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D. L. Lorenz

Publications and source records attributed to D. L. Lorenz.

27 records · Page 2Linked to original sources
USGS1994

Physical characteristics of stream subbasins in the Pomme de Terre River Basin, west-central Minnesota

Data describing the physical characteristics of stream subbasins upstream from selected points on streams in the Pomme de Terre River Basin, located in west-central Minnesota, are presented in this report. The physical characteristics are the drainage area of the subbasin, the percentage area of the subbasin covered only by lakes, the percentage area of the subbasin covered by both lakes and wetlands, the main-channel length, and the main-channel slope. The points on the stream include outlets of subbasins of at least 5 square miles, outfalls of sewage treatment plants, and locations of U.S. Geological Survey low-flow, high-flow, and continuous-record gaging stations.

Minnesota↗
USGS1992

Physical characteristics of stream subbasins in the Blue Earth River Basin, south-central Minnesota and north-central Iowa

This report presents data describing the physical characteristics of stream basins upstream from selected points on streams in the Blue Earth River basin, located in south-central Minnesota and north-central Iowa. The physical characteristics are the drainage area of the basin, the percentage area of the basin covered only by lakes, the percentage area of the basin covered by both lakes and wetlands, the main-channel length, and the mainchannel slope. The points on the stream include outlets of subbasins of at least five square miles, outfalls of sewage treatment plants, and locations of U.S. Geological Survey gaging stations.

Iowa, Minnesota↗
USGS1990

Simulation of ground-water flow in the St Peter aquifer in an area contaminated by coal-tar derivatives, St Louis Park, Minnesota

A model constructed to simulate ground-water flow in part of the Prairie du Chien-Jordan and St. Peter aquifers, St. Louis Park, Minnesota, was used to test hypotheses about the movement of ground water contaminated with coal-tar derivatives and to simulate alternatives for reducing the downgradient movement of contamination in the St. Peter aquifer. The model, constructed for a previous study, was applied to simulate the effects of current ground-water withdrawals on the potentiometric surface of the St. Peter aquifer. Multiaquifer wells served as conduits for vertical exchange of water from the St. Peter aquifer to the Prairie du Chien-Jordan aquifer. Model simulations predict that the multiaquifer wells have the potential to limit downgradient migration of contaminants in the St. Peter aquifer caused by cones of depression created around the multiaquifer wells. Differences in vertical leakage to the St. Peter aquifer may exist in areas of bedrock valleys. Model simulations indicate that these differences are not likely to affect significantly the general patterns of ground-water flow. Model simulations also indicated that drawdown caused by pumping two wells, each pumping at 75 gallons per minute and located about 1 mile southeast of the source of contamination, would be effective in controlling movement and volume of contaminated ground water in the immediate area of the source of contamination. Some contamination may already have moved beyond the influence of these wells, however, because of a complex set of hydraulic conditions.

Minnesota↗
USGS1988

Techniques for estimating the magnitude and frequency of floods in Minnesota

Log-Pearson type III flood-frequency analyses were made of annual series peak-flow records from 246 gaging stations on unregulated streams in Minnesota having watersheds ranging in area from 0.08 to 2,520 square miles. These flood discharges were related to watershed and climatic characteristics by using multiple-regression techniques. On the basis of this preliminary regression analysis of the frequency-analysis results, the data from these stations were grouped into four hydrologically distinct regions for the State. Regression analyses were performed on data from each region relating the 2-, 5-, 10-, 25-, 50-, and 100-year recurrence interval flood discharges to basin characteristics. The resulting regression equations, which may be used to estimate flood flows at ungaged sites, relate basin characteristics (contributing drainage area, main-channel slope, percent of basin covered by water, percent of basin covered by lakes, and mean annual runoff) to estimated flood flows. Different basin characteristics are significant for each of the four regions. Drainage area was found to be most significant and is included in all regional equations. Standard errors of estimate of the regression equations ranged from 33 to 60 percent.

Minnesota↗
USGS1987

Low-flow-frequency characteristics for continuous-record streamflow stations in Minnesota

Annual and summer (May 1 to September 30) low-flow frequency curves are presented for 175 continuous-record streamflow stations in Minnesota. The curves were developed for all stations with 10 or more years of continuous record. The 1-, 7-, and 30-day low-flow discharges at selected recurrence intervals obtained from these curves are listed. Low-flow characteristics can and will vary for a station depending upon the number of years of record and the period gaged. When comparing low-flow characteristics between two or more stations, it should be remembered that no provisions were made to use concurrent periods of record for stations along the same stream.

Minnesota↗