Aquifer Analysis During Large Scale Agricultural Pumping

The Lower Tuscan Aquifer Monitoring, Recharge, and Data Management Project is funded by a Proposition 50 Grant awarded by the California Department of Water Resources (DWR) and managed by Butte County Department of Water and Resource Conservation (BCDWRC).  The primary objective of the project is to collect and analyze technical data through development of innovative analytical investigative tools to further the scientific understanding of the Lower Tuscan aquifer system.  A key component of the overall project was the development of cost effective methods to conduct and analyze aquifer parameters during the agricultural pumping season using newly installed and existing groundwater monitoring systems.  Of particular interest were the results from data collected during the full scale pumping of an agricultural well screened in the Lower Tuscan Aquifer (LTA).  Through innovative, cost effective instumentation of pumping wells and groundwater monitoring wells, we were able to collect operational, flow, and drawdown data from more than 20 wells that could be used for both qualitative and quantative analysis.  Pumping wells selected for the project were screened within the LTA whereas groundwater monitoring wells were screened within the LTA, Upper Tuscan Aquifer, and an underlying aquifer within the Ione Formation.  Qualitative analysis of drawdown curves provided significant insights into the interactions between the three aquifer systems and that the drawdown curves within wells completed in the LTA met the assumptions for quantative curve matching analysis for estimating aquifer properties of the LTA.  The results of this test and other tests in the area also provided valuable insights for additional data needs and design of future tests to provide the BCDWRC a comprehenisve, defendable characterization of the LTA to assist BCDWRC’s management and protection of this important regional asset.