Geology topics

Neil C. Koch

Publications and source records attributed to Neil C. Koch.

4 recordsLinked to original sources

USGS2010

A graphic presentation of stream gain or loss as an aid in understanding streamflow characteristics

A graphic presentation of cumulative monthly stream gain or loss on a given stream reach is used as a tool to show whether the stream gain or loss is apparent or real, and to determine the magnitude, time, and cause of the gain or loss. The graphic method could also be used to determine how much of the base flow is ground-water discharge. Interpretations of the cumulative gain or loss graph are described for three reaches on the James River in northeastern South Dakota and southeastern North Dakota.

North Dakota, South Dakota↗

USGS1985

Drainage areas in the Big Sioux River basin in eastern South Dakota

The Big Sioux River basin of eastern South Dakota contains an important surface water supply and a sizeable aquifer system of major importance to the economy of South Dakota. The aquifers are complex, consisting of many small aquifers that are hydrologically associated with several large aquifers and the Big Sioux River. The complexity and interrelation of the surface water/groundwater systems has already created management problems. As development continues and increases, the problems will increase in number and complexity. To aid in planning for future development, an accurate determination of drainage areas for all basins, sub-basins, and noncontributing areas in the Big Sioux River basin is needed. All named stream basins, and all unnamed basins > 10 sq mi within the Big Sioux River basin in South Dakota are shown and are listed by stream name. Stream drainage basins in South Dakota were delineated by visual interpretation of contour information shown on U.S. Geological Survey 77-1/2 minute topographic maps. One table lists the drainage areas of major drainage basins in the Big Sioux River basin that do not have a total drainage area value > 10 sq mi. Another shows the drainage area above stream gaging stations in the Big Sioux River basin. (Lantz-PTT)

Open-File Report↗

USGS1980

Appraisal of the water resources of the Big Sioux aquifer, Brookings, Deuel, and Hamlin counties, South Dakota

The Big Sioux aquifer in Brookings, Deuel, and Hamlin Counties, South Dakota, has been extensively developed and in some areas discharge, principally by wells, from the aquifer may be exceeding recharge to the aquifer. A finite-difference method digital model was used to simulate steady-state conditions of the Big Sioux aquifer. Average annual water levels in the Big Sioux aquifer and base flow discharge of the Big Sioux River near Brookings for 1970 through 1976 were used in the model. The model-computed water levels were within a few feet of the actual annual average water levels and the computed annual average base flow was 66 cubic feet per second compared to the actual base flow of 58 cubic feet per second. The computer model was used to model transient conditions by simulating water levels and base flow from April through August 1976 and comparing the results with actual data. Evapotranspiration and pumpage changes were made for each month. There was no recharge from precipitation during the test period. Several different computer simulations were made using different estimates of hydrologic parameters and conditions. Specific yield was increased from 10 to 15 percent which resulted in a much greater base flow for each month. Effective depth of evapotranspiration was changed from 5 to 10 feet which resulted in a very large decrease in base flow. A computer simulation made without irrigation pumpage resulted in an increase in the base flow from 0.66 to 9 cubic feet per second for August 1976 in the Big Sioux River near Brookings. The actual base flow for August 1976 was .01 cubic foot per second. A water budget showed 22.2 inches of precipitation (average annual), 0.65 inch of surface runoff, 1.06 inches of ground-water outflow (base flow to river, 1970-76), and 20.49 inches of evapotranspiration. The water from the Big Sioux aquifer is a calcium bicarbonate type and specific conductance ranged from 407 to 1,790 micromhos per centimeter at 25°C. The water is generally very hard, having a mean of 454 milligrams per liter of hardness. A model simulation using all the pumpage that would be allowed by irrigation permits approved as of February 1979 simulated the withdrawal of 43,900 acre-feet of water for about 4 months during which time there was no recharge from precipitation. If there had been no pumping for that period, evapotranspiration would have been 7,800 acre-feet more than occurred under pumping conditions and discharge to streams would have increased by 3,600 acre-feet.

South Dakota↗

USGS1979

A geohydrologic overview for the Pecora Symposium field trip, June 1979

The settlement and development of South Dakota has been closely related to both its mineral and water resources In 1874 the discovery of gold in the Black Hills led to the opening and development of the area west of the Missouri River. Towns and farms both here and east of the Missouri were located near dependable water supplies which the settlers learned were not as plentiful as in the more humid areas in the east. Although there is still much dry-land farming and cattle raising throughout the State, the expansion of agriculture has depended heavily on the development of controlled water supplies. Water from flowing artesian wells was extremely important to early settlers and developers. Today, thousands of these wells still supply an important part of the water on which South Dakota's agricultural, tourist, and industrial economy thrive.

South Dakota↗