Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska

Home , Arikaree River, Merritt Dam

Prepared in cooperation with the Nebraska Department of Roads

Water-Resources Investigations Report 99–4032

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey

Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska

By Philip J. Soenksen, Lisa D. Miller, Jennifer B. Sharpe, and Jason R. Watton

Water-Resources Investigations Report 99–4032

Prepared in cooperation with the Nebraska Department of Roads U.S. DEPARTMENT OF THE INTERIOR Bruce Babbitt, Secretary

U.S. GEOLOGICAL SURVEY Charles G. Groat, Director

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Lincoln, Nebraska, 1999

For additional information write to:

District Chief U.S. Geological Survey, WRD 406 Federal Building 100 Centennial Mall North Lincoln, NE 68506

Copies of this report can be purchased from:

U.S. Geological Survey Branch of Information Services Box 25286 Denver, CO 80225 CONTENTS Page

Abstract ...... 1 Introduction ...... 1 Background ...... 2 Purpose and Scope ...... 2 Acknowledgments ...... 4 Quantification of Drainage-Basin Characteristics ...... 4 Morphometric Characteristics ...... 4 Soil Characteristics ...... 5 Precipitation Characteristics ...... 5 Peak-Flow Frequency Analyses ...... 5 Standard Analyses ...... 6 Adjustments for Historic Data ...... 6 Adjustments for High and Low Outliers ...... 6 Generalized Skew Coefficients...... 7 High-Permeability Regional Skew Equation ...... 9 Northern and Western Regional Skew Equation ...... 10 Northeastern Regional Skew Equation ...... 10 Southeastern Regional Skew Equation ...... 12 Low-Permeability Skew Map ...... 12 Composite Analyses ...... 12 Peak-Flow Frequency Relations ...... 16 Unregulated Streams ...... 16 Regional Equations ...... 19 High Permeability Region ...... 21 Northern and Western Region ...... 23 Northeastern Region ...... 24 Central and South-Central Region ...... 25 Eastern Region ...... 26 Upper Republican River Region ...... 27 Big Blue River Region ...... 28 Application of Equations ...... 28 Regulated Streams ...... 29 Niobrara River ...... 29 North Platte River ...... 29 South Platte River ...... 33 Platte River ...... 33 Salt and Antelope Creeks ...... 33 Republican River ...... 33 Frenchman Creek ...... 38 Red Willow Creek ...... 38 Network Evaluation ...... 41 Station Selection ...... 41 Analyses and Output ...... 41 Discussion of Results ...... 44 Summary and Conclusions ...... 44 Selected References ...... 46

CONTENTS iii CONTENTS--Continued Page Appendixes A—Descriptions of Selected Drainage-Basin Characteristics Quantified Using Basinsoft, ARC-INFO, and Related GIS Programs ...... A-1 Morphometric Characteristics ...... A-2 Modifications to Basinsoft ...... A-2 Areal-Size Quantifications ...... A-2 Linear-Size Quantifications ...... A-2 Shape Quantifications ...... A-2 Relief Quantifications ...... A-2 Aspect Quantification ...... A-3 Stream-Network Quantifications ...... A-3 Relief-Stream Network Quantifications ...... A-3 Soil Characteristics ...... A-3 Precipitation Characteristics ...... A-4 B—Tables of Drainage-Basin Characteristics and Peak-Flow Frequency Data ...... B-1 C—Graphs of Composite Peak-Flow Frequency Curves for Selected Stations ...... C-1

Figures

1-3. Maps showing: 1. Selected streams and dams, and areas with sandhills in Nebraska and parts of adjacent states...... 3 2. Location of streamflow-gaging stations in Nebraska and adjacent states used to develop generalized skew coefficient relations for log-Pearson Type III peak-flow- frequency analyses...... 8 3. Regions of generalized skew-coefficient equations for Nebraska, and distribution of generalized skew-coefficients for basins with average permeability of the top 60 inches of soil (P60) of less than 4 inches per hour but including the entire Elkhorn River Basin ...... 11 4. Graphs showing peak-flow frequency curves and daily discharge lag plots for three Nebraska streamflow-gaging stations...... 13 5. Graphs showing four examples of Nebraska streamflow-gaging stations requiring composite frequency curves because of apparent mixed populations of data that are not caused by basins with large proportions of noncontributing drainage area or by average permeability of the top 60 inches of more than 4 inches per hour ...... 15

6-9. Maps showing: 6. Location of streamflow-gaging stations in Nebraska and selected stations in adjacent states with at least 10 years of unregulated peak-flow record...... 17 7. Location of streamflow-gaging stations in Nebraska and selected stations in adjacent states with at least 10 years of regulated peak-flow record...... 18 8. Hydrologic regions in Nebraska for unregulated peak-flow frequency equations...... 20 9. Location of flood-control dams in the Salt Creek drainage basin and of streamflow-gaging stations along the mainstem of Salt Creek ...... 31 10-18. Graphs showing: 10. Peak-flow frequencies for the current regulated condition of the Niobrara River in Nebraska estimated from streamflow-gaging station data ...... 32 11. Peak-flow frequencies for the current regulated condition of the North Platte River in Nebraska estimated from streamflow-gaging station data ...... 34

iv Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska CONTENTS--Continued Page 12. Peak-flow frequencies for the current regulated condition of the South Platte River in Nebraska and part of Colorado estimated from streamflow-gaging station data ...... 35 13. Peak-flow frequencies for the current regulated condition of the Platte River in Nebraska estimated from streamflow-gaging station data ...... 36 14. Peak-flow frequencies for the current regulated conditions of Salt and Antelope Creeks in Lancaster, Cass, and Saunders Counties of Nebraska estimated from streamflow-gaging station data...... 37 15. Peak-flow frequencies for the current regulated condition of the Republican River in Nebraska and part of Kansas estimated from streamflow-gaging data ...... 39 16. Peak-flow frequencies for the current regulated conditions of Frenchman and Red Willow Creeks in Nebraska estimated from streamflow-gaging station data ...... 40 17. Results of network analyses for 10- and 20-year planning horizons for High-Permeability– Standard, High Permeability–Composite, Northern and Western, and Northeastern regional 100-year peak-flow-frequency equations...... 42 18. Results of network analyses for 10- and 20-year planning horizons for Central and South-Central, Eastern, Upper Republican River, and Big Blue River regional 100-year peak-flow frequency equations...... 43

A1-A3. Maps showing: A1. Maximum expected precipitation for Nebraska and parts of adjacent state, for a duration of 24 hours and a recurrence interval of 2 years...... A-5 A2. Thiessen polygons of mean annual precipitation for National Oceanic and Atmospheric Administration and National Weather Service rain gages in Nebraska and parts of adjacent states for the period 1961–90 ...... A-6 A3. Average permeability of the 60-inch soil profile for Nebraska and parts of adjacent states...... A-7

C1-C4. Graphs showing: C1. Composite peak-flow frequency curves for selected Nebraska and South Dakota streamflow-gaging stations in the White and Niobrara River Basins with average soil permeability of the top 60 inches of more than 4 inches per hour ...... C-2 C2. Composite peak-flow frequency curves for selected Nebraska streamflow-gaging stations in the North Platte and Platte River Basins with average soil permeability of the top 60 inchesof more than 4 inches per hour...... C-3 C3. Composite peak-flow frequency curves for selected Nebraska streamflow-gaging stations in the Platte River Basin with average soil permeability of the top 60 inches of more than 4 inches per hour ...... C-4 C4. Composite peak-flow frequency curves for selected Nebraska streamflow-gaging stations in the Republican River Basin with average soil permeability of the top 60 inches of more than 4 inches per hour...... C-5 Tables 1. Generalized skew equations ...... 10 2-8. Peak-flow equations for the: 2. High-Permeability Region...... 22 3. Northern and Western Region ...... 23 4. Northeastern Region ...... 24 5. Central and South-Central Region ...... 25 6. Eastern Region ...... 26

CONTENTS v CONTENTS--Continued Page 7. Upper Republican River Region ...... 27 8. Big Blue River Region ...... 28 9. Summary of regulation data for selected stream reaches ...... 30 B1. Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations ...... B-2 B2. Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, and drainage areas for regulated streams ...... B-19

CONVERSION FACTORS

Multiply By To obtain inch (in.) 2.54 centimeter inch (in.) 25.4 millimeter foot (ft) 0.3048 meter mile (mi) 1.609 kilometer square mile (mi2) 2.590 square kilometer foot per mile (ft/mi) 0.3048 meter per mile cubic foot per second (ft3/s) 0.02832 cubic meter per second inch per hour (in/hr) 0.0254 meter per hour

vi Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska

By Philip J. Soenksen, Lisa D. Miller, Jennifer B. Sharpe, and Jason R. Watton

ABSTRACT The regional networks of streamflow-gaging stations on unregulated streams were analyzed to Estimates of peak-flow magnitude and evaluate how additional data might affect the frequency are required for the efficient design of average sampling errors of the newly developed structures that convey flood flows or occupy peak-flow equations for the 100-year frequency floodways, such as bridges, culverts, and roads. The occurrence. Results indicated that data from new U.S. Geological Survey, in cooperation with the stations, rather than more data from existing stations, Nebraska Department of Roads, conducted a study probably would produce the greatest reduction in to update peak-flow frequency analyses for selected average sampling errors of the equations. streamflow-gaging stations, develop a new set of peak-flow frequency relations for ungaged streams, INTRODUCTION and evaluate the peak-flow gaging-station network for Nebraska. Data from stations located in or within Estimates of peak-flow magnitude and about 50 miles of Nebraska were analyzed using frequency are required for the efficient design of guidelines of the Interagency Advisory Committee structures that convey flood flows, such as bridges on Water Data in Bulletin 17B. New generalized and culverts, or of structures that occupy floodways, skew relations were developed for use in frequency such as roads. In the fall of 1994, a 4-year coopera- analyses of unregulated streams. Thirty-three tive study was begun by the Nebraska Department of drainage-basin characteristics related to Roads and the U.S. Geological Survey (USGS) to morphology, soils, and precipitation were quantified update the methods for making these estimates. using a geographic information system, related Objectives of the study included (1) updating of the computer programs, and digital spatial data. peak-flow frequency analyses for selected streamflow-gaging stations, (2) development of a new set For unregulated streams, eight sets of regional of regional peak-flow frequency relations for regression equations relating drainage-basin to peak- ungaged streams, and (3) evaluation of the peak- flow characteristics were developed for seven flow gaging-station network for Nebraska. regions of the state using a generalized least squares procedure. Two sets of regional peak-flow frequency A number of new technologies had recently equations were developed for basins with average become available that made improvements in the soil permeability greater than 4 inches per hour, and peak-flow relations possible. New computer six sets of equations were developed for specific programs and procedures had been developed by the geographic areas, usually based on drainage-basin USGS for analyzing peak-flow frequency data for boundaries. Standard errors of estimate for the gaging stations. A geographic information system 100-year frequency equations (1percent probability) (GIS) and digital data could be used to compute ranged from 12.1 to 63.8 percent. For regulated drainage-basin characteristics that previously were reaches of nine streams, graphs of peak flow for undefined because they were too difficult or time- standard frequencies and distance upstream of the consuming to compute manually. For relating mouth were estimated. drainage-basin characteristics to peak-flow charac-

ABSTRACT 1 teristics, a generalized least squares (GLS) regression made to the default frequency analyses for individual program was available that could adjust for differ- stations (Rollin Hotchkiss, University of Nebraska- ences in record length and flow variance, and for Lincoln, oral commun., 1997). The mean-square cross-correlations among gaging stations. A errors (MSEs) for the updated equations, as reported companion network-analysis program (NET) also by Cordes (1993, p. 70), apparently were based on was available that could use the output from the GLS natural logarithms (Rollin Hotchkiss, University of program to evaluate how the addition of new data Nebraska-Lincoln, oral commun., 1998). The MSEs from existing or new peak-flow gaging stations might were converted to standard errors of estimate (SEEs), reduce the average sampling errors of any newly in natural logarithms, by taking the square root of the developed peak-flow frequency equations. These two values; those values then were converted to SEEs, in programs were available together as GLSNET from percent, using tabled values from Tasker (1978, Gary Tasker (USGS, written commun., 1995). p. 87). A comparison of SEEs, in percent, for corresponding equations shows that SEEs are smaller, in Background all cases, for the Beckman (1976) equations than for Several methods of computing peak flows for the Cordes (1993) equations. Therefore, newly devel- selected frequencies of occurrence had been developed equations in this report are compared only to the oped previously by the USGS and others for Beckman (1976) equations. Nebraska. Furness (1955) presented a method for Experience has shown that the Bulletin 17B computing peak flows up to the 50-year frequency (recurrence interval or probability) for two regions in default low-outlier tests are not well suited for Nebraska. The equations were considered applicable detecting multiple low outliers and that the to sites with at least 100 mi2 of drainage area. log-Pearson Type III (LP3) distribution recom- Beckman and Hutchison (1962) presented a method mended by Bulletin 17B is sensitive to high outliers. for computing peak flows up to the 100-year recur- The treatment of outliers can have substantial effects rence interval for sites with less than 300 mi2 of on peak-flow analyses, including skew coefficients drainage area. There are 10 hydrologic areas within from which a generalized skew-coefficient map is two regions for this method. Patterson (1966) and developed. Matthai (1968) developed methods for sections of Nebraska as part of regional studies on the Missouri As part of this study, annual peak-flow data for River Basin. All of the above are index-flood Nebraska were compiled, checked, and published by methods; they use a dimensionless frequency curve Boohar and Provaznik (1996). Provaznik also inves- and a relation for predicting the mean-annual flood tigated L-moments and several frequency distribu- from hydrologic characteristics to estimate a tions as possible alternatives to the methods recom- frequency curve for any location in a region. mended in Bulletin 17B. Results of the L-moment Beckman (1976) used multiple-regression techniques investigation can be found in Provaznik (1997), and to develop regional equations for peak flows up to the Provaznik and Hotchkiss (1998). 100–year recurrence interval. Basin characteristics were used as the explanatory variables in the five sets Purpose and Scope of regional equations. The purposes of this report are to: (1) present Cordes (1993) updated Beckman’s (1976) updated peak-flow frequency analyses for selected equations based on additional data and the new flood- streamflow-gaging stations in Nebraska; (2) present flow frequency guidelines of Bulletin 17B (Inter- and describe the development of new methods to agency Advisory Committee on Water Data, 1982). estimate peak flows for selected frequencies for He developed a generalized skew coefficient map (of ungaged streams in Nebraska; and (3) present an base-10 logarithms of annual maximum peak flows) evaluation of the peak-flow gaging-station network for Nebraska and included several new explanatory in Nebraska. Peak-flow frequency analyses and the variables in the regional regression analyses of peak- network analyses were done for streamflow-gaging flow frequencies. However, no new hydrologic stations in or within about 50 miles of Nebraska regions were developed, and no adjustments were (fig. 1).

2 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska Selected streams and dams, and areas with andSelected sandhillsstreams dams, and in parts and adjacent Nebraska of states. Figure 1. Figure

INTRODUCTION 3 Acknowledgments remaining basin boundaries for Nebraska and surrounding states were delineated on The authors acknowledge Milo Cress of the 1:250,000-scale USGS maps and digitized manually Federal Highway Administration for his support in to produce GIS digital data layers. Because of the initiating this study, and the dedicated USGS student difficulty in delineating noncontributing drainage employees who spent many hours digitizing drain- area (NCDA) over the large sandhills areas of age-basin data layers and computing basin character- Nebraska (fig. 1), basin-characteristic measurements istics with GIS programs: Christopher P. Stanton, were made over the total drainage area (TDA) rather David L. Rus, Cody L. Knutson, John T. Shulters, than over the contributing drainage area (CDA). and Mary Kay Provaznik. Some basin characteristics were computed from other characteristics rather than being measured QUANTIFICATION OF DRAINAGE-BASIN directly. Characteristics that required CDA in their CHARACTERISTICS computations were computed using published values of CDA. Morphometric, soil, and precipitation drainage- basin characteristics were determined for stream- Stream-network source-data layers were flow-gaging stations having 10 or more years of created by scanning mylar maps of 1:250,000-scale record in Nebraska and for selected stations outside USGS hydrography data, which were converted to of Nebraska. Most of the out-of-state stations had digital data layers using ARC/INFO version 7.0.4 25 years of record and had basin centroids within (Environmental Systems Research Institute, 1996). 50 miles of Nebraska; however, some stations had as Unfortunately, 1:250,000-scale hydrography data did few as 18 years of record or were as far away as about not always extend to some small drainage-area 80 miles. GIS-related programs and procedures were basins. USGS 1:100,000 digital line graph (DLG) used or modified to quantify drainage-basin charac- Quadrangle Series hydrography data were retrieved teristics from digital data layers of basin boundaries, from the EROS Data Center of USGS, but these data elevations, streams, soil, and precipitation. were not used because of edge-matching problems.

Morphometric Characteristics Source-data layers of elevation contours and the lattice elevation model were created from Twenty-seven drainage-basin characteristics 1:250,000-scale U.S. Defense Mapping Agency were quantified using a modified version of Basinsoft digital elevation model (DEM) data. GIS software (Harvey and Eash, 1996), a computer program devel- was used to convert the DEM data into a lattice of oped by the USGS (Majure and Soenksen, 1991; and point elevations and create elevation contours Eash, 1994). These morphometric characteristics (Harvey and Eash, 1996). The elevation contour generally describe the form and structure of a interval was selected to provide at least 10 contour drainage basin and its drainage network, including lines per basin. measurements of area, length, relief, aspect, and stream order (appendix A and table B1). Four source- Manual topographic-map measurements of data layers, representing the surface-water drainage selected drainage-basin characteristics were made for divide (basin boundary), hydrography (stream 11 drainage basins in Iowa by Harvey and Eash network), hypsography (elevation contours), and a (1996) to verify the accuracy of drainage-basin char- lattice elevation model of the drainage basin, were acteristics quantified using Basinsoft. Manual required to run Basinsoft. measurements and Basinsoft quantifications were made at identical scales. Comparison tests indicated Existing data layers of drainage-basin bound- that Basinsoft quantifications were not significantly aries for gaging stations were obtained from the different from manual measurements. Nebraska Natural Resources Commission and the Iowa City, Iowa, office of the USGS. Boundaries for As an additional check of Basinsoft quantifica- Nebraska basins had been delineated using tions, manual topographic-map measurements of 1:24,000-scale USGS topographic maps; those for selected drainage-basin characteristics were made for Iowa basins had been delineated using five Nebraska drainage basins. Basinsoft quantifica- 1:250,000-scale USGS topographic maps. The tions did not appear to be significantly different than

4 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska the corresponding manual measurements. Also, all calculations were performed to verify precipitation TDAs determined using Basinsoft were compared values for selected drainage basins. with published values. Basinsoft was unable to compute basin characteristics for several stations; PEAK-FLOW FREQUENCY ANALYSES the reasons are not understood. These stations were not used in the development of peak-flow Relations between peak flows and frequency of occurrence (recurrence interval or probability of frequency relations for unregulated streams. occurrence) for individual drainage basins are basic Soil Characteristics to the development of peak-flow frequency relations for larger areas. Bulletin 17B of the Four drainage-basin characteristics (Dugan, IACWD (Interagency Advisory Committee on 1984) that describe some aspect of the interaction of Water Data, 1982) contains guidelines for the soil and water were computed from developed development of these basic relations using the log- equations using ARC/INFO. Soil data for Nebraska Pearson Type III (LP3) frequency distribution. and surrounding states were obtained from a digital Three parameters—the mean, the standard data layer of the State Soil Geographic Data Base deviation, and the skew coefficient of the loga- (STATSGO) (Natural Resources Conservation rithms of the annual maximum peak flows—are Service, 1994). The upper 60 inches of the soil used to fit the station data to the LP3 distribution. profile were used to determine the majority of the These parameters can be thought of as the middle soil characteristics, which include average perme- point, average slope, and bend or shape of a ability rate of the soil profiles (P60), average avail- computed peak-flow frequency curve. Increasing able water capacity of the soil profiles (AWC), the standard deviation or range of the peak-flow data increases the slope or steepness of the average permeability of the least permeable layers frequency curve, and decreasing the standard of the soil profile (PLP), and the average maximum deviation flattens the slope of the curve. Positive soil slope (MSS) (appendix A and table B1). Manual skew coefficients cause the frequency curve to calculations were made to verify soil characteristics bend upward, negative skews cause the curve to for selected drainage-basins. bend downward, and zero skews produce a straight line. Precipitation Characteristics For stations with unregulated (natural) Two drainage-basin characteristics streamflow, station skew coefficients of peak flows describing expected precipitation were quantified should be weighted with generalized skew coeffi- using ARC/INFO. The 2-year (recurrence interval), cients for that area or for basins with similar char- 24-hour (duration) precipitation (TTP) 1-inch acteristics. The assumption is that skews will be contours were digitized manually from Weather similar for stations that have similar basin charac- Bureau Technical Paper 40 (Hershfield, 1961) into teristics or are in close proximity, and that the accu- a GIS digital data layer. Additionally, 0.1-inch racy of the applied skew can be improved by incor- interval contours were interpolated and digitized porating the influence of other stations. The (fig. A1). Mean annual precipitation (MAP) data national map of generalized skew coefficients in compiled by the National Oceanic and Atmospheric Bulletin 17B provides default values for areas Administration were retrieved for the period 1961– where local values have not been determined inde- 90 from the National Climatic Data Center Web site pendently. For stations with regulated streamflow, (URL http://www.ncdc.noaa.gov/ol/climate/online/ only the station skew coefficients were used in coop-precip.html). These data were used to create a peak-flow frequency analyses because the flow data layer of points from which Thiessen polygons characteristics are based on imposed criteria, not on were created (fig. A2). TTP and MAP values then the characteristics of the drainage basins. Bulletin were determined by taking the area-weighted 17B also provides guidelines for making adjust- average of precipitation polygons coincident to the ments for historic data and low outliers. It also total drainage area of each basin (table B1). Manual provides guidelines for developing composite

PEAK-FLOW FREQUENCY ANALYSES 5 peak-flow frequency relations for stations with peak streams. The first set of standard analyses was used flows that are produced by different runoff-producing to determine skew coefficients from the peak-flow mechanisms, such as rainfall and snowmelt. data for each station. Using these station skews, several generalized skew relations then were devel- Standard Analyses oped. The second set of standard analyses was done using the individual station skews weighted with the Annual peak flows for USGS gaging stations newly developed generalized skews. For stations on with at least 10 years of record through 1993 and regulated streams, one set of standard analyses was located in or within about 50 miles of Nebraska were made based on station skews only. Adjustments were retrieved from the USGS’s national streamflow data made to individual peak-flow frequency analyses, as base (Dempster, 1983). Peak-flow data were loaded appropriate, for historic data, and for high and low into a Watershed Data Management (WDM) file outliers as described in the following sections. (Flynn and others, 1995) and then checked and Results of frequency analyses for peak-flow gaging updated as necessary. Stations in the study area, but stations are listed in table B2. with streams that do not flow into Nebraska and with drainage areas that are mostly outside of the study area, were not used. The program PEAKFQ—an Adjustments for Historic Data updated version of program J407 (Kirby, 1981) that The number of annual peak flows, during utilizes WDM files— follows the guidelines of which data were collected systematically at a gaging Bulletin 17B and was used for the peak-flow station (systematic record), is used in the computa- frequency analyses for all the gaging stations. The tion of the LP3 parameters and in the determination program outputs computed peak flows for standard of the plotting positions of the peak flows for the exceedance probabilities (frequencies) in a tabular frequency curve. If one or more of the peak flows form and as a peak-flow frequency curve in graphical within the systematic record are known to be the form. largest in a period longer than the systematic record, Peak flows that were known to have been or the frequency analysis can be adjusted to this historic could possibly have been affected to some degree by period. This provides a means to correct, at least regulation—such as flood control, irrigation diver- partially, for the adverse effects that a very large peak sions, power generation, storage detention, or other flow might otherwise have on the computed peak- factors—were separated from unregulated peaks flow frequency curve. Historic peak flows without an before further analysis. Determinations generally associated historic period cannot be added to the were based on information from the peak-flow data record being analyzed. Historic periods for peak- base, water-data and flood-frequency reports, USGS flow data were determined primarily from the peak- files, topographic maps, and a statewide data base for flow data base, but also from water-data and flood- dams, which contains location, year of completion, frequency reports, USGS files, newspaper accounts and amount of storage. A rough criterion was devel- of floods, and comparisons with records for other oped for estimating possible effects of regulation on nearby stations. peaks using a comparison of the average flow to the amount of storage in the basin. It was developed from Adjustments for High and Low Outliers data for stations with significant changes in storage during their periods of record by comparing changes Extremely high or low annual peak flows that in peak-flow frequency relations to the changes in significantly depart from the trend of the rest of the storage for both earlier and later periods of record. data are outliers that can have a disproportionate The criterion was developed primarily for estimating effect on the LP3 parameters used to compute whether the cumulative storage of numerous small frequency curves. High outliers tend to increase both dams might be affecting peaks at downstream skew coefficients and standard deviations. Low stations. Because of the limited data upon which it outliers tend to decrease skew coefficients but was based, the criterion was used only as a guideline. increase the standard deviations. The outcome can be varied depending on the number of outliers and their Two sets of standard peak-flow frequency anal- values. Decreasing the skew bends the frequency yses were computed for stations on unregulated curve downward and reduces expected high-end peak

6 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska flows; increasing the standard deviation steepens flows were grouped together below a data break, the slope and increases expected high-end peak then the gage-base threshold was set to the second flows. Statistical tests done by the program largest peak flow of the group, to isolate the largest PEAKFQ identify both high and low outliers, but peak flow below the data break, and the analysis adjustments cannot be made for high outliers unless was recomputed. Judgment was used in both of the historic data are available, as previously discussed. low-outlier identification procedures when the By default, any identified low outliers are elimi- criterion was within at least 90 percent of the peak- nated (censored) by PEAKFQ and a conditional flow value being tested. probability adjustment is made based on the assumption that the remaining values are represen- Another low-outlier test used was to censor tative of the entire period of record. Experience of peak-flow values, either individually or in groups, the authors has shown that the statistical tests and observe the effects on the high end of the peak- included in Bulletin 17B are not well suited for flow frequency curve. This was done by setting the detecting multiple low outliers for many Nebraska low-outlier criterion to the value of interest. For stations. Therefore, adaptations of the existing stations with multiple low outliers, this procedure procedure, other tests, and considerable judgment was usually not very effective until most or all of were used to identify and censor low outliers in the low outliers were censored. Considerable judg- those situations. If numerous enough, multiple low ment was used with this procedure, but usually at outliers can become a special case of mixed popula- least a 10-percent change in the 100-year frequency tions, as discussed later, requiring the development peak flow was required before the censored value of composite frequency curves (see Composite or values were considered low outliers. For many Analyses). stations, although the lower peak-flow values did not appear to be representative, there was no clear- The default PEAKFQ procedure for identi- cut data break and the quantitative outlier tests were fying low outliers was adapted to test other peak not definitive. In these cases, a visual evaluation of flows suspected of being low outliers based on a the fit, especially of the upper half of the peak-flow visual inspection of the default peak-flow frequency curve, from which all of the peak-flow frequency curve. The gage-base threshold can be frequency values of interest were determined, was set in PEAKFQ to isolate specific peak flows to be the final and overriding test of low outliers. tested as low outliers. Peaks below the user-set gage base are not used in PEAKFQ computations, except Generalized Skew Coefficients for determining plotting positions, and a new low- outlier threshold is computed from the remaining Regional equations relating generalized skew data. This allowed the first peak above the gage coefficients (of base–10 logarithms (log10) of base to be tested as a low outlier against the annual maximum peak flows) to basin characteris- remainder of the data. This was done in two ways: tics were developed for most of the state, and a (1) by raising sequentially the gage-base threshold statewide map of generalized skew coefficients for from the lowest flows, and (2) by setting the gage- basins with relatively low soil permeability also base threshold based on breaks in the data. Data was developed. These relations were based on breaks were identified visually on plots of the frequency analyses from 224 gaging stations (fig. 2 default peak-flow frequency curves. The sequential and table B2) and the procedures given in test was used when at least one low outlier had Bulletin 17B (Interagency Advisory Committee on already been identified, either by the original outlier Water Data, 1982). The national skew coefficient test or by a break test. The gage-base threshold was map included in Bulletin 17B was developed origi- set to the value of the largest identified low outlier nally for Bulletin 17 (U.S. Water Resources and the analysis was recomputed. If a new outlier Council, 1976), and was based on a relatively small was identified, the process was repeated until no number of stations with minimal evaluation of low more low outliers were identified. This worked well outliers, no adjustments for historic data, no identi- if the low-end values were well spaced. If peak fication or treatment of high outliers, and no

