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J. T. Dugan

Publications and source records attributed to J. T. Dugan.

13 recordsLinked to original sources
USGS2007

Simulation and mapping of soil-water conditions in the Great Plains

Soil-water conditions provide valuable insight into the hydrologic system in an area. A soil-water balance quantitatively summarizes soil-water conditions and is based on climatic, soil, and vegetation characteristics that vary spatially and temporally. Soil-water balances in the Great Plains of the central United States were simulated for 1951-1980. Results of the simulations were mean annual estimates of infiltration, runoff, actual evapotranspiration, potential recharge, and consumptive water and irrigation requirements at 152 climatic data stations. A method was developed using a geographic information system to integrate and map the simulation results on the basis of spatially variable climatic, soil, and vegetation characteristics. As an example, simulated mean annual potential recharge was mapped. Mean annual potential-recharge rates ranged from less than 0.5 inch in much of the north-central and southwestern Great Plains to more than 10 inches in parts of eastern Texas and southwestern Arkansas.

Water Resources Bulletin↗
USGS1995

Land-cover sampling designs, data-collection procedures, and land-cover data for the Central Nebraska Basins, 1993-94

Within the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program, land-cover data are used in characterizing drainage areas upstream from surface-water sampling sites and areas selected for spatially distributed ground-water sampling. During the period of time when the initial 20 NAWQA study study-unit investigations were evaluating existing land-cover data, a Prototype 190 Conterminous U.S. land Cover Characteristics Data Set was produced by the Survey's EROS Data Center in Sioux Falls, South Dakota. As part of the Central Nebraska Basins (CNB) study-unit investigation, a method was developed to estimate the areal extent of the principal land-cover types within selected seasonally distinct land-cover (SDLC) regions defined in the 1990 prototype data set. This report describes the sampling designs and methods used to collect land-cover data in the CNB study unit. Data collected at 309 sampling sites during the summers of 1993 and 1994 are presented and statistically summarized. Eleven land-cover categories were quantified, including major field crops and broad noncropland cover types.

Open-File Report↗
USGS1995

Simulated response of the High Plains aquifer to ground-water withdrawals in the Upper Republican Natural Resources District, Nebraska

The U.S. Geological Survey, in cooperation with the National Soil Tilth Laboratory of the U.S. Department of Agriculture, Agricultural Research Service, conducted a study as part of the multi- scale, interagency Management Systems Evaluation Area (MSEA) program to evaluate the effects of agricultural management (farming) systems on water quality. Data on surface flow, tileflow, and streamflow in the Walnut Creek watershed just south of Ames, Iowa, were collected during April 1991-September 1993 at five sites with drainage areas ranging from 366 to 5,130 hectares. Precipitation, flow discharge, and concentration, loads, and yields of nitrate as nitrogen, atrazine, and metolachlor were analyzed to relate the transport of agricultural chemicals to major water-flow processes and to examine and transport differences among three subwatersheds. Antecedent conditions and basin-characteristic differences had significant effects on the flow response from the subwatersheds. Monthly streamflow-to- precipitation ratios were greater than 1.0, as a result of snowmelt, and negative when streamflow was lost to the ground-water system in the downstream subwatershed. Dry antecedent conditions resulted in ratios less than 0.3 (July 1992), whereas wet antecedent conditions resulted in ratios from 0.7 to almost 1.0 (July 1993) during months with similar large rainfall amounts. Most of the streamflow from the upland subwatersheds came from tileflow. Surface flow (surface runoff, interflow, and return flow0 was highly variable and intermittent, usually lasting for only a few days after a storm, although it could be the dominant source of flow when stormflow was large. Tileflow was less variable and much more persistent, ceasing only after prolonged dry periods. Large quantities of nitrate as nitrogen were transported in Walnut Creek, with concen- trations often greater than the Maximum Contaminant Level of 10 milligrams per liter established by the U.S. Environmental Protection Agency for finished drinking water. In the upland subwatersheds, ground-water flow from the tiles appears to have been the primary means of transport to the streams. Concentrations in tileflow and streamflow generally were 4 to 16 milligrams per liter, with the lower concen- trations often the result of dilution by surface runoff. Loss ratios, chemical yields expressed as a percentage of average application rates of nitrate as nitrogen for October 1992-September 1993, were about 10 percent for surface flow and more than 100 percent for tileflow from the 366-hectare basin and were more than 200 percent for streamflow from the downstream subwatershed. Concentrations of atrazine and metolachlor in streamflow, typically, were less than the Maximum Contaminant Level of 3.0 micrograms per liter, but were as high as 59 and 80 micrograms per liter, respectively, during stormflow. Concentrations as high as 170 micrograms per liter occurred in tileflow, but these were related to surface flow through surface inlets. The transport of herbicides was extremely variable, with most of the loads occurring during stormflow. Atrazine appeared more susceptable to transport losses to streamflow than did metolachlor. Loss ratios for streamflow from the subwatersheds for April- September periods were 0.3 to 20 percent for atrazine and 0.1 to 2.9 percent for metolachlor. Chemical loss ratios indicated differences in the transport characteristics of the three subwatersheds. The downstream subwatershed, which has steeper terrain, a more-developed natural drainage system, and fewer tiles than the two upland subwatersheds, had the largest loss rates for all three chemicals--206 percent for nitrate as nitrogen (October 1992-September 1993) and 20 percent for atrazine and 2.9 percent for metolachlor (April-September 1993). For May-July 1993, when most of the herbicides were transported, the downstream subwatershed also had the largest cumulative unit discharge and the largest streamflow-to-precipitation ra

