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Geohydrology of Rice County (1950)

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Ground-water Regions of Rice County

For purposes of discussion of the ground-water resources of Rice County, the county has been divided into two major ground-water subdivisions-the Great Bend Prairie province and the Smoky Hills Upland province. These two provinces are divided into regions and areas, in each of which the ground water occurs under similar conditions. The provinces, regions, and areas in Rice County and the symbols shown on Plate 2 are as follows:

Symbols used for ground-water discussion
Division Symbol used
on Plate 2
Great Bend Prairie province G
Arkansas River Valley region G-1
Chase Channel region G-2
Channel gravel area G-2a
Cow Creek terrace area G-2b
Channel border area G-2c
Little Arkansas River Valley region G-3
Alluvial terrace area G-3a
Silt terrace area G-3b
Smoky Hills Upland province S
Mantled upland region S-1
Upland loess area S-1a
Hutchinson dune-sand area S-1b
Dissected border region S-2
Cretaceous sandstone area S-2a
Lower Kiowa shale area S-2b
Permian shale and siltstone area S-2c

Great Bend Prairie Province (G)

The Great Bend Prairie province shown by the prefix G on Plate 2 is characterized by a low-lying flat or gently rolling surface of thick, unconsolidated fill. Stream erosion has removed the Tertiary-capped upland and reduced the Cretaceous and Permian rocks to the low base level afforded by the valleys to the southeast. The lowlands were later covered with gravel, sand, and silt carried into the area by stream and wind action to produce broad depositional plains.

The Great Bend Prairie province has been subdivided into three ground-water regions, namely, the Arkansas River Valley region, G-1; the Chase Channel region, G-2; and the Little Arkansas River Valley region, G-3.

Arkansas River Valley Region (G-1)

Most of southern Rice County west of the Hutchinson dune-sand area is placed in the Arkansas River Valley region, because of the similarity of origin of the alluvial material composing the aquifers and the uniform depth to water over the entire region. The area embraces terrace deposits of early to late Wisconsinan age and buried channel deposits of early and middle Pleistocene age (cross sections D-E and G-H, Pl. 3). Adequate supplies for industrial, municipal, and domestic use can be developed at almost any point in this region. Wells yielding 500 to more than 1,000 gallons a minute have been developed at several points in the Arkansas River Valley. Dune sand, terrace sand, and gravel exposed at the surface provide excellent facilities for recharge from precipitation. The water table is from 7 to 10 feet below the surface in most places, although it may range to about 30 feet beneath some of the higher terrace surfaces and more than 40 feet below the high sand dunes. The water table fluctuates greatly in response to local precipitation. The annual change in water level near Sterling and Alden has been as much as 4 feet.

The quality of water in this area is discussed under Late Wisconsinan terraces in the section on geologic formations and their water-bearing properties.

Chase Channel Region (G-2)

The Chase Channel region is essentially an extension of conditions in the Arkansas River Valley region, but is at a higher altitude and includes areas with different lithology and ground-water conditions. It is separated from Arkansas River Valley by the upland divide on the southwest and constitutes an independent precipitation catchment and ground-water basin region.

Channel gravel area (G-2a)--Pleistocene channel deposits in the Chase Channel area are shown on cross sections A-B, D-E, and G-H (Pl. 3). There are three channel zones above the consolidated rocks. The lowermost zone (Holdrege) yields highly mineralized water and is not used for water supply in this area. The middle zone (Grand Island) yields potable water but is generally not exploited because abundant supplies are available in most places from the overlying gravel (Todd Valley). This upper gravel is the aquifer for most of the wells in this area and yields large supplies of moderately hard water. The municipal well at Chase obtains its supply from this gravel. The water table ranges from a few feet to about 20 feet below the surface in most of the area.

Cow Creek terrace area (G-2b)--The Cow Creek alluvial terrace contains poorly sorted silty sand and gravel which yields small supplies of water, generally adequate for domestic and stock use. These water-bearing beds are usually encountered between 20 and 60 feet below the surface. The water level in wells in this area ranges from a few feet to about 20 feet below the surface.

Channel border area (G-2c)--Small supplies of water are obtainable from a variety of aquifers in the Channel border area. Some shallow wells end in dune sand. Others get small supplies from poorly sorted fine-grained slope deposits. Many wells in this area are drilled into the underlying Cretaceous rocks, especially where oil-field brines have contaminated the upper aquifers. The depth to water varies widely owing to the uneven topography. Depths of 2 and 58 feet below the surface have been recorded. Fluctuations of the water level are large. The water level in most wells in the area shows a marked response to precipitation, owing to the good recharge facilities afforded by the dune sand. Interdune low areas may contain water-table ponds for years during a humid cycle which go dry in years of insufficient precipitation.

Little Arkansas River Valley Region (G-3)

The part of the Great Bend Prairie, known as the Little Arkansas River Valley region is distinct from the rest of the lowlands of Rice County in that the alluvial material of the valley fill is derived entirely from rocks in the valley sides and headwater drainage area within the county. The sediments found in the valley are mostly fine grained and poorly sorted.

Alluvial terrace area (G-3a)--Moderate supplies of hard water are available from the medium to fine sand in the alluvial terrace of Little Arkansas River. The old Little River municipal supply was obtained from large-diameter wells in this material. The thickness of the alluvium is 30 to 50 feet over most of the area, and the water table is 10 to 20 feet below the land surface in most places.