PEAK-FLOW FREQUENCY ANALYSES 7 or log-Pearson Type or log-Pearson peak- III f Location of streamflow-gaging stations in Nebraska and adjacent states used to develop generalized skew coefficient relations relations coefficient skew generalized develop to used states adjacent and Nebraska in stations of streamflow-gaging Location Figure 2. Figure analyses. flow-frequency

8 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska detailed evaluation of individual peak-flow explanatory variables in the equation must be frequency curves. In Nebraska, values shown by the measured or computed. national map were influenced by the high positive skews from a few stations with drainage areas A skew equation first was developed for mostly in the sandhills. Because the map is general- basins with average soil permeability (P60) greater ized, this influence went beyond the actual area of than 2.5 in/hr (high-permeability regional skew the sandhills. equation); this eliminated the need to map the high positive skew areas of the sandhills as was done for Station skew coefficients were computed the national map. A skew map then was developed using PEAKFQ for stations in or within about for basins with P60 less than 4 in/hr, and for the 50 miles of Nebraska that, generally, had 25 years entire Elkhorn River Basin (see fig. 1 for location or more of unregulated peaks. Several stations with of specific streams), which includes basins with as few as 18 annual peaks were used where data P60 greater than 4 in/hr. This resulted in some were lacking. Adjustments for historic information overlap with the high-permeability equation. and low outliers were made as previously Regional equations, based mostly on geographic described. Low outliers tend to make the station areas, also were developed; however, only those skew more negative and high outliers tend to make with mean-square errors (MSEs) less than those for it more positive. Because procedures were applied the newly developed skew map were used, as to reduce the effects of low outliers in most cases, it recommended in Bulletin 17B. Because of the also was considered necessary to limit the effects of importance of P60 in deciding which skew relation high outliers, identified by PEAKFQ, to limit bias to use, a generalized map of P60_SS (appendix A) in any skew relations developed. is presented (fig. A3). For actual measurements of P60 for a drainage basin, values should be quanti- After other adjustments had been made to the fied using a GIS, as previously described. Using peak-flow frequency analyses, stations with Statit statistical programs (Statware, Inc., 1990) PEAKFQ high outliers were analyzed further to standard multiple-regression techniques were used estimate how sensitive the station skew coefficients to develop skew estimation equations (table 1). were to the high outliers. Using the historic adjust- Residuals were analyzed to define regions and to ment procedure in PEAKFQ, high outliers for a try and determine the best combination of explana- station were assumed to be historic peaks and then tory variables. Equations were examined to ensure the record length was doubled, tripled, and quadru- that they were hydrologically reasonable. The pled arbitrarily. The new skew coefficients were adjusted R-square, MSE, ratio of MSE to variance, noted and differences from the original values were and standard error of estimate (SEE) were computed. The skew was considered fairly stable if computed from or taken from Statit output files for it did not change by more than 0.20, 0.30, or 0.40, each equation (table 1). Regions and skew coeffi- respectively, for sandhills stations, and by more cients that have been defined geographically are than 0.10, 0.15, or 0.20, respectively, for all other shown in figure 3. stations. Stations with skew changes greater than these were considered unstable because of the high High-Permeability Regional Skew Equation outlier(s), and those stations were eliminated from further consideration in the skew relations. The high-permeability regional skew equation is based on 38 stations with at least 25 years of Equations to predict skew coefficients were record and with P60 greater than 2.5 in/hr, except preferred to a skew map because equations elimi- those in the Elkhorn River Basin. The equation nate the assumption that basins in close proximity applies to high-permeability basins, not to a distinct have similar skew values. Rather, skews estimated geographic area. However, it is uncertain whether using equations are based on measurable character- the equation is applicable to: right-bank tributaries istics for each individual basin. It is more difficult of the Little White River and adjoining left-bank to compute skews with equations compared to tributaries of the Niobrara River upstream of and determining skews from maps because each of the including Minnechaduza Creek; and right-bank

PEAK-FLOW FREQUENCY ANALYSES 9 Table 1. Generalized skew equations

[BS, basin slope, in feet per mile; CR, compactness ratio, dimensionless; GSkew, generalized skew coefficient of base–10 logarithms (log10) of annual maximum peak flows, dimensionless; MSE, mean square error; MSS, average maximum soil slope, in percent; P60, permeability of the 60-inch soil profile, in inches per hour; PLP, permeabilitiy of the least permeable layer, in inches per hour; SEE, standard error of estimate; SR, slope ratio of main-channel slope to basin slope, dimensionless; >, greater than]

Ratio of Adjusted MSE to R-square MSE variance SEE

(based on log10 transforms of Estimation equation peak-flow data)

High Permeability Skew Region

(38 stations with 25 or more years of record) –1.261 GSkew = ------+ 1 . 1 6 9() l o g P60 – 0.112 0.74 0.055 0.23 0.234 CR 10 Northern and Western Skew Region

(31 stations with 20 or more years of record) 1.216 0.6688 GSkew = 0.1716PLP ++------–0.109------.84 .033 .16 .182 MSS CR Northeastern Skew Region

(30 stations with 20 or more years of record) 0.4452 GSkew = 0.4811() log SR –------–1.129 0.5595() log MSS + .63 .024 .35 .155 10 P60 10 Southeastern Skew Region

(28 stations with 25 or more years of record)

() .54 .018 .46 .134 GSkew = –0.001853BS+0.4928 log10P60 – 0.058

NOTE: CR, SR, and BS are data-scale dependent. tributaries of the Niobrara River that are Wyoming, southern South Dakota, and adjacent to the Elkhorn River Basin (left and northern and western Nebraska. Stations are right banks are referenced to facing in the in the following basins: right-bank Cheyenne downstream direction). Stations from these River, upper White River, Little White River, areas were not used because of insufficient Missouri River tributaries from the South record length or problems in computing the Dakota-Nebraska state line to and including basin characteristics. Three stations in the Little right-bank tributaries of the Big Sioux River, White River-Minnechaduza Creek divide area and the North and South Platte Rivers. This had negative skews, which were not consistent region (fig. 3) overlaps with the northeastern with the equation results of positive skews for skew region and includes some stations used stations with high permeabilities and low in the high-permeability regional skew compactness ratios (CR). Therefore, station equation. skews were used in the peak-flow frequency analyses for this area instead of skews Northeastern Regional Skew Equation estimated from the equations. The northeastern regional skew equation is based on 30 stations with at least Northern and Western Regional Skew Equation 20 years of record, from northeastern The northern and western regional skew Nebraska, southeastern South Dakota, and equation is based on 31 stations with at least northwestern Iowa. 20 years of record, from southeastern

10 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska y analyses of unregulated of unregulated analyses y ith average permeability of the top top the of permeability average ith ) of lessthan 4 inches perhour butincluding the entire ElkhornRiver Basin. Coefficientsare for log-Pearson Type III frequenc

P60 Regions of generalized skew-coefficient equations for Nebraska, and distribution of generalized skew-coefficients for basins w basins for skew-coefficients of generalized distribution and Nebraska, for equations skew-coefficient generalized of Regions Figure 3. Figure 60 inches of soil ( annual peak flows. peak annual

PEAK-FLOW FREQUENCY ANALYSES 11 Stations are in the following basins: Ponca 0.052 and a SEE of 0.24. The skew map in Creek, lower Niobrara River (adjacent to the Elkhorn Bulletin 17B has a standard deviation (computed the River Basin), Missouri River tributaries from the same as the SEE reported here) of 0.55, but this is not Niobrara River to the Platte River, Middle Loup and comparable because it is for the whole country. Loup River tributaries downstream of and including Turkey Creek, Shell Creek, and the Elkhorn River. Cordes (1993, p. 59–60) reports that the standard The region also is considered to include other left- deviation is 0.78 for the Nebraska part of the national bank Platte River tributaries downstream of the Loup map in Bulletin 17B. The skew map for Nebraska River. This region (fig. 3) overlaps with the northern presented by Cordes, which includes the high-perme- and western skew region and includes some stations ability sandhills areas, as was done for the national used in the high-permeability regional skew equa- map, has a standard deviation of 0.59. tion. Composite Analyses Southeastern Regional Skew Equation The southeastern regional skew equation is Using a conditional probability method based on 28 Nebraska stations with at least 25 years suggested by William Kirby (USGS) (Wilbert of record, from the Salt and Weeping Water Creek Thomas, Jr., USGS, written commun., 1995), an Basins, the Little and Big Nemaha River Basins, and alternative set of frequency analyses were computed the Little and Big Blue River Basins. The region also for selected high-permeability stations that appar- is considered to include other right-bank tributaries ently have two different populations of annual peak of the Platte River downstream of Hydrologic Unit 10200103 (U.S. Geological Survey, 1976) (which flows in the data. A pattern that showed different extends several miles below the mouth of the Loup flow characteristics for the largest peaks seemed River) and of the Missouri River between the Platte apparent from the initial peak-flow frequency curves River and the Nebraska-Kansas state line. The region for most of the high-permeability stations. Because is shown in figure 3. sandhills terrain typically includes large areas of

Low-Permeability Skew Map noncontributing drainage and high permeability, it was theorized that most of the lower-flow peaks A low-permeability skew map of Nebraska consisted primarily of interflow and baseflow and (lines of equal generalized skew coefficient, fig. 3) that the higher-flow peaks had a significantly greater was developed for basins with P60 less than 4 in/hr, proportion of surface runoff than the lower-flow and including the entire Elkhorn River Basin regard- less of soil permeability. Skew values were plotted at peaks. the centroid of the drainage area for each station. The Unit-value flow data were not readily available skew values were clustered geographically based on judgment with consideration given to such factors as for using a flow-hydrograph separation technique to basin similarity and apparent trends. An average test the theory. Therefore, plots of peak flow versus skew value, weighted by the number of annual peak the lower of the 1- or 2-day lag of daily flow were years for each station, was computed for each cluster. made for several stations to determine if the theory The weighted-average value then was assigned to was at least plausible. Three such plots, along with every point in the cluster. Lines of equal skew coeffi- their respective peak-flow frequency plots, are shown cient initially were determined using a contouring in figure 4. The results are not definitive because program and were revised manually using judgement. Differences between the lines and the actual daily value data are so generalized compared to unit station skew values were determined and the MSE value data (commonly 15-minute intervals) and true was computed by summing the squares of the differ- recessions are not always apparent, especially if ences and dividing by the total number of stations secondary peaks are masked within the daily values. used. Several clustering schemes were used in an Even so, there is a general tendency for the higher attempt to minimize the MSE while still keeping the flows to have a greater proportionate drop-off in flow lines general enough to represent broad trends. The map became more general as the number of clusters than do the lower flows. This supports the theory was reduced; a single cluster would result in an because flows with proportionately more surface overall average skew for the state. The final map runoff than interflow or baseflow would have steeper (fig. 3) is based on 189 stations and has an MSE of recessions for a given station. Based on the

12 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska 50,000 12,000 40,000 7885 NORTH LOUP RIVER Selected peak 30,000 AT ORD 10,000 20,000

ine l e Composite 8,000 10,000 enc er 7,000 Annual peak Ref 1 4: 5,000 6,000 4,000 e lin 3,000 ce feren 4,000 1 Re 2,000 2:

1,000 2,000 700 500 0 01,000 2,000 3,000 10,000 1,400

7,000 7765 DISMAL RIVER Selected peak 5,000 AT DUNNING 1,200 4,000 3,000 1,000 2,000 Composite

Annual peak 800 1,000

700 600 500 ine 400 400 l 300 ence er ef e R lin 200 ce 200 2:1 en DISCHARGE, IN CUBIC FEET PER SECOND DISCHARGE, IN CUBIC FEET PER fer Re 1:1 100 0 07000 100 200 300 400 500 600 5,000 600 4,000 6780 SHEEP CREEK Selected peak 3,000 NEAR MORRIL (Regulated by irrigation, composite 500 2,000 frequency curve not computed)

1,000 Bulletin 17B--station skew 400

700 Annual peak 500 300 line 400 rence e 300

200 4:1 Ref 200

100 e 100 lin ce en fer 70 Re 2:1 50 0 99 98 95 90 80 70 60 5040 30 20 10 5 2 1 01500 50 100 ANNUAL EXCEEDANCE PROBABILITY, IN PERCENT DAILY DISCHARGE, IN CUBIC FEET PER SECOND, 1 OR 2 DAYS AFTER SELECTED PEAK FLOW

Figure 4. Peak-flow frequency curves and daily discharge lag plots for three Nebraska streamflow-gaging stations.

PEAK-FLOW FREQUENCY ANALYSES 13 observed patterns in the peak-flow frequency plots mixed populations were dropped from the regional and the lag plots, it was decided to treat the peak analyses of peak-flow frequency but are listed with flows above and below the breaks on the peak-flow appropriate notes in table B2. Preliminary composite frequency plots as two different populations, or analyses were done for several Platte River stations, regimes, of flow for an alternative set of frequency analyses. including Platte River at Brady (7660) (fig. 5). However, most stations on partially regulated streams Kirby's method of developing a composite were simply computed with station skews and, where peak-flow frequency curve for a station requires that mixed populations appeared to be most apparent, there be enough annual peaks of each flow regime to notes were included in the appropriate figures and compute separate frequency curves. PEAKFQ tables. requires at least three peaks to make a computation. Peak-flow values for the selected stations were sepa- In the more arid areas of Nebraska, annual rated into higher- and lower-flow regimes and loaded maximum peak flows can be very small or even zero. into special WDM files. Because there were no generalized skew relations established for these situ- The lower-regime flows are essentially low outliers ations, analyses were computed with PEAKFQ using from the remaining peak-flow data. When these station skews only. The use of zero skews or lower flows comprise a large proportion of the data, weighted skews might have been preferable in some they cannot all be censored because Bulletin 17B situations to limit the effects of outliers on curves analyses require that at least half of the data be used. with already limited data. The results from the indi- If they are numerous enough and their range in flow vidual analyses were combined using conditional is great enough, the computed peak-flow frequency probabilities as shown in Kirby’s equation modified from Thomas (Wilbert Thomas, Jr., USGS, written curves are too steep and the indicated high-end peak commun., 1995): flows can be unreasonable. Chadron Creek tributary at Chadron Creek State Park near Chadron (4455a) []PF()> x\F ∈ H × PF()∈ H + and Antelope Creek tributary near Gordon (4578) are PF()> x = (1) []PF()> x\FL∈ × PF()∈ L two examples of this situation (fig. 5). For the Chadron Creek tributary station, 12 of the 26 peaks where: P = probability that were zero and no more peaks could be cut off in the F = annual maximum peak flow standard Bulletin 17B analyses or the calculations x = given value of peak flow would abort. For this station the data were simply split into zero and non-zero flows, analyzed sepa- \ = given that rately and then recombined with the conditional F ∈ H = annual maximum peak flow is a probability adjustment. higher-regime flow For the Antelope Creek tributary station F ∈ L = annual maximum peak flow is a lower- regime flow (4578), less than half of the non-zero flows appear to be true indicators of flood flow and splitting the data Composite peak-flow frequency curves were into zero and non-zero flows does not produce a plotted and peak flows for the standard exceedance reasonable fit of the largest flows. The fairly obvious probabilities were determined visually from the break used to split the non-zero flow data for this graphs. This was done for 22 high-permeability (P60 station is not always as apparent for other stations and greater than 4 in/hr) stations with unregulated flows (fig. 4 and figs. C1 to C4). is difficult to justify without more investigation. Another solution might be to use a different type of Other types of mixed populations in station analysis that uses all of the peak flows above a data also were apparent, including stations with rela- selected base flow in the computations (partial-dura- tively low permeability and precipitation—especially tion series) rather than just the annual maximum peak in northwestern Nebraska—and stations on partially regulated streams. The thorough investigations flows (annual maximum series). Some, if not all, of required to split the data and to do the analyses of all the lower peak flows from dry years potentially could of these other cases were beyond the scope of this be replaced in the analyses with larger peak flows study. Low-permeability stations with apparent from wetter years. Unfortunately, all of the stations

14 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska

0.1

5 10

station skew station skew

Bulletin 17B-- Composite Annual peak Bulletin 17B-- Annual peak 20

50 60

of data that are not caused by by caused not are that data of

70 s 80

(1953-93)

90 95

EXCEEDANCE PROBABILITY EXCEEDANCE

98 99 4 inches per hour. per 4 inches

8535 REPUBLICAN RIVER NEAR HARDY RIVER REPUBLICAN 8535 7660 PLATTE RIVER AT BRADY (1941-93) AT BRADY RIVER PLATTE 7660 (Composite frequency curve not computed) Total drainage area is about 56,200 squaremiles Regulated drainage area is about 29,300 square miles since 1941 32,300 square miles since 1975 Unregulated drainage area is about 23,900 square miles since 1975 or about 43 percent of total Total drainage area is about 22,400 squaremiles Regulated drainage area is about 20,800 square miles since 1952 Unregulated drainage area is about 1,600 square miles since 1952 total7 percentor about of 99.9 700 500 7,000 5,000 4,000 3,000 2,000 1,000 7,000 5,000 4,000 3,000 2,000 1,000

70,000 50,000 40,000 30,000 20,000 10,000 70,000 50,000 40,000 30,000 20,000 10,000

100,000 100,000

RANKED DISCHARGE RANKED 0.1

90 95 skew (3-section)-- 7 larger flows, 7 smaller flows, 12 zero flows

Bulletin 17B--station skew Bulletin 17B--weighted Composite Annual peak (1953-78) 98

TRIBUTARY 99 NEAR GORDON NEAR

4578 ANTELOPE CREEK Total drainage area is 26.6 square miles Number of zero values is 12 of 26 99.9 IN PROBABILITY, PERCENT EXCEEDANCE ANNUAL 7 5 4 3 2 1 70 50 40 30 20 10 0.7 0.5 0.4 700 500 400 300 200 100

7,000 5,000 4,000 3,000 2,000 1,000

10,000

0.1

90 95 14 non-zero flows, flows zero 12 14 non-zero flows with 2 low outliers, flows zero 12

Bulletin 17B--station skew skew 17B--weighted Bulletin Composite (2-section)--A Composite (2-section)--B Annual peak 98 99 PROBABILITY EXCEEDANCE ANNUAL NEAR CHADRON (1953-78) CHADRON NEAR AT CHADRON STATE PARK CHADRON STATE AT

4455a CHADRON CREEK TRIBUTARY 4455a CREEK CHADRON Total drainage area is 2.6 square miles Number of zero values is 12 of 26 99.9 7 5 4 3 2 1 70 50 40 30 20 10 0.7 0.5 0.4 700 500 400 300 200 100 Four examples of Nebraska streamflow-gaging stations requiring composite frequency curves because of apparent mixed population mixed apparent of because curves frequency composite requiring stations streamflow-gaging Nebraska of examples Four

7,000 5,000 4,000 3,000 2,000 1,000

10,000

ANNUAL PEAK DISCHARGE, IN CUBIC FEET PER SECOND PER FEET CUBIC IN DISCHARGE, PEAK ANNUAL SECOND PER FEET CUBIC IN DISCHARGE, Figure 5. Figure tha more of inches 60 top of the permeability soil average by or area drainage noncontributing of proportions large with basins

PEAK-FLOW FREQUENCY ANALYSES 15 where this was observed were operated as peak-stage development of unregulated peak-flow frequency gages where only annual maximum peaks were relations (fig. 6). reported. For both the Chadron Creek and Antelope Creek tributary stations, regional skews were used Stations along streams with flows that are when analyzing the higher flows. known to have been or possibly could have been affected to some degree by regulation (flood control, For regulated or partially regulated streams, the irrigation diversions, power generation, storage farther downstream from a control structure a station detention, or other factors) were excluded from is located, the more likely it is that peaks will be regional analyses relating drainage-basin characteris- produced from the unregulated drainage area between tics to peak-flow characteristics (fig. 7). Log-linear the structure and the station; even a small amount of relations of peak-flow frequency and distance drainage area can produce a large peak if a storm over upstream from the mouth were developed for parts of the area is intense enough. The Republican River at nine streams. Hardy (8535) is an example of a partially regulated station with an apparent mixed population (fig. 5). Unregulated Streams Based on a comparison with two other long-term Using analyses for stations with at least stations between the Hardy station and the Harlan 10 years of record, preliminary peak-flow frequency County Dam upstream, it is apparent that at least the equations were developed and regions were defined two largest peaks at the Hardy station, which are using ordinary least squares (OLS) multiple-regres- distinctly different from the majority of the other sion procedures. Final equations were developed peaks, were produced from the unregulated drainage using a generalized least squares (GLS) multiple- area below the dam. regression procedure. OLS regression procedures were used to identify the most likely combinations of PEAK-FLOW FREQUENCY RELATIONS drainage-basin characteristics for the development of Peak-flow frequency relations were developed peak-flow frequency equations and to define regions. for standard exceedance probabilities of 50, 20, 10, 4, OLS regression analyses were done using Statit 2, 1, 0.5, and 0.2 percent, or frequencies of occur- statistical programs (Statware, Inc., 1990). Peak-flow rence (recurrence intervals) of 2, 5, 10, 25, 50, 100, data were transformed to base-10 logarithms (log10). 200, and 500 years, respectively. For unregulated Several additional drainage-basin characteristics streams, eight sets of regression equations relating were computed using Statit from the existing charac- drainage-basin characteristics to annual peak flows teristics before log10 and reciprocal transforms were for selected frequencies of occurrence were devel- computed. Correlation coefficients and plots of the oped for seven regions of the state. Two sets of data were used to screen out drainage-basin charac- regional peak-flow frequency equations were devel- teristics that were highly correlated with each other oped for a high-permeability region that includes or were poorly distributed relative to the peak-flow basins with P60 greater than 4 in/hr. Six sets of equa- data for statistical analyses. Multiple-regression tions were developed for specific geographic areas, programs ALLREG, GREGRES, and REGRES primarily on the basis of drainage-basin boundaries. (Statware, Inc., 1990) were used to identify statisti- One set of the high-permeability equations was cally significant combinations of explanatory vari- developed using data from standard frequency anal- ables (basin characteristics) for predicting peak flows yses and the other was developed using data from for standard frequencies of occurrence. Initial selec- composite frequency analyses. In general, the two tion of explanatory variables for OLS regression sets of high-permeability equations were developed equations was based primarily on minimizing the for basins with sandhills-type terrain. Statewide Mallow's Cp statistic in ALLREG. Mallow’s Cp was regression equations also were computed, but they used to achieve a balance between minimizing bias, are not presented because MSEs were larger than by including all relevant variables, and minimizing those for regional equations. Data from stations in the variance of the estimator, by keeping the number Wyoming, South Dakota, Colorado, and Kansas were of variables small (E.J. Gilroy, D.R. Helsel, and used along with data from stations in Nebraska in the T.A. Cohen, USGS, written commun., 1991).

16 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska

This also usually resulted in minimizing the MSE commun., 1995). The t-ratios for each of the and in keeping the absolute value of the t-ratios explanatory variables also were examined; those greater than 2. The t-ratio was computed for each with an absolute value of less than 2 were not used, explanatory variable as the fitted coefficient in most cases. Also, explanatory variables that were divided by its standard error; it was used to test not considered hydrologically valid were elimi- whether or not the coefficient (slope) of each nated from the regression analyses on a case-by- explanatory variable was significantly different case basis. than zero. Short-record stations with less than 15 years of peak-flow record were not used, except for two Regional Equations regions in eastern and southeastern Nebraska. In Residual values and plots from preliminary general, use of short-record stations added consid- OLS regression analyses were used to delineate the erable variability to peak-flow frequency relations; six hydrologic regions (fig. 8) based on geography commonly, these stations had individual peak-flow and outlier stations before final regression equa- frequency relations that did not fit the data well. tions were developed using the GLS program in Stations with an excessive number of low outliers GLSNET (Gary Tasker, USGS, written commun., that precluded development of reasonable peak- 1995). The GLS program adjusts for differences in flow frequency curves, most typically in northern record lengths, differences in peak-flow variances, and western Nebraska, also were not used (see and cross-correlations of concurrent peak-flows previous discussion “Composite Analyses”). In among stations used in the regression analysis addition, stations with total drainage areas (TDA) of less than 1 mi2 generally were not used. For most (Tasker and Stedinger, 1989). Only log10 transforms of peak-flow and drainage-basin character- regions where a slope characteristic was identified as significant, stations with drainage areas of less istic data were used for GLS regression analyses. 2 This allowed for the simple transformation of the than 5 mi were not used. The 1:250,000-scale final equations to exponential form. Selection of DEM data used to quantify basin characteristics drainage-basin characteristics as explanatory vari- resulted in some characteristics that were regarded ables for GLS regression equations was based as too low and unreliable for use in the regression primarily on minimizing the GLS version of the analyses—this was particularly evident for basins prediction error sum of squares, or PRESS statistic, with small drainage areas and low relief. (Gilroy and Tasker, 1989; and E.J. Gilroy, D.R. For both OLS and GLS regression analyses, Helsel, and T.A. Cohen, USGS, written commun., allowances were made in the basic selection 1991) and, to a lesser extent, on minimizing the process to try to keep drainage-basin characteristics standard error of prediction (SEP). consistent for the various peak-flow frequency The PRESS statistic is the sum of the squared equations within a region. This was not always prediction residuals. The prediction residuals are possible, however, and some equations for the same the differences between each observed value of the region have different sets of characteristics as dependent variable and its predicted value that is explanatory variables. Judgement must to be used determined from a regression equation computed in the application of these equations in these situa- with all data except that of the observed value for tions. which the residual is being determined. The SEP For each region, equations were developed was preferable to the standard error of estimate for the 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year (SEE) for equation comparisons because the SEE is frequencies of occurrence (recurrence intervals), based only on the model error (error in the equation designated as Q2, Q5, Q10, Q25, Q50, Q100, Q200, that will change only if the equation itself is and Q500 respectively. A table of equations for each changed, not by collecting more data) while the region with summary statistics follows a discussion SEP also includes the sampling error (error in esti- of each of the regions. There is overlap between mating the true equation parameters from limited several of the regions where more than one equa- data) (Gary Tasker, U.S. Geological Survey, written tion can be used to estimate peak flows.

