Kansas Geological Survey, Open-file Report 1998-25
by
David P. Young, Julie L. Grauer, and Donald O. Whittemore
KGS Open-file Report 1998-25
June 1998
Appreciation is expressed to local, federal and other state agencies and institutions for assistance in conducting the Upper Arkansas River Corridor (UARC) study. The study is being conducted in cooperation with the Kansas Water Office; Division of Water Resources, Kansas Department of Agriculture; Division of Plant Health, Kansas Department of Agriculture; Southwest Kansas Groundwater Management District No. 3; Kansas Department of Health and Environment; and Southwest Kansas Local Environmental Planning Group. The UARC study is funded through the State Water Plan Fund of the Kansas Water Office.
Other members of the Geohydrology section provided useful input. Melany Miller and Chenoa Simmons assisted in the production of the report. Mark Schoneweis provided assistance with graphics.
This report presents lithologic characterization of the unconsolidated Tertiary and Quaternary deposits that compose the aquifer system in Kearny and Finney counties, particularly along the Arkansas River corridor. It includes a brief review of literature concerning the geology and hydrology of the study area, and describes geologic cross sections developed for Kearny and Finney counties.
The cross sections presented in this report supersede those presented in the 1997 progress report. They include refinements and improvements to those presented in the previous progress report, and incorporate additional data. To produce the sections, lithologic descriptions were converted into material identification codes based on the relative permeability of the materials. A procedure was developed to electronically represent, manage, and display lithologic data as cross sections with accompanying color gradation. The cross sections help to characterize the shallow alluvial aquifer, the deeper High Plains aquifer, and a relatively impermeable layer between the two aquifers. The alluvial aquifer comprises a fairly continuous permeable unit of sands and gravels, especially south of the Arkansas River. The permeable material typically ranges in thickness from 10-50 feet. The deeper High Plains aquifer varies widely in type of material, thickness, and layer continuity. This aquifer has more clay, silt, and cemented units than the alluvial aquifer. The relatively impermeable layer between the aquifers is discontinuous and highly variable in thickness and materials composition. It is generally made up of clay, or clay interbedded with lenses of silt, caliche or sand.
The Arkansas River in southeastern Colorado and westernmost Kansas is one of the most saline rivers in the United States. Consumption of water by evapotranspiration in Colorado has substantially decreased the flow and greatly increased the salinity of the river water entering Kansas. In addition to salinity, the concentration of many other dissolved constituents in the river water is high.
Ground-water levels have declined in the High Plains aquifer in southwest Kansas from decreased recharge from the river and consumptive pumping from the aquifer. As a result, Arkansas River flow entering Kansas from Colorado is lost in the river stretch from the state line to Dodge City. Some of this loss is due to infiltration and consumptive use of water diverted from the river for irrigation. Saline water from the river and fields irrigated with river water is infiltrating to and contaminating the ground water in the alluvial and High Plains aquifers in the upper Arkansas River corridor. Ground-water declines in the High Plains aquifer have also decreased the amount of fresh subsurface flow to the alluvium that can dilute salinity and other constituent concentrations. Another ground-water quality problem in the upper Arkansas River corridor is increasing nitrate concentrations in many well waters. The ground waters which have been and could become contaminated by salinity and nitrate include sole sources for several towns and cities, including Syracuse, Lakin, Garden City, Cimarron, and Dodge City.
The distribution of salinity and the mechanisms for entrance to and movement of the saline water within the aquifer system is not well known. An assessment of the source, migration, and present and possible future extent of the ground water contamination is critical for developing plans for minimizing or mitigating water-quality problems in the aquifers. The Upper Arkansas River Corridor Study was developed to provide information that will improve understanding of the river and ground-water salinity in the corridor to enable agencies, municipalities, farmers, and industries in the area to better manage water resources to minimize or mitigate water-quality problems.
Layers of low permeability clays and silty clays occur within and underlie the Arkansas River alluvium. This low-permeability material restricts the infiltration of the saline river water to the deeper ground water. As a result, perched saline water exists in some areas above the main body of the High Plains aquifer. Clay layers also occur within the main aquifer and further retard the downward movement of saline water. The sand and gravel units comprising the alluvial and High Plains aquifers vary substantially in hydraulic conductivity and thickness. The distribution and character of the low and high permeability layers in the aquifer system (both the alluvial and High Plains aquifers in most of the study area) have not been well known. Understanding of the distribution of the different lithologic units is necessary for conceptual and quantitative models of the intrusion of the saline river water in the areas of the river valley and ditch irrigation, and the migration of the saline water within the High Plains aquifer.
Description of components of the objectives and scope of work for the overall project have been listed by Whittemore et al. (1996). This report addresses objectives related to the intrusion of the saline water into the alluvial and High Plains aquifers and migration of the intruded water. It describes the lithology in the aquifer region most affected by the saline river water, Kearny and Finney counties. It includes a brief review of previous literature on geology and hydrology, and presents and discusses geologic cross sections produced for the Arkansas River corridor and surrounding area in Kearny and Finney counties.
