Spatial Analysis of Suitability for Managed Aquifer Recharge in a Groundwater Basin in Central Coastal California
Abstract
The Pajaro Valley Groundwater Basin (PVGB), central coastal California, relies almost entirely on groundwater to satisfy agricultural and municipal/domestic needs (83% and 17% of water usage, respectively). The rate of groundwater extraction and other outflows from the PVGB over the last five decades has exceeded the total rate of inflows, resulting in chronic overdraft. This has led to a lowering of water levels throughout the basin and seawater intrusion near the coast. Managed aquifer recharge (MAR) likely will become increasingly important for sustaining groundwater supply in future years; however, identifying areas amenable to MAR remains challenging. A geographical information system (GIS) analysis was completed to evaluate areas of the PVGB suitable for MAR. Initially GIS analyses used topographic, land use, bedrock geology, and soil property data to assess shallow conditions, and subsequent analyses have included subsurface information such as aquifer and associated confining layer locations, properties, thicknesses, and historical changes in water levels. Additional GIS coverages included potential supplemental water supplies. A preliminary map of MAR site suitability suggests that about 10% of the basin may be suitable for MAR. Ongoing field testing will provide "ground truth" for the assessment of GIS-based calculations, and both field and GIS analyses will provide critical input for regional hydrologic models that will be used to quantify the potential influences of different MAR scenarios. Collectively, these studies are helping to evaluate management options for improving long-term groundwater conditions throughout the PVGB.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.H13E1259R
- Keywords:
-
- 1819 HYDROLOGY / Geographic Information Systems;
- 1830 HYDROLOGY / Groundwater/surface water interaction;
- 1847 HYDROLOGY / Modeling;
- 1880 HYDROLOGY / Water management