PEAK-FLOW FREQUENCY RELATIONS 19 Hydrologic regions in Nebraska for unregulated peak-flow frequency equations. frequency peak-flow unregulated for Nebraska in regions Hydrologic Figure 8. Figure

20 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska Tables of equations include: the average River Basin is included within one of the six sampling error (ASE), average model error (AME), geographically based regions. SEP, and SEE— all based on the log10 transforms of the data; SEE in percent of the untransformed data; Equations for the High-Permeability Region and the average equivalent years of record (AEYR) and standard-frequency analyses (HPS) (table 2) for each equation. SEP was computed as the square are based on data from 49 stations with at least root of the sum of ASE and AME. SEE was 15 years of record and TDAs of 94.8 to 15,200 mi2. computed as the square root of AME (Gary Tasker, The explanatory variables for the HPS equations U.S. Geological Survey, written commun., 1995). were not entirely consistent for all frequencies. For comparisons to equations developed by Contributing drainage area (CDA) and mean annual Beckman (1976), for which SEPs were not reported, SEEs in percent were computed from the precipitation (MAP) were the two most significant variables in all equations. Basin slope (BS) was SEEs in log10 units using tabled values from Tasker (1978, p. 87). The AEYR is an estimate of the significant at the smaller frequencies, and available number of years of at-site streamflow data that water capacity (AWC) and main-channel slope would be required to predict the streamflow charac- (MCS) were significant at the middle and larger teristic with accuracy equivalent to that of the frequencies. Stations with TDAs less than 5 mi2 regression equation (Hardison, 1971, p. C232). The were not considered because BS and MCS were in explanatory variables are listed in the equations in the equations (see previous discussion of Regional the order of decreasing t-ratios from the GLS output. This was done to illustrate the changing Equations). significance, if any, among the variables from one Equations for the High-Permeability Region frequency of occurrence (recurrence interval) to and composite-frequency analyses (HPC)(table 2) another. were based on data from 23 stations with at least For unregulated stations, estimated peak 20 years of record and TDAs of 172 to 4,490 mi2. flows were computed (table B2) from the appli- The number of stations used to develop the regres- cable regional equations using basin-characteristic sion equations was limited because of the amount data (table B1). Code(s) designating the applicable of time required to compute the composite- set of regional equation(s) are also listed for each frequency curves. Also, not every high-perme- station. ability station had enough peaks in the higher-flow High Permeability Region regime to which a separate peak-flow frequency curve could be fitted. The explanatory variables for This region generally includes drainage basins with sandhills terrain (figs. 1 and 8); it the composite-analysis equations are very similar includes a large area of Nebraska, not all of it to those for the standard-analysis equations except contiguous, and smaller areas in Colorado, South for the addition of drainage frequency (DF), which Dakota, and Wyoming. The region is nearly coinci- is significant for all frequencies. dent with Beckman's Region 2 (1976, p. 10-11), SEEs for both sets of high-permeability equa- which was defined geographically; in this report the region is defined by basin characteristics. Only tions are lower than are those corresponding to basins with P60 greater than 4 in/hr and with some Beckman's Region 2 (1976, p. 60) equations. The noncontributing drainage area (NCDA) were used SEEs for the standard equations generally are lower to develop the equations. These criteria eliminated than are those for the composite equations; this the lower Niobrara River Basin stations down- could be because of the limited number of stations stream of Long Pine Creek (fig. 1). Although these used to develop the composite equations. However, basins have values of P60 greater than 4 in/hr, they the peak-flow frequency curves that are the basis have little or no NCDA and the terrain is distinctly for the composite equations are considered to fit the different from that of the nearby sandhills areas, as determined from visual inspection of topographic peak-flow frequency data better at the high ends maps. Peak-flow frequency data from these basins than do the standard peak-flow frequency curves. also did not fit well with that from the sandhills- Judgment is required in determining which equa- type basins. Consequently, the lower Niobrara tions should be used in a particular instance.

PEAK-FLOW FREQUENCY RELATIONS 21 Table 2. Peak-flow equations for the High-Permeability Region [AEYR, average equivalent years of record; AME, average model error; ASE, average sampling error; AWC, available water capacity of 60–inch soil profile, in inches per inch; BS, basin slope, in feet per mile; CDA, contributing drainage area, in square miles; DF, drainage frequency, in first-order streams per square mile; MAP, mean annual precipitation, in inches; MCS, main-channel slope, in feet per mile; Q, peak discharge, in cubic feet per second, for a given recurrence interval, in years; SEE, standard error of estimate; SEP, standard error of prediction]

ASE AME SEP SEE SEE Estimation equation (based on variables in (per- AEYR log10 units) cent) (years)

Standard analysis

(49 stations with 25 or more years of record)

0.750 0.548 0.933 () 0.003 0.030 0.183 0.174 41.8 3.6 Q2 = 0.0662CDA MAP – 15 BS 0.777 0.525 0.653 () .004 .030 .182 .172 41.2 7.0 Q5 = 0.408CDA MAP – 15 BS 0.736 0.527 0.539 0.835 () .005 .031 .189 .176 42.2 9.7 Q10 = 8.76CDA MAP – 15 BS AWC 0.773 0.695 1.17 0.546 0.318 () .007 .033 .200 .181 43.5 13.2 Q25 = 14.8CDA MAP – 15 AWC MCS BS 0.779 0.756 1.35 0.766 () .007 .036 .208 .189 45.8 15.9 Q50 = 73.2CDA MAP – 15 AWC MCS 0.777 0.787 1.56 0.860 () .008 .038 .214 .195 47.2 18.7 Q100 = 119CDA MAP – 15 AWC MCS 0.774 0.816 1.74 0.942 () .009 .041 .224 .203 49.3 20.8 Q200 = 184CDA MAP – 15 AWC MCS 0.769 0.850 1.94 1.04 () .011 .047 .240 .217 53.1 22.7 Q500 = 313CDA MAP – 15 AWC MCS

Composite analysis

(23 stations with 20 or more years of record)

0.684 0.968 0.715 0.456 () .006 .022 .167 .149 35.4 3.3 Q2 = 0.127CDA BS MAP – 15 DF 0.774 0.590 0.576 0.454 () .008 .031 .196 .175 42.0 5.2 Q5 = 1.09CDA MAP – 15 BS DF 0.744 0.626 0.602 0.399 1.17 () .011 .033 .211 .182 43.9 7.1 Q10 = 21.8CDA MAP – 15 BS DF AWC 0.805 0.718 0.637 1.40 0.773 () .014 .038 .229 .195 47.2 9.2 Q25 = 159CDA MAP – 15 DF AWC MCS 0.817 0.730 0.637 1.76 0.864 () .016 .040 .238 .201 48.8 11.3 Q50 = 368CDA MAP – 15 DF AWC MCS 0.828 0.741 2.07 0.641 0.941 () .019 .044 .251 .210 51.4 13.0 Q100 = 776CDA MAP – 15 AWC DF MCS 0.838 2.35 0.752 0.645 1.01 , () .022 .050 .267 .223 55.0 14.1 Q200 = 1 520CDA AWC MAP – 15 DF MCS 0.851 2.67 0.767 0.654 1.09 , () .026 .060 .293 .244 61.0 15.0 Q500 = 3 390CDA AWC MAP – 15 DF MCS

APPLICABLE RANGES OF VARIABLES: Standard-analysis equations—CDA 8.6–6,230; MAP 15.12–26.09; AWC 0.07–0.17; MCS 4.41–28.22; BS 41.0–286 Composite-analysis equations—CDA 8.6–1,310; BS 55.7–249; MAP 16.39–26.09; DF 0.05–0.60; AWC 0.08–0.15; MCS 5.6–19.4

NOTE: BS, MCS, and DF are data-scale dependent.

22 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska Northern and Western Region stations with P60 greater than 4 in/hr were used if the ratio of CDA to TDA was at least 50 percent. This region was developed from stations in eastern Wyoming, southern South Dakota, and Equations for the Northern and Western northern and western Nebraska and includes the Region (table 3) are based on data from 34 stations Cheyenne, White, and Niobrara River Basins with at least 15 years of record and TDAs of 0.6 to except as noted (figs. 1 and 8). The region is 2,160 mi2. CDA and MAP are significant explana- roughly coincident with Beckman's Region 1 tory variables at all frequencies. Relative relief (RR) (1976, p. 10-11), but excludes (1) the Niobrara and average permeability of the least permeable River mainstem, (2) the Platte River Basin down- layer (PLP) are significant for the Q2 through Q50 stream of where the sandhills near the Platte River equations, and BS is a significant explanatory vari- end along the left bank of the Platte and down- able for the Q100 through Q500 equations. SEEs for stream of Plum Creek on the right bank, and (3 the all equations, except for Q2, are lower than Republican River Basin. There is some overlap Beckman's Region 1 equations (1976, p. 60), espe- with the High-Permeability Region, because cially at the larger frequencies.

Table 3. Peak-flow equations for the Northern and Western Region [AEYR, average equivalent years of record; AME, average model error; ASE, average sampling error; BS, basin slope, in feet per mile; CDA, contributing drainage area, in square miles; MAP, mean annual precipitation, in inches; PLP, permeability of least permeable layer, in inches per hour; Q, peak discharge, in cubic feet per second, for a given recurrence interval, in years; RR, relative relief, in feet per mile; SEE, standard error of estimate; SEP, standard error of prediction]

ASE AME SEP SEE SEE (based on variables in (per- AEYR Estimation equation log10 units) cent) (years)

(34 stations with 15 or more years of record)

0.762 0.878 0.929 –0.357 () 0.032 0.180 0.460 0.424 126 1.7 Q2 = 0.176CDA RR MAP – 12 PLP 0.642 0.932 1.05 –0.360 () .014 .061 .275 .247 61.8 6.0 Q5 = 0.686CDA RR MAP – 12 PLP 0.577 1.08 0.892 –0.337 () .014 .049 .251 .222 54.5 9.5 Q10 = 1.69CDA MAP – 12 RR PLP 0.508 1.07 0.802 –0.302 () .016 .050 .257 .224 55.2 12.4 Q25 = 5.06CDA MAP – 12 RR PLP 0.464 1.06 0.731 –0.272 () .018 .056 .271 .236 58.5 13.5 Q50 = 10.7CDA MAP – 12 RR PLP 0.213 0.589 0.643 () .018 .064 .288 .254 63.8 14.0 Q100 = 35.2CDA BS MAP – 12 0.192 0.629 0.711 () .020 .067 .295 .259 65.3 15.3 Q200 = 37.4CDA BS MAP – 12 0.168 0.669 0.786 () .023 .075 .313 .274 70.0 16.1 Q500 = 41.6CDA BS MAP – 12

APPLICABLE RANGES OF VARIABLES: CDA 0.61–2,160; RR 4.2–48.3; MAP 14.19-24.69; PLP 0.10-5.00; BS 52.5–462

NOTE: BS and RR are data-scale dependent.

PEAK-FLOW FREQUENCY RELATIONS 23 Northeastern Region Elkhorn and Cedar Rivers and Beaver Creek. The left bank Loup River tributary basins also overlap This region covers most of the northeastern with the low-permeability Central and South- part of Nebraska. It includes (1) the right bank Central Region discussed next. Missouri River tributary basins downstream of the Niobrara River and upstream of the Platte Equations for the Northeastern Region River, (2) the left bank Platte River tributary (table 4) are based on data from 40 stations with basins downstream of the Loup River, and (3) the at least 15 years of record and TDAs of 1.5 to left bank Loup River tributary basins downstream 6,950 mi2. TDA, shape factor (SF), and DF are of the North Loup River (figs. 1 and 8). It significant explanatory variables for all of the includes all of Beckman's Region 3 (1976, p. 10– Northeastern Region equations. PLP is the 11) north of the Platte River plus some other areas second most significant variable for the Q2 and farther west. Unlike Beckman’s Region 3, but Q5 equations, but it becomes less significant at similar to the Northern and Western Region, there larger frequencies and is not significant for the is some overlap of the Northeastern Region with Q200 and Q500 equations. SEEs for all equations the High-Permeability Region (P60 greater than are lower than Beckman's Region 3 equations 4 in/hr), most notably the entire basins of the (1976, p. 60).

Table 4. Peak-flow equations for the Northeastern Region [AEYR, average equivalent years of record; AME, average model error; ASE, average sampling error; DF, drainage frequency, in first-order streams per square mile; PLP, permeabilitiy of the least permeable layer, in inches per hour; Q, peak discharge, in cubic feet per second, for a given recurrence interval, in years; SEE, standard error of estimate; SEP, standard error of prediction; SF, shape factor, dimensionless; TDA, total drainage area, in square miles]

ASE AME SEP SEE SEE (based on variables (per- AEYR cent) Estimation equation in log10 units) (years)

(40 stations with 15 or more years of record)

0.676 –0.592 –0.335 0.295 0.007 0.037 0.209 0.191 46.2 4.4 Q2 = 132TDA PLP SF DF 0.652 –0.514 –0.421 0.323 .006 .023 .170 .153 36.3 8.6 Q5 = 395TDA PLP SF DF 0.633 –0.469 –0.443 0.338 .006 .022 .167 .147 34.9 11.9 Q10 = 715TDA SF PLP DF 0.612 –0.518 0.356 –0.352 , .007 .023 .173 .151 35.8 15.2 Q25 = 1360TDA SF DF PLP 0.597 –0.548 0.370 –0.286 , .008 .025 .182 .157 37.5 16.9 Q50 = 2070TDA SF DF PLP 0.583 –0.573 0.384 –0.223 , .010 .028 .192 .166 39.6 17.9 Q100 = 3000TDA SF DF PLP 0.562 –0.667 0.452 , .009 .031 .201 .176 42.3 19.0 Q200 = 5240TDA SF DF 0.551 –0.655 0.440 , .011 .034 .213 .185 44.7 20.1 Q500 = 7030TDA SF DF

APPLICABLE RANGES OF VARIABLES: TDA 1.50–6,950; PLP 0.38–5.56; SF 0.49–56.4; DF 0.01–1.33

NOTE: DF is data-scale dependent.

24 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska Central and South-Central Region presumed to include right bank Platte River tribu- This region consists of low-permeability (P60 tary basins, for which there are no stations, down- less than 4 in/hr) basins, generally south and east stream of Plum Creek, to the Loup River. Spring of the central sandhills, that are tributaries within Creek, a left-bank Loup River tributary, overlaps the middle Platte, Loup, and middle Republican with the Northeastern Region. River Basins (figs. 1 and 8). It includes (1) left Equations for the Central and South-Central bank Platte River tributary basins downstream of Region (table 5) are based on data from 37 where the sandhills end along the left bank of the stations with at least 15 years of record and with Platte River to just downstream of the Loup River TDAs of 1.5 to 711 mi2. Explanatory variables are but excluding the left-bank Loup River tributary the same for all equations, and include TDA, RR, basins downstream of Spring Creek (shortly 2–year, 24–hour precipitation (TTP), and SF. For below the confluences of the Middle and North the Q and Q equations, TTP is the second most Loup Rivers)—Beckman's Region 4 (1976, 2 5 significant variable, but for equations Q10 and p. 10–11), and (2) Republican River tributary larger, RR is more significant. SEEs are lower basins in Nebraska downstream of Harlan County than Beckman's Region 1 equations (1976, p. 60), Dam—part of Beckman's Region 1 (1976, p. 10– and lower than Beckman’s Region 4 equations 11). The Central and South-Central Region is (1976, p. 60) for equations Q25 and larger.

Table 5. Peak-flow equations for the Central and South-Central Region [AEYR, average equivalent years of record; AME, average model error; ASE, average sampling error; Q, peak discharge, in cubic feet per second, for a given recurrence interval, in years; RR, relative relief, in feet per mile; SEE, standard error of estimate; SEP, standard error of prediction; SF, shape factor, dimensionless; TDA, total drainage area, in square miles; TTP, 2–year, 24–hour precipitation, in inches]

ASE AME SEP SEE SEE (based on variables (per- AEYR Estimation equation in log10 units) cent) (years)

(37 stations with 15 or more years of record) 0.994 4.24 –0.738 1.00 () 0.016 0.072 0.297 0.269 68.3 4.1 Q2 = 54.8TDA TTP – 2 SF RR 0.942 3.98 1.32 –0.647 () .011 .038 .222 .196 47.4 8.2 Q5 = 73.4TDA TTP – 2 RR SF 0.931 1.51 3.92 –0.614 ()() .012 .035 .216 .187 45.1 11.0 Q10 = 80.8TDA RR TTP – 2 SF 0.923 1.71 3.88 –0.587 () .014 .039 .230 .198 47.9 13.0 Q25 = 89.4TDA RR TTP – 2 SF 0.918 1.83 3.84 –0.572 () .016 .045 .247 .212 51.8 13.5 Q50 = 96.4TDA RR TTP – 2 SF 0.914 1.93 3.83 –0.560 () .019 .052 .263 .228 56.4 13.6 Q100 = 104TDA RR TTP – 2 SF 0.910 2.02 3.81 –0.549 () .021 .060 .285 .245 61.3 13.5 Q200 = 111TDA RR TTP – 2 SF 0.906 2.12 3.80 –0.538 () .025 .072 .310 .268 68.0 13.2 Q500 = 121TDA RR TTP – 2 SF APPLICABLE RANGES OF VARIABLES: TDA 1.50–711; TTP 2.35–2.55; SF 0.89–13.0; RR 2.72–21.4

NOTE: RR is data-scale dependent.

PEAK-FLOW FREQUENCY RELATIONS 25 Eastern Region Equations for the Eastern Region (table 6) are based on data from 42 stations with at least This region consists of Missouri River trib- 10 years of record and TDAs of 1.6 to 1,640 mi2. utary basins from and including Omaha Creek The explanatory variables of CDA, BS and, PLP (several miles below the mouth of the Big Sioux are consistent for all equations. SEEs are lower River) to the Nebraska-Kansas state line, but only than Beckman's Region 3 equations (1976, p. 60), includes Platte River tributary basins down- especially at the larger frequencies. Five stations stream of Hydrologic Unit 10200103 (U.S. with TDAs less than 5 mi2 were used to develop Geological Survey, 1976)(which extends several the equations even though BS was a significant miles below the mouth of the Loup River) along explanatory variable; all values of BS for the five the right bank and downstream of the Elkhorn stations were relatively large (greater than River along the left bank (figs. 1 and 8). It is a 100 ft/mi) and appeared very reasonable sub-area of Beckman's Region 3 (1976, p. 10-11). compared to other stations in the region with The Eastern Region north of the Platte River larger TDAs. overlaps with the Northeastern Region.

Table 6. Peak-flow equations for the Eastern Region [AEYR, average equivalent years of record; AME, average model error; ASE, average sampling error; BS, basin slope, in feet per mile; CDA, contributing drainage area, in square miles; PLP, permeability of the least permeable layer, in inches per hour; Q, peak discharge, in cubic feet per second, for a given recurrence interval, in years; SEE, standard error of estimate; SEP, standard error of prediction]

ASE AME SEP SEE SEE (based on variables (per- AEYR Estimation equation in log10 units) cent) (years)

(42 stations with 10 or more years of record) 0.558 0.655 –0.470 0.006 0.036 0.206 0.191 46.1 4.4 Q2 = 5.70CDA BS PLP 0.533 0.551 –0.528 .004 .016 .141 .126 29.7 10.9 Q5 = 21.1CDA BS PLP 0.519 0.495 –0.537 .004 .012 .125 .107 25.1 18.0 Q10 = 42.1CDA BS PLP 0.504 0.433 –0.520 .005 .011 .124 .104 24.3 24.5 Q25 = 90.2CDA BS PLP 0.494 0.390 –0.498 .005 .012 .131 .109 25.4 26.6 Q50 = 151CDA BS PLP 0.485 0.349 –0.474 .006 .013 .140 .116 27.2 27.3 Q100 = 242CDA BS PLP 0.476 0.310 –0.450 .007 .015 .150 .124 29.3 27.2 Q200 = 377CDA BS PLP 0.465 0.260 –0.417 .008 .019 .163 .136 32.2 26.6 Q500 = 650CDA BS PLP

APPLICABLE RANGES OF VARIABLES: CDA 1.55–1,640; BS 12.8–315; PLP 0.13–0.60

NOTE: BS is data-scale dependent.

26 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska Upper Republican River Region Equations for the Upper Republican River Region (table 7) are based on data from This region was developed from stations in 33 stations with at least 15 years of record and the Republican River Basin upstream of Harlan TDAs of 6.8 to 7,740 mi2. The explanatory vari- County Dam, and includes parts of southwestern ables CDA, MCS, and compactness ratio (CR) are Nebraska, northeastern Colorado, and north- included in all of the equations, with CR and MCS western Kansas (figs. 1 and 8). The South Fork of varying in significance after CDA. SEEs are the Republican River (below Bonny Dam in lower than Beckman's Region 1 and 2 equations Colorado) and the mainstem of the Republican (1976, p. 60), especially for Region 1. Stations River downstream of the South Fork are not with TDAs less than 5 mi2 were not used to included in this region because of regulation. develop the equations because MCS is a signifi- Because the upper Republican River Region cant explanatory variable (see previous discus- includes basins with P60 greater than 4 in/hr, it sion of “Regional Equations”). overlaps with the High-Permeability Region and contains parts of Beckman's Regions 1 and 2 (1976, p.10–11).

Table 7. Peak-flow equations for the Upper Republican River Region [AEYR, average equivalent years of record; AME, average model error; ASE, average sampling error; CDA, contributing drainage area, in square miles; CR, compactness ratio, dimensionless; MCS, main-channel slope, in feet per mile; Q, peak discharge, in cubic feet per second, for a given recurrence interval, in years; SEE, standard error of estimate; SEP, standard error of prediction]

ASE AME SEP SEE SEE (based on variables (per- AEYR Estimation equation in log10 units) cent) (years)

(33 stations with 15 or more years of record) 0.545 1.19 –0.735 0.008 0.045 0.229 0.211 51.6 5.0 Q2 = 1.97CDA MCS CR 0.570 –0.895 1.32 .008 .037 .210 .192 46.3 8.1 Q5 = 3.67CDA CR MCS 0.583 –0.937 1.39 .008 .038 .216 .196 47.5 10.3 Q10 = 4.93CDA CR MCS 0.597 1.46 –0.946 .010 .044 .233 .211 51.5 12.3 Q25 = 6.58CDA MCS CR 0.606 1.50 –0.931 .012 .050 .250 .224 55.3 13.3 Q50 = 7.84CDA MCS CR 0.613 1.54 –0.905 .014 .057 .266 .239 59.6 13.9 Q100 = 9.12CDA MCS CR 0.619 1.57 –0.868 .016 .065 .284 .255 64.2 14.2 Q200 = 10.4CDA MCS CR 0.626 1.61 –0.809 .018 .076 .307 .276 70.5 14.5 Q500 = 12.2CDA MCS CR

APPLICABLE RANGES OF VARIABLES: CDA 6.78–4,450; MCS 7.1–46.3; CR 1.22–11.2

NOTE: MCS and CR are data-scale dependent.

PEAK-FLOW FREQUENCY RELATIONS 27 Big Blue River Region range of values of the drainage-basin characteris- This region was developed from stations in tics used to develop the equations. The minimum the Big Blue River Basin, which includes parts of and maximum values of the characteristics used southeastern Nebraska and northeastern Kansas to develop the equations are listed in tables 2–8. (figs. 1 and 8). It is the same as Beckman's For the best compatibility with the equations, Region 5 (1976, p. 10–11). drainage-basin characteristics should be determined using the same scale and type of data used Equations for the Big Blue River Region in the development of the equations. The same (table 8) are based on data from 32 stations with method of quantification (GIS/Basinsoft) also at least 10 years of record and TDAs of 2.0 to should be used for the measurement of MCS and 4,450 mi2. The explanatory variables, TDA, BS. For equations that have different explanatory average maximum soil slope (MSS), and stream variables for the various frequencies, judgment density (SD) are significant for all equations. SF must be used, because predicted peak flows may is significant for all equations except Q , and TTP 2 not always increase for successively larger is significant only for Q and smaller. Except for 10 frequencies. One approach might be to compute the Q equation, SEEs are lower than Beckman's 2 estimated peak-flow values from the equations Region 5 equations (1976, p. 60), especially for for each recurrence interval and then plot the equations Q and larger. 25 results on probability paper. A smoothed curve then could be drawn through the points, perhaps Application of Equations giving more influence to points with lower SEEs. The applicability of each of the regional peak-flow frequency equations is limited to the

Table 8. Peak-flow equations for the Big Blue River Region [AEYR, average equivalent years of record; AME, average model error; ASE, average sampling error; MSS, average maximum soil slope, in percent; Q, peak discharge, in cubic feet per second, for a given recurrence interval, in years; SEE, standard error of estimate; SEP, standard error of prediction; SD, stream density, in miles per square mile; SF, shape factor, dimensionless; TDA, total drainage area, in square miles; TTP, 2–year, 24–hour precipitation, in inches]

ASE AME SEP SEE SEE (based on variables (per- AEYR Estimation equation in log10 units) cent) (years)

(32 stations with 10 or more years of record) 0.627 1.69 0.468 0.425 0.007 0.027 0.185 0.164 39.1 4.9 Q2 = 54.0TDA ()TTP – 2 SD MSS 0.580 0.492 0.533 1.05 –0.220 .004 .006 .103 .079 18.4 19.6 Q5 = 160TDA MSS SD ()TTP – 2 SF 0.546 0.534 –0.264 0.511 0.790 .004 .002 .075 .044 10.2 49.7 Q10 = 267TDA MSS SF SD ()TTP – 2 0.500 0.618 –0.360 0.631 .004 .002 .075 .041 9.5 69.2 Q25 = 463TDA MSS SF SD 0.491 0.638 –0.372 0.617 .005 .002 .081 .045 10.3 71.2 Q50 = 607TDA MSS SF SD 0.483 0.656 –0.382 0.601 .006 .003 .091 .052 12.1 67.2 Q100 = 764TDA MSS SF SD 0.477 0.672 –0.389 0.584 .006 .004 .101 .061 14.1 61.8 Q200 = 936TDA MSS SF SD 0.469 0.692 –0.396 0.557 .008 .005 .116 .074 17.2 55.0 Q500 = 1, 190TDA MSS SF SD

APPLICABLE RANGES OF VARIABLES: TDA 2.03–4,450; TTP 2.62–3.35; SD 0.14–1.39; MSS 1.9–14.5; SF 0.13–7.60

NOTE: SD is data-scale dependent.