Many studies have dealt with the geology and water resources of southwestern Kansas. The literature covering the entire Upper Arkansas River Corridor study area was reviewed by Young et al. (1997). Historical data were obtained from the following reports: Lobmeyer and Sauer (1974) [Hamilton County]; McLaughlin (1943) [Hamilton and Kearny counties]; Gutentag et al. (1972a) [Kearny County]; Dunlap et al. (1985) [Kearny and Finney counties]; Meyer et al. (1969, 1970), and Gutentag et al. (1972b) [Finney County]; Latta (1944) [Finney and Gray counties]; McGovern and Long (1974) [Gray County]; Waite (1942), and Spinazola and Dealy [Ford County]; and Gutentag et al. (1981) [southwest Kansas]. Most of these publications include generalized geologic cross sections, and some contain maps showing surficial and bedrock geology. The cross sections generally do not contain information on the lithology of the unconsolidated Tertiary and Quaternary deposits.
The project study area covers approximately 3,560 mi2 along the Arkansas River corridor from the Colorado state line to the Ford-Edwards county line in southwestern Kansas. It includes parts of Hamilton, Kearny, Finney, Gray, and Ford counties (Figure 1).
Figure 1. Location of the area of the Upper Arkansas River Corridor Study within the 5-county region. The study area boundary is the bold line.
Southwestern Kansas lies in the High Plains region of the Great Plains physiographic province. The land surface in the study area generally varies from a flat upland covered with loess in the north to rolling sand dunes in the south. In most of the study area, the Arkansas River and its flood plain separate the uplands from the sand dunes (Figure 2).
Figure 2. Surface geology of Kearny and western Finney counties.
Tertiary and Quaternary deposits underlie most of Kearny and Finney counties and range in thickness up to 500 feet. The saturated part of the Ogallala Formation of Pliocene age, the undifferentiated Pleistocene deposits, and the Quaternary alluvium in the Arkansas River corridor form the aquifer system in the study area. The Pliocene and undifferentiated Pleistocene deposits are hydraulically connected and lithologically similar, and are considered as one aquifer, the High Plains aquifer. In this report the High Plains aquifer is differentiated from the shallower Arkansas River valley alluvial aquifer. Although both aquifers are hydraulically connected to some extent, the distinction is made on the basis of differences in water levels due to a relatively impermeable zone between them. Also, the permeability is greater in the Arkansas River alluvium. The Arkansas River meanders through the study area and interacts hydraulically with the aquifer system. The surface of the Cretaceous bedrock defines the lower limit of the aquifer system. In parts of the area, the Dakota aquifer may be considered as part of the aquifer system, but it will not be discussed in this report.
Consolidated rocks of Cretaceous age, which underlie the unconsolidated Tertiary and Quaternary deposits, are referred to as bedrock in this report. As a rule, undifferentiated Lower Cretaceous rocks form the bedrock surface in the southern part of the study area, and Upper Cretaceous rocks in the north. Upper Cretaceous rocks, which may include Graneros Shale, Greenhorn Limestone, Carlile Shale, and Niobrara Chalk, subcrop in normal stratigraphic sequence as the elevation of the bedrock surface rises to the north. The dip of the Cretaceous formations is northeastward. Upper Cretaceous rocks crop out in areas where streams have eroded the Tertiary and Quaternary deposits, particularly north of the Arkansas River (Figure 2).
The configuration of the bedrock surface underlying Kearny and Finney counties, shown in Figure 3, indicates a southeast-trending drainage system that has been altered by faulting. The major structural feature on the bedrock surface is the Bear Creek Fault in Kearny County. Vertical displacement across the fault may be as much as 250 ft. The sandstones of the Dakota aquifer (Lower Cretaceous) may be a source of water in some locations (see Macfarlane et al., 1989). Upper Cretaceous rocks yield little or no water to wells. Some solution channels are present in the Niobrara Chalk, but they are not believed to constitute a continuous aquifer. Table 1 provides a generalized description of the geologic formations in the study area and their water-bearing properties.
Figure 3. Configuration of base of High Plains aquifer in Kearny and western Finney counties (after USGS, 1985).
Table 1. Generalized section of geologic formations and their water-bearing properties (from Gutentag et al., 1981). The classification and nomenclature of the stratigraphic units used in this report are those of the Kansas Geological Survey and differ somewhat from those of the U.S. Geological Survey.
