Hydrogeology, Hydrologic Effects of Development, and Simulation of Groundwater Flow in the Borrego Valley, San Diego County, California

The quality of water in the Borrego Valley is a concern because of the basin's reliance on groundwater for agricultural, recreational, and municipal supply. Groundwater quality can be affected by land-use activities occurring at or near land surface. These activities include irrigation of vegetated landscapes and the use of septic systems to dispose of wastewater. Groundwater quality can also be affected by declining water levels, as there is the potential to change the distribution of flow from underlying aquifers to wells. Historic and current water-quality data was used to determine which constituents had relatively high concentrations compared to water-quality thresholds and if these constituent concentrations were changing in response to declining water levels. Water-quality data can be downloaded in an Excel format from this website. The Excel workbooks contain current and historical water-quality data for groundwater samples collected in the Borrego Valley and spring samples collected in pertinent watersheds. The workbooks are categorized by constituent class. These classes are: Chemical and physical water quality indicators Inorganic and nutrient constituents Isotopic tracers Microbial Other organic compounds Pharmaceutical constituents Pesticide and pesticide degradates Radiological constituents Volatile organic compounds