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Kansas Geological Survey, Open-File Rept. 96-1a
Proposed Management Areas--Page 16 of 16


Subdivision of the Kansas Dakota aquifer into reasonably distinct management areas is an effective way to address the water resources management of this complex aquifer system that underlies much of western and central Kansas. The hydrogeologic setting, including sources of recharge, discharge, ground-water flow paths, and water quality vary from one management area to another. As a result, the policies adopted by state and local planning agencies need to be tailored to the subregional hydrogeologic setting of each management area, including the response of the flow system to the effects of pumping over a specific period of time. We have chosen an arbitrary planning horizon of 20 yrs. Some of the boundaries between management areas are not well defined due to insufficient data and should be considered only an approximation based on the currently available data. The following is a brief summary of the six management areas defined for the Kansas Dakota aquifer.

Management Area I: The Dakota and High Plains aquifers are in hydraulic connection and behave as a single complex aquifer system. As a result, the policies developed for one of the aquifers will have an impact on the other. Ground water in the Dakota is generally fresh.

Management Area II: The Dakota aquifer is confined by the Upper Cretaceous aquitard near the edge of the outcrop/subcrop belt. Leakage moving across the aquitard may be as much as 10% of the lateral flow in the Dakota in some areas where the aquitard is thin and more permeable. Ground water in the Dakota is fresh. Wells located in this part of the aquifer are likely to induce additional recharge from the area of hydraulic connection with the overlying High Plains aquifer in Management Area I within the 20 yr planning period. The potential for inducing recharge from the High Plains aquifer in Management Area I strongly suggests that the Dakota aquifer in Management Areas I and II should be managed along with the High Plains aquifer as a single complex system.

Management Area III: The Dakota is a near-surface aquifer or is confined by thin erosional remnants of the Upper Cretaceous aquitard. The flux of water through the Dakota is highest in this management region because the flow patterns are controlled by local flow systems. Recharge rates are on the order tenths of an in/yr in the outcrop area and less where the aquifer is confined. Water quality is locally variable and may be saline in the lower parts of the confined aquifer. Poorer quality water is generally found near the discharge areas of these local systems. Ground-water withdrawals in the unconfined area generally have the effect of reducing discharge to streams and inducing flow from the confined aquifer.

Management Area IV: The Dakota is confined by the Upper Cretaceous aquitard. Recharge from overlying sources may account for as much as a few percent of the lateral flow in the aquifer. This management area is located near the regional and local discharge areas of the Dakota and the regional discharge area of the underlying Cedar Hills Sandstone aquifer. Saltwater intrusion in the upper part of the Dakota aquifer is widespread. Pumping may diminish freshwater discharge from the Dakota or induce additional saltwater intrusion from underlying sources if the rates of withdrawal and spacing between pumping centers are not carefully regulated.

Management Area V: The Dakota is confined by the Upper Cretaceous aquitard and receives nearly negligible recharge from overlying sources in this management area. In part of this area the water quality is acceptable for most uses and elsewhere the water quality is marginally usable. Wells located in this part of the aquifer remove water entirely from storage and are unlikely to generate capture during the 20 yr planning period.

Management Area VI: Defined as the unusable portion of the aquifer because the ground-water total dissolved solids exceed 10,000 mg/L.

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Kansas Geological Survey, Dakota Aquifer Program
Original report available from the Kansas Geological Survey.
Electronic version placed online July 1996
Scientific comments to P. Allen Macfarlane
Web comments to webadmin@kgs.ku.edu