Silt terrace area (G-3b)--The wide loess-covered terrace deposits, mostly east of the present Little Arkansas River, contain irregular lenses of poorly sorted, locally derived sand and gravel. Many test holes drilled in this material, especially toward the eastern margins in Ts. 19 and 20 S., fail to encounter water-bearing beds. The thickness of the terrace fill, including the overlying loess, ranges from 90 feet to a featheredge at the margins.

Smoky Hills Upland Province (S)

Areas in Rice County included in the Smoky Hills Upland province are shown on the ground-water map (Pl. 2) and are indicated by the prefix S in the area index number. This province is made up of those areas that have been dissected by Pleistocene erosion, but have not reached the level of erosion of the central low-lands. It is the transition zone from the High Plains and is characterized by uneven to rugged topography of the dissected Cretaceous rocks and by isolated erosional remnants of the High Plains surface.

Mantled Upland Region (S-1)

This region, comprising most of the Smoky Hills Upland province in Rice County, is characterized by a mantle of late Pleistocene eolian deposits which mask the character of the dissected Cretaceous rocks of the Smoky Hills Upland. Only the altitude of the area, relative to the lowlands, and the occasional exposures of resist.ant sandstone which project above the mantle rocks reveal the nature of the region. This region includes all the high-level loess and dune-sand tracts. The Raymond sand-dune area, just north and northwest of the town of Raymond, belongs in this region in the physiographic division of the county. It is not differentiated on Plate 2 because the water-bearing characteristics of the Raymond sand-dune area are intimately related to other features.

Several small isolated areas, which should be included in the dissected border region, are not differentiated on Plate 2, but are shown on the geologic map, Plate 1, as Cretaceous outcrop areas.

Upland loess area (S-1a)--The Upland loess area is the largest ground-water division of Rice County. This area is characterized by a thick silt mantle which overlies the water-bearing material. The silt rests on the irregular surface of Cretaceous sandstone, clay, and shale. The most extensive aquifer in the area is the underlying Cretaceous sandstone, although many wells, especially the older dug wells, obtain water from a rubble zone at the base of the silt. This rubble zone is a lag concentrate of Cretaceous sandstone, "ironstone" fragments, and caliche nodules.

Near present small intermittent or temporary streams, irregular lenses of sand and locally-derived gravel in Pleistocene alluvial channels yield water sufficient in quantity for domestic and stock wells. The depth of Pleistocene channeling in the valleys of these now incompetent streams is illustrated in Little Cow Creek Valley, on cross section E-F on Plate 3 and log 26 (Table 7).

In the northwestern part of this area, wells of moderate yield (30 to 70 gallons a minute) can be developed from thick channel sandstones underlying the silt. In a few places channel sandstones are absent in the entire section of underlying Cretaceous rocks, and ground-water supplies are meager.

Over most of the area the thick silt mantle acts as a confining bed over the aquifers and water rises as much as 30 feet when the water-bearing beds are encountered.

Hutchinson dune-sand area (S-1b)--This dune area is separated from other dune tracts in Rice County because it rests on material of low permeability and therefore is locally important as a source of water. The dune sand rests on silt and Permian shale, separated in places by a thin rubble zone. The dune sand yields relatively soft water to wells, but the water generally contains an objectionable quantity of iron. A few wells in this area are drilled into the Permian shale to avoid the mechanical troubles involved in developing water supplies from unconsolidated fine to medium sand and in the northeastern part of the area to avoid water polluted by oil-field brines discharged into the sand. The depth to water ranges from a few feet to more than 50 feet, owing to the irregularity of the dune topography.

Dissected Border Region (S-2)

This region is characteristic of the Smoky Hills Upland province. The eroded surface of Cretaceous and Permian rocks is at the surface or under a very thin cover of mantle rock. Most of the region is characterized by rugged topography and rocky slopes. The depth to water throughout the entire region varies widely owing to the uneven topography.

Cretaceous sandstone area (S-2a)--A number of outcrop areas of Cretaceous sandstone are included in this designation. Sandstones in the lower part of the Dakota formation and the upper part of the Kiowa shale generally provide abundant supplies of relatively soft water to wells in this area. Springs are common and small valley fills yield water to shallow wells. The new wells of the Little River municipal supply are located in this area.

Lower Kiowa shale area (S-2b)--The outcrop area of the Kiowa shale is the largest area in the county that is nearly devoid of groundwater in quantities sufficient for domestic use. The dark-gray shale of the lower part of the Kiowa yields very little water to a few wells in the area. Cisterns for domestic supply and ponds for stock supply are common. Exceptions to this are the few wells in small alluvial fills or streams, a few wells obtaining highly mineralized water from the underlying Permian, and wells in the southern-most part of the area, in the south-central part of T. 20 S., R. 6 W., where some Cretaceous sandstone zones occur just above the Permian rocks.

Permian shale and siltstone area (S-2c)--This area ranks next above area S-2b in dearth of available ground water. The Permian shales and siltstones have low permeability and yield small supplies of highly mineralized water to wells. Wells in this area are mostly large-diameter dug wells which provide space for storage of water.


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Kansas Geological Survey, Geohydrology
Placed on web June 16, 2015; originally published July 1950.
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