Groundwater Contamination

For over 80 years the USGS' Kansas Water Science Center has worked in cooperation with the city of Wichita with the goal of maintaining the Equus Beds Aquifer as the regions primary water resource. In recent history, the Equus Beds Aquifer Storage and Recovery (ASR) Project was created with the goal of ensuring minimal water loss and slowing the movement of contaminants towards the Wichita well fields. The project consists of two phases that both use injection wells in order to decrease the hydraulic gradient between the saltwater plume and the well field (KSWSC, 2025). The contaminants observed by the USGS within the Equus Beds that most frequently exceed the EPA's Federal drinking water-quality criteria are chloride, nitrate plus nitrite, sulfate, iron, manganese, and arsenic (Stone et al., 2019).

Chloride and sulfate are of particular concern as they are associated with a large saltwater plume located near Burrton, Kansas that is actively moving towards the Wichita well field and is considered a major risk for Wichita's water quality (Stone et al., 2019; KSWSC, 2025; Rubin et al., 2001; Klager et al. 2014 ). This saltwater plume was most likely derived from past oil and gas activities, the Arkansas River, and municipal wastewater and industrial discharges (Whittemore, 2007). Slowing the movement of this plume is one of the primary concerns of the Equus Beds ASR Project (KSWSC, 2025).

Iron, manganese and arsenic are all derived from rocks and soils within the aquifer. Unlike iron and manganese, which mainly cause staining and damage to property, excess arsenic can pose significant health risks, including but not limited to skin damage and an increase risk of cancer. All three of these constituents can be found in increasing quantities with increased depth, as reducing conditions provide environments that lead to their dissolution. (Stone et al., 2019)