and Salinas Valley have drinking water supplies susceptible or potentially susceptible to nitrate groundwater contamination. Water users that are served by a community water system exceeding a nitrate threshold, or lacking historical nitrate records, account for about 675,000 people. The remaining 88,000 people are estimated to be connected to a self-supplied household or local small water system that is located in an area exceeding the nitrate threshold. Assuming unchanging and unabated basin-wide trends in nitrate groundwater levels, the susceptible community water system population is estimated to increase 80% by 2050.;The most promising options for communities connected to highly susceptible water systems are to consolidate with a larger system; consolidate with nearby smaller systems and regionalize into a larger system; install ion exchange community water treatment; drill a new well; blend sources; and as an interim solution, provide point-of-use treatment to households. There is significant potential for consolidation of systems. Solely based on system size and spatial proximity to surrounding systems, there is great possibility for smaller water systems to consolidate with larger water systems. Promising solutions for self-supplied households or local small water systems within a highly susceptible sub-area are to install a point-of-use reverse osmosis treatment system, or drill a new or deeper well.;The overall cost of providing nitrate-compliant drinking water to the Tulare Lake Basin and Salinas Valley is estimated to be about...