| System | Series | Stratigraphic unit |
Thickness, Feet |
Physical character | Water supply |
|---|---|---|---|---|---|
| Quaternary | Pleistocene | Alluvium | 0-80 | Stream-laid deposits ranging from silt and clay to sand and gravel that occur along principal stream valleys. | Yields to wells range from 500 to more than 1,000 gal/min in the Arkansas River valley; 50 to 500 gal/min in the Pawnee River valley; and 50 to 1,000 gal/min in the Cimarron River valley. |
| Dune sand | 0-75 | Fine to medium quartzose sand with small amounts of clay, silt, and coarse sand formed into mounds and ridges by the wind. | Lies above the water table and does not yield water to wells. The sand has a high infiltration rate and is important as area of ground-water recharge. | ||
| Loess | 0-45 | Silt with subordinate amounts of very fine sand and clay deposited as wind-blown dust. | Lies above the water table and does not yield water to wells. Serves as minor area of ground-water recharge. | ||
| Undifferentiated deposits | 0-550 | Sand, gravel, silt, clay, and caliche overlie Ogallala Formation when both formations are present; composite of stream-laid and wind-blown deposits. | The sand and gravel of the undifferentiated Pleistocene deposits and the Ogallala Formation are the principal water-bearing deposits in the area. Yields range from 100 to 3,100 gal/min. | ||
| Tertiary | Pliocene | Ogallala Formation | 0-500 | Poorly sorted clay, silt, sand, and gravel generally calcareous; when cemented by calcium carbonate, Forms caliche layers or mortar beds. | The sand and gravel of the undifferentiated Pleistocene deposits and the Ogallala Formation are the principal water-bearing deposits in the area. Yields range from 100 to 3,100 gal/min. |
| Cretaceous | Upper Cretaceous | Niobrara Chalk | 0-250 | Upper unit (Smoky Hill Chalk Member)--yellow to orange-yellow chalk and light- to dark-gray beds of chalky shale. Lower unit (Fort Hays Limestone Member)--consists of a white to yellow massive chalky limestone: contains thin beds of dark-gray chalky shale. | Not generally considered an aquifer. Initially (1968-72), yielded 500 to 2,500 gal/min to wells in northern Finney and eastern Kearny counties where the Fort Hays Limestone Member has been honeycombed by fractures and solution openings. Because of increased irrigation development, yields have been reduced by 100 to as much as 2,000 gal/min. |
| Carlile Shale | 0-330 | Upper unit consists of a dark-gray to blue-black noncalcareous to slightly calcareous shale that locally is interbedded with calcareous silty very fine-grained sandstone. Lower part consists of very calcareous dark-gray shale and thin gray interbedded limestone layers. | Sandstone in upper part may yield 5 to 10 gal/min to wells. | ||
| Greenhorn Limestone | 0-200 | Chalky light yellow-brown shale with thin-bedded limestone. Dark-gray calcareous shale and light-gray thin-bedded limestone; contains layers of bentonite. | Not known to yield water to wells in southwestern Kansas. | ||
| Graneros Shale | 0-130 | Dark-gray calcareous shale interbedded with black calcareous shale; contains thin beds of bentonite. Also contains thin-bedded gray limestone and fine-grained silty sandstone layers. | Not known to yield water to wells in southwestern Kansas. | ||
| Lower Cretaceous | Undifferentiated rocks | 0-450 | Upper unit (Dakota Formation)--brown to gray fine- to medium-grained sandstone; interbedded with gray sandy shale and varicolored shale; contains lignite lenses (0-160 feet). Middle unit (Kiowa Formation)--dark-gray to black shale; interbedded with light yellow-brown and gray sandstone (0-150 feet). Lower unit (Cheyenne Sandstone)--gray and brown very fine- to medium-grained sandstone; interbedded with dark-gray shale (0-125 feet). | The sandstone units commonly yield from 50 to 500 gal/min to wells. Yields of more than 1,000 gal/min are reported in a few areas. Water may be more mineralized in the lower unit than in the upper unit. | |
| Jurassic | Upper Jurassic | Undifferentiated rocks | 0-350 | Dark-gray shale; interbedded with grayish-green and bluish-green calcareous shale. Contains very fine- to medium-grained silty sandstone and some thin limestone beds at the base. | In Morton and Stanton counties, sandstone beds are yielding in combination with the overlying Lower Cretaceous units. In the northernmost counties where the aquifer is deepest, the water may be mineralized. |
| Permian | Upper Permian | Big Basin Formation | 0-160 | Brick-red to maroon siltstone and shale; contains very fine-grained sandstone. | Where not highly mineralized, may yield small quantities of usable water for domestic and stock purposes. |
| Day Creek Dolomite | 0-80 | White to pink anhydrite and gypsum; contains interbedded dark-red shale. | Solution cavities have yielded large quantities (300 to 1,000 gal/min) of high sulfate water to wells in Morton County. | ||
| Whitehorse Formation | 100-350 | Red to maroon fine-grained silty sandstone, siltstone, and shale. | Fresh to highly mineralized water. Not known to yield significant amounts of water to wells in southwestern Kansas. | ||
| Lower Permian | Dog Creek Formation | 15-60 | Maroon silty shale, siltstone, very fine sandstone, and thin layers of dolomite and gypsum. | Not known to yield significant amounts of water to wells in southwestern Kansas. Water probably highly mineralized. | |
| Blaine Formation | 20-150 | Generally consists of four gypsum and anhydrite beds separated by red shale; contains bedded halite at some sites. | Not known to yield significant amounts of water to wells in southwestern Kansas. Water probably highly mineralized. |
Thick, layered unconsolidated sediments of Tertiary and Quaternary age underlie most of Kearny and Finney counties. The principal sources of water are sand and gravel layers in Pliocene (Ogallala Formation) and undifferentiated Pleistocene deposits. The unconsolidated Pliocene and Pleistocene deposits are hydraulically connected and lithologically similar, and are considered as one aquifer, the High Plains aquifer. The Quaternary alluvium in the Arkansas River valley is also a source of water and will be discussed in the next section. The Arkansas River, the Quaternary alluvial aquifer, and the underlying High Plains aquifer are hydraulically connected.