28 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska Regulated Streams Patterson (1966, p. 410) noted that the peak flows at Agate are materially affected by diversions for Peak-flow frequency analyses for stations on irrigation; however, the ratios of irrigated acres to regulated streams in Nebraska with at least 10 years drainage area are nearly identical (8.0 to 10.4) for of regulated peak flows were done using program all three stations, with Agate actually having the PEAKFQ based on Bulletin 17B guidelines and the log-Pearson Type III (LP3) distribution with skew smallest ratio (Boohar and others, 1992, p. 55–57). coefficients derived only from each station’s peak- It is possible that the flow records for one or more flow data. All available peak-flow records within of the stations is not representative of their long- the period of current regulated condition were used term peak-flow characteristics, but the differences for these analyses; they are identified as “REG” are so large that some additional explanation seems under the type of analysis in table B2. For reaches warranted. One possible explanation, or contrib- of streams that include more than one station with uting factor, could be that the drainage basin at least 25 years of regulated record, approximate narrows and the channel gradient decreases from graphical relations of peak-flow frequency and the state line to Agate; this could result in signifi- distance upstream of the mouth also were devel- cant attenuation of flows. Because of the uncer- oped. These relations are very generalized. tainty, no estimated relations between peak-flow frequency and distance from the mouth were devel- Graphical peak-flow frequency relations oped for this reach of the Niobrara River. were developed for the Niobrara, North Platte, South Platte, Platte, and Republican Rivers, and for Two major dams are located in the Niobrara Salt, Antelope (not shown), Frenchman, and Red River Basin—Box Butte on the mainstem and Willow Creeks (fig. 1). Peak-flow frequency values Merritt on the Snake River (table 9). Except for Q2, for 58 stations were plotted against distance, in Box Butte Dam causes large reductions in the peak miles, as measured upstream from the mouth along flows downstream, especially as frequencies their respective streams. Only the 49 stations with increase (fig. 10). The effects of the dam appear to at least 25 years of regulated record were used to diminish within about 70 mi downstream of the develop approximate log-linear relations. The dam. Merritt Dam appears to have little effect on remaining stations, with less than 25 years of the Niobrara River peak flows, especially consid- record, were used only for reference. The periods of ering its small reduction in peak flows for the Snake the current regulated condition for each of these River itself (table B2). streams were identified and used to determine the period for which the peak-flow frequency analyses North Platte River would be computed for each station (table 9). Each The North Platte River originates in the of the nine regulated streams is discussed separately mountains of northern Colorado and flows through in the following sections, and the locations of the mountains and plains of Wyoming to its conflu- selected dams are shown on figures 1 and 9. ence with the South Platte River in western Nebraska. There are four major dams on the North Niobrara River Platte River—Seminoe, Pathfinder, and Glendo, in The Niobrara River originates in Wyoming, Wyoming, and Kingsley in Nebraska (table 9). flows through northern Nebraska, and drains as a Glendo was the last of these dams built on the right-bank tributary into the Missouri River in North Platte River, and it is the most downstream of northeastern Nebraska. Major tributaries to the the three Wyoming dams; therefore, its operational Niobrara include, in downstream order: Snake date of October 1957 was used as the beginning River, Minnechaduza Creek, and Keya Paha River. date of the current regulated condition of the North Values of Q5 through Q500 decrease measurably Platte River between Glendo and Kingsley Dams. from the station at the Wyoming state line to the The operational date of Kingsley Dam, February station at Agate and they increase from there to the 1941, was used as the beginning date for stations station above Box Butte Reservoir (fig. 10) even for downstream of Kingsley Dam because the large concurrent periods of record (data shown). storage capacity of Lake McConaughy would be

PEAK-FLOW FREQUENCY RELATIONS 29 Table 9. Summary of regulation data for selected stream reaches [Apr, April; Aug, August; Feb, February; Nov, November; Oct, October; Sept, September; POR, period of record]

Period of current regulated Stream name Stream reach condition Remarks1

Niobrara Wyoming state line to Box Butte Dam Entire POR Affected by irrigation during entire POR River Box Butte Dam to Snake River Oct 1945– Box Butte Dam (1,460 mi2, approximately; Oct 1945) (fig. 10) Snake River to mouth Feb 1964– Merrit Dam (640 mi2, approximately; Feb 1964)

North Platte Wyoming state line to Kingsley Dam Oct 1957– Affected by Seminoe (7,230 mi2, Apr 1939), Pathfinder River (10,711 mi2, Apr 1909), and Glendo (15,545 mi2, Oct 1957) (fig. 11) Dams in Wyoming Kingsley Dam to mouth Feb 1941– Kingsley Dam (29,300 mi2, approximately; Feb 1941)

South Platte South Platte River near Balzac, Colorado Entire POR Affected by transmountain and irrigation diversions, storage River to mouth reservoirs, power generation, and irrigation return flows (fig. 12) during entire POR; because of large amount of intervening drainage area, Chatfield Dam (3,018 mi2, May 1975) assumed not to increase regulation significantly

Platte River Confluence of North and South Platte Feb 1941– Effects of regulation much less below Loup River (fig. 13) Rivers to mouth

Salt Creek Hickman Branch to Cardwell Branch 1965– Olive Creek Lake (8.2 mi2, 1964), Bluestem Lake (16.6 mi2, (fig. 14) 1963), Wagon Train Lake (15.6 mi2, 1963), and Stagecoach Lake (9.2 mi2, 1964) Dams Cardwell Branch to Oak Creek 1966– Yankee Hill Lake (8.4 mi2, 1965), Conestoga Lake (15.1 mi2, 1964), Pawnee Lake (35.9 mi2, 1965), East and West Twin Lakes (11.0 mi2, 1965), and Holmes Lake (5.4 mi2, 1962) Dams Oak Creek to mouth 1968– Branched Oak Lake Dam (88.7 mi2, 1967)

Antelope Holmes Lake Dam to mouth 1962– Holmes Lake Dam (5.4 mi2, 1962) Creek (fig. 14)

Republican South Fork Republican River to Trenton July 1950– Bonny Dam (1,820 mi2, approximately; July 1950) River Dam (fig. 15) Trenton Dam to Frenchman Creek May 1953– Trenton Dam (8,620 mi2, approximately; May 1953) Frenchman Creek to Red Willow Creek May 1953– Enders Dam (950 mi2, approximately; Oct 1950) Red Willow Creek to Medicine Creek Sept 1961– Red Willow Dam (730 mi2, approximately; Sept 1961) Medicine Creek to Harlan County Dam Sept 1961– Medicine Creek Dam (880 mi2, approximately; Aug 1949) Harlan County Dam to Kansas state line Nov 1952– Harlan County Dam (20,750 mi2, approximately; Nov 1952)

Frenchman Colorado state line to Enders Dam Entire POR Affected by irrigation during entire POR Creek Enders Dam to mouth Oct 1950– Enders Dam (950 mi2, approximately; Oct 1950) (fig. 16)

Red Willow Above Red Willow Dam Entire POR Peak flows do not appear to be affected substantially by Creek irrigation development although natural streamflow is affected (fig. 16) Red Willow Dam to mouth Sept 1961– Red Willow Dam (730 mi2, approximately; Sept 1961)

1For dams, numbers in parentheses are drainage area and beginning date of operation.

30 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska Figure 9. Location of flood-control dams in the Salt Creek drainage basin and of streamflow-gaging stations along the mainstem of Salt Creek.

PEAK-FLOW FREQUENCY RELATIONS 31

(4655)

NR near Verdel near NR

Spencer (4650) Spencer NR near NR

50 Keya Paha River Paha Keya

ing station data Long Pine Creek Pine Long current for record of regulated condition current for record of regulated condition

Station with 10 to 24 years Station with 25 or more years

Plum Creek Plum 100

(4620)

NR near Norden near NR

(4615) NR near Sparks near NR

150

(Merritt Dam) (Merritt Snake River Snake

50-year peak flow 100-year peak flow 200-year peak flow 500-year peak flow

(4590) NR at Cody at NR 200 250

2-year peak flow peak 2-year flow peak 5-year 10-year peak flow 25-year peak flow

(4575)

NR near Gordon near NR Springs (4565) Springs

300 NR near Hay near NR

(4559)

NR near Dunlap near NR

(4555)

Butte Dam Butte NR below Box below NR

DISTANCE UPSTREAM FROM RIVER, IN OF UPSTREAM MOUTH NIOBRARA DISTANCE MILES (4545)

350

Butte Dam Butte NR above Box above NR

400 (4510)

NR at Agate at NR

line (4540) line

Nebraska state Nebraska 450 NR at Wyoming- at NR Peak-flow frequencies for the reach above Box Butte Dam are not shown because of uncertainty in estimating them.

Niobrara River Niobrara Peak-flow frequencies for the current regulated condition of the Niobrara River (NR) in Nebraska estimated from streamflow-gag from estimated Nebraska in (NR) River Niobrara of the condition regulated current the for frequencies Peak-flow 500 70 50 40 700 500 400 300 200 100

7,000 5,000 4,000 3,000 2,000 1,000

50,000 40,000 30,000 20,000 10,000 70,000 DISCHARGE, IN CUBIC FEET PER SECOND PER FEET CUBIC IN DISCHARGE, (number following station name is map number referred in tables B1 and B2). and B1 tables in referred number map is name station following (number Figure 10. Figure

32 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska expected to mask the effects of the operation of above and below the Elkhorn River (also a discon- Glendo Dam that began in 1957. Peak-flow tinuity on fig. 13) were extrapolated from the frequency relations for the North Platte River values for the Platte River at North Bend (7960) downstream of the Wyoming-Nebraska state line based on respective estimated drainage areas. The are fairly uniform, with a noticeable reduction in effect of Salt Creek could not be determined reli- peak flows downstream of Kingsley Dam (fig. 11). ably. Although Kingsley Dam appears to have little effect on the peak-flow frequency values of the South Platte River Platte River below the Loup River, for consistency, The South Platte River originates in the none of the Platte River stations were analyzed for mountains of central Colorado and flows across the periods prior to the Kingsley Dam operational date plains to its confluence with the North Platte River of February 1941. in western Nebraska. Regulation of the South Platte River began prior to collection of streamflow Salt and Antelope Creeks records. Reservoir storage created by dams in the Salt Creek originates in southeastern South Platte River Basin is less than in the North Nebraska and flows north and northeast through Platte River Basin (Eschner and others, 1983, page Lincoln before draining into the Platte River in A6). Chatfield, the largest dam in the South Platte northwestern Cass County (fig. 9). The upper basin River Basin, began operation in May 1975. Because is fan shaped with a number of tributaries Chatfield Dam is located near the upstream end of converging with the main stream in or near Lincoln, the basin and controls less than 13 percent of the including Antelope Creek (not shown), which drainage area upstream of Nebraska, it was flows northwest through the middle of Lincoln. assumed that its affect on peak flows in Nebraska After two large floods in the early 1950s, a series of was minimal. Therefore, the entire periods of flood-control dams were constructed on several record were used for South Platte River stations. streams around Lincoln (table 9). Peak-flow Peak-flow frequency relations decrease in the frequency analyses for periods since regulation downstream direction, generally with only small began were computed for three stations on Salt increases for several frequencies from South Platte River at Paxton (7650) to South Platte River at Creek and for three stations on Antelope Creek North Platte (7655) (fig. 12). (fig. 14). Olive Creek, Bluestem Lake, Wagon Train Lake, and Stagecoach Lake Dams are located Platte River upstream of Salt Creek at Roca (8030). Yankee Hill Lake, Conestoga Lake, Pawnee Lake, East and The Platte River begins at the confluence of West Twin Lakes, Holmes Lake, and Branched Oak the North and South Platte Rivers in western Nebraska and drains into the Missouri River as a Lake Dams are located downstream of Roca and right-bank tributary in eastern Nebraska. In addi- upstream of Salt Creek at Lincoln (8035). Holmes tion to the mainstem Platte River stations, peak- Lake Dam is located upstream of the three Ante- flow frequency values were computed for Wood lope Creek stations (not shown). The peak-flow River near Alda (7720), Loup River at Columbus frequency relations for both Salt and Antelope (7945), Elkhorn River at Waterloo (8005), and Salt Creeks increase in the downstream direction with Creek at Ashland (8050) to estimate each tributary's the exception of Q500 on the upper reach of Ante- effect on Platte River peak flows. Wood River peak lope Creek, which decreases slightly (fig. 14). flows were relatively small, but the peak flows for Republican River the Loup River were larger than those estimated graphically for the Platte River just upstream of the The Republican River Basin is in parts of mouth of the Loup River. Therefore, the peak-flow three states—Colorado, Nebraska, and Kansas. The values for the Loup River are used for the Platte Republican River begins at the confluence of the River mainstem at their junction; this results in a North Fork Republican and the Arikaree Rivers, discontinuity in the plots at that point (fig. 13). The both of which originate in Colorado. It then flows peak-flow frequency values for the Platte River through southern Nebraska, and joins the Smoky

PEAK-FLOW FREQUENCY RELATIONS 33

0 (6930) NPR at North Platte North at NPR 10

20 (6910) NPR near Sutherland near NPR 30 gaging station data station gaging - of record for current regulated condition 40

200-year peak flow 500-year peak flow Station with 25 or more years

(6905) 50

NPR near Keystone near NPR Kingsley Dam Kingsley 60 Lake 70 McConoughy

25-year peak flow 50-year peak flow 100-year peak flow NPR at Lewellen (6875) Lewellen at NPR 80 90

100 NPR at Lisco (6860) Lisco at NPR 110 2-year peak flow peak 2-year flow peak 5-year flow peak 10-year 120

130 NPR at Bridgeport (6845) Bridgeport at NPR 140 DISTANCE UPSTREAM FROM MOUTH FROM MOUTH RIVER, IN MILES NORTH PLATTE OF UPSTREAM DISTANCE 150

160

(6820) NPR near Minatare near NPR 170

180 NPR at Mitchell (6795) Mitchell at NPR

190 (6745) 200

North Platte River River Platte North Wyoming state line state Wyoming NPR at Nebraska- at NPR Peak-flow frequencies for the current regulated condition of the North Platte River (NPR) in Nebraska estimated from streamflow from estimated Nebraska in (NPR) River Platte North of the condition regulated current the for frequencies Peak-flow

210 700 500 400 300 200 100 7,000 5,000 4,000 3,000 2,000 1,000

70,000 50,000 40,000 30,000 20,000 10,000

100,000 DISCHARGE, IN CUBIC FEET PER SECOND PER FEET CUBIC IN DISCHARGE, Figure 11. Figure B2). and B1 tables in referred number map is name station following (number

34 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska

(7655) SPR at North Platte North at SPR 10 20 30

imated from streamflow-gaging streamflow-gaging from imated SPR at Paxton (7650) Paxton at SPR 40

50 SPR at Roscoe (7648a) Roscoe at SPR 60 70

80 State line State

Colorado (7640) Colorado

SPR at Julesberg, at SPR Lodgepole Creek Lodgepole 100 110 of record for current regulated condition of record for current regulated condition 120 Station with 10 to 24 years Station with 25 or more years 130 140 DISTANCE UPSTREAM FROM OF MOUTH UPSTREAM SOUTH RIVER,DISTANCE IN PLATTE MILES 150 50-year peak flow 100-year peak flow 200-year peak flow 500-year peak flow

160

Colorado (7600) Colorado SPR at Balzac, at SPR 170 180 2-year peak flow peak 2-year flow peak 5-year flow peak 10-year flow peak 25-year 190 200 South Platte River Platte South 210 Peak-flow frequencies for the current regulated condition of the South Platte River (SPR) in Nebraska and part of Colorado est of Colorado and part in Nebraska (SPR) River South Platte of the condition regulated the current for frequencies Peak-flow 700 500 400 7,000 5,000 4,000 3,000 2,000 1,000

70,000 50,000 40,000 30,000 20,000 10,000

200,000 100,000 300,000 DISCHARGE, IN CUBIC FEET PER SECOND PER FEET CUBIC IN DISCHARGE, station data (number following station name is map number referred in tables B1 and B2). B1 and in tables referred number map is name station following (number data station Figure 12. Figure

PEAK-FLOW FREQUENCY RELATIONS 35

(8055)

PR at Louisville at PR Salt Creek Salt

20 (8010)

PR near Ashland near PR Elkhorn River Elkhorn 40 g station data station g of record for current regulated condition of record for current regulated condition 60

Station with 10 to 24 years Station with 25 or more years

(7960) PR at North Bend North at PR

Loup River Loup

100

(7740) PR near Duncan near PR EXPLANATION 50-year peak flow 100-year peak flow 200-year peak flow 500-year peak flow 120

140 Wood River Wood

160 Island (7705) Island PR near Grand near PR 2-year peak flow peak 2-year flow peak 5-year flow peak 10-year flow peak 25-year 180

200

(7702)

PR at Kearney at PR

(7700) MILES IN RIVER, OF PLATTE MOUTH FROM UPSTREAM DISTANCE

220 PR near Odessa near PR

(7680) PR near Overton near PR

240

(7670)

PR near Lexington near PR

(7665) 260 PR near Cozad near PR

280 PR at Brady (7660) Brady at PR 300

Platte River Platte 320 700 500 Peak-flow frequencies for the current regulated condition of the Platte River (PR) in Nebraska estimated from streamflow-gagin from estimated Nebraska in (PR) River Platte the of condition regulated current for the frequencies Peak-flow 7,000 5,000 4,000 3,000 2,000 1,000

70,000 50,000 40,000 30,000 20,000 10,000

400,000 300,000 200,000 100,000 500,000 DISCHARGE, IN CUBIC FEET PER SECOND PER FEET CUBIC IN DISCHARGE, Figure 13. Figure (number following station name is map number referred in tables B1 and B2). B2). B1 and tables in referred number map is name station following (number

36 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska P

Lincoln (8034) Lincoln AC at (17th Street) (17th at AC

Lincoln (8033) Lincoln 2 AC at 27th Street 27th at AC

3 Lincoln (8032) Lincoln

4 AC at 48th Street 48th at AC ers Counties of Nebraska Nebraska of Counties ers

Antelope Creek Antelope Holmes Lake Dam Lake Holmes 60 700 500 400 300 200 100 7,000 5,000 4,000 3,000 2,000 1,000 30,000 20,000 10,000

DISTANCE, IN MILES, UPSTREAM OF MOUTH OF ANTELO OF MOUTH OF UPSTREAM IN MILES, DISTANCE,

(8050) SC near Ashland near SC of record for current regulated condition

Station with 25 or more years Wahoo Creek Wahoo 5 SC near Ashland data for period prior to regulation; shown for comparison only DISTANCE UPSTREAM FROM MOUTH, IN FROM MOUTH, MILES UPSTREAM DISTANCE

(8035f) SC at Greenwood at SC

15 Rock Creek Rock 200-year peak flow 500-year peak flow 20

25 (8035) EXPLANATION

30 SC at Lincoln at SC

50-year peak flow 100-year peak flow Oak Creek Oak Antelope Creek Antelope 35 40 DISTANCE, IN MILES, UPSTREAM OF IN MILES, UPSTREAM CREEK MOUTH OFDISTANCE, SALT 10-year peakflow 25-year peakflow 45

50 SC at Roca (8030) Roca at SC 55

Salt Creek 2-year peak flow peak 2-year flow peak 5-year 60 Peak-flow frequencies for the current regulated conditions of Salt (SC) and Antelope Creeks (AC) in Lancaster, Cass, and Saund and Cass, Lancaster, in (AC) Creeks Antelope and (SC) Salt of conditions regulated current the for frequencies Peak-flow 7,000 5,000 4,000 3,000 2,000 1,000

70,000 50,000 40,000 30,000 20,000 10,000

200,000 100,000 300,000 DISCHARGE, IN CUBIC FEET PER SECOND PER FEET CUBIC IN DISCHARGE, Figure 14. Figure estimated from streamflow-gaging station data (number following station name is map number referred in tables B1 and B2). and B1 tables in referred number map is name station following (number data station streamflow-gaging from estimated

PEAK-FLOW FREQUENCY RELATIONS 37 Hill River to form the Kansas River in north-central McCook (8370) (fig. 15). There are discontinuous Kansas. Two mainstem dams and five tributary dams increases in peak flows at the junction with Sappa have been constructed in the Republican River Basin Creek, especially at the larger frequencies. Else- upstream of the Nebraska-Kansas state line. The where, peak-flow frequency relations increase in the operational dates for Bonny, Trenton, Enders, Red downstream direction with the exception of Q500 and Willow, Medicine Creek, and Harlan County Dams Q200 between the stations at Guiderock (8530a) and and their effects on the period of current regulated near Hardy (8535), where they decrease slightly. condition were determined (table 9). Norton Dam is Frenchman Creek not listed because Prairie Dog Creek, on which it is located, flows directly into Harlan County Lake Frenchman Creek originates in northeastern below which the effects of Norton Dam are masked Colorado and drains as a left-bank tributary into the because of Harlan County Lake’s relatively large Republican River in southwestern Nebraska. Irriga- storage capacity. Analyses for eight mainstem tion has affected flows in Frenchman Creek since stations were used in estimating peak-flow frequency before streamflow gaging began and the entire relations for the Republican River (fig. 15). periods of record were used to compute peak-flow frequency analyses for stations above Enders Dam, The operational date of July 1950 for Bonny the only major dam on Frenchman Creek. The oper- Dam on the South Fork of the Republican River in ational date of October 1950 for Enders Dam was northeastern Colorado was used as the beginning date used for the beginning date of analyses for stations of the current regulated condition for the South Fork downstream of the dam. In addition to the Frenchman below Bonny Dam and for the Republican River Creek stations (fig. 16), peak-flow frequency values mainstem between the mouth of the South Fork and were computed for Stinking Water Creek near Pali- Trenton Dam farther downstream. Considering the sade (8350) to estimate its effect on Frenchman amount of intervening drainage area, the effect of Creek values. Bonny Dam on most peak flows into Nebraska is Enders Dam causes reductions in peak flows probably not very significant. However, it could have for Q through Q , with increasingly larger reduc- had a significant effect, had it existed, on the very 10 500 tions for the larger frequencies (fig. 16). Peak flows large flood of 1935 because much of the flow for that increase in the downstream direction below the dam, flood originated in the upper part of the basin. See the except for Q between the junction with Stinking maximum peak flows for South Fork Republican 2 Water Creek and Frenchman Creek at Culbertson River near Idalia, Colorado (8250) and Republican (8355), which decreases slightly. River at Max (8280) in table B2. Red Willow Creek The peak-flow frequency values for the Repub- lican River above Trenton Dam were extrapolated Red Willow Creek originates in southwestern from those for Republican River at Stratton (8285) Nebraska and flows to the southeast before draining based on respective drainage areas. Peak-flow values as a left-bank tributary into the Republican River. for the Republican River below Sappa Creek were Red Willow Dam is the only major dam on the creek. based on the larger of those computed for Sappa Its operational date of September 1961 was used as Creek near Stamford (8475) and those for Republican the beginning date for peak-flow frequency analyses River near Orleans (8445) extrapolated for the of the two stations located downstream of the dam increased drainage area from Sappa Creek. The peak- (fig. 16). For comparison, the peak-flow frequency flow values for the Republican River above Harlan values for an unregulated station, Red Willow Creek County Dam were extrapolated from the values above Hugh Butler Lake (8373) located upstream of below Sappa Creek, previously described, based on the dam, also are included on figure 16. drainage areas. Trenton and Harlan County Dams cause large reductions in Republican River peak flows, and Enders Dam on Frenchman Creek probably contributes to the decreases in Q200 and Q500 between the Republican River stations at Trenton (8295) and at

38 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska 100

120

itself is in Kansas) in is itself

(8535) (gage (8535) RR near Hardy near RR streamflow-gaging from

140 d State line State 160 of record for current regulated condition Peak-flow data for RR nearPeak-flow Hardy appears to be a mixed population requiring composite frequency analysis (see fig. 5)

200-year peak flow 500-year peak flow Station with 25 or more years

(8530a) RR at Guide Rock Guide at RR

180 Thompson Creek Thompson 200 EXPLANATION

220

25-year peak flow 50-year peak flow 100-year peak flow County Dam (8495) Dam County

RR below Harlan below RR Harlan County Dam County Harlan

240

Sappa Creek Sappa (8445)

260 RR near Orleans near RR 2-year peak flow peak 2-year flow peak 5-year flow peak 10-year

280 Muddy Creek Muddy

300

(8435)

RR at Cambridge at RR Medicine Creek Medicine 320

DISTANCE RIVER, FROM OF MOUTH INUPSTREAM DISTANCE REPUBLICAN MILES

Red Willow Creek Willow Red

(8370)

340

RR at McCook at RR

Driftwood Creek Driftwood Frenchman Creek Frenchman

360

RR at Trenton (8295) Trenton at RR Trenton Dam Trenton

380 RR at Stratton (8285) Stratton at RR

400 South Fork RR Fork South

Republican River Republican 420 Peak-flow frequencies for the current regulated condition of the Republican River (RR) in Nebraska and part of Kansas estimate Kansas of part and Nebraska in (RR) River Republican the of condition regulated current the for frequencies Peak-flow 700 500 400 300 200 100 7,000 5,000 4,000 3,000 2,000 1,000

70,000 50,000 40,000 30,000 20,000 10,000

100,000 DISCHAGE, IN CUBIC FEET PER SECOND PER FEET CUBIC IN DISCHAGE, Figure 15. Figure B2). B1 and tables in referred number map is name station following (number data

PEAK-FLOW FREQUENCY RELATIONS 39 K

Willow (8380) Willow RWC near Red near RWC 5 10 from streamflow-gaging streamflow-gaging from years of record for current regulated condition

Station with 25 or more 15

(8375)

RWC near McCook near RWC RWC Dam RWC 20

Butler Lake (8373) Lake Butler RWC above Hugh above RWC Creek Willow Red RWC above HughRWC above Butler Lake not considered regulated; shown for comparison only years of record for current regulated condition 30 0 Station with 10 to 24 DISTANCE, IN MILES, UPSTREAM OF OF MOUTH IN MILES, UPSTREAM RED WILLOWDISTANCE, CREE 700 500 400 300 200 100 7,000 5,000 4,000 3,000 2,000 1,000 30,000 20,000 10,000

(8355) FC at Culbertson at FC 10 DISTANCE UPSTREAM OF UPSTREAM MOUTH, IN MILESDISTANCE

200-year peak flow 500-year peak flow 20

Stinking Water Creek Water Stinking

(8340) FC at Palisade at FC 30 EXPLANATION 40 50-year peak flow 100-year peak flow 50

(8325) 70

FC near Enders near FC

Enders Dam Enders flow peak 10-year flow peak 25-year (8315) 80

DISTANCE, IN MILES, UPSTREAM OF MOUTH OF FRENCHMAN CREEK FRENCHMAN OF MOUTH OF UPSTREAM MILES, IN DISTANCE, FC nr Imperial nr FC

Sand Creek Sand Creek Frenchman (8310) FC below Champion below FC Peak-flow frequencies for the current regulated conditions of Frenchman (FC) and Red Willow (RWC) Creeks in Nebraska estimated Nebraska in Creeks (RWC) Willow Red and (FC) Frenchman of conditions regulated current the for frequencies Peak-flow 100 2-year peak flow 5-year peak flow 700 500 400 300 200 100

7,000 5,000 4,000 3,000 2,000 1,000

20,000 10,000 30,000 PEAK DISCHARGE, IN CUBIC FEET PER SECOND PER FEET CUBIC IN DISCHARGE, PEAK Figure 16. Figure station data (number following station name is map number referred in tables B1 and B2). B2). and B1 tables in referred number map is name station following (number data station

40 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska Red Willow Dam causes large reductions in of any “new” stations could be analyzed, their lati- peak flows compared to the unregulated flows tude and longitude needed to be known or deter- upstream. In the downstream direction below the mined along with values of the explanatory dam, peak flows increase. variables that had been used in the development of the equation being evaluated. With the exception of NETWORK EVALUATION the Eastern and Big Blue River Regions, stations For each peak-flow frequency region, statis- with 10 to 14 years of record were not used in the tical analyses were done to estimate how additional development of regional peak-flow frequency years of peak-flow data might affect the average equations (tables 2–8). However, because basin sampling errors (ASEs) of the newly developed characteristics already had been determined for 100-year frequency (recurrence interval) equations. most stations with 10 to 14 years of record, they Four different scenarios were evaluated—10- and were used as the “new” stations for the network 20-year periods of additional data collection (plan- analyses. The special nature of the composite equa- ning horizons) with “equation” stations (those tions prevented their evaluation by the network stations used in the development of the equations) analysis program for any of the “new” station and 10- and 20-year planning horizons with “equa- scenarios. tion” stations plus with new stations. Output for the various scenarios for each region can be compared Analyses and Output to determine where the largest reduction in ASE of the newly developed peak-flow frequency equa- To do the network analyses, output from the tions could be gained for the least amount of new GLS (regression) part of the GLSNET program that data collection, and hence for the least cost. had been used to compute a particular peak-flow frequency equation was input to the NET program Station Selection of GLSNET. The stations used in the development of the equation were flagged as either active or Three types of stations were identified and inactive. The NET program then was run for each used for the network analyses of a particular of the planning horizons being considered (10 and regional equation: active, inactive, and new. Active 20 years). For the other two scenarios, data for any stations were “equation” stations that were still “new” stations within the region were input, and the being operated as of 1994. For analytical purposes, program was run again for the two planning hori- it was assumed that they would continue to be oper- zons. ated for the planning horizons with existing base- For each scenario, the expected ASE of the network funds. Inactive stations were “equation” equation was computed first by NET assuming that stations that had been discontinued by 1994; it was all available stations had been operated for the assumed that they would be operated for the plan- given planning horizon. Then the discretionary ning horizons but only with new discretionary station that would cause the ASE to increase the funds. “New” stations could be completely new least if it were not operated for the planning horizon stations with no peak-flow record available or they was identified and removed from the data set, and could be stations with some record but not enough the ASE was recomputed. This process was to have been used in the development of the equa- repeated internally within NET until only the active tions. In either case, it was assumed they would be stations remained. For each scenario, the output operated for the planning horizons but only with from the NET analysis was used to produce a plot new discretionary funds. of the number of stations in relation to the ASE (figs. 17 and 18). The analyses that include “new” The future operation of “new” stations would stations are unique for those sets of stations; a not only provide additional peak-flow data for different set of “new” stations would produce updating the regional equations, but potentially different results. Therefore, those analyses should could increase the range of the explanatory vari- be considered only examples of, not accurate deter- ables in the regional equation, thereby broadening minations of, how “new” stations would affect the the applicability of the equations. Before the effects ASEs.

