Geology topics

Duane H. Conger

Publications and source records attributed to Duane H. Conger.

3 recordsLinked to original sources

USGS1992

Flood-frequency characteristics of Wisconsin streams

Flood-frequency characteristics for 269 gaged sites on Wisconsin streams are presented for recurrence intervals of 2 to 100 years. Annual flood peaks for the period of record for each gaged site are included. Equations of the relations between flood-frequency and drainage-basin characteristics were developed by multiple-regression analyses. Flood-frequency characteristics for ungaged sites on unregulated, rural streams can be estimated by use of these equations. The State was divided into five areas of similar physiographic characteristics. The most significant basin characteristics are drainage areas, main-channel slope, soil permeability, storage, rainfall intensity, and forest cover. The standard error of prediction for the equation for the 100-year flood discharge ranges from 25 to 33 percent in the State. A comparison of multiple-regression analyses by use of generalized least squares and ordinary least squares was made to determine the best method for analysis. A split-sampling technique was used for all the stations in the State. Differences in results of the two methods were minimal. The generalized least-squares method was chosen for use because its theoretical basis is superior to that of ordinary least squares and its estimates of accuracy of the equations for estimating flood-frequency characteristics at ungaged sites is better than that of ordinary least squares. A method for estimating flood-frequency characteristics of regulated streams was developed from the relation of discharge and drainage area. Graphs for the major regulated streams are presented in the report. Drainage-basin characteristics derived from satellite imagery and channel morphology data were tried in the regression equations but did not improve their accuracy.

Wisconsin↗

USGS1981

Techniques for estimating magnitude and frequency of floods for Wisconsin streams

This report provides improved methods for estimating the magnitude and frequency of floods for Wisconsin streams. Proper design of hydraulic structures and adequate flood-plain management depend on this information. Multiple-regression techniques were used to develop equations for estimating flood frequencies at ungaged sites. The State is divided into five areas and has equations developed for each area. These areas are based on areal factors determined from previous studies and physical basin characteristics. Significant characteristics in the equations are soil permeability, drainage area, slope, storage, forest cover, snowfall, precipitation intensity, and mean annual precipitation. Standard errors of estimate for the regression equations ranged from 23 to 38 percent. Annual flood peaks, basin characteristics, and flood-frequency values are presented in this report. Data from 184 gaging stations were used in the regression analysis, of which 20 had rainfall-runoff data collected. Long-term synthetic peaks were generated from the rainfall-runoff data and were weighted with the observed peak data to improve the flood-frequency distributions. A method to estimate flood-frequency values for regulated streams was developed by discharge-drainage area relationships. Graphs for the major regulated streams are presented in the report.

Wisconsin↗

USGS1971

Estimating magnitude and frequency of floods in Wisconsin

This report provides methods for estimating flood characteristics at most sites where flood information may be needed for planning and design and summatizes the significant flood data and related information available on Wisconsin streams. Individual equations are presented for estimating flood discharges for selected recurrence intervals up to a 25-year flood for drainage areas 0.5 square miles and larger, a 50-year flood for drainage areas 20 square miles and larger, and a 100-year flood for drainage areas 50 square miles and larger. A ratio method is used for estimating a 50-year flood for drainage areas 0.5 to 20 square miles. The equations were defined from multiple-regression analysis of flood peak records and basin characteristics for 119 continuous-record gaging stations and 114 crest-stage partial-record stations in Wisconsin and adjoining States. Of the severai basin characteristics used in this study, only drainage area, main-channel slope, lake and marsh area, and areal factors were found to be statistically significant at the 99 percent effectiveness level for all flood frequencies. Solution of a hypothetical problem is given for using the flood-frequency equations. Graphs are presented for solution of flood discharges on regulated streams where the formulas are not applicable. Flood-frequency characteristics, 2-year flood to 100-year flood, and drainage basin characteristics for stations used in the multiple regression are presented in the appendices of this report.

Wisconsin↗