The High Plains aquifer consists of a heterogeneous assortment of alluvial sediments. Individual beds of silt, clay, sand, gravel, and caliche generally are not continuous and within very short distances may grade laterally or vertically into material of different composition. Where the aquifer has been divided at aquifer test sites into the Pliocene Ogallala Formation and the undifferentiated Pleistocene deposits, the sand and gravel beds of the Ogallala contain a greater amount of interbedded and mixed silt, clay, and caliche than do those of Pleistocene age (Meyer et al., 1970).
The Ogallala Formation was deposited by east- to southeast-flowing streams. The source material was erosional debris from the Rocky Mountains, and exposed sedimentary rocks of southeastern Colorado and western Kansas. The pre-Ogallala surface was a Cretaceous southeastward-sloping erosional base, which was gradually filled in by Ogallala sediments, forming an alluvial plain. The sediment deposition by meandering streams created a discontinuous, heterogeneous assortment of alluvial sediments. The Ogallala Formation consists primarily of silt, sand, gravel, and clay. It may be loosely consolidated or tightly cemented by calcium carbonate to form a very compact "mortar bed" that resembles concrete. Caliche is common and occurs as cementing material, pipy concretions, nodules, or irregular beds. In some places, the Ogallala is capped by a hard limestone bed (Meyer et al., 1970).
The undifferentiated Pleistocene deposits are the result of filling in of valley cuts in the Ogallala Formation. A heterogeneous mixture of coarse-grained channel sediment and fine-grained stream or lake sediment was deposited by meandering streams. These deposits consist primarily of unconsolidated sand and gravel, interbedded with clay, silt, and local deposits of volcanic ash. The coarse-grained deposits commonly are not cemented with caliche, as they are in the Ogallala. Sand is generally the most abundant material. Similar to the Ogallala, the Pleistocene deposits generally are poorly sorted, and individual layers are discontinuous (McLaughlin, 1943).
Because the aquifer consists of alternating lenses of fine- and coarse-grained sediments, ground-water movement may be retarded vertically and laterally. Further, the water-yielding capacity varies widely and water may be unconfined or semiconfined. Ground-water flow is mainly eastward. The aquifer system is recharged by infiltration of precipitation and irrigation water, by seepage of water from the Arkansas River and irrigation canals, and by underflow from adjacent areas. Discharge from the aquifer is by underflow eastward, by transpiration and evaporation in areas of shallow water table, and by wells. Since the 1970's, baseflow to the river and ground-water evapotranspiration have been practically nonexistent (Dunlap et al., 1985). Today the discharge is primarily by wells.
The thickness of the Pliocene and Pleistocene sediments increases from north to south, with the greatest thicknesses, more than 500 feet, located in southwestern Finney and southeastern Kearny counties. Areas of greatest thickness coincide with ancient stream-channel courses (Gutentag et al., 1972b). Although the lithology of the deposits differs from one area to another, Gutentag et al. (1972a) found a general relationship between saturated thickness and well yield.
West of the Bear Creek fault, the alluvium rests on Cretaceous bedrock, and the High Plains aquifer is absent. Water may be obtained from the Arkansas River alluvium (however its quality may be poor) or underlying sandstones in the Dakota aquifer.
Dunlap et al. (1985) separated an upper and lower aquifer in Kearny and Finney counties with a confining layer for modeling purposes. The lower aquifer consisted of undifferentiated Pliocene or Miocene and Pleistocene deposits. The confining zone consisted of fine-grained Lower Pleistocene deposits. The upper layer was composed of coarse materials of Pleistocene age. The model also included the Arkansas River valley aquifer of Pleistocene and Holocene age. The confining zone ranged from near zero to about 200 feet thick. The authors noted that individual clay and silt lenses were difficult to correlate from one area to the next.
It is important to recognize the heterogeneity of the sediments and the difficulty in characterizing the aquifer system. Nearly all previous reports emphasize that individual beds and lenses are not continuous over wide areas. As Meyer et al. (1970) reported, "...the individual beds pinch out or grade, almost imperceptibly, both laterally and vertically, into finer or coarser material of another bed or lense." Because of the heterogeneity, most of the reports recommend test drilling for locating a large-capacity well.