NETWORK EVALUATION 41 0.020 0.020

Average sampling error High Permeability---Standard for equation = 0.0187 Regional Equation

0.015 0.015

0.010 0.010 High Permeability---Composite Regional Equation Average sampling error for equation = 0.0081

0.005 0.005 UNITS 10 AVG SAMPLING ERROR 10 YEARS---WITHOUT NEW STATIONS 10 YEARS---WITHOUT ERROR SAMPLING AVG NEW STATIONS 10 YEARS---WITHOUT ERROR SAMPLING AVG Stations used to develop equation---49 Stations used to develop equation---23 Active---31 Active---13 Inactive---18 Inactive---10 New stations---5 New stations---None 0 0 0550 5 10 15 20 25 30 35 40 45 50 0550 5 10 15 20 25 30 35 40 45 50 0.020 0.020 NUMBER OF STATIONS NUMBER OF STATIONS Average sampling error for equation = 0.0185 Northeastern Regional Equation

0.015 0.015 AVERAGE SAMPLING ERROR, IN LOG IN ERROR, SAMPLING AVERAGE

0.010 0.010 Average sampling error for equation = 0.0095

Northern and Western Regional Equation 0.005 0.005

Stations used to develop equation---34 Stations used to develop equation---40 Active---11 Active---20 Inactive---23 Inactive---20 New stations---17 New stations---7 0 0 0550 5 10 15 20 25 30 35 40 45 50 0550 5 10 15 20 25 30 35 40 45 50 NUMBER OF STATIONS EXPLANATION 10 years---without new stations 20 years---without new stations 10 years---with new stations 20 years---with new stations

Figure 17. Results of network analyses for 10- and 20-year planning horizons for High-Permeability—Standard, High Permeability—Composite, Northern and Western, and Northeastern regional 100-year peak-flow-frequency equations. 42 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska 0.020 0.020

Average sampling error for equation = 0.0186 Eastern Regional Equation

0.015 0.015

0.010 0.010

Central and South-Central Average sampling error Regional Equation for equation = 0.0061 0.005 0.005 UNITS 10 Stations used to develop equation---37 Stations used to develop equation---42 Active---5 Active---10 Inactive---32 Inactive---32 New stations---7 New stations---5 0 0 0.020 0550 5 10 15 20 25 30 35 40 45 50 0.020 0550 5 10 15 20 25 30 35 40 45 50

Upper Republican River Big Blue River Regional Equation Regional Equation

0.015 0.015 AVERAGE SAMPLING ERROR, LOG ERROR, IN SAMPLING AVERAGE

Average sampling error for equation = 0.0137

0.010 0.010

Average sampling error 0.005 0.005 for equation = 0.0055

Stations used to develop equation---33 Stations used to develop equation---32 Active---12 Active---17 Inactive---21 Inactive---15 New stations---4 New stations---0 0 0 0550 5 10 15 20 25 30 35 40 45 50 0550 5 10 15 20 25 30 35 40 45 50 NUMBER OF STATIONS EXPLANATION 10 years---without new stations 20 years---without new stations 10 years---with new stations 20 years---with new stations

Figure 18. Results of network analyses for 10- and 20-year planning horizons for Central and South-Central, Eastern, Upper Republican River, and Big Blue River regional 100-year peak-flow-frequency equations. NETWORK EVALUATION 43 Discussion of Results tion, which had the largest ASE and the smallest number of stations of all the regional equations. For each of the plots (figs. 17 and 18), the point associated with the smallest number of stations repre- Based on the results, data from new stations, sents the ASE with only the active or base-network rather than more data from stations used to develop stations being operated for the various scenarios. The the regional peak-flow frequency equations, prob- second point represents the ASE with one discre- ably would most reduce the ASE of the equations. tionary station being operated, the one that most reduces the ASE for that scenario. The effect of that SUMMARY AND CONCLUSIONS station is actually the difference in ASE of the two Estimates of peak-flow magnitude and points. The points associated with the largest number frequency are required for the efficient design of of stations for each plot represent the ASEs with all structures that convey flood flows, such as bridges discretionary stations being operated for the various and culverts, or of structures that occupy floodways, scenarios. For scenarios with “new” stations, the first such as roads. In the fall of 1994, a cooperative study stations included after the base-network stations was begun by the Nebraska Department of Roads and were, in all cases, the “new” stations.The results illus- the U.S. Geological Survey (USGS) to update peak- trate that collecting data at “new” stations in a region flow frequency analyses for selected streamflow- probably would reduce the ASE for that region’s gaging stations, develop a new set of peak-flow peak-flow equations more than would collecting the frequency relations for ungaged streams, and eval- same amount of data at stations that are inactive but uate the peak-flow gaging-station network for that were used in the development of the regional Nebraska. Using a geographic information system equation. (GIS) and digital spatial data, drainage-basin characteristics—many of which were previously undefined Note that the ASEs for the active stations only for Nebraska—were quantified. Regional equations are not the same for scenarios with and without relating drainage-basin characteristics to peak-flow “new” stations, even for the same planning horizon. frequency characteristics were developed using a In most cases, the ASEs actually are larger for the generalized least-squares (GLS) regression program. scenarios with “new” stations. This is because NET An evaluation of each of the regional gaging-station covers the entire range of basin characteristics, networks also was made to estimate how additional including those of the possible “new” stations, even peak-flow data might reduce average sampling errors before the assumed benefits of data from those “new” (ASEs) of future equations. stations have been incorporated into the analysis. The updated equations would be applicable over a broader Twenty-seven morphometric characteristics were quantified using Basinsoft, a computer program range of characteristics than the existing equations, developed by the USGS. Four soil characteristics but the ASE could be larger until data actually were were quantified using ARC/INFO. Two precipitation available from those stations that had broadened the characteristics were quantified using ARC/INFO. range of the characteristics. Manual measurements and calculations were made to Based on the plots, it appears that the Northern verify computer-quantified values for selected and Western, and Central and South-Central regional drainage basins. equations, which have the second and third largest Peak-flow frequency analyses were done for ASEs, would benefit the most from additional discre- unregulated streamflow-gaging stations with at least tionary peak-flow data, especially if collected at 10 years of annual peak-flow record through 1993 “new” stations. The High-Permeability—Standard, and located in or within about 50 miles of Nebraska Eastern, and Big Blue River regional equations prob- using the log-Pearson Type III (LP3) frequency ably would benefit the least from additional discre- distribution and the guidelines in Bulletin 17B of the tionary peak-flow data. Although not directly Interagency Advisory Committee on Water Data. apparent from the plots, "new" data that could be Two sets of standard analyses were made. The first provided by additional composite analyses for set of standard analyses for unregulated streams was existing stations probably would be of considerable done using skew coefficients derived only from each benefit for the High-Permeability—Composite equa- station’s peak-flow data. These station skews then

44 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska were used to develop generalized skew relations. define regions and to determine the best combina- The second set of standard analyses was done using tion of explanatory variables that were reasonable station skews weighted with generalized skews hydrologically. from the new skew relations. One set of standard An alternative set of peak-flow frequency analyses, using station skews only, was done for analyses were computed for selected stations using stations on regulated streams. Adjustments were a conditional probability method suggested by made to peak-flow frequency analyses, as appro- William Kirby (USGS). Peak-flow frequency priate, for historic data and high and low outliers. curves for most of the high-permeability stations Experience of the authors showed that the statistical appeared to indicate a pattern of different character- tests for low outliers included in Bulletin 17B were istics for the larger peak flows. Because of the rela- not well suited for detecting multiple outliers. tively high permeabilities and large amounts of Therefore, adaptations of the existing procedure, noncontributing drainage area in typical sandhills other tests, and considerable judgment were used to terrain, it was theorized that most of the smaller identify and censor low outliers in these situations. peak flows primarily were interflow and baseflow Regional equations relating generalized skew and that the larger peak-flows included a signifi- coefficients to basin characteristics were developed cantly greater proportion of surface runoff. Plots of for most of the state, and a statewide map of gener- peak flow compared to the 1- or 2-day lag of daily alized skew coefficients for basins with relatively flow for several stations appeared to indicate that low average permeability also was developed. the theory was plausible. Station skew coefficients were computed for Other types of mixed populations in peak- stations in or within about 50 miles of Nebraska flow data also were apparent, including partially that, generally, had 25 years or more of unregulated regulated stations and low-permeability stations peak flows. Several stations with as few as 18 peak that were usually from the more arid parts of the flows were used where data were lacking. After state. Composite analyses were done for several of other adjustments had been made, stations with these stations; however, the thorough investiga- identified high outliers were analyzed further to tions required to justify and split the data, and actu- estimate how sensitive the station skew coefficients ally do composite analyses for all of these other were to the high outliers. As a result, some stations stations were beyond the scope of this study. were eliminated from further consideration in the Instead, peak-flow frequencies for partially regu- development of skew relations. lated sites were computed using only station skews, An equation to estimate skew was developed and low-permeability stations were excluded from first for basins with average permeability of the the regional analyses of peak-flow frequency. 60-inch soil profile (P60) of more than 2.5 inches Peak-flow frequency relations were devel- per hour. A skew map of the state then was developed for standard probabilities of 50, 20, 10, 4, 2, 1, oped for basins with P60 less than 4 inches per 0.5, and 0.2 percent or for frequencies of 2, 5, 10, hour, except for the Elkhorn River Basin where all 25, 50, 100, 200, and 500 years, respectively. basins were included. Regional equations, based on Streamflow-gaging stations with peak flows that geographic areas, also were developed; those with are known to have been or that could have been mean-square errors (MSEs) less than those for the affected to some degree by regulation (flood new skew map were adopted. The standard error of control, irrigation diversions, power generation, estimate (SEE) of the statewide skew map is 0.24. storage detention, or other factors) were excluded This compares to 0.78 for the Nebraska part of the from regional peak-flow frequency analyses. National skew map and to 0.59 for the map devel- Preliminary regional equations were developed and oped by Cordes (1993), both of which include the regions were defined using ordinary least squares high-permeability sandhills areas. SEEs for the (OLS) multiple-regression procedures. Final skew equations ranged from 0.13 to 0.23. The equa- regression equations were developed using a GLS tions were developed using multiple-regression multiple-regression procedure. The GLS procedure analyses; residuals from the analyses were used to adjusts for differences in record lengths, differ-

SUMMARY AND CONCLUSIONS 45 ences in peak-flow variances, and cross-correlations done to estimate how additional years of peak-flow of concurrent peak flows among stations used in the data might affect the ASEs of the equations for the regression analysis. 100-year frequency of occurrence. For each regional equation, analyses were done for four different For unregulated streams, eight sets of regres- scenarios—10 and 20 years of additional record from sion equations relating drainage-basin characteristics the stations used to develop the equation; and 10 and to peak flows for selected frequencies of occurrence 20 years of additional record from new stations as were developed for seven regions of the state. Two well as from the stations used to develop the equa- sets of regional peak-flow frequency equations were tion. developed for a high-permeability region that includes basins with P60 greater than 4 inches per Various scenarios and regions can be compared hour. Six sets of equations were developed for to determine where the greatest overall benefits specific geographic areas, usually based on drainage- might be gained for the least amount of new data and basin boundaries. Of the two sets of high-perme- hence for the least cost. For each scenario, plots of ability equations, one set was developed using data ASE and number of stations in the network were from standard frequency analyses and the other was presented. Based on the results, data from new developed using data from composite frequency anal- stations, rather than more data from stations used to yses. In general, these two sets of equations are for develop the regional peak-flow frequency equations, drainage basins with sandhills-type terrain. The six probably would most reduce the ASE of the equa- hydrologic regions based on geography were delin- tions. eated using residual values and plots from preliminary regression analyses. There is overlap between SELECTED REFERENCES several of the regions where more than one equation can be used to estimate peak flows. Beckman, E.W., 1976, Magnitude and frequency of floods in Nebraska: Water-Resources Tables for each region include the equations, Investigations Report 76–109, 128 p. the SEE in log10 units and in percent, the average Beckman, E.W., and Hutchison, N.E., 1962, Floods standard error of prediction (SEP) in log10 units, the in Nebraska on small drainage areas, magnitude average equivalent years of record for each equation, and frequency: Geological Survey Circular 458, and the applicable range of the explanatory variables 33 p. used to develop the equations. SEEs for the 100-year Boohar, J.A., and Provaznik, M.K., 1996, Peak flows recurrence interval equations ranged from 12.1 to for the period of record for current and 63.8 percent. discontinued streamflow stations in Nebraska: U.S. Geological Survey Open-File For streamflow-gaging stations on regulated Report 96-101, 518 p. streams in Nebraska with at least 10 years of regulated peak flows, peak-flow frequency analyses were Boohar, J.A., Hoy, C.G., and Jelinek, F.J., 1995, done using the LP3 distribution and the guidelines in Water resources data, Nebraska, water year Bulletin 17B of the Interagency Advisory Committee 1994: U.S. Geological Survey Water-Data Report NE–94–1, 421 p. on Water Data. Skew coefficients used were those derived only from each station’s peak-flow data. Boohar, J.A., Hoy, C.G., and Steele, G.V., 1992, Peak-flow records within the period of the current Water resources data, Nebraska, water year regulated condition were used for the station anal- 1991: U.S. Geological Survey Water-Data Report NE–91–1, 354 p. yses. For nine streams that included more than one station with at least 25 years of regulated record, Cordes, K.E., 1993, Design discharges of culverts: graphs of peak-flow frequency and distance upstream Lincoln, Nebr., University of Nebraska, of the mouth were estimated. Log-linear graphs were unpublished thesis, 106 p. developed for the Niobrara, North Platte, South Dempster, G.R., Jr., 1983, WATSTORE User’s Platte, Platte, and Republican Rivers, and for Salt, Guide, instructions for streamflow/basin Antelope, Frenchman, and Red Willow Creeks. characteristics file—U.S. Geological Survey National Water Data Storage and Retrieval For the regional peak-flow frequency equations System (WATSTORE): U.S. Geological Survey, for unregulated streams, statistical analyses were v. 4, chap. II, sec. A, 34 p.

46 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska Dugan, J.T., 1984, Hydrologic characteristics of Harvey, C.A., and Eash, D.A., 1996, Description, Nebraska soils: U.S. Geological Survey Water- instructions, and verification for Basinsoft, a Supply Paper 2222, 19 p. and 12 pls. computer program to quantify drainage-basin characteristics: U.S. Geological Survey Water- ____ 1986, Hydrologic characteristics of soils in Resources Investigations Report 95–4287, parts of Arkansas, Colorado, Kansas, Missouri, 25 p. Nebraska, New Mexico, Oklahoma, South Dakota, and Texas: U.S. Geological Survey Hershfield, D.M., 1961, Rainfall frequency atlas of Hydrologic Investigations Atlas HA–678, the United States: Washington, D.C., U.S. 1sheet. Department of Commerce, Weather Bureau Technical Paper No. 40, 115 p. Dugan, J.T., Hobbs, R.D., and Ihm, L.A., 1990, Hydrologic characteristics of soils in the High Interagency Advisory Committee on Water Data Plains, northern Great Plains, and Central (IACWD), 1982, Guidelines for determining Texas Carbonates Regional Aquifer Systems: flood flow frequency: Hydrology U.S. Geological Survey Hydrologic Subcommittee Bulletin 17B, U.S. Department Investigations Atlas HA–714, 1 sheet. of the Interior, 28 p. and 14 appendices. Eash, D.A., 1994, A geographic information system Kirby, W.H., 1981, Annual flood frequency procedure to quantify physical drainage-basin analysis using U.S. Water Resources Council characteristics: Water Resources Bulletin, guidelines (program J407): U.S. Geological v. 30, no. 1, p. 1–8. Survey Open-File Report 79–1336–I, WATSTORE User’s Guide, v. 4, chap. I, Environmental Systems Research Institute (ESRI), sec. C, 56 p. 1996, ARC/INFO user’s guide, version 7.0.4: Redlands, Calif., Environmental Systems Majure, J.J., and Soenksen, P.J., 1991, Using a Research Institute. geographic information system to determine Eschner, T.R., Hadley, R.F., and Crowley, K.D., physical basin characteristics for use in flood- 1983, Hydrologic and morphologic changes in frequency equations, in Balthrop, B.H., and channels of the Platte River Basin in Colorado, Terry, J.E., eds., U.S. Geological Survey Wyoming, and Nebraska—a historical National Computer Technology perspective: U.S. Geological Survey Meeting—Proceedings, Phoenix, Arizona, Professional Paper 1277–A, 39 p. November 14–18, 1988: U.S. Geological Survey Water-Resources Investigations Flynn, K.M., Hummel, P.R., Lumb, A.M., and Report 90–4162, p. 31–40. Kittle, J.L., Jr., 1995, User’s manual for ANNIE, version 2, a computer program for Matthai, H. F., 1968, Magnitude and frequency of interactive hydrologic data management: U.S. floods in the United States, Part 6–B, Missouri Geological Survey Water-Resources River Basin below Sioux City, Iowa: Investigations Report 95–4085, 211 p. U.S. Geological Survey Water-Supply Paper 1680, 471 p. Furness, L.W., 1955, Floods in Nebraska, magnitude and frequency: Lincoln, Nebr., Natural Resources Conservation Service, 1994, Nebraska Department of Roads and Irrigation, State soil geographic (STATSGO) data base, 103 p. data use information: U.S. Department of Agriculture, National Soil Survey Center, Gilroy, E.J., and Tasker, G.D., 1989, Miscellaneous Publication 1492, 110 p. Multicollinearity and influential observations in hydrologic model selection, in Berk, Patterson, J.L., 1966, Magnitude and frequency of Kenneth, and Malone, Linda, eds., Computing floods in the United States, Part 6–A, Missouri Science and Statistics—Proceedings of the 21st River Basin above Sioux City, Iowa: Symposium on the Interface: Alexandria, Va., U.S. Geological Survey Water-Supply Paper American Statistical Association, p. 350–354. 1679, 491 p. Hardison, C.H., 1971, Prediction error of regression Provaznik, M.K., 1997, Flood frequency for estimates of streamflow characteristics at Nebraska using L-moments: Lincoln, Nebr., ungaged sites: U.S. Geological Survey University of Nebraska, unpublished thesis, Professional Paper 750–C, p. C228-C236. 58 p. and 16 appendices.

SELECTED REFERENCES 47 Provaznik, M.K., and Hotchkiss, R.H., 1998, Analysis of gaging station flood-frequency estimates in Nebraska, using L-moment and region-of-influence methods: Washington, D.C., National Research Council, Transportation Research Board, Transportation Research Record no. 1647, p. 53–60. Statware, Inc., 1990, Statit statistics reference manual release 2.3x: Corvallis, Oreg., Statware, Inc., chap. 6, 50 p., and chap 10, 42 p. Tasker, G.D., 1978, Relation between standard errors in log units and standard errors in percent: U.S. Geological Survey, WRD Bulletin, Jan– Mar–Apr–June 1978. Tasker, G.D., and Stedinger, J.R., 1989, An operational GLS model for hydrologic regression: Amsterdam, Journal of Hydrology, Elsevier Science Publishers, v. 111, p. 361–375. Ugland, R.C., Cochran, B.J., Hiner, M.M., and Steger, R.D., 1994, Water resources data, Colorado, water year 1993–volume 1–Missouri River Basin, Arkansas River Basin, and Rio Grande River Basin: U.S. Geological Survey Water-Data Report CO–93–1, 518 p. U.S. Geological Survey, 1976, Hydrologic unit map– 1974–State of Nebraska: Reston, Va., U.S. Geological Survey, scale 1:500,000, 1 sheet. U.S. Water Resources Council, 1976, Guidelines for determining flood flow frequency: Washington, D.C., Bulletin 17 of the Hydrology Committee, Water Resources Council.

48 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska APPENDIX A—DESCRIPTIONS OF SELECTED DRAINAGE-BASIN- CHARACTERISTICS QUANTIFIED USING BASIN- SOFT, ARC-INFO, AND RELATED GIS PROGRAMS

APPENDIX A A-1 Descriptions of Selected Drainage- Areal-Size Quantifications Basin Characteristics Quantified TDA—Total drainage area, in square miles, includes all area Using Basinsoft, ARC-INFO, and within the drainage-basin boundary. Related GIS Programs NCDA—Noncontributing drainage area, in square miles, Morphometric Characteristics includes all area within the drainage-basin boundary that does not contribute directly to surface runoff; from published Morphometric characteristics were quantified using value (or computed from published values of TDA and CDA) Basinsoft (modified from Harvey and Eash, 1996) and data manually input during Basinsoft computations. layers representing the basin boundary (originally delineated CDA—Contributing drainage area, in square miles, includes on 1:24,000-scale maps for Nebraska stations and on all area within the drainage-basin boundary that contributes 1:250,000-scale maps for stations outside of Nebraska), directly to surface runoff; computed as CDA = TDA - NCDA. hydrography (stream network from 1:250,000-scale maps), hypsography (elevation contours created from 1:250,000- Linear-Size Quantifications scale digital elevation model), and lattice elevation model BL—Basin length, in miles, measured along a line areally (created from 1:250,000-scale digital elevation model). centered through the drainage-basin boundary data layer Modifications to Basinsoft from basin outlet to the intersection of the main channel (extended) and the basin boundary. In Basinsoft, noncontributing drainage area (NCDA) is intended to be delineated and measured like total drainage BP—Basin perimeter, in miles, measured along entire drainage-basin boundary. area (TDA), and contributing drainage area (CDA) is to be computed as CDA = TDA - NCDA. Because it was extremely BW—Effective basin width, in miles, computed as difficult to delineate NCDA in the large areas of sandhills, BW = CDA /BL. Basinsoft was modified to allow for manual input of NCDA instead. Values of NCDA were determined from published Shape Quantifications values of NCDA or of TDA and CDA. This modification did CR—Compactness ratio, dimensionless, computed as not affect CDA computations, but did affect several other CR = BP/2(πCDA)0.5. characteristics. ER—Elongation ratio, dimensionless, computed as Basin slope (BS), number of first-order streams (FOS), ER = [4CDA/π(BL)2]0.5=1.13(1/SF)0.5. and total stream length (TSL) are all intended to be measured only for the CDA by excluding the delineated NCDA(s) from RB—Rotundity of basin, dimensionless, computed as the measuring process. Because NCDA(s) were not delin- RB = [π(BL)2]/4CDA=0.785SF. eated, measurements for FOS and TSL were, therefore, made for the TDA. For BS, TDA was substituted for CDA in the SF—Shape factor, dimensionless, computed as SF = BL/BW. internal computations and this characteristic, therefore, was representative of the TDA and not just of the CDA. Slope ratio Relief Quantifications (SR), computed from BS, also was affected by this modification. BR—Basin relief, in feet, measured as the elevation difference in the lattice elevation model between the highest grid However, because most stream segments from the cell and the grid cell at the basin outlet. 1:250,000-scale data were concentrated in the CDA, the values of FOS and TSL actually are fairly representative of BS—Average basin slope, in feet per mile, quantified using the CDA as well as the TDA. Therefore, characteristics that the “contour-band” method and computed as BS =[(total length of all selected elevation contours within the use CDA and either FOS or TSL in their computations were TDA)(contour interval)]/TDA. not modified; these included drainage frequency (DF), stream density (SD), constant of channel maintenance (CCM), and RR—Relative relief, in feet per mile, computed as relative stream density (RSD). RR=BR/BP.

A-2 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska Aspect Quantification MCSP—Main-channel slope proportion, dimensionless, computed as MCSP=MCL/(MCS)0.5. BA—Basin azimuth, in degrees, measured as the compass direction (clockwise from north at 0 degrees) of a line from RN—Ruggedness number, in feet per mile, computed as the intersection of the main channel (extended) and the RN=(TSL)(BR)/CDA basin boundary to the basin outlet. SR—Slope ratio, dimensionless, computed as Stream-Network Quantifications SR=MCS/BS.

FOS—Number of first-order streams, dimensionless, Soil Characteristics designated as the Strahler method within the TDA. These were based on characteristics defined by BSO—Basin stream order, dimensionless, designated as the Dugan (1984), quantified using ARC/INFO using equa- Strahler stream order of the main channel at the basin tions A1 through A7 and data layers representing the basin outlet. boundary (originally delineated on 1:24,000-scale maps for Nebraska stations and on 1:250,000-scale maps for stations MCL—Main-channel length, in miles, measured along the outside of Nebraska), and the State Soil Geographic Data main channel from the basin outlet to the intersection of the Base (STATSGO) (Natural Resources Conservation main channel (extended) and the basin boundary. Service, 1994).

TSL—Total stream length, in miles, computed by summing P60—Average permeability rate of 60-inch soil profile for the lengths of all stream segments within the TDA. drainage basin, in in/hr, computed from equations A1 through A3 next. DF—Drainage frequency, in number of first-order streams per square mile, computed as DF = FOS/CDA. Although PAvgH= () PMinH+ PMaxH ⁄ 2 (A1) FOS was quantified for TDA, CDA was used in the computation of DF because most stream segments are concen- where: PAvgH = average permeability rate of soil hori- trated in the CDA—see “Modifications to Basinsoft”. zon, in in/hr, PMinH = minimum value for range in permeabil- MCSR—Main-channel sinuosity ratio, dimensionless, ity of soil horizon, in in/hr, and computed as MCSR = MCL/BL. PMaxH = maximum value for range in permeability of soil horizon, in in/hr. SD—Stream density, in miles per square mile, computed as SD = TSL/CDA. Although TSL was quantified for TDA, CDA was used in the computation of SD because most P60_SS = ()Σ()HT× PAvgH ⁄ 60 (A2) stream segments are concentrated in the CDA—see “Modi- fications to Basinsoft”. where: P60_SS = average permeability rate of 60-inch soil profile for soil series, in in/hr, CCM—Constant of channel maintenance, in square miles (fig. A3) and per mile, computed as CCM = CDA/TSL = 1/SD. Although HT = thickness of soil horizon, in inches. TSL was quantified for TDA, CDA was used in the computation of CCM because most stream segments are concen- Σ()× trated in the CDA—see “Modifications to Basinsoft.” P60 = P60_SS FA (A3)

RSD—Relative stream density, dimensionless, computed where: P60 = average permeability rate of 60-inch soil as RSD=(FOS)(CDA)/(TSL)2=DF/(SD)2. Although TSL profile for drainage basin, in in/hr, was quantified for TDA, CDA was used in the computation and of RSD because most stream segments are concentrated in FA = fractional area of drainage basin occupied the CDA—see “Modifications to Basinsoft”. by soil series.

Relief-Stream Network Quantifications

MCS—Main-channel slope index, in feet per mile, computed as MCS=(E85-E10)/(0.75MCL) where E10 and E85 are the respective elevations of points 10 and 85 percent of the distance along the main channel upstream from the basin outlet to the basin boundary.

APPENDIX A A-3 AWC—Average available water capacity of the 60-inch soil profile for the drainage basin, in in/hr, computed using equations A4 and A5 next.

AWC_SS = ()Σ()HT× AWCH ⁄ 60 (A4)

AWC = Σ()AWC_SS× FA (A5)

PLP—Average of minimum permeabilities of the least permeable layers for drainage basin, in in/hr, computed using equation A6 next.

PLP = Σ()PLP_SS× FA (A6)

where: PLP_SS = minimum permeability of the least permeable layer for soil series, in in/hr.

MSS—Average maximum soil slope for drainage basin, in percent, computed using equation A7 next.

MSS = Σ()MSS_SS× FA (A7)

where: MSS = average maximum soil slope for drainage basin, in percent, and MSS_SS = maximum soil slope for soil series, in percent.

