31-20 Evaluating impacts of reduced groundwater pumping on water quality in northwest Kansas, USA

Session: Environmental Geochemistry and Health (Posters)

Poster Booth No.: 46

Presenting Author:

Caeli Richard

Authors:

Richard, Caeli Elizabeth¹, Indralal, Thisura², Lyle, Rex³, Puthalath, Saranya⁴, Seybold, Erin C.⁵, Yucel, Umut⁶, Avocat, Helene⁷, Kirk, Matthew F.⁸

(1) School of Earth and Environment, Kansas State University, Manhattan, KS, USA, (2) School of Earth and Environment, Kansas State University, Manhattan, KS, USA, (3) School of Earth and Environment, Kansas State University, Manhattan, KS, USA, (4) School of Earth and Environment, Kansas State University, Manhattan, KS, USA, (5) Kansas Geological Survey, Lawrence, KS, USA, (6) School of Health Sciences, Kansas State University, Manhattan, KS, USA, (7) School of Earth and Environment, Kansas State University, Manhattan, KS, USA, (8) School of Earth and Environment, Kansas State University, Manhattan, KS, USA,

Abstract:

In response to groundwater storage depletion, irrigation pumping restrictions are being implemented in some locations. However, the consequences of these pumping restrictions for groundwater quality are not well known. To help fill this knowledge gap, we examined groundwater quality in and near the Sheridan 6 Local Enhanced Management Area (LEMA) in northwest Kansas. Pumping restrictions within the LEMA were implemented in 2013 to help reduce the depletion of groundwater in the Ogallala Aquifer, with an average pumping reduction of 23.5% within the LEMA relative to a control area nearby. During summer 2026, we sampled 43 wells (domestic, irrigation, and livestock) and analyzed concentrations of major ions and trace elements, per- and polyfluoroalkyl substances (PFAS), microplastics, herbicides, non-purgeable organic carbon (NPOC), total nitrogen (TN) as well as concentrations of groundwater age and recharge temperature tracers (sulfur hexafluoride (SF₆), ³He/⁴He, and noble gases) and water stable isotope ratios. Several analyses are in progress, but initial findings indicate groundwater in the study area is Ca-HCO₃ type with near-neutral pH (avg. 7.34), elevated dissolved oxygen levels and relatively low total dissolved solids (TDS) content (avg. 428 mg/L). Nitrate concentration was below the standard for drinking water in groundwater from all but three wells. Moreover, a preliminary comparison of inorganic chemical concentrations inside vs outside of the LEMA does not reveal significant differences in groundwater composition, indicating that a pumping reduction has not altered groundwater quality at least for the data we have so far. Our ongoing efforts will further test relationships between pumping and water quality by examining additional parameters and evaluating pumping rates on a finer spatial scale using historic pumping data from irrigation wells. We expect that our study findings will help improve management of water quality alongside water quantity in agricultural regions. 

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