The Arkansas River alluvial sediments are the most permeable water-bearing deposits. The alluvial material underlying the Arkansas River valley consists of coarse-grained deposits of Pleistocene age overlain by fine-grained deposits of Holocene age. The alluvium is composed of sand and gravel and lesser amounts of silt and clay. The material is poorly sorted and grades into material of different composition within short distances both laterally and vertically. Clay is generally found at or near the base of the alluvium.
West of the former town of Hartland in Kearny County, the alluvium overlies Cretaceous bedrock. East of Hartland the alluvium is underlain by undifferentiated Pliocene and Pleistocene deposits. The former town of Hartland is located where the course of the Arkansas River changes from a southeast to a northeast direction (see Figures 1 and 2).
In Kearny County, the Arkansas River valley is less than 1 mile at its narrowest point near Hartland. East of Hartland the valley broadens and attains a maximum width of about 5 miles near Lakin (Figures 1 and 2). In Finney County the width of the Arkansas River alluvium ranges from 1 mile in the east to 3.5 miles west of Garden City, and averages about 2 miles.
The thickness of the alluvium ranges from about 10 feet southwest of Hartland to as great as 70 feet in parts of Kearny County (Dunlap et al., 1985). Generally, the thickness in Kearny County is between 40 and 50 feet. Between Hartland and Deerfield, the bed of clay that is encountered at depths of 35 to 45 feet represents the base of the alluvium (McLaughlin, 1943). The average thickness of the alluvium in Finney County is about 40 feet (Meyer et al., 1970).
Geologic data used in producing cross sections were obtained from lithologic logs of water wells (WWC-5 forms filed by well drillers since 1975), wells and test holes published in previous reports of the U.S. Geological Survey and Kansas Geological Survey, and monitoring wells drilled for the UARC study. Cross sections are presented in Appendix A; lithologic logs are available from the authors. The goal was to develop procedures that would allow electronic storage, processing, and display of the lithologic data. This method could allow easier printing of copies as needed and updating based on new lithologic data.
The first step taken for electronic handling of data and production of displays was the simplification of the wide variety of lithologic descriptions into general categories. Each described material from the lithologic logs was assigned a numerical geologic code from 1 to 10, based on relative permeability (see Young et al., 1997). The lithologic logs were then transformed into numerical logs based on the geologic codes. The materials were then assigned one of five colors (light to dark) based on relative permeability. The range of colors corresponding to the different (permeability) materials is shown in Figure 4.
Figure 4. Generalized material identification codes.
The colors representing the numerical logs were entered into a Microsoft Excel spreadsheet. Each column in the spreadsheet represents either a borehole or space between the boreholes as appropriate for hardcopy production. Each spreadsheet row represents a uniform depth interval in the borehole. An interval of one foot was used for this study. Thus, geologic intervals of more than one foot occupy multiple adjoining rows in the column for that borehole. Once a cross section was completed, the Excel file was imported as a PostScript file into Adobe Illustrator for final editing and labeling.
The cross sections presented in this report supersede the sections presented in the progress report by Young et al. (1997). They have been improved and expanded, and new north-south sections have been added. Some of the modifications arose out of some potential problems or uncertainties discovered since the production of the previous report. Following is discussion of these and the means used to ensure better sections, as well as some qualifiers.
A primary source of uncertainty is the location of a well or test hole. Locations listed on WWC-5 sheets and test hole logs are sometimes in question. Further, elevations are normally not listed on WWC-5 forms, so an incorrect location can result in the wrong estimated elevation. A lot of work went into ensuring that locations (and therefore elevations) were as accurate as possible. For example, on WWC-5 forms, legal locations were compared with distance and direction from nearest town or city. Also county rural phone books were consulted for landowner/tenant information and compared with owner of the well listed on the WWC-5 sheet.
Elevations were estimated from 7.5 minute topographic maps with a scale of 1:24,000 and contour intervals of 5 or 10 feet. Estimated elevations in the alluvial valley, which is relatively flat, are usually within 5 feet and probably always within 10 feet of the actual elevation (assuming accurate locations), but the uncertainty increases greatly on or near terraces or bluffs, and in dune sand. Fortunately, the focus is on the alluvial valley, and most wells used in the cross sections are located in the valley.
A frequent dilemma was deciding which log(s) to include if many were available. (However, in some areas, such as western Kearny County, very few were available, so all available logs were used.) Logs of test holes were used where available. Additionally, virtually every WWC-5 form was examined in the townships studied. Generally only wells that went to bedrock were included in sections (unless none were available). It became apparent that the quality and consistency of the information on the WWC-5 forms varied depending on the driller or drilling company. Logs by Henkle and Minter-Wilson were abundant, generally consistent, and were often favored over some of the others, based on the character of the lithologic reporting.
An accurate depth to bedrock was not always easy to determine from WWC-5 forms. Logs of test holes have the advantage that the geologic formation is normally listed. Some Cretaceous (bedrock) materials may actually appear as a clay or clay-shale. Therefore, what appears near the bottom of a WWC-5 log as a hard clay may actually be Cretaceous bedrock. If enough nearby information was available to suggest with confidence that the clay was actually Cretaceous material, then the column was truncated at the top of the clay. Thus, the bottom of the columns in the sections provides an approximation of the bedrock surface underlying the wells, but is subject to uncertainties.