Precipitation Characteristics

These were quantified using ARC/INFO and data layers representing the basin boundary (originally delineated on 1:24,000-scale maps for Nebraska stations and on 1:250,000-scale maps for stations outside of Nebraska), the 2-year (recurrence interval), 24-hour (duration) precipitation contours (from Weather Bureau Technical Paper 40 (Hersh- field, 1961)), and Theissen polygons of mean annual precipitation for the period 1961–90 (from the National Climatic Data Center Web site).

TTP—Two-year (recurrence interval), 24-hour (duration) precipitation, in inches, computed as the area-weighted average of precipitation polygons within the TDA (fig. A1).

MAP—Mean annual precipitation, in inches, computed as the area-weighted average of precipitation polygons within the TDA (fig. A2).

A-4 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska

ce rain gages in in gages ce rain . Thiessen polygons of mean annual precipitation for National Oceanic and Atmospheric Administration and National Weather Servi National Weather and Administration Atmospheric Oceanic and National for precipitation annual of mean polygons Thiessen . Figure A2 Nebraska and parts of adjacent states for the period 1961-90. period adjacent states the for parts of and Nebraska

A-6 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska Average permeability of the 60-inch soil profile for nebraska and parts of adjacent states. parts of and nebraska for soil profile 60-inch of the permeability Average Figure A3. Figure

APPENDIX A A-7 APPENDIX B—TABLES OF DRAINAGE-BASIN CHARACTERISTICS AND PEAK-FLOW FREQUENCY DATA

APPENDIX B B-1 1.19 0.83 0.83 0.83 2.02 2.13 3.44 3.58 3.40 3.58 0.30 1.00 0.63 2.23 0.63 0.63 0.93 24.2 46.3 46.2 46.3 21.5 21.6 23.6 24.5 27.9 24.5 20.2 20.2 17.7 15.7 17.7 17.7 27.4 P60 MSS , relative, relief, DF SR 0.178 0.051 0.333 1.17 0.280 0.348 0.363 0.311 0.141 0.096 0.140 0.100 0.137 0.130 0.101 0.202 0.189 0.252 0.132 0.273 0.199 0.288 0.068 0.379 0.819 0.492 5.47 1.64 0.709 0.369 0.804 , permeability, of ------RR PLP , available water capacity capacity water available , 0.10 0.39 0.10 0.31 0.10 0.31 0.10 0.31 0.07 0.63 0.10 0.66 0.10 1.04 0.09 1.07 0.08 0.95 0.09 1.08 0.07 0.09 0.08 0.30 0.08 0.11 0.12 0.61 0.08 0.11 0.08 0.11 0.07 0.10 PLP AWC AWC 2.02 2.05 2.05 2.05 1.97 1.96 1.93 1.95 1.95 1.95 2.01 1.90 1.95 1.85 1.95 1.85 1.75 16.35 15.43 15.43 15.43 15.78 15.82 15.97 16.84 14.21 16.84 16.55 15.99 15.90 16.84 15.68 14.19 14.91 , compactness ratio, dimensionless; TTP MAP CR 1.68 0.82 1.32 1.06 1.28 0.982 1.56 1.43 1.58 0.820 1.56 0.816 1.51 0.730 1.53 0.539 1.45 0.543 1.34 0.534 1.47 1.19 1.73 0.560 1.17 0.880 1.33 0.596 1.07 1.50 1.78 1.17 1.00 -- SD CR , maximum soil slope, percentage; percentage; slope, soil maximum , Drainage-basin characteristics 9.5 -- -- 11.2 12.2 63.7 83.0 86.7 28.2 29.5 43.5 66.5 98.2 56.3 87.1 73.8 75.3 , , 2-year (recurrence interval) 24-hour (duration) precipitation, 117 BS 240 306 239 212 293 294 335 329 462 360 167 106 343 171 126 101 MSS MCS TTP noted;see appendix A for descriptions); 3.48 6.98 1.43 1.58 5.18 2.52 2.24 2.05 2.35 3.06 1.80 2.50 9.58 2.01 6.38 1.34 1.38 1.10 1.14 1.64 SF 11.4 30.3 29.2 40.5 10.8 14.1 23.5 48.3 38.7 41.5 13.3 54.5 17.3 41.6 RR 9.01 2.75 7.59 5.28 0.18 0.61 5.42 14.3 49.3 10.6 24.4 709 635 256 186 967 TDA CDA 2,160 , slope ratio, dimensionless, ratio of main-channel slope to basin slope; SR ) 2 area total total (mi drainage drainage Published , main channel slope, in feet per mile; mile; per feet in slope, channel , main , total drainage area, in square miles; ) MCS TDA ’ ” ’ o ( Longitude , contributing, drainage area, in square miles,derived from published data; ) ’ ” CDA o ( Latitude 42 42 27 103 00 33 15.4 14.3 42 48 35 103 10 05 676 635 42 41 49 41 42 0900 103 2.59 2.75 , shape factor, dimensionless; dimensionless; factor, , shape SF , mean annual precipitation, in inches; inches; in precipitation, annual , mean MAP , permeability of the 60-inch soil profile, in inches per hour; , square, miles;--, not determined; __, value known tobe incorrect;number] #, , basin slope, infeet per mile; 2 BS P60 Station name—remarks Nebraska Chadron, Nebraska Nebraska , stream density, in miles per square mile; mile; square per miles in density, stream , SD Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected , degrees;’, minutes; ’’, seconds; mi o Station number , in drainage streamssquare per frequency, mile; ber Map num- 4460 06446000 White River near Oglala, South Dakota 43 15 17 102 49 28 2,200 2,160 4455c 06445590 Big Bordeaux Creek near Chadron, Nebraska 42 43 30 102 55 44 9.42 9.01 4455b 06445560Chadron, near Park at Chadron State Chadron Creek 4455a 06445530 Chadron tributaryCreek at Chadron Park State near 4455 06445500 White River near Chadron, Nebraska 42 49 59 103 07 00 750 709 4450 06445000 White River below Cottonwood Creek near Whitney, 4440 06444000 White River at Crawford, Nebraska 42 41 32 103 25 03 313 256 4437 06443700Crawford, Soldiers Creek near Nebraska18 41 42 0832 103 52.6 49.3 4433 06443300Glen, Nebraska Deep Creek near 36 36 42 2133 103 10.87 10.6 4432 06443200 White River tributary near Glen, Nebraska 42 37 11 103 39 09 7.97 7.59 4008a 06400875Oelrichs, HorseheadDakota South Creek at 17 11 43 3413 103 187 186 4000 06400000 HatSouthCreek near Edgemont, Dakota 24 14 43 1635 103 1,044 967 3997 06399700near Ardmore,South Pine Creek Dakota 13 11 43 2338 103 5.47 5.28 3964a 06396490 Creek near Harrison, Warbonnet Nebraska 42 50 43 103 54 41 24.5 24.4 3963 06396300 Cottonwood Creek tributarySouth near Edgemont, Dakota 48 17 43 0152 103 0.09 0.18 3962 06396200Edgemont, FiddleDakota South Creek near 15 18 43 4559 103 0.64 0.61 3822 06382200 Pritchard Draw near Lance Creek, Wyoming 43 12 00 104 40 59 5.10 5.42 Table B1. DF theleast permeable in incheslayer, hour;per in inches; inches; in of the 60-inchsoilprofile, in inches perinch; in feet per mile; Table B1. [Drainage-basin characteristics(quantified from 1:250,000-scale data using geographic-information-system procedures,except as

B-2 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska 1.10 3.0 1.17 1.36 1.13 1.08 7.57 3.42 6.53 9.5 3.89 8.79 5.79 4.27 0.63 2.01 9.1 2.67 11.6 26.5 12.76 10.5 26.6 12.76 17.2 10.92 20.2 16.9 13.9 18.0 21.5 12.20 16.8 23.3 18.8 13.6 24.7 28.3 P60 MSS DF SR 0.231 1.13 0.239 0.274 0.179 0.048 0.026 0.115 0.383 0.346 0.195 0.246 0.291 0.331 0.534 0.672 0.130 0.079 0.098 0.058 0.032 0.134 0.159 0.144 0.099 0.075 0.200 0.077 0.148 0.100 0.307 0.644 0.303 0.336 0.414 0.000 -- -- 0.08 5.62 0.14 0.37 0.08 5.63 0.08 4.48 0.16 0.39 0.11 0.44 0.12 0.37 0.14 0.36 0.10 3.01 0.12 0.81 0.08 5.21 0.10 2.72 0.12 0.70 0.10 3.87 0.09 2.18 0.12 1.72 0.06 0.14 0.08 0.78 0.10 0.44 PLP AWC inued 2.15 2.13 2.16 2.25 2.05 2.05 2.05 2.05 2.19 2.41 2.22 2.15 2.39 2.15 2.21 2.15 2.25 2.05 2.25 18.37 18.55 18.65 18.65 16.83 16.90 16.66 15.43 18.09 23.96 18.56 17.59 24.69 17.17 18.21 17.08 18.96 15.86 19.32 TTP MAP 3.17 1.54 1.10 3.48 2.07 0.193 2.03 1.37 1.35 0.989 1.78 1.16 1.61 0.995 2.41 0.642 2.49 0.624 2.23 0.297 2.03 0.688 1.96 0.608 2.31 0.759 1.78 0.677 1.19 1.10 1.28 0.740 1.12 0.596 -- -- SD 10.6 12.2 CR Drainage-basin characteristics 0.0 9.0 8.8 8.0 8.7 5.6 -- -- 11.9 11.9 11.6 14.6 34.2 49.2 17.0 28.8 37.2 54.3 52.5 35.2 86.4 55.7 10.8 55.7 92.9 59.8 53.5 17.9 117 113 114 116 BS 240 249 124.8 103 152 141 MCS 5.70 5.24 4.76 1.46 8.12 7.58 2.93 5.96 0.66 3.38 7.99 5.79 9.91 4.80 4.59 6.82 6.13 6.01 5.71 5.21 6.66 5.83 4.83 6.02 1.67 3.65 -- -- SF 11.9 11.9 80.0 14.7 16.7 13.26 19.0 19.2 RR 21.7 120 2.42 3.74 6.51 26.0 28.0 25.1 76.5 31.3 82.2 24.1 94.8 23 16.5 760 812 415 504 230 TDA CDA 1,310 ) 2 area total total (mi drainage drainage Published ) ’ ” ’ o ( Longitude ) ’ ” o ( Latitude Station name—remarks Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations--Cont out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected Station number ber Map num- 4591a 06459175 Snake Nebraska River at Doughboy, 42 36 51 101 16 38 405 391 4592 06459200above NebraskaRiver Merritt Snake Reservoir, 39 35 42 2002 101 440 426 4578 06457800 Antelope Creek tributary near Gordon, Nebraska 42 49 57 102 12 09 26.6 25.1 4609 06460900Kilgore,Nebraska Minnechaduza Creek near 10 59 42 5553 100 85 76.5 4572 06457200Alliance, Nebraskanear Creek Berea 23 08 42 3151 102 32.3 31.3 4564 06456400Dunlap, Nebraska Cottonwood Creek near 29 29 42 0858 102 82.2 82.2 4563 06456300near Dunlap, Pebble Nebraska Creek 47 29 42 3558 102 23.5 24.1 4497 06449700 Little Oak Creek near Mission, South Dakota 43 19 44 100 42 33 2.58 2.42 4562 06456200 Nebraskanear Esther, Pebble Creek 38 35 42 5503 103 3.07 3.74 4492a 06449250 Spring Creek near Francis, St. South Dakota4495 06449500 Little White River near Rosebud, South Dakota 43 04 21 43 19 31 101 01 49 100 52 59 57 1,020 94.8 999 4536 06453600 NebraskaCreek at Verdel, Ponca 39 48 42 34 10 98 812 812 4491 06449100 South Dakota Little White River near Vetal, 43 06 02 101 13 49 590 556 4535 06453500 NebraskaCreek at Anoka, Ponca 25 56 42 30 50 98 505 504 4480 06448000South Dakota Creekabove refuge Lake near Tuthill, 07 05 43 0336 101 58 58 4505 06450500 Little White River below SouthWhite River, Dakota 43 36 05 100 44 57 1,570 1,520 4475 06447500near Martin, LittleRiverWhite South Dakota 00 10 43 4637 101 310 265 4497b 06449750near Mission,CreekDakota Branch HorseSouth West 35 23 43 3242 100 6.31 6.51 4464 06446400Dakota South Imlay, Cain Creek tributary at 59 42 43 2223 102 15.8 16.5 Table B1.

APPENDIX B B-3 2.92 4.0 0.96 3.7 0.94 4.3 0.98 8.9 1.95 3.69 5.14 7.9 8.7 5.0 5.3 7.17 6.66 2.7 9.1 11.2 11.6 10.7 20.6 10.50 12.10 13.82 10.80 13.88 12.5 12.6 21.8 12.47 13.36 13.50 23.0 12.51 19.5 12.17 P60 MSS DF SR 0.116 0.089 0.082 0.410 0.074 0.389 0.073 0.487 0.431 0.187 0.153 0.074 0.736 0.247 0.049 0.235 0.071 0.177 0.051 0.201 0.627 0.194 0.350 0.404 0.102 0.071 0.086 0.092 0.052 0.188 1.83 0.619 0.030 0.153 0.056 0.184 -- -- 0.18 1.01 0.18 0.17 0.18 0.16 0.18 0.18 0.18 0.64 0.17 1.15 0.10 0.85 0.10 2.91 0.08 2.14 0.08 1.64 0.08 1.39 0.08 1.43 0.09 2.31 1.64 0.08 4.70 0.09 1.09 0.08 1.62 0.08 5.16 0.08 4.95 41.61 PLP AWC inued 2.71 2.52 2.55 2.50 2.65 2.61 2.55 2.52 2.45 2.45 2.45 2.45 2.32 2.30 2.35 2.35 2.35 2.35 2.31 25.05 23.30 23.31 23.09 26.32 24.50 22.01 23.22 22.83 23.30 23.10 23.60 21.11 20.47 22.38 22.42 22.42 22.51 21.50 TTP MAP 1.88 0.638 1.39 0.645 1.66 0.644 1.73 0.550 1.36 1.18 1.98 0.738 1.92 1.76 1.90 0.287 1.51 0.467 1.54 0.470 1.58 1.16 1.29 0.692 1.81 0.559 1.65 0.495 1.78 0.339 1.54 1.33 1.13 1.81 0.239 3.03 0.599 -- SD CR Drainage-basin characteristics 7.4 7.6 -- 15.5 37.1 15.2 45.4 17.7 29.8 14.5 51.3 13.8 49.6 86.1 20.2 20.8 21.5 72.8 14.1 32.8 13.3 82.6 19.4 27.8 34.3 21.2 18.2 73.9 13.6 117 119 BS 176 274 188 201 107 104 103 MCS 2.50 6.13 3.23 8.72 6.17 5.17 7.01 2.26 2.41 4.76 1.72 2.06 6.75 2.42 8.37 3.16 8.78 1.84 7.42 1.10 6.35 4.78 4.57 2.76 4.17 1.63 6.67 1.26 9.39 1.03 7.16 4.38 5.31 -- SF 12.6 34.8 16.8 10.4 RR 2.32 6.79 1.60 2.86 1.08 2.19 97.3 27.1 54.8 302 457 141 212 157 458 230 340 TDA CDA 1,690 1,130 ) 2 area total total (mi drainage drainage Published ) ’ ” ’ o ( Longitude ) ’ ” o ( Latitude Station name—remarks HoneyCreek near O’Neill, Nebraska 28 37 42 24 40 98 2.54 2.86 Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations--Cont out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected Station number ber Map num- 4785a 06478518James, NebraskaSt. Bow Creek near 47 43 42 53 08 97 304 302 4783 06478300near Parkston, DryDakota South Creek 17 22 43 22 49 97 97.2 97.3 4782b 06478280Parkston,near SouthSouth Branch Dry Creek Dakota 21 21 43 34 49 97 25.8 27.1 4782a 06478260Parkston, NorthnearSouth Branch Dry Creek Dakota 12 22 43 51 50 97 54.1 54.8 4669a 06466950near Crofton,Nebraska Creek Weigand 36 43 42 55 37 97 2.3 2.32 4665 06466500Niobrara,nearNebraska Bazile Creek 25 45 42 50 56 97 440 457 4658a 06465850near Niobrara, BinghamNebraska Creek 12 42 42 54 02 98 6.5 6.79 4656a 06465680 NebraskaVerdigre, near Creek North Branch Verdigre 51 35 42 03 08 98 137 141 4653b 06465310Redbird, Nebraskanear Eagle Creek 51 45 42 13 34 98 206 212 4654a 06465440at Redbird, Redbird Nebraska Creek 36 45 42 26 26 98 157 157 4653 06465300Creek near O’Neill, Camp Nebraska 08 39 42 26 39 98 1.65 1.60 4652 06465200 4649 06464900 NebraskaNaper, Keya Paha River near 0 55 0 42 49 05 99 1,690 1,690 4645 06464500 South DakotaWewela, Keya Paha River at 44 01 43 48 46 99 1,070 1,130 4635 06463500Nebraska LongCreek near Riverview, Pine 20 41 42 20 41 99 460 458 4633 06463300tributary SandAinsworth, Draw Nebraska near 33 06 42 59 56 99 1.07 1.08 4632 06463200 BoneAinsworth, Creek tributaryNebraska #2 near 45 34 42 02 48 99 2.18 2.19 4630a 06463080 Pine, Long NebraskaCreek near Long Pine 55 37 42 46 40 99 246 230 4625 06462500Meadville, Plum Creek at Nebraska05 45 42 05 52 99 600 536 Table B1.

B-4 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska 1.29 1.29 1.29 1.28 1.28 0.91 0.96 1.08 4.9 1.61 1.21 9.9 1.20 1.30 8.8 1.19 8.2 1.20 9.7 1.28 3.1 0.76 4.2 0.79 3.4 0.77 9.3 2.03 11.6 11.7 13.5 13.2 13.0 14.6 14.2 13.9 12.1 14.6 P60 MSS DF SR 0.634 0.183 0.450 0.198 1.29 0.174 0.541 0.182 0.044 0.031 0.305 0.110 0.313 0.134 0.767 0.260 0.062 0.392 0.155 0.036 0.176 0.060 1.22 0.238 0.262 0.109 0.388 0.305 0.155 0.071 0.081 0.396 0.483 0.561 0.081 0.430 0.170 0.174 0.21 0.60 0.21 0.60 0.21 0.60 0.20 0.60 0.21 0.59 0.19 0.39 0.19 0.41 0.20 0.46 0.19 0.56 0.20 0.53 0.20 0.50 0.21 0.60 0.20 0.46 0.20 0.43 0.21 0.59 0.18 0.15 0.18 0.17 0.18 0.16 0.19 0.80 PLP AWC inued 2.95 2.95 2.95 2.95 3.05 2.95 2.95 2.95 3.05 2.85 2.85 2.85 2.85 2.85 2.85 2.75 2.75 2.75 2.65 29.49 29.33 29.33 29.33 29.64 29.33 29.33 29.33 29.10 27.58 27.72 27.57 27.57 27.57 26.17 23.51 23.51 23.51 25.90 TTP MAP 1.37 1.32 1.26 1.11 1.28 1.55 1.42 1.42 1.65 0.336 1.50 0.800 1.50 0.717 1.31 1.10 1.21 0.385 1.59 0.647 1.90 0.629 1.43 1.42 1.44 0.749 1.40 0.964 1.54 0.739 1.56 0.642 1.45 1.47 1.26 0.440 1.75 0.727 SD CR Drainage-basin characteristics 9.0 7.7 11.3 29.5 31.5 27.2 25.0 24.7 57.8 50.1 54.2 21.3 18.0 56.3 23.1 51.1 13.2 47.4 18.8 56.4 31.6 48.9 21.0 25.3 BS 162 159 156 137 289 224 193 315 300 236 212 167 187 146 MCS 2.45 2.41 3.49 3.28 5.09 4.29 2.04 0.863 4.21 0.889 2.28 1.64 5.65 0.491 5.92 2.29 0.688 2.20 4.82 8.21 4.98 9.40 3.90 2.29 9.20 2.92 SF 13.1 15.7 17.4 17.7 12.4 23.2 10.9 26.2 12.5 25.2 22.1 RR 10.6 6.66 1.55 1.85 9.58 3.91 1.65 2.58 2.07 14.2 22.9 16.0 51.2 15.3 64.7 24.7 12.3 53.0 410 174 TDA CDA ) 2 area total total (mi drainage drainage Published ) ’ ” ’ o ( Longitude ) ’ ” o ( Latitude 41 45 15 45 41 10 17 96 4.08 3.91 Station name—remarks Nebraska Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations--Cont out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected Station number ber Map num- 6089 06608900Nebraska Spiker, of Creek east New York 52 36 41 14 16 96 13.9 14.2 6088 06608800Nebraska Creek north of Spiker, New York 31 37 41 34 18 96 6.50 6.66 6087 06608700 NebraskaCreek tributarynear Spiker, New York 23 38 41 27 18 96 1.55 1.55 6086 06608600 NebraskaCreek near Spiker, New York 00 38 41 00 20 96 1.75 1.85 6085 06608500 SoldierIowaat Pisgah,River 51 49 41 50 55 95 407 410 6080 06608000 Nebraskaat Tekamah, Creek Tekamah 30 46 41 09 13 96 23.0 22.9 6079 06607900 Nebraskanear Tekamah, Creek South Branch Tekamah 00 46 41 59 16 96 9.73 9.58 6078 06607800 Tekamah, Creek tributary near South Branch Tekamah 6067b 06606790Alta,near Maple Iowa Creek 56 44 42 16 22 95 15.5 16.0 6010 06601000 Nebraskaat Homer, Creek Omaha 28 19 42 42 29 96 168 174 6009 06600900Nebraska at Walthill, South Omaha Creek 53 08 42 58 28 96 51.2 51.2 6008 06600800 Nebraska tributary South #2 near Walthill, Omaha Creek 18 08 42 36 28 96 1.65 1.65 6007 06600700 NebraskaWalthill, near South Omaha Creek 08 07 42 24 29 96 15.1 15.3 6006 06600600Nebraska tributary South near Walthill, Omaha Creek 00 06 42 59 29 96 2.64 2.58 6000 06600000Iowa Sioux City, 38th Perry Street, Creek at 0832 42 39 24 96 65.1 64.7 4788c 06478840 SaddlerockBeresford,South Dakota Creek near 55 12 43 32 49 96 23.1 24.7 4788b 06478820 Saddlerock Creek tributary near Beresford,South Dakota 20 12 43 50 45 96 2.22 2.07 4788 06478800 SaddlerockCanton,Dakota South Creek near 19 12 43 36 43 96 13.0 12.3 4785b 06478520near Fordyce, Nebraska Bow Creek West 30 41 42 06 25 97 52.7 53.0 Table B1.

APPENDIX B B-5 1.28 1.30 1.30 1.32 1.30 1.30 1.30 1.30 1.30 8.5 1.89 7.6 4.67 2.4 1.26 4.18 1.58 9.6 1.27 1.29 1.30 11.9 11.79 11.2 19.3 16.2 21.2 14.2 15.4 13.8 13.7 13.7 20.8 12.77 18.2 14.9 19.2 14.0 P60 MSS DF SR 0.674 0.132 0.959 0.168 1.44 1.74 0.200 0.069 0.161 0.100 0.148 0.094 0.259 0.165 0.547 0.180 0.192 0.165 0.166 0.428 0.103 0.073 0.087 0.397 0.113 0.086 0.063 0.198 0.312 0.701 0.352 0.100 0.023 0.033 0.537 0.107 -- -- 0.20 0.58 0.20 0.60 0.20 0.60 0.20 0.60 0.20 0.60 0.20 0.60 0.20 0.60 0.20 0.60 0.20 0.60 0.14 0.47 0.13 0.53 0.08 5.75 0.19 0.58 0.08 5.26 0.11 1.51 0.12 0.65 0.20 0.60 0.21 0.59 0.21 0.60 PLP AWC inued 2.35 2.35 2.35 2.37 2.35 2.35 2.35 2.35 2.35 2.05 1.79 2.20 2.05 2.06 1.70 1.65 2.95 3.05 2.95 23.54 23.54 23.54 21.82 21.50 21.57 21.17 21.01 20.99 17.29 18.00 18.93 18.41 16.39 15.12 14.25 30.07 32.05 29.67 TTP MAP 1.87 1.34 1.84 1.50 1.55 1.77 2.53 0.841 1.70 0.792 1.99 0.694 1.73 1.09 1.45 1.65 1.88 1.11 1.67 0.516 1.22 7.26 0.864 1.37 0.398 7.96 0.502 1.90 0.500 1.15 0.925 1.53 0.827 1.96 0.333 1.72 1.31 -- SD CR Drainage-basin characteristics 6.4 7.8 -- 11.6 11.8 16.4 23.5 35.7 62.2 93.2 12.6 13.1 87.7 14.5 64.4 16.9 47.9 20.5 35.2 12.6 32.8 13.0 27.4 14.1 24.9 BS 124 140 126 139 102 173 138 138 143 100 140 233 232 MCS 2.31 8.67 5.86 1.07 8.69 9.75 4.47 3.63 5.93 4.61 6.20 4.24 9.74 4.35 4.89 2.40 4.81 1.84 5.09 4.05 5.42 2.39 3.05 8.67 5.44 1.82 -- SF 11.2 14.1 15.2 10.2 10.7 16.8 10.8 10.3 18.1 38.8 10.4 RR 5.22 2.09 1.83 5.67 6.41 8.52 32.7 80.6 40.5 19.3 10.4 18.1 78.0 45.7 26.1 215 106 130 TDA CDA 1,530 ) 2 area total total (mi drainage drainage Published ) ’ ” ’ o ( Longitude ) ’ ” o ( Latitude Station name—remarks Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations--Cont out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected Station number ber Map num- 7682 06768200Nebraska Buffalo, Buffalo Creek at 20 59 40 51 49 99 33.5 32.7 7681 06768100 East Buffalo Creek near Nebraska Buffalo, 41 00 17 99 50 14 5.21 5.22 7680b 06768050NebraskaBuffalo,near Buffalo Creek tributary #1 44 00 41 48 48 99 2.08 2.09 7675 06767500Smithfield, Plum Creek near Nebraska39 39 40 59 41 99 229 215 7674b 06767410Farnam, PlumNebraska Creek near 13 41 40 4108 100 80.4 80.6 7674 06767400 Northnear Farnam,Creek Plum Nebraska 54 43 40 5609 100 38.3 40.5 7673 06767300 PlumFarnam, Creek tributaryNebraska at 08 42 40 5212 100 19.8 19.3 7672 06767200 NorthPlum Fork Creek tributary near Farnam, Nebraska18 42 40 2314 100 1.83 1.83 7671 06767100 South ForkCreek tributary Plum near Farnam, Nebraska06 42 40 2115 100 9.81 10.4 7632 06763200 LodgepoleCreek tributary near Sunol, Nebraska00 10 41 2543 102 15.6 18.1 6920 06692000 NebraskaHershey, Birdwood Creek near 7626 06762600 LodgepoleAlbin,Creek tributaryWyoming #2 near 10 19 41 19 13 41 4904 104 1104 101 5.69 940 5.67 963. 6876 06687600 Ashnear Oshkosh, Hollow Nebraska 05 15 41 2820 102 54.9 45.7 6870 06687000Lewellen,Nebraska Blue Creek near 07 20 41 2110 102 1,190 1,140 6775 06677500Nebraska HorseCreek near Lyman, 21 56 41 1259 103 1,570 1,700 6524 06652400 Draw near Lost Springs, Watson Wyoming 42 45 19 104 57 29 6.95 6.41 6107 06610700 BigPapillionCreek near Orum, Nebraska 44 32 41 09 13 96 8.52 8.52 6106 06610600 Mosquito IowaCreek at Neola, 35 26 41 41 36 95 131 130 6090 06609000NebraskaCreek at Herman, New York 39 39 41 09 12 96 25.4 26.1 Table B1.

