Electrical resistivity tomography data collected near a groundwater replenishment and reuse project, Yucca Valley, San Bernardino County, California, 2019

Hi-Desert Water District (HDWD) is constructing a wastewater treatment plant as part of a groundwater replenishment and reuse project (GRRP) in the east hydrogeologic unit (Nishikawa, and others, 2003) of the Warren Valley Basin (7-012) (California Department of Water Resources, 2016) in Yucca Valley, CA. The HDWD plans to use reclaimed wastewater for managed aquifer recharge by spreading treated wastewater into unlined ponds at the GRRP facility. Reclaimed wastewater will percolate through the unsaturated alluvium by gravity drainage through the unsaturated zone to the water table located about 370 feet (ft) below land surface (bls). As part of the cooperative efforts between the HDWD and the USGS, the electrical resistivity tomography (ERT) geophysical surveying technique was proposed to monitor the movement of reclaimed wastewater through the unsaturated zone to the water table. This data release presents ERT data collected before water was placed into the ponds. Data from two ERT surveys (YVHDWW_L1 and YVHDWW_L2) were collected in May and September of 2019 to determine background resistivity values for the unsaturated alluvium south of the GRRP facility prior to recharge. The surveys were collected normal to each other and located downslope from the GRRP facility. This location was chosen in order to collect resistivity data in anticipation of movement of recharged water downslope through the unsaturated zone. References Advanced Geosciences , Inc., 2009, Instruction Manual for EarthImager 2D, v. 2.4.0: Austin, TX, accessed March 25, 2020, at ftp://ftpcrustal.cr.usgs.gov/pub/Powers/EarthImager2D/ California Department of Water Resources, 2016, Bulletin 118 Groundwater Basin Boundary GIS Data - v6_1: California Department of Water Resources Bulletin 118, accessed May 9, 2020, at https://water.ca.gov/Programs/Groundwater-Management/Bulletin-118. Day-Lewis, F. D., Johnson, C.D., Singha, K., and Lane, J W., 2008, Best Practices in Electrical Resistivity Tomography: Data Collection and Processing, and Application to Data from Corinna, Maine. An Administratrive Report for EPA Region 1, Washington D.C., accessed April 11, 2020 at https://clu-in.org/programs/21m2/projects/EPA_admin_report_02Dec2008_fi…. Minsley, B.J., Ball, L.B., Caine, J.S., Curry-Elrod, E., and Manning, A.H., 2010, Geophysical characterization of subsurface properties relevant to the hydrology of the Standard Mine in Elk Basin, Colorado: U.S. Geological Survey Open-File Report 2009-1284, 46 p., accessed June 1, 2020 at https://pubs.usgs.gov/of/2009/1284. Nishikawa, Tracy, Densmore, J. N., Martin, Peter, and Matti, Jonathan, 2003, Evaluation of the source and transport of high nitrate concentrations in groundwater, Warren subbasin, California: U. S. Geological Survey Water-Resources Investigations Report 2003-4009, 133 p., accessed June 5, 2020 at https://pubs.er.usgs.gov/publication/wri034009. Zohdy, A.R.R, Eaton, G.P., and Mabey, D.R., 1974, Application of surface geophysics to groundwater investigations: Techniques of Water-Resources Investigations of the U.S. Geological Survey, book 2, chap. D1, 66 p., accessed May 9, 2020 at http://pubs.usgs.gov/twri/twri2-d1/pdf/%0ATWRI_2-D1.pdf.