Lithologic cross sections for Kearny and Finney counties are presented in Appendix A; the corresponding lithologic logs (copies of WWC-5 forms and test hole logs) are available from the authors. Locations of the wells used for the cross sections are shown in Figure 5 and listed in Table 2.
Figure 5. Locations of transect wells and test holes. A larger version of the figure is available as an Acrobat PDF file (232 kB).
Table 2. Locations of wells and test holes used in geologic cross sections.
| West-East Alluvial Valley Transects | |
|---|---|
| North of Arkansas RiverRiver in Kearny County 25S 38W 12 A 25S 37W 08 DDC 25S 37W 08 DDD 25S 37W 09 DDD 25S 37W 10 CDC 25S 37W 11 CC 25S 37W 11 CCA 25S 37W 11 DDC 25S 36W 06 CAC 24S 36W 33 BAB 24S 36W 26 C 24S 36W 26 BCB 24S 36W 23 CCC 24S 35W 17 A 24S 35W 15 BAC 24S 35W 11 CBB South of Arkansas River in Kearny County 25S 37W 18 BBB 25S 37W 14 ACC 25S 37W 24 CBB 25S 36W 18 D 25S 36W 17 ACB 25S 36W 09 CBB 25S 36W 16 ABC 25S 36W 04 DAA 25S 36W 03 BAD 24S 36W 35 C 25S 36W 02 DDA 25S 36W 01 DBD 24S 35W 31 BCC 24S 35W 30 CCB 24S 35W 29 C 24S 35W 32 DDD 24S 35W 29 A 24S 35W 28 CDD 24S 35W 28 ABB 24S 35W 28 DDD 24S 35W 22 CCC 24S 35W 27 C 24S 35W 27 D 24S 35W 23 B 24S 35W 14 A 24S 35W 24 BCB 24S 35W 13 CCD 24S 35W 13 AAA |
North of Arkansas River in Finney County 24S 34W 07 BBB 24S 34W 03 DDC 24S 34W 11 AC 24S 34W 12 B 24S 33W 06 CC 24S 33W 08 BBD 24S 33W 09 BCB 24S 33W 16 BBB 24S 33W 10 BAA 24S 33W 11 BAB 24S 33W 12 CCA 24S 32W 07 DCC 24S 32W 07 DAB 24S 32W 17 BAA 24S 32W 21 BBB 24S 32W 22 BAA 24S 32W 23 CCC 24S 32W 26 BAB 24S 32W 25 DDD South of Arkansas River in Finney County 24S 34W 07 CCC 24S 34W 17 ABD 24S 34W 08 AAB 24S 34W 09 BDC 24S 34W 10 C 24S 34W 14 B 24S 34W 13 AAC 24S 33W 22 A 24S 33W 23 A 24S 32W 19 CAB 24S 32W 26 C 25S 31W 05 C 25S 31W 08 A 25S 31W 09 B 25S 31W 09 C 25S 31 W 09 DBC |
Table 2. Locations of wells and test holes used in geologic cross sections.
| North-South Transects | |
|---|---|
| Hartland 24S 37W 04 CBC 24S 37W 08 ADD 24S 37W 21 BBB 24S 37W 21 CD 24S 37W 28 DDD 24S 37W 33 CAD 25S 37W 05 DDD 25S 37W 08 DDC 25S 37W 18 BBB 25S 38W 13 CBC 25S 38W 23 C 25S 38W 35 BBB Lakin 24S 36W 10 BCC 24S 36W 15 BBC 24S 36W 15 DDC 24S 36W 23 CCC 24S 36W 26 BCB 24S 36W 26 C 24S 36W 35 C 25S 36W 02 DDA 25S 36W 13 B 25S 36W 13 D 25S 36W 24 C Deerfield 22S 35W 14 AAA 22S 35W 35 ADB 23S 35W 11 ACD 23S 35W 14 BDC 23S 35W 14 CDC 23S 35W 23 CCB 23S 35W 27 AAD 23S 35W 35 ABB 23S 35W 34 DAA 24S 35W 02 BBB 24S 35W 11 BC 24S 35W 11 CBB 24S 35W 14 A 24S 35W 13 CCD 24S 35W 24 BCB 24S 35W 25 A 24S 35W 25 C 24S 35W 35 C 25S 35W 03 D 25S 35W 10 AC 25S 35W 26 DDD |
Western Finney County 22S 34W 18 ABB 22S 34W 30 DDA 22S 34W 31 CCD 23S 34W 06 AAD 23S 34W 18 ACD 23S 34W 19 ABB 23S 34W 30 AC 23S 34W 32 BCC 24S 34W 06 CAB 24S 34W 07 BBB 24S 34W 07 CCC 24S 34W 17 ABD 24S 34W 30 DCC 25S 34W 08 D 25S 34W 19 B 25S 34W 30 D Garden City 22S 32W 06 DD 22S 33W 13 AAA 23S 32W 06 BBB 23S 33W 24 DC 23S 32W 31 C 23S 32W 31 DDD 24S 32W 06 CBA 24S 32W 07 DA 24S 32W 17 BAA 24S 32W 19 CAB 24S 33W 36 A 25S 33W 01 DC 25S 33W 12 AB 25S 33W 24 AA 26S 32W 06 AB |
The cross sections presented in Appendix A supersede the sections presented in the progress report by Young et al. (1997). Efforts were made to produce the most complete and accurate sections as was reasonably possible within the given time frame. The sections represent the most detailed characterization of the lithology in Kearny and Finney counties to date. In recognition of the uncertainties discussed above, it should be noted that actual elevations and lithology may vary from those portrayed in the sections depending on the accuracy of the data reporting and materials identification. The sections are based on lithologic well logs that are subjective, and differ in quality depending on the individual driller or site geologist.
