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D. L. Lorenz

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

At least 19 recordsLinked to original sources
USGS2011

Flooding and Flood Management

Floods result in great human disasters globally and nationally, causing an average of $4 billion of damages each year in the United States. Minnesota has its share of floods and flood damages, and the state has awarded nearly $278 million to local units of government for flood mitigation projects through its Flood Hazard Mitigation Grant Program. Since 1995, flood mitigation in the Red River Valley has exceeded $146 million. Considerable local and state funding has been provided to manage and mitigate problems of excess stormwater in urban areas, flooding of farmlands, and flood damages at road crossings. The cumulative costs involved with floods and flood mitigation in Minnesota are not known precisely, but it is safe to conclude that flood mitigation is a costly business. This chapter begins with a description of floods in Minneosta to provide examples and contrasts across the state. Background material is presented to provide a basic understanding of floods and flood processes, predication, and management and mitigation. Methods of analyzing and characterizing floods are presented because they affect how we respond to flooding and can influence relevant practices. The understanding and perceptions of floods and flooding commonly differ among those who work in flood forecasting, flood protection, or water resource mamnagement and citizens and businesses affected by floods. These differences can become magnified following a major flood, pointing to the need for better understanding of flooding as well as common language to describe flood risks and the uncertainty associated with determining such risks. Expectations of accurate and timely flood forecasts and our ability to control floods do not always match reality. Striving for clarity is important in formulating policies that can help avoid recurring flood damages and costs.

Minnesota↗
USGS2010

Comparison of two parametric methods to estimate pesticide mass loads in California's Central Valley

Mass loadings were calculated for four pesticides in two watersheds with different land uses in the Central Valley, California, by using two parametric models: (1) the Seasonal Wave model (SeaWave), in which a pulse signal is used to describe the annual cycle of pesticide occurrence in a stream, and (2) the Sine Wave model, in which first-order Fourier series sine and cosine terms are used to simulate seasonal mass loading patterns. The models were applied to data collected during water years 1997 through 2005. The pesticides modeled were carbaryl, diazinon, metolachlor, and molinate. Results from the two models show that the ability to capture seasonal variations in pesticide concentrations was affected by pesticide use patterns and the methods by which pesticides are transported to streams. Estimated seasonal loads compared well with results from previous studies for both models. Loads estimated by the two models did not differ significantly from each other, with the exceptions of carbaryl and molinate during the precipitation season, where loads were affected by application patterns and rainfall. However, in watersheds with variable and intermittent pesticide applications, the SeaWave model is more suitable for use on the basis of its robust capability of describing seasonal variation of pesticide concentrations.

California↗
USGS2007

Comparison of local- to regional-scale estimates of ground-water recharge in Minnesota, USA

Regional ground-water recharge estimates for Minnesota were compared to estimates made on the basis of four local- and basin-scale methods. Three local-scale methods (unsaturated-zone water balance, water-table fluctuations (WTF) using three approaches, and age dating of ground water) yielded point estimates of recharge that represent spatial scales from about 1 to about 1000 m 2 . A fourth method (RORA, a basin-scale analysis of streamflow records using a recession-curve-displacement technique) yielded recharge estimates at a scale of 10–1000s of km 2 . The RORA basin-scale recharge estimates were regionalized to estimate recharge for the entire State of Minnesota on the basis of a regional regression recharge (RRR) model that also incorporated soil and climate data. Recharge rates estimated by the RRR model compared favorably to the local and basin-scale recharge estimates. RRR estimates at study locations were about 41% less on average than the unsaturated-zone water-balance estimates, ranged from 44% greater to 12% less than estimates that were based on the three WTF approaches, were about 4% less than the age dating of ground-water estimates, and were about 5% greater than the RORA estimates. Of the methods used in this study, the WTF method is the simplest and easiest to apply. Recharge estimates made on the basis of the UZWB method were inconsistent with the results from the other methods. Recharge estimates using the RRR model could be a good source of input for regional ground-water flow models; RRR model results currently are being applied for this purpose in USGS studies elsewhere.

Minnesota↗
USGS2006

A regression model to estimate regional ground water recharge

A regional regression model was developed to estimate the spatial distribution of ground water recharge in subhumid regions. The regional regression recharge (RRR) model was based on a regression of basin-wide estimates of recharge from surface water drainage basins, precipitation, growing degree days (GDD), and average basin specific yield (SY). Decadal average recharge, precipitation, and GDD were used in the RRR model. The RRR estimates were derived from analysis of stream base flow using a computer program that was based on the Rorabaugh method. As expected, there was a strong correlation between recharge and precipitation. The model was applied to statewide data in Minnesota. Where precipitation was least in the western and northwestern parts of the state (50 to 65 cm/year), recharge computed by the RRR model also was lowest (0 to 5 cm/year). A strong correlation also exists between recharge and SY. SY was least in areas where glacial lake clay occurs, primarily in the northwest part of the state; recharge estimates in these areas were in the 0- to 5-cm/year range. In sand-plain areas where SY is greatest, recharge estimates were in the 15- to 29-cm/year range on the basis of the RRR model. Recharge estimates that were based on the RRR model compared favorably with estimates made on the basis of other methods. The RRR model can be applied in other subhumid regions where region wide data sets of precipitation, streamflow, GDD, and soils data are available.