Water-Resources Investigations Report↗
USGS1994

Water-level changes in the High Plains aquifer -- Predevelopment to 1992

Changes in water levels in the High Plains aquifet underlying parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming result from the variability of precipitation, land use, and ground-water withdrawals. From the beginning of development of the High Plains aquifer to 1980, water levels declined throughout much of the area; the declines exceeded 100 feet in parts of the central and southern High Plains. From 1980 to 1992, water levels continued to decline in these same areas, but at a slightly slower overall annual rate. This slower rate of decline was associated, in part, with a decrease in ground-water application for irrigated agriculture and above normal precipitation throughout the High Plains during 1980-91. Declines exceeding 20 feet were common from 1980 to 1992 in areas of intense irrigation development in Kansas, New Mexico, Oklahoma, and Texas. In the northern High Plains, declines of 10 to 20 feet from 1980 to 1992 were widespread in northeastern Colorado, southwestern Nebraska, and the Nebraska Panhandle. Water levels were generally stable from 1980 to 1992 in most other areas of the High Plains. In a large area in the southern High Plains of Texas, however, water-level rises exceeded 20 feet. Also, scattered rises of 5 to 10 feet occurred in eastern Nebraska. The estimated average area-weighted water-level change, from 1991 to 1992 was -0.55, even though precipitation was well-above normal in 1991 in the High Plains. Water- level declines of 3 to 5 feet were widespread in the intensively irrigated areas of southwestern Kansas and the northern part of the Southern High Plains of Texas. These large declines were not closely related to 1991 precipitation patterns in those areas. Declines of 1 to 3 feet were common throughout the intensively irrigated areas of the Northern High Plains and the less intensively irrigated areas of the Central and Southern High Plains. Water levels continued to rise, generally 1 to 3 feet in the extreme Southern High Plains of Texas. Rises of 1 to 3 feet also occurred in parts of northeastern and central Nebraska.

