From introduction: In July 1977, the South Dakota Geological Survey and the U.S. Geological Survey began a 4-year study to evaluate the water resources and geology of Hanson and Davison Counties. The purpose of this report is to provide hydrogeologic information for future water development and planning in the counties. This study is part of an evaluation of the water resources and geology of eastern South Dakota (fig. 1).

From objectives and scope: The objectives of this study were to more accurately define certain hydrologic and hydraulic characteristics of the James River and its tributaries in South Dakota, to analyze the water budget and water quality within the Sand Lake National Wildlife Refuge, and to identify the need for additional studies.

From purpose and approach of study: The purpose of this study was to use the digital-computer model developed from the previous study (Koch, 1982) to examine the effects on the aquifer of a pumping rate of 25 million gallons a day under the worst-drought conditions that occurred during 1974-78. A frequency rating was determined for the most severe low-flow condition in the Big Sioux River.

Abstract: This report lists the machine-readable data files developed for the Madison Limestone and Northern Great Plains Regional Aquifer System Analysis (RASA) projects that are stored on magnetic tape and available from the U.S. Geological Survey. Record format, file content, and size are given for: (1) Drill-stem-test data for Paleozoic and Mesozoic formations; (2) geologic data from the Madison Limestone project; (3) data sets used in the regional simulation model; (4) hydraulic-head data for the Lower and Upper Cretaceous aquifers; and (5) geologic data for Mesozoic formations of the Northern Great Plains.

From abstract: The High Plains Regional Aquifer System Analysis study has developed a regional water-resources (and related) data storage and retrieval system to organize and preserve areal interpretive data. The system is general and can easily be adapted for other studies. This report documents the High Plains data base as well as the general system that is independent of the High Plains area.

From introduction: "The U.S. Geological Survey began a 5-year study of the High Plains regional aquifer during the 1978 to provide the hydrologic information needed for the development of computer models to evaluate the aquifer's response to ground-water management alternatives." It contains maps, graphs, and tables.

From introduction: The overall purpose of this study were twofold: (1) To determine where greatest yielding wells at shallowest depths would produce water of suitable quality for municipal and industrial supplies; and (2) to determine regional effects of additional water development on the hydrologic system.

From purpose and approach of study: The purpose of this study was to develop a predictive model of the ground-water system for use as a management tool. The model will be used by State and local officials in evaluating the effects of alternative methods of controlling or developing the ground-water resources of the Big Sioux aquifer in Minnehaha County.

Abstract: A digital simulation model was used to analyze regional ground-water flow in the Madison Group aquifer in the Powder River Basin and adjacent areas. Most recharge to the aquifer originates in or near the outcrop areas of the Madison in the Bighorn Mountains and Black Hills , and most discharge occurs through springs and wells. Results from the model calculations indicate that the total flow through the aquifer in the modeled areas was approximately 200 cubic feet per second (5.7 cubic metres per second). The aquifer can probably sustain increased ground-water withdrawals probably would significantly lower the potentiometric surface in the Madison aquifer in a large part of the basin. The digital model could better predict the effects of withdrawals if more accurate estimates of the storage coefficient, transmissivity, and leakance could be obtained.

From introduction: This report describes the results of 1980 sampling of ground-water pumpage for irrigation on the High Plains, one phase of the High Plains Regional Aquifer-System Analysis project. These data were collected to estimate the volume of irrigation water pumped during 1980 and to determine current trends in irrigation pumpage on the High Plains.

Purpose: The objectives of this study were (1) to collect, synthesize, and interpret geologic and hydrologic data on the aquifer in the southern South Dakota area; (2) to evaluate, by digital-computer-model simulation, values assigned to the aquifer parameters; and (3) to evaluate the sensitivity of the calibrated digital-computer-model to changes in magnitude of the selected hydrologic parameters. Results of this study are, therefore, applicable to solving potential water-resource management problems in the southern South Dakota and northern Nebraska model area.