Ground-water resources in Lyon County are determined primarily by the nature of the underlying rock materials, or the geology, and the structure of the area. On this basis the county is divided into several ground-water regions in which ground water occurs under similar conditions and is obtained chiefly from one dominant rock type. The region boundaries are necessarily generalized and within each region the discussion is not applicable to some wells.
Within the region designated A (Pl. 3) most wells derive water from alluvium. Wells having the largest yields are in Cottonwood River valley, Neosho River valley, Marais des Cygnes River valley, Verdigris River valley, and the larger tributary valleys of these streams. Wells in alluvium are preferred generally to other ground-water sources because of their larger yields, better chemical character (Table 4), and greater reliability during drought periods.
The thickness of alluvium ranges from a maximum of about 50 feet in Cottonwood River valley to less than 5 feet in small tributary valleys. Maximum yields which can be developed are about 150 gallons of water per minute. Excellent stock and domestic supplies can be developed in this area as well as small to moderate municipal supplies.
Pleistocene terrace deposits of Kansan age or younger are the chief water-bearing beds in region B (Pl. 3). Terrace deposits older than Kansan are generally above the water table or contain only an intermittent zone of saturation and are not included in this region. Thickness of the terrace deposits ranges from a featheredge to a maximum of about 50 feet.
Ground water in region B generally has greater hardness and larger amounts of dissolved solids than water in alluvium of region A (Table 4). Yields of wells in region B reach a maximum of about 100 gallons of water per minute. Locally in region B little or no water can be obtained from wells in terrace deposits because the saturated thickness of the deposits is thin or because they are above the water table. In most of this area, however, excellent stock and domestic water supplies and locally small municipal supplies can be developed.
Region C includes the area underlain by Permian rocks of the Chase and Council Grove groups between the Florence limestone and the base of the Americus limestone. Wells in this area derive water supplies chiefly from jointed and fractured limestones and cavernous limestones, secondarily from open joints and fractures in the calcareous shales. Except for local limy sandstone beds in the Funston limestone, there are no sandy beds which contain freshwater in this area.
The most important aquifers of region C are the Wreford, Beattie, Grenola, and Long Creek limestones. Other limestones such as the Crouse, Eiss, and Red Eagle are local sources of good supplies of well water. A few wells, generally rather shallow in depth, obtain small supplies of ground water from open joints or fractures in shale or from cherty or gypsiferous zones in shales. Many, if not most of the wells in this region are drilled wells ranging in depth from about 30 to 90 feet, depending in part on topographic position. Dug wells range from about 12 to 60 feet in depth. Yields of 5 to 10 gallons per minute are not uncommon and supplies of 40 gallons per minute or more can be obtained locally. In most parts of this region supplies of ground water adequate for domestic and stock use are available.
Many ponds have been constructed in parts of this region to supplement water supplies from wells or in preference to wells. In some places cisterns are used where soft water is desired, or to supplement well-water supplies. Springs and seeps are numerous along the creeks.
Ground water in this region is variable in quality but generally good.
Region D (P1. 3) includes areas underlain by rocks of the Admire and Wabaunsee groups of early Permian and late Pennsylvanian age. In this region an adequate and dependable water supply from wells is difficult to obtain.
The predominant rock type is argillaceous shale, which is an extremely poor aquifer. Next in the order of abundance is sandstone and sandy shale. Limestone is the least abundant of the common rock types and most of the limestone beds are very thin.
The principal water-bearing beds in this region are the sandstones and sandy zones in the shales. Most of the sandstones are composed of very fine to medium sand grains which have enough mica and clay minerals associated with them to render the sandstones low in permeability. Most of the sandstones are shallow channel fillings in the shales rather than extensive sheet sands, and commonly, the channel sandstones are separated by areas of shale or shaly sandstone. These sandy beds are present locally in nearly all the shale formations. A few wells, which are constructed in locally thick sandstone beds, obtain yields of 10 gallons per minute or more, enough for good stock and domestic supplies.
The Aspinwall, Grandhaven, Wakarusa, and Burlingame limestones, where present in the zone of saturation and not too deeply buried, locally are the principal aquifers and may yield adequate supplies for stock or domestic wells. Other limestones generally yield little or no water to wells.
Many farm wells are large-diameter, shallow dug wells constructed in shale. Many of these are inadequate for even small domestic or stock supplies. Numerous farms have no water wells, but depend on cisterns for domestic water supplies and ponds for stock water supplies. Ponds and cisterns are important supplements to ground-water supplies in this region.
The water in this region is generally hard and high in dissolved solids as indicated by the 14 water samples collected from wells in this region. The dissolved solids ranged from 323 to 2,251 parts per million and averaged 919 parts per million. Hardness ranged from 270 to 1,049 parts per million with an average of 545 parts per million. The sampled wells ranged in depth from 10.9 to 75 feet and averaged 34 feet.
Wells obtain freshwater at depths of 10 feet or less to as much as 75 feet depending in part on topographic location. In some places wells less than 30 feet in depth may yield water that is too highly mineralized for ordinary domestic use.
Pennsylvanian rocks of the upper part of the Shawnee group are the principal aquifers in region E. Shallow wells in the Topeka limestone and sandstone in the Calhoun shale yield small amounts of water to wells in this region. Deeper water is highly mineralized.
Kansas Geological Survey, Lyon County Geohydrology
Web version Sept. 2001. Original publication date March 1953.
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