B-6 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska 1.42 1.36 1.35 1.36 1.35 1.35 1.36 1.34 1.30 1.30 1.30 1.48 1.30 1.29 23.1 12.49 23.3 12.79 21.3 12.72 26.8 12.80 25.2 12.85 13.3 14.4 16.9 20.3 21.4 21.0 21.7 23.3 17.2 20.2 16.5 15.8 21.7 25.5 P60 MSS DF SR 0.196 0.051 0.100 0.053 0.278 0.069 0.300 0.047 0.267 0.046 0.265 0.080 0.281 0.075 0.339 0.075 0.978 0.093 0.771 0.137 0.814 0.422 0.816 0.211 1.46 0.374 0.182 0.433 0.268 0.547 0.305 0.082 0.617 0.145 0.881 0.165 -- -- 0.08 5.59 0.08 5.73 0.08 5.64 0.08 5.72 0.08 5.80 0.20 0.59 0.20 0.59 0.20 0.60 0.20 0.60 0.20 0.60 0.20 0.60 0.20 0.60 0.20 0.60 0.20 0.60 0.20 0.60 0.20 0.60 0.20 0.62 0.20 0.59 0.20 0.59 PLP AWC inued 2.23 2.21 2.20 2.18 2.22 2.45 2.44 2.43 2.36 2.35 2.35 2.35 2.35 2.45 2.45 2.45 2.39 2.35 2.35 20.18 19.84 19.75 18.54 19.84 23.54 23.36 22.76 23.54 23.54 23.54 23.54 23.54 21.99 21.99 21.99 23.05 23.54 23.50 TTP MAP 8.19 1.40 7.83 1.17 3.21 3.37 3.49 3.12 0.965 2.83 0.950 2.44 0.992 1.88 2.16 1.82 1.67 1.94 1.78 2.38 1.86 1.50 1.97 1.60 0.528 1.59 1.59 0.649 2.13 1.18 1.90 1.44 1.93 1.58 -- SD 13.1 17.8 19.1 CR Drainage-basin characteristics 5.8 6.0 7.0 8.6 -- 11.2 11.6 10.8 12.0 13.5 72.3 79.4 94.5 10.8 18.7 48.2 20.3 21.4 77.4 28.9 37.6 16.3 34.4 34.2 18.7 17.4 24.7 211 116 BS 242 220 173 286 136 102 106 121 150 MCS 3.09 3.49 3.20 3.98 4.06 3.64 3.68 6.08 4.20 2.74 7.31 1.51 8.01 1.42 8.84 2.66 2.77 2.31 3.84 4.18 2.97 4.82 9.88 5.96 4.47 8.03 5.08 -- SF 38.8 34.0 82.6 13.0 12.4 10.8 18.1 RR 12.1 115 122 2.05 5.65 11.0 79.0 30.0 45.0 74.6 42.8 24.6 33.0 14.9 64.8 17.0 433 360 600 526 369 190 TDA CDA ) 2 area total total (mi drainage drainage Published ) ’ ” ’ o ( Longitude ) ’ ” o ( Latitude Station name—remarks Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations--Cont out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected Station number ber Map num- 7775 06777500 NebraskaWalworth, MiddleLoup River at 20 39 41 59 33 99 4,340 4,320 7755 06775500 Middle Loup River at Dunning, Nebraska 41 49 49 100 05 59 1,830 1,840 7759 06775900near Thedford, DismalRiver Nebraska 45 46 41 2931 100 966 966 7765 06776500at Dunning, DismalRiver Nebraska 23 49 41 0506 100 2,040 2,040 7770 06777000 MiddleLoup River near Milburn, Nebraska02 49 41 15 58 99 3,690 3,960 7720 06772000Alda, Nebraska River near Wood 10 51 40 19 28 98 599 600 7715 06771500Gibbon,Nebraska River near Wood 17 46 40 51 47 98 572 526 7710 06771000Riverdale, Nebraska River near Wood 5647 40 47 11 99 379 369 7709b 06770910Lomax, River near Nebraska Wood 39 03 41 50 40 99 79.6 76.3 7709 06770900Oconto, Nebraska River at Wood 49 08 41 26 45 99 44.8 42.8 7708 06770800Oconto, Nebraska River near Wood 46 09 41 37 47 99 26.4 24.6 7707 06770700Lodi, River near Nebraska Wood 14 10 41 17 48 99 12.9 11.0 7706 06770600 River tributary Nebraska near Lodi, Wood 57 11 41 21 50 99 2.02 2.05 7695 06769500 ElmCreek near Overton, Nebraska 40 50 40 20 30 99 31.0 33.0 7693 06769300 ElmOverton,Creek tributaryNebraska #2 near 02 51 40 21 32 99 5.62 5.65 7692 06769200 Nebraska ElmCreek near Sumner, 24 51 40 21 32 99 14.94 14.9 7690 06769000Overton,Nebraska Buffalo Creek near 00 44 40 20 30 99 175 190 7685 06768500 NebraskaDarr, Buffalo Creek near 05 54 40 05 50 99 63 64.8 7684 06768400 Nebraskanear Buffalo, Creek Buffalo West 21 59 40 21 52 99 17.1 17.0 Table B1.

APPENDIX B B-7 8.74 1.32 1.33 4.28 1.81 1.66 1.81 4.43 6.2 3.75 5.40 1.34 1.30 1.30 11.7 11.18 11.62 25.1 12.81 23.4 12.62 25.5 12.81 20.6 12.6 13.4 18.3 18.6 25.6 10.4 18.4 22.4 22.5 22.8 12.15 23.6 26.4 26.8 P60 MSS DF SR 0.120 0.080 0.237 0.073 0.114 0.104 0.405 0.034 0.928 0.145 1.03 0.130 0.463 0.035 0.508 0.054 0.506 0.427 0.370 0.378 2.63 0.241 2.46 1.08 0.445 0.035 0.340 0.048 0.310 0.049 0.284 0.050 0.488 0.288 1.06 0.210 1.99 0.624 0.08 5.71 0.08 5.59 0.08 5.68 0.12 3.87 0.20 0.61 0.20 0.61 0.17 1.83 0.20 0.79 0.20 0.76 0.20 0.76 0.17 1.95 0.18 1.57 0.16 2.31 0.10 4.99 0.09 5.19 0.09 5.43 0.20 0.60 0.20 0.60 0.20 0.60 PLP AWC inued 2.39 2.29 2.36 2.32 2.54 2.53 2.40 2.43 2.43 2.35 2.35 2.35 2.37 2.26 2.25 2.23 2.45 2.35 2.35 23.80 21.70 24.14 21.74 24.36 24.66 23.04 23.71 22.57 22.58 23.04 22.50 22.61 20.88 20.67 20.30 23.54 22.63 22.57 TTP MAP 8.13 1.45 9.82 2.07 7.72 1.50 4.13 1.28 1.89 1.68 1.93 1.68 3.52 1.31 2.28 1.31 1.63 1.11 2.24 1.06 5.64 5.13 1.59 3.64 4.41 1.34 6.45 1.30 6.63 1.30 8.28 1.57 1.68 1.36 1.62 1.22 1.44 2.40 SD CR Drainage-basin characteristics 7.9 9.1 9.3 6.3 5.9 7.8 6.0 9.1 9.3 7.3 11.7 98.9 88.6 85.1 12.4 15.8 66.0 41.0 97.4 23.5 21.9 23.6 10.4 53.3 28.1 BS 125 187 122 172 146 155 109 170 191 191 208 185 134 MCS 2.90 3.66 3.22 8.58 2.75 5.96 6.18 5.68 7.12 8.33 2.98 4.69 4.82 2.29 8.88 8.25 2.77 4.45 3.09 3.02 3.10 3.02 3.58 1.85 1.36 6.21 SF 46.2 91.6 47.6 21.4 12.3 18.3 17.0 24.1 29.5 41.2 18.4 17.4 RR 5.93 9.87 0.41 2.05 4.71 2.01 70.0 65.7 27.3 10.8 100 186 655 842 820 475 TDA CDA 3,130 1,590 1,090 ) 2 area total total (mi drainage drainage Published ) ’ ” ’ o ( Longitude ) ’ ” o ( Latitude 41 25 56 25 41 08 42 99 0.40 0.41 Station name—remarks Nebraska Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations--Cont out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected Station number ber Map num- 7870 06787000 Calamus River near Harrop, Nebraska48 56 41 09 23 99 693 693 7875 06787500 CalamusNebraska River near Burwell, 34 48 41 55 10 99 994 994 7860 06786000 Nebraska Northat Taylor, River Loup 36 46 41 45 22 99 2,350 2,350 7850 06785000 Paul, NebraskaSt. MiddleLoup River at 54 11 41 50 26 98 8,090 8,080 7848 06784800NebraskaCreek near Dannebrog, Turkey 23 09 41 21 33 98 66.2 65.7 7847 06784700Creek near Farwell, Nebraska Turkey 14 13 41 45 40 98 27.2 27.3 7840 06784000 Michael, Nebraska Southat St. River Loup 53 01 41 24 44 98 2,320 2,320 7835 06783500 NebraskaSweetwater, Mud Creek near 14 02 41 34 59 98 707 711 7829 06782900 Nebraska Mud Creek tributary near Broken Bow, 31 22 41 16 38 99 5.90 5.93 7828 06782800 NebraskaBow, Broken NorthCreek at Branch Mud 35 24 41 44 39 99 15.5 15.8 7827 06782700 Nebraska Bow, Creek at Broken South Branch Mud 07 24 41 51 38 99 9.87 94.8 7826 06782600 SouthCreek tributary Branch Mudnear Broken Bow, 7825 06782500 Nebraska Southat Ravenna, River Loup 41 00 41 44 54 98 1,570 1,540 7800 06780000Rockville, Middle NebraskaLoup River at 38 41 06 19 50 98 5,310 5,310 7790 06779000Arcadia, MiddleNebraskaLoup River at 19 25 41 09 08 99 5,040 5,020 7780 06778000NebraskaSargent, MiddleLoup River at 35 37 41 15 22 99 4,480 4,490 7778 06777800Nebraska LillianCreek tributarynear Walworth, 32 37 41 12 34 99 2.04 2.05 7777 06777700Nebraska LillianCreek near Broken Bow, 35 30 41 26 39 99 4.77 4.71 7776 06777600Nebraska LillianCreek tributarynear Broken Bow, 12 30 41 29 39 99 2.02 2.01 Table B1.

B-8 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska 7.03 3.9 0.80 8.92 3.60 1.30 1.34 1.30 1.35 1.32 1.32 1.32 1.32 1.30 1.37 11.9 11.21 11.9 11.5 11.23 11.74 11.6 10.4 15.0 17.6 12.48 15.9 12.1 16.2 21.9 10.54 23.2 22.5 23.6 22.9 26.8 22.5 23.0 P60 MSS DF SR 0.207 0.051 1.71 0.604 0.033 0.103 0.310 0.056 0.464 0.058 0.600 0.079 0.793 0.136 0.770 0.130 0.758 0.142 1.33 0.255 0.369 0.054 0.419 0.176 0.543 0.120 0.616 0.140 0.737 0.209 0.865 0.216 0.336 0.062 0.517 0.076 0.320 0.066 0.14 2.98 0.18 0.27 0.09 4.74 0.12 3.94 0.18 1.62 0.08 5.57 0.20 0.60 0.20 0.61 0.20 0.61 0.20 0.60 0.10 4.65 0.20 0.60 0.20 0.60 0.20 0.60 0.20 0.60 0.20 0.60 0.10 4.96 0.20 0.60 0.09 5.19 PLP AWC inued 2.59 2.65 2.54 2.52 2.55 2.48 2.55 2.55 2.55 2.55 2.35 2.48 2.45 2.45 2.45 2.45 2.34 2.45 2.33 26.09 27.83 24.71 24.51 25.37 23.43 25.61 25.61 25.61 25.61 22.63 24.50 24.64 24.72 24.72 24.72 22.47 24.12 22.38 TTP MAP 2.95 0.808 1.52 2.29 2.88 0.280 3.77 1.09 1.74 1.16 8.20 3.20 1.53 1.40 1.72 1.38 1.62 1.42 1.73 1.76 5.37 1.32 1.73 1.13 1.54 1.25 1.43 1.35 1.38 1.40 1.32 1.11 5.80 1.36 1.61 1.17 6.28 1.41 SD CR Drainage-basin characteristics 5.6 6.4 6.3 9.6 7.2 7.5 5.3 8.2 9.2 8.0 43.3 26.2 61.6 91.2 22.4 17.9 17.1 84.4 21.5 30.0 19.4 18.9 23.5 24.3 111 113 112 BS 108 165 165 138 121 139 161 135 131 121 122 MCS 7.32 3.11 3.10 3.91 3.05 3.09 5.06 5.99 3.06 2.27 4.56 9.75 3.87 8.08 4.56 3.33 2.77 2.31 2.03 9.58 1.81 9.84 1.93 1.02 3.39 1.21 9.10 3.36 SF 13.6 13.6 56.4 14.5 13.5 23.7 15.2 19.8 39.0 42.6 RR 0.59 7.57 1.50 6.79 2.31 50.0 19.5 36.9 81.5 31.3 21.1 65.8 429 209 480 188 910 700 TDA CDA 1,240 ) 2 area total total (mi drainage drainage Published ) ’ ” ’ o ( Longitude ) ’ ” o ( Latitude Station name—remarks Mary’s Creek at Wolbach, NebraskaWolbach, Creek at Mary’s 00 24 41 39 23 98 7.63 7.57 Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations--Cont out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected Station number ber Map num- 7940 06794000NebraskaGenoa, Beaver Creek at 31 26 41 10 44 97 677 677 7939a 06793995Creek tributary Nebraska Skeedee near Genoa, 46 29 41 2352 97 0.59 0.59 7935 06793500Loretto, Beaver Creek atNebraska 50 45 41 50 04 98 311 372 7915 06791500near Spalding,NebraskaRiver Cedar 41 42 41 48 26 98 762 752 7920 06792000near Fullerton,River Cedar Nebraska 45 23 41 14 00 98 1,220 1,220 7911 06791100 SpringCreekNebraska near Cushing, 08 17 41 42 22 98 184 188 7909 06790900 7907 06790700at Brayton, Branch SpringNebraska Creek West 7908 06790800 NebraskaWolbach, near Branch Spring Creek West 27 27 41 00 26 41 38 28 98 04 26 98 19.5 36.9 19.5 36.9 7905 06790500Nebraska Paul, NorthSt. nearRiver Loup 34 15 41 50 26 98 4,290 4,300 7906 06790600Nebraska EastBranchSpring Creek tributary near Wolbach, 28 27 41 44 25 98 1.52 1.50 7895 06789500Cotesfield, Nebraska Davis Creek near 50 23 41 00 41 98 94.0 81.5 7894 06789400 DavisNorth of Loup, Nebraska Creek southwest 32 24 41 32 48 98 31.2 31.3 7893 06789300North Davis Loup, Nebraska Creek near 44 24 41 00 52 98 21.1 21.1 7892 06789200 DavisNorthnear Creek tributary Loup, Nebraska #2 45 25 41 15 54 98 6.79 6.79 7891 06789100 DavisNorth Creek tributary near Loup, Nebraska21 24 41 07 54 98 2.29 2.31 7889a 06788988 Mira Creek near North Loup, Nebraska 41 30 09 98 47 47 65.8 65.8 7890 06789000 Northat Scotia,River Nebraska Loup 30 27 41 39 42 98 4,100 3,970 7885 06788500 Northat Ord,River Nebraska Loup 26 36 41 16 55 98 3,760 3,760 Table B1.

APPENDIX B B-9 9.5 7.0 1.37 9.9 7.5 1.47 7.6 8.4 7.2 1.87 6.8 1.18 7.7 1.26 8.4 8.14 8.6 1.29 7.6 1.37 7.4 1.02 4.3 0.84 6.2 6.09 8.94 6.5 9.54 11.33 11.1 10.61 12.10 12.55 18.0 12.60 12.44 19.4 P60 MSS DF SR 0.075 0.074 0.107 0.035 0.058 0.106 0.106 0.044 0.080 0.203 0.042 0.103 0.034 0.166 0.079 0.092 0.010 0.153 0.219 0.118 0.316 0.043 0.080 0.052 0.322 0.087 0.063 0.113 0.229 0.208 0.768 0.133 0.052 0.076 0.348 0.042 0.007 0.151 0.10 4.26 0.19 0.51 0.08 4.87 0.19 0.56 0.09 4.58 0.08 5.00 0.07 5.14 0.19 0.68 0.08 5.37 0.19 0.39 0.20 0.53 0.12 3.21 0.20 0.55 0.19 0.57 0.19 0.23 0.18 0.29 0.15 2.20 0.12 3.93 0.11 3.71 PLP AWC inued 2.50 2.80 2.47 2.77 2.55 2.44 2.46 2.75 2.42 2.85 2.69 2.59 2.65 2.71 2.85 2.75 2.65 2.37 2.62 23.73 27.16 23.27 26.75 24.19 23.28 22.49 25.73 23.41 29.26 27.36 24.55 27.27 25.88 29.83 25.90 24.83 22.68 24.04 TTP MAP 2.87 0.508 2.12 0.612 2.63 0.521 1.69 0.593 1.89 0.381 2.73 0.481 2.731 0.397 1.59 0.569 2.65 0.195 1.42 0.834 2.28 0.913 2.56 0.453 1.60 0.862 1.61 0.416 1.33 0.919 1.27 1.15 1.93 0.386 3.55 1.18 0.187 1.85 SD CR Drainage-basin characteristics 5.2 5.2 5.8 6.5 8.3 5.5 8.6 7.9 6.5 4.7 8.1 6.5 6.0 7.4 8.9 11.6 70.8 54.9 41.0 53.6 51.8 86.1 76.0 12.8 91.2 13.3 71.7 31.1 48.8 79.3 58.9 BS 146 148 108. 150 153 149 177 MCS 7.13 2.75 5.71 2.79 6.06 3.03 2.82 3.42 2.46 3.60 6.25 3.19 6.48 4.51 3.78 6.37 4.75 3.86 3.10 6.06 4.49 6.32 2.38 2.84 6.26 1.25 4.22 0.69 4.28 1.18 1.18 2.70 4.12 2.82 3.84 4.79 SF 10.4 12.7 RR 6.51 8.75 25.4 139 736 150 740 204 289 206 294 121 174 670 TDA CDA 1200 1,790 1,020 4,100 6,230 ) 2 area total total (mi drainage drainage Published ) ’ ” ’ o ( Longitude ) ’ ” o ( Latitude 42 10 3710 42 01 40 97 137 139 Station name—remarks contributing drainage area apparent on 1:24,000-scale topographic maps Willow Creek near Foster, Nebraska—considerablenon- near Foster, Creek Willow Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations--Cont out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected Station number ber Map num- 7990b 06799080 7990 06799000 ElkhornNorfolk, Nebraska River at 1400 42 30 25 97 2,790 2,860 7995 06799500Uehling, Nebraskanear Logan Creek 50 42 41 15 31 96 1,030 1,020 7985 06798500 ElkhornNeligh, Nebraska River at 1907 42 40 01 98 2200 2290 7994b 06799450 NebraskaPender, at Logan Creek 39 06 42 59 41 96 731 736 7983 06798300Nebraska near Clearwater, Clearwater Creek 2008 42 9 12 98 210 182 7994a 06799423 North NebraskaCreek near Laurel, Logan 00 28 42 55 02 97 25.3 25.4 7975 06797500 ElkhornEwing,Nebraska River at 0316 42 10 20 98 1,400 1,420 7980 06798000 South ForkEwing, Elkhorn River at Nebraska2914 42 53 23 98 314 292 7969b 06796978 Holtnear Emmet,Nebraska Creek 19 25 42 46 51 98 -- 289 7993b 06799385 Nebraskaat Scribner, Pebble Creek 34 39 41 59 40 96 204 206 7955 06795500Columbus,near Shell Nebraska Creek 32 31 41 54 16 97 294 294 7993a 06799350 Point, Nebraska ElkhornWest River at 1150 41 32 43 96 5,100 4,680 7950 06795000Nebraskaat Newman Grove, Shell Creek 30 44 41 00 45 97 122 121 7992a 06799230 Unionat Madison, Nebraska Creek 51 49 41 18 27 97 174 174 7991b 06799190 SouthtributaryCornlea, Forknear Nebraska Union Creek 00 42 41 22 34 97 6.54 6.51 7947a 06794710 NebraskaCity, David Bone Creek near 41 16 41 51 02 97 8.75 8.75 7991 06799100 NorthElkhorn ForkPierce,Nebraska River near 4410 42 03 29 97 700 701 7945 06794500 Loup River at Columbus,Nebraska 05 25 41 45 21 97 15,200 15,200 Table B1.

B-10 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska 2.1 1.04 1.6 1.02 1.6 1.02 2.9 1.07 4.2 1.32 7.1 0.95 9.3 0.82 0.67 9.4 0.87 0.66 8.0 1.03 8.3 0.92 7.1 0.80 0.78 7.0 0.44 7.8 6.00 4.1 1.21 7.7 1.18 8.6 1.26 11.8 12.8 10.6 P60 MSS DF SR 0.156 0.224 0.140 0.642 0.137 0.849 0.299 0.129 0.299 0.379 0.369 0.078 0.690 0.119 0.664 0.288 0.778 0.162 2.38 0.202 0.380 0.254 0.502 0.112 0.272 0.149 0.643 0.181 0.257 0.062 0.117 0.042 0.161 0.229 0.201 0.042 1.91 0.000 0.19 0.19 0.19 0.18 0.19 0.18 0.19 0.21 0.19 0.29 0.19 0.25 0.18 0.23 0.17 0.19 0.18 0.22 0.17 0.18 0.19 0.23 0.19 0.24 0.18 0.22 0.18 0.20 0.16 0.15 0.15 2.34 0.19 0.21 0.20 0.46 0.20 0.44 PLP AWC inued 2.95 2.95 2.95 2.95 2.95 2.93 2.92 2.94 2.88 2.95 3.05 2.95 3.05 2.95 3.03 2.67 2.95 2.82 2.85 32.37 31.75 30.43 30.56 30.42 32.77 32.37 28.45 31.65 28.24 30.51 30.48 31.01 28.59 30.22 25.77 30.42 25.77 27.73 TTP MAP 2.13 0.708 2.30 0.707 1.86 0.770 1.98 0.832 1.51 0.654 1.54 1.03 1.53 1.37 1.47 1.25 1.37 1.50 1.35 2.54 1.34 0.892 1.57 1.25 1.40 0.812 1.67 1.50 1.64 0.779 2.57 0.588 1.42 0.637 2.02 0.767 1.19 1.55 SD CR Drainage-basin characteristics 7.4 9.1 5.8 4.4 9.9 0.0 6.6 11.6 11.9 33.1 14.2 12.8 10.9 45.1 61.3 23.2 21.7 42.3 30.8 28.6 27.6 17.9 19.8 10.4 43.5 69.9 110 BS 148 182 147 191 142 109 106 120 168 105 156 MCS 6.10 4.29 6.60 3.20 4.26 3.50 3.44 4.07 1.03 8.30 1.01 5.94 2.99 1.86 1.87 2.35 2.30 2.87 6.59 2.53 8.90 4.12 9.23 1.25 4.05 6.59 2.27 1.56 6.26 6.65 4.07 1.13 SF 10.9 17.2 14.5 23.2 14.0 17.2 RR 7.30 6.70 9.03 0.42 7.90 6.21 0.52 64.1 14.3 23.4 43.5 15.4 47.8 43.6 268 120 167 369 TDA CDA 5,870 ) 2 area total total (mi drainage drainage Published ) ’ ” ’ o ( Longitude ) ’ ” o ( Latitude Station name—remarks Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations--Cont out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected Station number ber Map num- 8045 06804500 NebraskaIthaca, at SilverCreek 43 09 41 38 31 96 80 77.0 8044 06804400 SilverCreek tributaryNebraska at Colon, 54 17 41 17 36 96 17.6 17.6 8043 06804300tributaryColon,near Silver NebraskaCreek 02 21 41 44 38 96 10.3 10.2 8042 06804200 SilverNebraskaCreek near Colon, 25 18 41 47 33 96 30.3 30.0 8041 06804100 NebraskaBluffs, SilverCreek near Cedar 48 22 41 15 35 96 7.00 7.01 8040 06804000Nebraskaat Ithaca, Creek Wahoo 40 8 41 09 32 96 271 273 8039 06803900Nebraska at Weston, Creek NorthWahoo Fork 19 12 41 39 43 96 43.3 43.5 8037 06803700 NebraskatributaryWeston, near Creek NorthWahoo Fork 00 13 41 00 49 96 8.90 9.03 8036 06803600near Prague, Nebraska Creek NorthWahoo Fork 37 15 41 47 48 96 15.2 15.4 8035g 06803570 Dunlap Nebraska Creek tributary near Weston, 41 12 24 96 48 46 0.43 0.42 8035e 06803540Alvo,near Nebraska Dee Creek 52 54 40 04 25 96 7.88 7.90 8035d 06803530Ceresco,Nebraska Rock Creek near 56 00 41 39 32 96 119 120 8035c 06803520 NebraskaCreek near Lincoln, Stevens 24 51 40 41 35 96 47.8 47.8 8035b 06803510Nebraska Little near Lincoln,Creek Salt 35 53 40 51 40 96 43.6 43.6 8030 06803000 Nebraskaat Roca, Salt Creek 29 39 40 54 39 96 167 167 8005 06800500Nebraska ElkhornWaterloo, River at 25 17 41 04 17 96 6,900 6,950 8003a 06800350 Elkhorn River tributary Nebraska near Nickerson, 34 30 41 06 33 96 6.53 6.21 8000 06800000Nickerson,near Nebraska Maple Creek 45 32 41 05 30 96 450 369 7998a 06799850 NebraskaSchuyler, near Pond Creek 15 31 41 33 03 97 0.54 0.52 Table B1.