Colorado, Kansas, Nebraska, New Mexico, Oklahoma, ↗
USGS1994

Water-level changes in the High Plains aquifer — Predevelopment to 1993

Water-level change in the High Plains aquifer underlying parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming results from differences in recharge from precipitation and ground-water withdrawals for irrigation. From the beginning of irrigation development (1940) to 1980, water levels declined in several areas, and exceeded 100 feet in parts of the Central and Southern High Plains. From 1980 to 1993, water-level declines continued in these same areas, but at a smaller annual rate. This smaller rate of decline was associated with above-normal precipitation during 1981-93 and a decrease in ground-water application rates. Declines exceeding 20 feet from 1980 to 1993 were common in areas of intense irrigation development in the Central and Southern High Plains. In the Northern High Plains, water levels declined 10 to 20 feet from 1980 to 1993 in parts of northeastern Colorado, northwestern Kansas, southwestern Nebraska, and the Nebraska Panhandle. Water-level rises exceeding 20 feet, however, occurred in the Southern High Plains of Texas. Also, rises of 10 to 20 feet occurred in parts of southeastern and south-central Nebraska. The average area-weighted water level rose 0.21 foot from 1992 to 1993 in association was well-above normal precipitation in 1992. Water-level declines, however, continued in the intensively irrigated areas of the Central High Plains. Declines also' continued in the northern part of the Southern High Plains in spite of well-above normal precipitation. Water-level rises from 1992 to 1993 was widespread in eastern and southern Nebraska, northwestern and south-central Kansas, and in the southern two-thirds of the Southern High Plains of Texas in association with well-above normal precipitation in 1992. These rises exceeded 3 feet.

Colorado, Kansas, Nebraska, New Mexico, Oklahoma, ↗
USGS1993

Water-level changes in the High Plains aquifer -- Predevelopment to 1991

Regional variability in water-level change in the High Plains aquifer underlying parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming results from large regional differences in climate, soils, land use, and ground-water withdrawals for irrigation. From the beginning of significant development of the High Plains aquifer for irrigation to 1980, substantial water-level declines have occurred in several areas. The estimated average area-weighted water-level decline from predevelopment to 1980 for the High Plains was 9.9 feet, an average annual decline of about 0.25 foot. These declines exceeded 100 feet in some parts of the Central and Southern High Plains. Declines were much smaller and less extensive in the Northern High Plains as a result of later irrigation development. Since 1980, water levels in those areas of large declines in the Central and Southern High Plains have continued to decline, but at a much slower annual rate. The estimated average area-weighted water-level decline from 1980 to 1991 for the entire High Plains was 1.41 feet, an average annual decline of about 0.13 foot. The relatively small decline since 1980, in relation to the declines prior to 1980, is associated with a decrease in ground-water application for irrigated agriculture and greater than normal precipitation. Water-conserving practices and technology, in addition to reductions in irrigated acreages, contributed to the decrease in ground-water withdrawals for irrigation.

Colorado, Kansas, Nebraska, New Mexico, Oklahoma, ↗
USGS1987

Surface water-quality assessment of the lower Kansas River basin, Kansas and Nebraska; project description

In 1986 the U.S. Geological Survey began a National Water-Quality Assessment Program to: (1) provide nationally consistent descriptions of the current status of water quality for a large, diverse, and geographically distributed part of the Nation 's surface water resources; (2) where possible, define trends in water quality; and (3) identify and describe the relation between water quality and natural and land use factors. This report describes the pilot study of the lower Kansas River basin, which is one of four surface water pilot studies that will be used to test, and modify as necessary, assessment concepts and approaches in preparation for future full implementation of the national program. Water quality issues in the lower Kansas River basin are dominated by possible nonpoint sources of contamination from agricultural land, with issues including: (1) large sediment discharge in the streams and sediment deposition in the reservoirs caused by intensive cultivation of row crops and subsequent erosion; (2) occurrence of pesticides in streams and reservoirs that could impair the suitability of water for aquatic life and has the potential for impairing the water 's suitability for public supply; (3) bacterial contamination caused by runoff from pastureland and feedlot operations and municipal wastewater discharges; and (4) nutrient enrichment of reservoirs. Data from fixed stations will be used to determine frequency distributions of constituent concentrations and mass balances of constituents between stations. Subbasin or river reach studies will provide a better understanding of the origin, movement, and fate of potential contaminants. (Lantz-PTT)

