Geology topics
Scott C. Christenson
Publications and source records attributed to Scott C. Christenson.
Ground-water quality assessment of the central Oklahoma aquifer, Oklahoma - Analysis of available water-quality data through 1987
Beginning in 1986, the Congress annually has appropriated funds for the U.S. Geological Survey to test and refine concepts for a National Water-Quality Assessment (NAWQA) Program. The long-term goals of a full-scale program would be to: Provide a nationally consistent description of current water-quality conditions for a large part of the Nation's surface- and ground-water resources; Define long-term trends (or lack of trends) in water quality; and Identify, describe, and explain, as possible, the major factors that affect the observed water-quality conditions and trends. The results of the NAWQA Program will be made available to water managers, policy makers, and the public, and will provide an improved scientific basis for evaluating the effectiveness of water-quality management programs. At present (1988), the assessment program is in a pilot phase in seven project areas throughout the country that represent diverse hydrologic environments and water-quality conditions. The Central Oklahoma aquifer project is one of three pilot ground-water projects. One of the initial activities performed by each pilot project was to compile, screen, and interpret the large amount of water-quality data available within each study unit. The purpose of this report is to assess the water quality of the Central Oklahoma aquifer using the information available through 1987. The scope of the work includes compiling data from Federal, State, and local agencies; evaluating the suitability of the information for conducting a regional water-quality assessment; mapping regional variations in major-ion chemistry; calculating summary statistics of the available water-quality data; producing maps to show the location and number of samples that exceeded water-quality standards; and performing contingency-table analyses to determine the relation of geologic unit and depth to the occurrence of chemical constituents that exceed water-quality standards. This report provides an initial description of water-quality conditions in the Central Oklahoma aquifer study unit. No attempt was made in this report to determine the causes for regional variations in major-ion chemistry or to examine the reasons that some chemical constituents exceed water-quality standards.
Geologic logs for selected deep wells in parts of Oklahoma, Texas, and New Mexico
A computerized data base of geologic logs for selected deep wells in parts of Oklahoma, Texas, and New Mexico was prepared by the U.S. Geological Survey as part of the Central Midwest Regional Aquifer-System Analysis. At least one well per county in the study area was selected, and the geologic logs for the wells were entered into the data base. Summaries of the geologic logs are presented in this report. Geophysical logs were used for interpretation of the geologic logs, and a list of these geophysical logs also is presented. These geophysical logs are available for inspection at the U.S. Geological Survey office in Oklahoma City, Oklahoma.
Hydrologic data for the alluvium and terrace aquifer of the Beaver-North Canadian River from the Panhandle to Canton Reservoir, northwestern Oklahoma
The U.S. Geological Survey has collected data on Oklahoma's groundwater resources since 1934. The data in this report were collected as part of a study in cooperation with the Oklahoma Water Resources Board to evaluate the geohydrology of the alluvium and terrace aquifer of the Beaver-North Canadian River 4] in northwestern Oklahoma. The data include records of approximately 900 wells, test-holes, and springs, results of chemical analyses of water from 30 wells tapping the aquifer, monthly water-level measurements for selected wells, and low-flow discharge measurements of the Beaver-North Canadian River and its tributaries (plate 1). All of the data were collected in the field during the period 1977-79. Information prior to this period is not included in this report but is contained in reports by Wood and Stacy (1965) and Morton (in press). The stratigraphic nomenclature is that of the Oklahoma Geological Survey and does.not necessarily agree with that of the U.S. Geological Survey. Acknowledgement is extended to the residents of the study area for their cooperation in obtaining the data in this report.
Geohydrology and numerical simulation of the alluvium and terrace aquifer along the Beaver-North Canadian River from the Panhandle to Canton Lake, northwestern Oklahoma
A quantitative description of the hydrologic system in alluvium and terrace deposits along the Beaver-North Canadian River in northwestern Oklahoma is needed as an aid for planning and management of the aquifer. A two-dimensional finite-difference model was used to describe the aquifer and to predict the effects of future ground-water withdrawals. The aquifer principally consists of three geologic units: Alluvium with an average thickness of 30 feet, low terrace deposits with an average thickness of 50 feet, and high terrace deposits with an average thickness of 70 feet. A thin cover of dune sand overlies much of the area and provides an excellent catchment for recharge, but is generally unsaturated. Hydraulic conductivity of the aquifer ranges from 0 to 160 feet per day and averages 59 feet per day. Specific yield is estimated to be 0.29. Recharge to the aquifer is approximately 1 inch annually. Under present conditions (1978), most discharge is the result of ground-water flow to the Beaver-North Canadian River at a rate of 36 cubic feet per second and to pumpage for public-supply, industrial, and irrigation use at a rate of 28 cubic feet per second. In 1978, the aquifer had an average saturated thickness of 31 feet and contained 4.07 million acre-feet of water. The model was used to predict future head response in the aquifer to various pumping stresses. For any one area, the pumping stress was applied until the saturated thickness for that area was less than 5 feet, at which time the pumping ceased. The results of the modeled projections show that if the aquifer is stressed from 1978 to 1993 at the 1977 pumpage rates and well distribution, the average saturated thickness will decrease 1.0 foot and the volume of water in storage will be 3.94 million acre-feet, or 97 percent of the 1978 volume. If the aquifer is stressed at this same rate until 2020, the average saturated thickness will decrease an additional 0.7 foot and the volume of water in storage will be 3.84 million acre-feet, or 94 percent of the 1978 volume. If all areas of the aquifer having a 1978 saturated thickness of 5 feet or more are stressed from 1978 to 1993 at a rate of approximately 1.4 acre-feet per acre per year, the average saturated thickness will decrease by 20.9 feet and the volume of water in storage will be 1.28 million acre-feet, or 31 percent of the 1978 volume. If the aquifer is stressed at this same rate until 2020, the average saturated thickness will decrease an additional 2.2 feet and the volume of water in storage will be 980,000 acre-feet, or 24 percent of the 1978 volume. The water in the aquifer is generally of the calcium bicarbonate type and is suitable for most uses. Most of the 30 water samples analyzed contained less than 500 milligrams of dissolved solids per liter.