Background electrical resistivity tomography data, 2019

Electrical resistivity Tomography (ERT) is a direct current geophysical method that is used to estimate the subsurface distribution of the electrical resistivity (measured in ohm-meters, or ohm-m) of a material, and is based on the assumption that measured electric potentials (voltages) near current carrying electrodes are influenced by the electrical resistivities of the underlying material (Zohdy and others, 1974; Day-Lewis and others, 2008). Bulk resistivity is controlled by lithology, porosity, degree of saturation, chemistry of groundwater, and the conductivity of earth materials at the surface. If the degree of saturation is the only expected variable, as is the case near the groundwater replenishment and reuse project (GRRP) facility, groundwater infiltration paths can be identified with sequential ERT surveys. Data from two ERT surveys (YVHDWW_L1 and YVHDWW_L2) were collected orthogonal to each other in May and September of 2019 to determine background resistivity values downslope of the GRRP facility prior to release of reclaimed wastewater to the infiltration ponds. The resistivity data are presented in native .stg format, as well as topographic data for each electrode in .trn format.