Appendix A includes the following lithologic cross-section transects:
West-East Transects
Figure A1. North of Arkansas River in Kearny County
Figure A2. South of Arkansas River in Kearny County
Figure A3. North of Arkansas River in Finney County
Figure A4. South of Arkansas River in Finney County
North-South Transects
Figure A5. Hartland Figure A6. Lakin Figure A7. Deerfield Figure A8. Western Finney County Figure A9. Garden City
Nearly all wells included in the west-east transects are located in the Arkansas River alluvial valley. The north-south transects all cross the Arkansas River.
West-East Alluvial Valley Transects
Surface elevation decreases from west to east, as shown by the position of the tops of the columns representing the wells in Figures A1-A4. The bottom of the columns suggests an eastward slope of the bedrock surface west of about Deerfield, and a more level surface east of Deerfield to about Garden City. East of Garden City, the bedrock elevation appears to increase, and the thickness of the deposits decreases. The sediments underlying the Arkansas River valley appear to be thickest, approaching 400 feet, in eastern Kearny County.
In westernmost Kearny County (Figs. A1 and A2), the alluvium is very thin and rests on Cretaceous bedrock. The thin alluvium is composed mostly of fine-grained materials. The Bear Creek Fault is evident, particularly in the south transect (Fig. A2) between wells 2 and 3. Note that the distance shown on the horizontal axis of the sections is approximate west-east river miles. Although wells 2 and 3 on Figure A2 appear to be in very close proximity, they are more than a mile apart; well 3 is mostly south and just slightly east of well 2 (Fig. 5).
A striking observation is the uniform and continuous alluvial valley aquifer south of the Arkansas River in Kearny County, and both north and south of the river in Finney County. The permeable sands and gravels of the Arkansas River alluvial aquifer are seen in the upper fifty feet of the majority of the wells. As the literature suggests, the alluvial aquifer is slightly thinner in Finney County, averaging about 40 feet. The alluvial aquifer in Finney is also composed primarily of sand and gravel, with thin lenses of silt or clay. The permeable materials are generally capped by 5 feet or less of surface materials or soil.
The alluvial valley is narrow north of the Arkansas River in most of Kearny County, and coarse-grained materials are generally thinner. Wells located north of the river indicate a somewhat less continuous and more heterogeneous alluvial aquifer, containing more fine-grained materials than are present south of the river. The fine-grained materials are particularly predominant in the areas near Deerfield and Lakin (see also Figs. A6 and A7).
Below the shallow alluvial aquifer is a relatively impermeable layer of varying thickness, which is most often made up of clay, or clay with lenses of silt, caliche or (cemented) sand. This relatively impermeable layer between the upper and lower aquifers tends to be thicker with more clay in the cross sections for north of the river than for south of the river (see also north-south sections, Figs. A5-A9). The impermeable layer appears to be thickest in vicinity of Deerfield and the county line, particularly north of the river. South of the Arkansas River in Finney County, the impermeable layer becomes thin in places (for example, a few miles west of Holcomb), and appears to nearly pinch out east of Garden City (Fig. A4).
Other permeable units are seen deeper in the profiles. These permeable units are generally the producing (screened) intervals in the High Plains aquifer. They are made up of varied sizes and combinations of sand and gravel, and are commonly cemented with calcium carbonate or caliche. The continuity of layers in the deeper High Plains aquifer is frequently difficult to correlate from one well to the next. The permeable sands and gravels are commonly interbedded with lenses of caliche, clay, and silt. Frequently, high-capacity water wells are screened across more than one permeable unit.
The High Plains aquifer south of the river generally has thicker, more continuous gravelly layers compared to the aquifer north of the river. However, relatively thick permeable horizons occur both north and south of the river. The permeable units appear thicker and more continuous in Finney compared with Kearny County.
North-South Transects
The north-south sections (Figures A5-A9) show that the unconsolidated deposits are generally thicker south of the Arkansas River. The bedrock surface in the north-south sections appears undulating. This is indicative of the channel features formed by ancient streams. The bedrock surface has been altered by faulting; the Bear Creek Fault is evident at the base of the northernmost wells in the Lakin section (Figure A6). Once again, the High Plains aquifer is absent and the bedrock is shallow near the former town of Hartland (Figure A5).
