U.S. GEOLOGICAL SURVEY
Water-Resources Investigations Report 03-4165
Prepared in cooperation with the Directorate of Public Works, Environmental Division, Fort Leonard Wood Military Reservation
By: D. N. Mugel and J. L. Imes
A pdf is available for this report
ABSTRACT
The Ozark aquifer is the principal source of ground water in the Gasconade River Basin upstream from Jerome, Missouri (herein referred to as the upper Gasconade River Basin), including the Fort Leonard Wood Military Reservation (FLWMR). The Ozark aquifer is composed of, in order of increasing age, the Cotter Dolomite, Jefferson City Dolomite, Roubidoux Formation, Gasconade Dolomite, Eminence Dolomite, and Potosi Dolomite. Sedimentary strata are nearly horizontal, except along folds and collapse zones where dips can be steep. The basin is cut by numerous faults, most of which trend generally northwest-southeast. The Jefferson City Dolomite and the Cotter Dolomite generally yield little water to wells. Wells completed in the Roubidoux Formation and Gasconade Dolomite commonly yield from several tens to several hundred gallons per minute of water. The Eminence Dolomite may form a weak hydrologic barrier to vertical ground-water flow between the overlying Gasconade Dolomite and the underlying Potosi Dolomite. The Potosi Dolomite is the most permeable formation in the Ozark aquifer. Wells completed in the Potosi Dolomite may yield from several hundred to 1,000 gallons per minute of water.
Water-table contours indicate several areas of high permeability karst terrain in the upper Gasconade River Basin. Ground-water levels may be as deep as 300 feet below the land surface beneath upland areas where karst features are prevalent. Although the Jefferson City Dolomite and the Roubidoux Formation are the uppermost bedrock formations in the upland areas of the FLWMR, the water table generally is deep enough to occur in the underlying Gasconade Dolomite throughout most of the FLWMR. Discharge from springs [311 ft3/s (cubic feet per second)] represented 56 percent of the August 1999 discharge of the Gasconade River at Jerome, Missouri (552 ft3/s).
From 1993 through 1997, annual pumpage from all public water-supply wells in the upper Gasconade River Basin ranged from 1,820 Mgal [million gallons; an average daily rate of 4.99 Mgal/d (million gallons per day)] in 1993 to 2,030 Mgal (an average daily rate of 5.56 Mgal/d) in 1997. Including an estimated 4 Mgal/d from domestic wells, the average daily pumping rate for all wells is estimated to range from 8.99 Mgal/d in 1993 to 9.56 Mgal/d in 1997. During the same period, annual pumpage from the Big Piney River, which supplies most of the water used at the FLWMR, ranged from 1,136 Mgal (an average of 3.11 Mgal/d) in 1997 to 1,334 Mgal (an average of 3.65 Mgal/d) in 1995, and as a percentage of total water use in the upper Gasconade River Basin, ranged from about 24.5 percent in 1997 to about 28.8 percent in 1993.
TABLE OF CONTENTS
Abstract
Introduction
Purpose and Scope
Description of Study Area
Previous Investigations
Geohydrologic Framework
Bedrock Geology
Stratigraphy and Geologic Structure
Ground-Water Hydrology
Domestic and Public Water-Supply Well Inventory
Ground-Water Occurrence and Flow
Ground-Water Discharge to Streams and Springs
Water Use for Public and Domestic Supply
Summary
References
FIGURES
1. Map showing location of the study area, streams, selected towns, major highways, county boundaries, and the Fort Leonard Wood Military Reservation boundary
2. Map showing streams, springs, and wells in and near the Fort Leonard Wood Military Reservation
3. Hydrostratigraphic column of geologic units for the study area
4.–13. Maps showing:
4. Bedrock geology of the study area showing location of generalized geologic sections
5. Altitude of the top of the Derby-Doe Run Dolomite in the study area
6. Thickness of the Potosi Dolomite in the study area
7. Altitude of the top of the Potosi Dolomite in the study area
8. Thickness of the Eminence Dolomite in the study area
9. Altitude of the top of the Eminence Dolomite in the study area
10. Thickness of the Gasconade Dolomite in the study area
11. Altitude of the top of the Gasconade Dolomite in the study area
12. Thickness of the Roubidoux Formation in the study area
13. Altitude of the top of the Roubidoux Formation in the study area
14. Generalized geologic section trending west-east across the northern part of the study area
15. Generalized geologic section trending west-east across the southern part of the study area
16. Generalized geologic section trending south-north across the central part of the study area
17.–24. Maps showing:
17. Pre-development water-table surface of the Ozark aquifer and recharge areas of selected springs in the study area
18. Area where the water table occurs within the indicated formation and where the formation is partially saturated in the study area, spring 1998
19. Saturated thickness of the Jefferson City and Cotter Dolomites in the study area, spring 1998
20. Saturated thickness of the Roubidoux Formation in the study area, spring 1998
21. Saturated thickness of the Gasconade Dolomite in the study area, spring 1998
22. Location of low-flow measurement sites and value of composite stream discharge
23. Location of selected springs in the study area and composite spring discharge values
24. Location of wells in the study area and in a 6-mile wide band surrounding the study area and the Fort Leonard Wood Military Reservation on the Big Piney River
25. Graph showing annual pumpage for 80 public water-supply wells in the study area and 63 public water-supply wells in a 6-mile wide band surrounding the study area from 1993 through 1997
TABLES
1. Location, well construction, depth to water, and specific conductance data for inventoried wells in the study area and in a 6-mile wide band surrounding the study area, spring 1998
2. Stream and spring low-flow discharge measurements made in September 1995, September 1998, and August 1999, estimated spring low-flow discharge measurements from published data, and composite stream and spring discharge data scaled to August 1999 discharge data
3. Average daily pumping rate and annual pumpage of public water-supply wells in the study area and in a 6-mile wide band surrounding the study area from January 1993 to June 1998
4. Annual pumpage of water from the Big Piney River for public water use at the Fort Leonard Wood Military Reservation, 1993–1997
VERTICAL DATUM
Vertical coordinate information is referenced to the National Geodetic Vertical Datum of 1929 (NGVD 29). Altitude, as used in this report, refers to distance above or below NGVD 29. NGVD 29 can be converted to the North American Vertical Datum of 1988 (NAVD 88) by using the National Geodetic Survey conversion utility available at URL http://www.ngs.noaa.gov/TOOLS/Vertcon/vertcon.html.
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For more information about USGS activities in Missouri contact:
District Chief
U.S. Geological Survey
Water Resources Discipline
1400 Independence Road
Rolla, Missouri 65401
Telephone: (573) 308-3667
Fax: (573) 308-3645
or access the USGS Water Resources of Missouri home page at: http://mo.water.usgs.gov/.
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