Minnesota↗
USGS2004

Estimation of travel times for seven tributaries of the Mississippi River, St. Cloud to Minneapolis, Minnesota, 2003

Travel times for seven streams tributary to the Mississippi River from St. Cloud to Minneapolis, Minnesota, were estimated for three flow conditions; low, median, and high. Travel times were estimated for Sauk, Elk, Crow, and Rum Rivers, and Elm, Coon, and Rice Creeks. Regression equations based on watershed characteristics of drainage area, river slope, mean annual discharge, and instantaneous discharge at the time of measurement from more than 900 streams across the nation were used to estimate travel times. Travel times were estimated for the leading edge, peak concentration, and trailing edge of tracer-response curves. To test the validity of these equations, a time of travel study, using a luminescent dye, was conducted on the Sauk River, from Rockville, to the confluence with the Mississippi River on June 16, 2003, at a discharge of 457 ft 3 /s at Rockville. Dye was injected in the Sauk River at Rockville, and time and concentrations were measured at three sampling sections downstream; at County Road 121, Veterans Drive, and County Road 1 near the mouth. The estimated travel times for the leading edge, peak concentration, and trailing edge at County Road 1 were 10.6 hrs, 11.9 hrs, and 14.6 hrs, respectively. The measured travel times for the leading edge, peak concentration, and trailing edge were 13.4 hrs, 15.5 hrs, and 20.5 hrs, respectively for the 15.7 mile reach.

Minnesota↗
USGS2000

Development of a stream habitat index for use with an Index of Biotic Integrity in the St. Croix River Basin, Minnesota

More than 70 streams in the St. Croix River Basin in Minnesota were sampled for fish community composition and physical habitat during 1996–98. A habitat index was developed based on measurements, field observations, and land use. The objective was to develope a habitat index for use to evaluate water quality and the effects of nonpoint-source effects not associated with habitat degradation. Core habitat variables were determined with a concurrence analysis using principal components of two subsets of sites with pristine or least affected habitat. Although core habitat variables differed slightly between data sets, sufficient similarities allowed development of an index. The index (the sum of pluses or minuses dependent on the variable’s correlation to biotic integrity), composed of 12 core habitat variables in 5 classification groups (hydrology, geomorphology, substrate, instream habitat, and riparian/land use), was able to distinguish sites with low Index of Biotic Integrity scores not related to habitat degradation.

Minnesota, Wisconsin↗
USGS1998

Water quality in the Red River of the North Basin, Minnesota, North Dakota, and South Dakota, 1992-95

This report is intended to summarize major findings that emerged between 1992 and 1995 from the water-quality assessment of the River River of the North basin study unit and to relate these findings to water-quality issues of regional and national concern. The information in primarily intended for those who are involved in water-resource management. Yet the information contained here may also interest those who simply wish to know more about the quality of water in the rivers and aquifers in the area where they live.

Circular↗
USGS1997

Nutrients, suspended sediment, and pesticides in streams in the Red River of the North basin, Minnesota, North Dakota, and South Dakota, 1993-95

Fifteen stream sites in the Red River of the North Basin were sampled during 1993-95 to assess levels of nutrients, organic carbon, and suspended sediment, and five sites were sampled for pesticides. Concentrations varied seasonally and were related to periods of fertilizer and pesticide application, and to runoff. Concentrations of several constituents were related to the physiographic area the stream drains, but other factors such as local land use frequently complicated that relation. Median dissolved nitrogen concentrations were highest in streams influenced by the Red River Valley Lake Plain physiographic area. Organic nitrogen comprised the largest part of the dissolved nitrogen in streams. Ammonia was negligible most of the year, but accumulated under ice in late winter. Nitrate concentrations generally were highest during snowmelt and rainfall runoff. Phosphorus in streams mostly was in the dissolved form, which is readily available to biota. Streams draining the Moraine and Lake-Washed Till Plain had the lowest concentrations of total phosphorus, while Drift Prairie and Red River Valley Lake Plain streams had the highest concentrations. Concentrations of both dissolved and suspended phosphorus increased substantially during runoff of snowmelt and rainfall. The Bois de Sioux River Basin had the highest nitrogen yield. High nitrogen and phosphorus yields probably were related to agricultural practices in the Bois de Sioux River Basin. High phosphorus concentrations in the Pembina River probably result from agricultural practices and runoff from the steep terrain in the basin. Improved wastewater treatment appears to have reduced ammonia concentrations in streams, but has resulted in increased nitrate concentrations. The loads of nitrogen and phosphorus in the Red River of the North during this study were about twice as high as historical loads, but still were only about 4.1 and 2.4 percent, respectively, of the amounts introduced to the study unit. Dissolved organic carbon concentrations above 15 mg/L were common in streams draining peatlands. Suspended organic carbon concentrations were highly variable and generally were highest during runoff. Most suspended sediment in streams was clay and silt sized particles. The Pembina River had the highest concentrations and yields of suspended sediment, probably the result of erosion along this relatively high-gradient stream. Streams having an abundance of lakes, reservoirs, and wetlands in their watersheds had the lowest sediment concentrations and yields. Several pesticides were frequently detected. Atrazine and other triazine compounds were detected in most stream-water samples throughout the study. Concentrations of triazine herbicides were highest in streams draining southern parts of the study unit where they are applied to corn. Triallate was commonly detected in northern streams where it is applied to small grains and sunflowers. Simazine and prometon were commonly detected, but generally are used only for nonagricultural purposes. Few insecticides were detected in stream-water samples. Carbofuran was the most commonly detected insecticide and was found in 16 percent of the samples. The most heavily used herbicides, 2,4-D and MCPA, were infrequently detected in stream-water samples. Of the estimated applications of atrazine, triallate, and 2,4-D, about 0.9, 0.06, and 0.02 percent of each of these compounds, respectively, was carried out of the study unit by the Red River of the North during 1993-95.

