Chemical Quality of Irrigation Waters in the Equus Beds Area, South-Central Kansas

Abstract

Wet-weather conditions in the Equus beds area during the scheduled sampling period in July 1979 limited sample collection to four irrigation wells. Water samples from an additional 41 irrigation wells were obtained in August 1979. The limited amount of pumpage of these systems prior to sampling in 1979 suggested the need for further sampling before evaluating the chemical quality of irrigation waters in the Equus beds region. In July 1980, water samples were obtained from 110 pumping irrigation wells and from tail-water pits associated with six of those wells.

Groundwaters from the portion of the study area north of the Little Arkansas River are predominately calcium-bicarbonate in character. Sodium-chloride-type waters are found locally in the Arkansas River Valley, and a gradation from these sodium-chloride waters toward the calcium-bicarbonate-type waters is noted for the region between the Arkansas and Little Arkansas rivers. Locally high chloride values within the Equus beds area reflect contamination of the fresh-water aquifer by natural processes or human activity.