Open-File Report↗
USGS1985

Mass water-level measurements of fall 1984 in the central Platte River basin, Nebraska

Mass water-level measurements were conducted in the Central Platte River basin, Nebraska, for the purpose of providing data to the U.S. Bureau of Reclamation for the development of a detailed map of water-table conditions during the fall of 1984. The objective was to provide a network of observation wells at approximately 2- to 3-mile intervals. In October and November 1984, 736 wells were measured, of which 526 were measured as part of existing ground-water observation-well networks. The remaining 210 wells not previously measured and required complete inventorying. The report consists of maps of the study area and locations of the observation wells. An appendix of pertinent well data includes: legal location, land-surface altitude, depth-to-water, water-table altitude, date of measurement, and type of well. (USGS)

Open-File Report↗
USGS1985

Effects of climate, vegetation, and soils on consumptive water use and ground-water recharge to the Central Midwest Regional aquifer system, mid-continent United States

The Central Midwest aquifer system, in parts of Arkansas, Colorado, Kansas, Missouri, Nebraska, New Mexico, South Dakota, and Texas, is a region of great hydrologic diversity. This study examines the relationships between climate, vegetation, and soil that affect consumptive water use and recharge to the groundwater system. Computations of potential recharge and consumptive water use were restricted to those areas where the aquifers under consideration were the immediate underlying system. The principal method of analysis utilized a soil moisture computer model. This model requires four types of input: (1) hydrologic properties of the soils, (2) vegetation types, (3) monthly precipitation, and (4) computed monthly potential evapotranspiration (PET) values. The climatic factors that affect consumptive water use and recharge were extensively mapped for the study area. Nearly all the pertinent climatic elements confirmed the extreme diversity of the region. PET and those factors affecting it--solar radiation, temperature, and humidity--showed large regional differences; mean annual PET ranged from 36 to 70 inches in the study area. The seasonal climatic patterns indicate significant regional differences in those factors affecting seasonal consumptive water use and recharge. In the southern and western parts of the study area, consumptive water use occurred nearly the entire year; whereas, in northern parts it occurred primarily during the warm season (April through September). Results of the soil-moisture program, which added the effects of vegetation and the hydrologic characteristics of the soil to computed PET values, confirmed the significant regional differences in consumptive water use or actual evapotranspiration (AET) and potential groundwater recharge. Under two different vegetative conditions--the 1978 conditions and pre-agricultural conditions consisting of only grassland and woodland--overall differences in recharge were minimal. Mean annual recharge under both conditions averaged slightly more than 4.5 inches for the entire study area, but ranged from less than 0.10 inches in eastern Colorado to slightly more than 15 inches in Arkansas.

Arkansas, Colorado, Kansas, Missouri, Nebraska, Ne↗
USGS1983

Hydrogeology of parts of the Central Platte and Lower Loup Natural Resources Districts, Nebraska

Water-level declines of at least 15 feet have occurred in this heavily irrigated area of central Nebraska since the 1930's, and potential for additonal declines is high. To test the effects of additional irrigation development on water levels and streamflow , computer programs were developed that represent the surface-water system, soil zone, and saturated zone. A two-dimensional, finite-difference ground-water flow model of the 3,374 square-mile study area was developed and calibrated using steady-state and transient conditions. Three management alternatives were examined. First, 125,000 acre-feet of water would be diverted annually from the Platte River. During a water year in which flows are similar to those in 1957, months of zero streamflow at Grand Island increased from the historical 2, to 7. After 5 years of such low flows, in 36 nodes (997.4 acres per node) water levels declined more than 5 feet, with a maximum decline of 10.7 feet. A second alternative would allow no new ground-water development after 1980. The third alternative would allow irrigable but unirrigated land to be developed at an annual rate of 2, 5, and 8 percent and to apply irrigation water at 80, 100, and 120 percent of consumptive irrigation requirements. The maximum projected declines by 2020 are 119 and 139 feet, respectively, for the second and third alternatives. (USGS)

Water-Resources Investigations Report↗