Minnesota, North Dakota, South Dakota↗
USGS1997

Generalized skew coefficients for flood-frequency analysis in Minnesota

This report presents an evaluation of generalized skew coefficients used in flood-frequency analysis. Station skew coefficients were computed for 267 long-term stream-gaging stations in Minnesota and the surrounding states of Iowa, North and South Dakota, Wisconsin, and the provinces of Manitoba and Ontario, Canada. Generalized skew coefficients were computed from station skew coefficients using a locally weighted regression technique. The resulting regression trend surface was the generalized skew coefficient map, except for the North Shore area, and has a mean square error of 0.182.

Water-Resources Investigations Report↗
USGS1997

Techniques for estimating peak flow on small streams in Minnesota

Two statistically-derived techniques, regional regression equation and region of influence regression, that estimate peak flow on small, ungaged streams in Minnesota were developed. Both techniques relate physical and climatic characteristics to peak flow for 2-, 5-, 10-, 25-, 50-, and 100-year recurrence intervals. Regional regression equations were developed for each recurrence interval in each of six regions in Minnesota. The region of influence regression technique dynamically selects stations with characteristics similar to a site of interest. Thus, the region of influence regression technique allows use of a potentially unique set of stations for estimating peak flow at each site of interest. Two methods of selecting streamflow gaging stations, similarity and proximity, are recommended for use in the region of influence regression technique. The regional regression equation technique is recommended as a first estimate of peak flow in regions C, E, and F. The similarity method of the region of influence regression technique should be used as a first estimate in regions A and D. The proximity method should be used as a first estimate in region B. Tables showing the peak-flow-frequency data and basin characteristics for streamflow gaging stations, and regional peak-flow prediction equations, are documented.

Minnesota↗
USGS1996

Sampling design for assessing water quality of the Red River of the North basin, Minnesota, North Dakota, and South Dakota, 1993-1995

This map report describes the sampling design for a comprehensive regional assessment of water quality in the Red River of the North Basin, a study unit under the U.S. Geological Survey’s National Water-Quality Assessment Program. The sampling design was developed to address questions about the presence, distribution, and loads of nutrients and pesticides associated with large agricultural regions in the basin and across the Nation. The design also begins to address major local and regional concerns about suspended sediment in surface water and naturally occurring salinity in ground water. Recognizing that the Red River of the North Basin study unit realistically could not be analyzed as a single homogeneous area, a hierarchical sampling stratification for assessing water quality was developed. Landscape features consisting of physiography, soils, land cover and land use, and cropping patterns provided the environmental framework for stratification of streams and surficial aquifers. The environmental framework characterizes the climate and hydrology and relates closely to an ecoregions framework. The environmental and ecoregions frameworks were considered in locating ecological sampling sites. For the subsurface framework, buried sand and gravel aquifers in study unit were subdivided into two general subregions of differing potential saline recharge from underlying bedrock aquifers. Actual sampling sites for streams, aquatic biology, and ground water were described within the proposed sampling stratification. Practical considerations of previously established sampling sites, background information from previous hydrologic investigations, and site suitability for sampling protocols also were considered for final site selection.

Minnesota, North Dakota, South Dakota↗
USGS1995

National Water-Quality Assessment Program: Data collection in the Red River of the North Basin, Minnesota, North Dakota, and South Dakota, 1992-95

A water-quality assessment began in 1991 for the Red River of the North (Red River) Basin as part of a national study. Data collection for the reconnainssance and intensive phases of the study briefly is described for each of the major components (streams, aquatic biology, and ground water) used to assess regional water quality. The data will be analyzed to address national and local water-quality concerns.

Red River of the North basin↗
USGS1994

Physical characteristics of stream subbasins in the Lac qui Parle River basin, southwestern Minnesota and eastern South Dakota

Data describing the physical characteristics of stream subbasins upstream from selected points on streams in the Lac qui Parle River basin, located in southwestern Minnesota and eastern South Dakota, are presented in this report. The physical charac- teristics 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, South Dakota↗
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↗
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↗