The shallow alluvial aquifer generally is well defined south of the Arkansas River, while more fine-grained materials occur north of the river, especially in Kearny County. Some of the sections suggest that the alluvial valley aquifer may be connected with the shallow High Plains aquifer south of the river. North of the river, the top hundred feet or so is commonly dominated by fine-grained sediments, indicating less hydraulic connection between upper and lower waters.
Similarly, the deeper High Plains aquifer contains more permeable materials and appears more continuous south of the river compared with north of the river. Also thicknesses are generally greater to the south. While permeable layers occur both north and south of the river, they are generally interspersed with layers of low permeability. What is particularly evident is the heterogeneity and apparent lack of lateral continuity of layers in the High Plains aquifer. In spite of the heterogeneity, the sections do indicate which type of materials (low permeability vs. high permeability) are potentially prominent in different areas.
Dunlap, L. E., Lindgren, R. J., and Sauer, C. G., 1985. Geohydrology and model analysis of stream-aquifer system along the Arkansas River in Kearny and Finney Counties, southwestern Kansas: U.S. Geological Survey, Water-Supply Paper 2253, 52 p. [available online]
Gutentag, E. D., Lobmeyer, D. H., and McGovern, H. E., 1972a. Ground water in Kearny County, southwestern Kansas: U.S. Geological Survey, Hydrologic Investigations Atlas HA-416. [available online]
Gutentag, E. D., Lobmeyer, D. H., McGovern, H. E., and Long, W. A., 1972b. Ground water in Finney County, southwestern Kansas: U.S. Geological Survey, Hydrologic Investigations Atlas HA-442. [available online]
Gutentag, E. D., Lobmeyer, D. H., and Slagle, S. E., 1981. Geohydrology of southwestern Kansas: Kansas Geological Survey, Irrigation Series 7, 117 p. [available online]
Latta, B. F., 1944. Geology and ground-water resources of Finney and Gray counties, Kansas: Kansas Geological Survey, Bulletin 55, 272 p. [available online]
Lobmeyer, D. H., and Sauer, C. G., 1974. Water resources of Hamilton County, southwestern Kansas: U.S. Geological Survey, Hydrologic Investigations Atlas HA-516. [available online]
McGovern, H. E., and Long, W.A., 1974. Ground water in Gray County, southwestern Kansas: U.S. Geological Survey, Hydrologic Investigations Atlas HA-517. [available online]
Macfarlane, P. A., Whittemore, D. O., Townsend, M. A., Doveton, J. H., Hamilton, V. J., Coyle, W. G., Wade, A., Macpherson, G. L., and Black, R. D., 1989. The Dakota aquifer program: annual report, FY89: Kansas Geological Survey Open-File Report 90-27. 169 p. plus appendices. [available online]
McLaughlin, T. G., 1943. Geology and ground-water resources of Hamilton and Kearny counties, Kansas: Kansas Geological Survey, Bulletin 49, 220 p. [available online]
Meyer, W. R., Gutantag, E. D., and Lobmeyer, D. H., 1969. Finney County basic data: U.S. Geological Survey, Open-File Report, March 1969.
Meyer, W. R., Gutantag, E. D., and Lobmeyer, D. H., 1970. Geohydrology of Finney County, southwestern Kansas: U.S. Geological Survey, Water-Supply Paper 1891, 117 p. [available online]
Spinazola, J. M., and Dealy, M. T., 1983. Hydrology of the Ogallala aquifer in Ford County, southwestern Kansas: U.S. Geological Survey, Water-Resources Investigations Report 83-4226, 58 p. [available online]
Waite, H. A., 1942. Geology and ground-water resources of Ford County, Kansas: Kansas Geological Survey, Bulletin 43, 250 p. [available online]
Whittemore, D. O., Tsou, M., and Grauer, J., 1996. Upper Arkansas River Corridor study: inventory of available data and development of conceptual models: Kansas Geological Survey, Open-File Report 96-19, 83 p.
Young, D., Grauer, J., and Whittemore, D., 1997. Upper Arkansas River Corridor Study: progress on lithologic characterization of unconsolidated deposits in the study area with emphasis on Kearny and Finney counties: Kansas Geological Survey, Open-File Report 97-43.
Nearly all wells included in the west-east transects are located in the Arkansas River alluvial valley. The north-south transects all cross the Arkansas River.
Figure A1. North of Arkansas River in Kearny County
Figure A2. South of Arkansas River in Kearny County
Figure A3. North of Arkansas River in Finney County
Figure A4. South of Arkansas River in Finney County
Figure A5. Hartland
Figure A6. Lakin
Figure A7. Deerfield
Figure A8. Western Finney County
Figure A9. Garden City
Kansas Geological Survey, Geohydrology
Placed online Dec. 10, 2007; original report dated June 1998
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