APPENDIX B B-11 7.6 0.45 8.8 1.09 6.2 0.54 6.5 0.44 6.7 0.44 6.6 0.45 7.8 0.67 1.28 9.5 1.34 9.5 1.34 9.4 1.33 7.1 0.89 7.7 1.04 6.9 0.95 6.2 0.56 6.0 0.47 7.0 0.77 9.3 1.27 7.4 0.88 10.4 P60 MSS DF SR 0.268 0.064 0.040 0.032 0.207 0.042 0.301 0.103 0.494 0.167 0.369 0.143 0.493 0.228 0.583 0.523 0.047 0.050 0.039 0.052 0.296 0.031 0.220 0.078 0.337 0.119 0.194 0.287 0.189 0.557 0.388 0.173 0.695 0.278 0.372 0.052 -- -- 0.15 0.19 0.19 0.49 0.16 0.19 0.16 0.17 0.16 0.18 0.16 0.15 0.17 0.18 0.20 0.60 0.20 0.59 0.20 0.59 0.20 0.59 0.19 0.25 0.19 0.24 0.19 0.24 0.17 0.15 0.17 0.13 0.18 0.18 0.20 0.60 0.18 0.24 PLP AWC inued 3.21 3.20 3.10 3.05 3.05 3.05 3.05 3.15 3.05 3.05 3.05 3.06 3.05 3.05 3.05 3.05 3.05 3.05 2.97 -- 32.35 34.50 31.65 31.69 30.69 32.10 32.26 31.73 32.33 32.33 32.46 32.81 32.91 32.89 32.87 32.79 29.66 30.34 TTP MAP 1.59 0.879 1.94 0.423 1.74 0.771 1.59 0.931 1.52 1.06 1.71 1.02 1.48 1.06 1.25 0.841 2.11 0.576 2.01 0.589 1.23 0.739 1.80 0.769 1.64 0.951 1.41 0.634 1.28 0.423 1.28 1.02 1.35 1.23 1.63 1.04 -- -- SD CR Drainage-basin characteristics 8.4 4.7 6.6 9.8 9.8 5.3 1.4 -- -- 12.5 21.4 15.9 96.0 21.9 80.8 42.2 12.0 14.0 76.5 22.0 52.8 29.4 86.5 14.9 95.5 26.6 27.1 111 117 BS 131 145 155 121 128 197 187 168 153 MCS 4.43 5.10 8.74 3.17 2.76 3.20 2.30 5.24 3.79 2.29 6.03 3.49 0.639 5.90 8.70 6.60 2.05 2.52 4.00 1.74 5.60 1.53 7.39 0.761 9.44 1.32 5.72 0.700 1.71 0.81 -- -- SF 11.4 11.0 10.6 16.0 14.4 10.6 RR 8.11 3.43 3.38 5.28 4.32 -- 26.3 59.6 42.8 25.9 80.2 10.3 20.6 277 479 793 209 241 TDA CDA 1640 ) 2 area total total (mi drainage drainage Published ) ’ ” ’ o ( Longitude ) ’ ” o ( Latitude 40 51 46 51 40 43 06 96 0.73 0.73 Station name—remarks Nebraska Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations--Cont out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected Station number ber Map num- 8140 06814000 Kansas Seneca, near Creek Turkey 52 56 39 29 06 96 276 277 8130 06813000at Fairfax,MissouriRiver Tarkio 20 20 40 32 24 95 508 479 8115 06811500Auburn,Nebraska LittleNemaha River at 32 23 40 46 48 95 793 793 8105 06810500 LittleNemaha River near Syracuse, Nebraska 57 37 40 45 10 96 218 209 8103 06810300Syracuse, Nebraska Creek near Wolf 00 40 40 00 13 96 25.4 26.3 8102 06810200Palmyra,Nebraska Hoopernear Creek 00 43 40 00 19 96 57.6 59.6 8101 06810100 Hooper Creek tributary near Palmyra, Nebraska 40 46 09 96 25 22 8.00 8.11 8100b 06810060 HoneyCreek near Peru, Nebraska 38 26 40 1145 95 3.43 3.43 8077c 06807780 Iowa MiddleTreynor, Silver Creek at 36 14 41 53 36 95 42.7 42.8 8077b 06807760Oakland, MiddleSilver Iowa Creek near 27 19 41 18 33 95 25.7 25.9 8077a 06807720Iowa Avoca, MiddleSilver Creek near 33 28 41 05 28 95 3.21 3.38 8065 06806500at Union, Nebraska Creek Water Weeping 35 47 40 39 54 95 241 241 8064e 06806470 Water, tributaryWeeping Creek near Water Weeping 8064d 06806460Nebraska Water, at Weeping Creek Water Weeping 17 51 40 10 07 96 80.1 80.2 8064c 06806440at Elmwood, Nebraska Stove Creek 31 50 40 36 17 96 10.3 10.3 8064b 06806420Elmwood,near Nebraska Stove Creek 59 48 40 00 18 96 5.23 5.28 8064 06806400at Elmwood, Creek Nebraska Water Weeping 59 50 40 59 16 96 20.8 20.6 8055b 06805510Gretna, Nebraska Buffalo Creek near 12 06 41 30 13 96 4.29 4.32 8050 06805000NebraskaAshland,near Salt Creek 49 02 41 30 20 96 1640 1640 Table B1.

B-12 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska 8.8 1.29 8.3 1.29 4.58 7.2 1.49 2.89 5.82 9.7 5.53 4.11 0.83 7.0 1.00 1.29 0.83 8.6 1.24 6.2 0.48 7.6 0.46 7.7 4.95 7.3 0.48 7.9 5.13 10.3 10.7 17.3 13.01 10.8 10.1 10.0 20.3 10.0 P60 MSS DF SR 0.220 0.349 0.267 0.373 0.161 0.187 0.104 0.129 0.088 0.169 0.233 0.213 0.279 0.242 0.954 0.207 0.151 0.218 0.418 0.487 0.177 0.147 0.225 0.157 2.33 0.050 0.331 0.430 0.177 0.098 0.215 0.042 0.155 0.154 0.191 0.051 0.036 0.182 0.20 0.59 0.20 0.59 0.14 1.59 0.17 0.45 0.15 0.96 0.08 4.96 0.13 2.00 0.13 1.84 0.14 1.32 0.18 0.25 0.18 0.26 0.21 0.59 0.18 0.25 0.20 0.58 0.16 0.17 0.15 0.18 0.13 1.84 0.16 0.19 0.13 1.89 PLP AWC inued 2.25 2.25 2.09 2.11 2.06 2.15 2.07 2.06 2.05 3.45 3.25 3.35 3.25 3.25 3.21 3.20 2.10 3.13 2.16 20.80 18.43 16.78 16.51 16.28 17.67 16.71 16.50 16.54 38.47 34.28 35.96 33.37 34.08 32.57 32.54 18.26 31.70 18.12 TTP MAP 1.25 0.884 1.24 0.775 1.91 0.835 1.88 0.650 1.33 0.580 4.75 3.41 1.46 5.24 4.62 2.48 0.838 1.13 1.09 1.42 0.969 1.11 0.680 1.22 2.39 1.36 0.927 1.71 0.821 2.02 0.808 3.69 1.05 2.07 0.739 1.81 0.256 11.2 SD CR Drainage-basin characteristics 4.3 9.2 6.2 7.8 11.0 11.0 52.0 61.8 82.5 15.4 16.8 18.5 69.9 14.9 70.4 17.0 71.5 14.8 80.8 17.6 58.4 28.5 16.8 20.3 86.0 90.7 39.0 93.4 71.1 60.2 110 114 BS 148 166 131 129 149 153 MCS 2.14 2.50 4.04 6.83 8.82 9.58 3.58 9.74 7.00 6.05 3.81 6.74 9.55 2.65 4.84 1.69 2.15 2.38 3.84 4.73 4.46 2.55 6.34 5.64 5.12 3.01 1.02 5.54 SF 11.1 19.7 30.8 15.2 12.1 10.1 12.3 18.5 15.6 RR 157 9.10 3.75 8.60 2.39 5.66 4.44 0.43 3.03 270 174 186 380 549 TDA CDA 1,340 4,450 1,460 1,230 1,020 1,340 ) 2 area total total (mi drainage drainage Published ) ’ ” ’ o ( Longitude ) ’ ” o ( Latitude 40 29 20 29 40 3019 101 1,330 1,340 40 04 09 04 40 0503 102 2,370 2,360 Station name—remarks known to be much less based on stationbeknown 06835000 based much less to line Stinking Water Creek near Wauneta, Nebraska—CDA near Wauneta, Creek Water Stinking Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations--Cont out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected Station number ber Map num- 8345 06834500 8297 06829700 Thompson Canyon Nebraskanear Trenton, 40 09 44 100 57 31 9.06 9.10 8281 06828100 NorthMax,Nebraska Branch Indian Creek near 52 09 40 5123 101 4.76 3.75 8280 06828000at Max, NebraskaRiver Republican 10 06 40 4923 101 7,580 7,740 8255 06825500 Landsman nearCreek Hale, Colorado 39 34 31 102 15 06 268 270 8250 06825000 SouthIdalia, Colorado ForknearRiver Republican 59 36 39 3114 102 1,300 1,460 8235 06823500 NebraskaHaigler, Buffalo Creek near 8245 06824500 Republican River at Benkelman, Nebraska21 02 40 40 01 54 5651 101 101 32 30 172 4,830 4,870 172 8230 06823000 North Fork Republican River at Colorado-Nebraska state 8215 06821500 NebraskaHaigler, Arikaree River at 45 01 40 0958 101 1,700 1,700 8210 06821000Missouri JenkinsGower, Branch at 28 37 39 00 36 94 2.72 2.39 8200 06820000CreekCloud White near Maryville, Missouri22 23 40 32 54 94 6.00 5.66 8160 06816000Missouri MillCreek at Oregon, 55 58 39 04 12 95 4.90 4.44 8155c 06815550Branch near Burlington StaplesMissouri Junction, 15 26 40 04 12 95 0.49 0.43 8155b 06815510 NebraskaFallsCity, Creek near Temple 36 08 40 27 36 95 2.99 3.03 8155 06815500 Nebraska MuddyCreek at Verdon, 40 08 40 09 43 95 186 186 8150 06815000 NebraskaFallsCity, Nemaha River at Big 59 01 40 30 35 95 1,340 1,340 8350 06835000 Creek near Palisade, Stinking Nebraska Water 40 22 09 101 06 50 1,500 1,510 8145 06814500Humboldt, NorthNemaha River at Big Nebraska Fork 24 09 40 39 56 95 548 549 Table B1.

APPENDIX B B-13 2.4 1.29 1.31 1.32 1.36 1.33 1.33 1.30 1.30 1.30 1.32 4.34 1.31 1.30 9.42 1.29 6.40 1.30 6.6 1.72 6.3 1.28 11.4 16.0 17.8 10.8 20.3 19.7 25.7 26.0 26.8 19.3 19.2 23.9 25.8 19.8 14.1 15.1 P60 MSS DF SR 0.214 0.161 0.201 0.158 0.198 0.081 0.191 0.118 0.094 0.138 0.234 0.068 0.274 0.054 0.255 0.072 0.448 0.072 0.266 0.324 0.222 0.154 0.227 0.147 0.590 0.136 0.127 0.165 0.102 0.105 0.108 0.102 0.273 0.232 0.103 0.069 0.142 0.200 0.21 0.59 0.20 0.60 0.20 0.60 0.20 0.59 0.20 0.60 0.20 0.59 0.20 0.60 0.20 0.60 0.20 0.60 0.20 0.60 0.17 1.84 0.20 0.60 0.20 0.60 0.12 4.23 0.20 0.60 0.14 2.78 0.20 0.60 0.19 0.76 0.20 0.58 PLP AWC inued 2.25 2.45 2.35 2.35 2.35 2.35 2.34 2.35 2.35 2.34 2.26 2.29 2.25 2.26 2.35 2.25 2.35 2.25 2.25 18.20 22.93 22.21 21.05 20.99 20.87 20.90 21.00 21.00 20.83 21.01 20.88 20.94 20.25 20.39 18.75 20.71 20.38 21.15 TTP MAP 1.45 0.346 1.93 0.801 1.64 1.01 1.86 0.787 1.67 0.732 1.88 0.923 2.04 0.969 1.60 0.895 1.33 1.02 1.22 0.923 2.07 0.853 1.62 0.865 1.41 1.17 3.24 0.700 1.71 0.664 3.55 0.770 1.27 1.02 2.04 0.575 1.41 0.583 SD CR Drainage-basin characteristics 5.4 9.9 33.5 17.8 12.2 13.6 23.8 21.6 18.2 24.0 27.2 46.3 28.2 37.4 34.4 17.9 15.0 96.8 23.9 12.9 28.6 113 115 BS 149 172 318 338 333 378 143 183 255 253 108.6 142 103 186 143 MCS 0.50 8.55 8.59 3.94 7.81 7.08 9.66 5.60 3.90 8.07 3.48 1.69 2.20 3.13 7.86 2.00 1.94 5.88 4.40 6.36 1.48 5.04 6.66 2.38 SF 11.1 11.5 10.9 14.6 13.7 12.6 18.4 17.9 14.5 15.4 15.9 10.4 12.6 RR 15.1 4.68 6.78 11.3 74.6 52.2 21.4 72.5 25.6 31.4 13.4 72.0 13.2 79.0 68.9 18.3 28.2 242 194 320 TDA CDA ) 2 area total total (mi drainage drainage Published ) ’ ” ’ o ( Longitude ) ’ ” o ( Latitude Station name—remarks Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations--Cont out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected Station number ber Map num- 8448 06844800 SouthtributaryCreeknear Goodland, Fork Kansas Sappa 13 19 39 5637 101 4.98 4.68 8442a 06844210 Creek Turkey at Edison, Nebraska 40 16 14 99 43 59 74.9 74.6 8440 06844000 Nebraska MuddyCreek at Arapahoe, 19 18 40 39 54 99 246 242 8415 06841500Nebraska Mitchell Lake,Creek above Harry Strunk 19 28 40 2415 100 52 52.2 8405 06840500near Curtis, Dry Nebraska Creek 32 38 40 3926 100 20.0 21.4 8400 06840000Nebraskaat Curtis, Fox Creek 59 37 40 2029 100 72.6 72.5 8399b 06839950NebraskaCanyon near Curtis, Cut 39 43 40 0932 100 25.6 25.6 8399 06839900Curtis,near Nebraska above Cut Canyon Fox Creek 40 44 40 5131 100 31.8 31.4 8398a 06839850north FoxNebraska of Curtis, Creek 35 49 40 2431 100 13.8 13.4 8396 06839600Maywood, Frazier Nebraska Creek near 05 35 40 4537 100 11.3 11.3 8395 06839500Creek near Maywood, Nebraska Brushy 50 37 40 4637 100 95 108 8394 06839400 Elkhornsouthwest of Maywood, CanyonNebraska 20 37 40 5738 100 13.2 13.2 8392 06839200 Elkhorn Canyon near Maywood, Nebraska 40 36 10 100 42 02 6.74 6.78 8390 06839000 MedicineMaywood, Creek at Nebraska20 39 40 3936 100 231 256 8382 06838200 Coon Creek at Indianola, Nebraska 40 14 03 100 25 37 69.0 68.9 8373 06837300Lake, NebraskaHugh Butlerabove Creek Red Willow 05 24 40 4546 100 582 582 8371 06837100 Nebraska Ash Creek near Red Willow, 40 09 45 100 29 24 18.32 18.3 8360 06836000NebraskaCreek near Culbertson, Blackwood 09 14 40 3848 100 320 320 8351 06835100 Bobtailnear Palisade,Nebraska Creek 17 18 40 40 101 06 30.2 29.4 Table B1.

B-14 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska 1.31 9.6 1.27 6.3 1.21 1.29 8.0 1.35 2.4 1.29 7.7 1.31 7.3 1.29 6.6 1.29 5.8 1.27 5.9 1.29 7.5 1.35 1.29 2.3 1.20 5.8 1.31 2.2 1.15 2.1 1.11 4.9 1.29 3.5 1.14 12.1 10.4 10.4 P60 MSS DF SR 0.240 0.513 0.184 0.226 0.103 0.334 0.920 0.468 0.350 0.102 0.252 0.453 0.285 0.066 0.250 0.077 0.255 0.097 0.512 0.352 0.170 0.099 0.313 0.071 0.614 0.246 0.122 0.260 0.259 0.109 0.111 0.297 0.109 0.239 0.288 0.127 0.161 0.373 0.20 0.59 0.20 0.58 0.20 0.54 0.20 0.60 0.20 0.62 0.21 0.59 0.20 0.59 0.20 0.58 0.19 0.57 0.20 0.58 0.19 0.57 0.20 0.61 0.20 0.60 0.20 0.49 0.20 0.60 0.20 0.48 0.20 0.46 0.20 0.59 0.20 0.48 PLP AWC inued 2.55 2.47 2.45 2.45 2.33 2.25 2.28 2.24 2.22 2.25 2.20 2.30 2.35 2.55 2.27 2.48 2.47 2.27 2.48 24.32 23.37 23.68 23.36 20.66 19.14 20.14 19.42 18.81 21.58 18.29 20.53 21.43 25.66 19.68 24.44 24.08 18.87 24.34 TTP MAP 1.70 0.960 2.00 0.836 1.50 0.61 1.24 1.67 2.09 1.12 1.23 0.716 2.20 1.01 2.73 0.951 2.32 0.976 1.35 1.11 1.83 0.686 2.26 0.976 1.36 1.36 1.62 0.375 1.70 0.841 3.14 0.868 3.29 0.836 2.11 0.942 4.24 1.12 SD CR Drainage-basin characteristics 0.00 9.2 7.1 8.3 9.6 8.0 4.3 4.4 4.4 9.4 11.4 32.1 50.8 26.1 54.0 12.2 34.3 82.6 38.6 90.2 42.3 19.2 99.5 96.2 33.8 10.0 85.9 21.1 16.4 98.7 10.8 14.9 18.2 74.0 112 BS 108 107 101 MCS 9.15 4.61 4.83 6.88 5.72 2.75 6.01 3.09 9.69 6.02 2.94 5.61 5.48 5.70 9.76 6.74 2.15 5.73 7.22 8.78 5.29 0.89 3.99 3.12 5.85 6.61 1.88 2.72 3.51 2.82 6.82 SF 10.4 16.5 10.4 12.9 14.0 10.2 10.2 RR 1.09 7.94 9.77 8.20 56 16.7 19.4 30.9 27.0 18.4 125 583 378 TDA CDA 3,370 1,760 1,320 1,430 1,480 1,030 ) 2 area total total (mi drainage drainage Published ) ’ ” ’ o ( Longitude ) ’ ” o ( Latitude 40 19 09 19 40 02 00 99 11.5 11.5 Station name—remarks Nebraska Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations--Cont out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected Station number ber Map num- 8510 06851000Creek at Franklin, Nebraska Center 1106 40 44 58 98 177 180 8502 06850200Bloomington, Cottonwood Creek near Nebraska08 05 40 56 03 99 15.6 16.7 8500 06850000Naponee, NebraskaCreek at Turkey 33 04 40 16 08 99 129 132 8496 06849600NebraskaCreek near Holdrege, Turkey 33 19 40 04 22 99 22.9 22.6 8482 06848200Creek tributary PrairieDog near Norton, Kansas14 51 39 17 53 99 1.02 1.09 8479 06847900 Prairie Dog Creek above Keith Sebelius Lake, Kansas 39 46 13 100 05 59 590 583 8476 06847600Kansas Creek tributary PrairieDog at Colby, 27 23 39 4302 101 7.53 7.94 8475 06847500 NebraskaCreek Sappa near Stamford, 53 07 40 15 33 99 3,840 3,840 8470 06847000 NebraskaBeaver City, Beaver Creek near 1107 40 34 53 99 2,080 2,080 8465 06846500 KansasCedar Bluffs, Beaver Creek at 06 59 39 3433 100 1,618 1,670 8462 06846200 Beaver Creek tributary Kansas near Ludell, 52 48 39 1852 100 10.2 9.77 8460 06846000KansasLudell, Beaver Creek at 54 50 39 2957 100 1,411 1,430 8452 06845200 NebraskaCity, Creek near Beaver Sappa 45 2 40 23 53 99 1,481 1,480 8451 06845100Kansas Norcatur, Long Branch Draw near 06 54 39 4210 100 31.7 30.9 8513 06851300Hildreth,tributary Branch Thompsonnear Creek West 8512 06851200 Branch Thompsonnear Hildreth,Nebraska Creek West 09 20 40 16 00 99 110 104 8450 06845000Creek Sappa near Oberlin, Kansas 07 47 39 2734 100 1,086 1,030 8511 06851100 Branch Thompsonat Hildreth, Nebraska Creek West 39 21 40 40 01 99 63.9 63.9 8449 06844900 SouthCreekKansasnear Achilles, Fork Sappa 36 40 39 1843 100 446 426 Table B1.

APPENDIX B B-15 3.4 0.75 2.0 0.72 2.4 0.81 2.2 0.88 2.3 0.86 1.9 0.95 9.7 1.02 7.5 1.31 5.4 1.12 7.5 1.41 7.4 1.11 6.3 1.43 8.5 1.30 6.5 0.74 6.8 0.81 8.3 1.17 1.19 5.3 1.69 2.8 1.59 12.4 P60 MSS DF SR 0.073 0.515 0.197 0.607 0.304 0.115 0.221 0.116 0.198 0.129 0.259 0.124 0.343 0.170 0.262 0.086 1.08 0.833 0.253 0.096 0.212 0.411 0.391 0.081 0.276 0.071 0.508 0.572 0.148 0.220 0.226 0.112 1.36 0.192 0.142 0.242 0.105 0.240 0.18 0.13 0.18 0.19 0.18 0.25 0.18 0.30 0.18 0.28 0.19 0.35 0.16 0.38 0.18 0.54 0.19 0.38 0.19 0.60 0.19 0.42 0.20 0.63 0.20 0.59 0.18 0.17 0.17 0.18 0.18 0.49 0.20 0.53 0.20 0.71 0.20 0.65 PLP AWC inued 2.73 2.65 2.86 2.78 2.77 2.74 2.75 2.44 2.55 2.39 2.65 2.42 2.40 3.25 2.95 2.70 2.65 2.53 2.50 27.36 26.66 27.85 27.86 27.43 27.67 27.76 21.59 22.91 20.63 24.15 21.25 21.22 30.48 29.72 26.83 26.15 25.14 24.65 TTP MAP 1.48 0.395 2.74 1.16 1.69 0.948 2.04 0.716 2.74 0.705 2.39 0.746 1.43 1.08 2.29 0.989 1.15 1.20 2.19 0.969 1.42 0.719 3.10 1.13 2.50 0.983 1.38 1.14 1.79 0.723 1.55 0.910 1.36 1.93 2.38 0.700 2.78 0.831 SD CR Drainage-basin characteristics 5.7 9.7 8.3 4.8 5.0 4.6 9.2 9.4 9.3 7.5 3.7 11.1 16.0 72.6 40.9 38.3 37.0 17.8 10.0 70.7 58.9 10.9 42.5 31.4 18.0 75.6 16.6 96.5 10.9 48.2 30.9 15.4 116 114 114 BS 104 103 133 MCS 1.85 3.39 5.38 3.14 4.38 4.14 2.47 1.96 7.60 2.28 5.71 2.11 4.45 9.98 5.88 1.32 9.85 6.51 2.50 6.01 6.00 3.25 7.96 6.83 3.02 5.60 2.89 8.75 5.01 4.35 3.56 2.80 SF 11.5 26.0 18.0 22.7 16.1 10.4 RR 5.08 0.93 4.72 3.94 0.74 13.6 85.4 26.2 40.5 47.6 438 351 340 938 226 197 TDA CDA 1,110 1,670 1,040 ) 2 area total total (mi drainage drainage Published ) ’ ” ’ o ( Longitude ) ’ ” o ( Latitude 40 47 03 47 40 56 08 98 7.52 7.24 39 22 26 22 39 54 34 99 1,040 1,040 Station name—remarks Nebraska Kansas Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations--Cont out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected Station number ber Map num- 8807a 06880710tributary SchoolHarvard,Nebraska Creek near 59 34 40 59 03 98 13.1 13.6 8805c 06880590 Fork Big NorthBlue River tributaryBranch West at Giltner, 8805b 06880508Seward, PlumNebraska Creek near 49 55 40 31 04 97 85.5 85.4 8805 06880500Seward,NebraskaBlue River at Big 05 54 40 54 05 97 1,107 1,110 8800 06880000Nebraska LincolnCreek near Seward, 57 54 40 42 08 97 438 438 8799 06879900Surprise,Blue River at Big Nebraska 05 06 41 35 18 97 345 351 8745 06874500Ionia, KansasnearLimestone East Creek 52 41 39 19 20 98 25.6 26.2 8735 06873500 South Forkat Alton,River Solomon Kansas 33 27 39 36 56 98 1,720 1,670 8733 06873300tributaryStockton, Ash Kansas Creek near 15 26 39 16 22 99 0.89 0.93 8730 06873000 Reservoir, South ForkaboveRiver Webster Solomon 8726 06872600Bellaire, Kansas Oak Creek at 53 47 39 59 39 98 4.75 4.72 8715 06871500Stockton, Kansas Bow Creek near 46 33 39 04 17 99 341 340 8710 06871000 NorthKansasSolomon Forkat Glade,River 40 40 39 30 18 99 849 938 8568 06856800KansasCreek near Green, Moll 48 22 39 27 00 97 3.60 3.94 8561 06856100 KansasTalmo, Creek near West 00 40 39 47 36 97 42.0 40.5 8538 06853800 KansasBurr Oak, Rock Creek near White 54 53 39 05 15 98 227 226 8531 06853100Rosemont, Nebraska Beaver Creek near 46 15 40 30 22 98 0.75 0.74 8515 06851500Riverton, ThompsonNebraskaCreek at 20 05 40 38 45 98 290 293 8514 06851400near Upland, Branch Thompson Nebraska Creek West 31 17 40 09 56 98 128 147 Table B1.

B-16 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska 6.1 1.43 5.2 0.80 5.0 1.10 4.4 0.82 3.8 0.77 3.6 0.76 3.7 0.77 6.3 1.55 2.7 0.72 5.6 1.61 3.9 0.81 3.6 0.84 5.5 0.56 5.5 0.86 2.6 0.85 2.6 0.83 2.8 0.73 2.5 0.72 2.9 0.73 P60 MSS DF SR 0.170 0.126 0.177 0.458 0.107 0.283 0.116 0.192 0.120 0.278 0.212 0.276 0.098 0.186 0.193 0.141 0.493 0.165 0.131 0.218 0.208 0.057 0.189 0.069 0.228 0.111 0.128 0.129 0.185 0.092 0.139 0.118 0.080 0.408 0.061 0.831 0.060 0.673 0.19 0.43 0.19 0.17 0.18 0.20 0.19 0.17 0.19 0.13 0.19 0.12 0.19 0.12 0.19 0.53 0.18 0.14 0.19 0.66 0.18 0.25 0.18 0.26 0.17 0.18 0.19 0.22 0.18 0.27 0.18 0.25 0.18 0.16 0.18 0.17 0.18 0.15 PLP AWC inued 2.74 2.86 2.81 2.81 2.79 2.75 2.75 2.69 2.85 2.62 2.87 2.83 3.05 2.87 2.78 2.75 2.72 2.72 2.70 27.38 28.96 27.96 27.50 26.74 26.61 26.61 26.91 27.73 26.27 28.52 28.08 30.23 28.61 27.65 27.30 27.33 27.33 27.47 TTP MAP 2.02 0.728 1.23 0.485 1.91 0.526 2.68 0.505 1.70 0.572 1.46 0.529 1.30 0.138 2.14 0.793 1.49 1.19 1.66 0.694 1.96 0.765 1.84 0.730 1.61 0.805 2.07 0.633 1.79 0.690 2.06 0.614 1.59 0.385 1.39 0.184 1.42 0.284 SD CR Drainage-basin characteristics 6.0 6.9 2.0 5.8 7.6 3.1 6.3 5.4 6.4 3.8 4.1 7.6 5.2 4.8 5.2 7.1 8.7 11.5 47.9 40.6 18.6 30.2 27.5 36.2 10.0 16.8 44.6 32.8 29.3 66.2 59.0 69.0 40.5 52.0 43.9 17.3 13.8 12.9 BS MCS 4.26 2.60 1.47 6.30 4.03 0.86 5.95 3.02 3.41 3.31 2.05 5.84 0.13 2.90 5.28 2.75 2.69 6.53 2.39 3.02 3.30 1.82 2.77 1.92 4.14 5.06 5.68 2.87 2.31 2.07 4.05 2.40 1.89 2.74 0.50 3.45 0.96 2.96 SF RR 2.03 11.3 49.9 28.3 10.2 74.5 87.0 16.5 49.6 617 103 984 461 TDA CDA 2,360 1,560 4,370 3,830 2,710 1,190 ) 2 area total total (mi drainage drainage Published ) ’ ” ’ o ( Longitude ) ’ ” o ( Latitude Station name—remarks Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations--Cont out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected Station number ber Map num- 8840 06884000Nebraska LittleBlue River near Fairbury, 53 06 40 12 10 97 2,350 2,360 8839c 06883955Nebraska LittleCreek near Ohiowa,Sandy 36 25 40 38 23 97 11.6 11.3 8839b 06883940NebraskaCreek at Alexandria,Sandy Big 6 14 40 20 23 97 607 617 8839 06883900 South near Hebron,Creek Sandy Fork Nebraska Big 40 13 40 34 34 97 90.3 103 8838 06883800 near Carleton, SouthCreek Sandy Nebraska Fork Big 48 15 40 48 47 97 50.4 49.9 8837 06883700 South near Davenport,Creek Sandy Fork Nebraska Big 26 18 40 39 52 97 28.1 28.3 8836 06883600 Nebraska South near Edgar, Creek Sandy Fork Big 09 20 40 19 58 97 10.3 10.2 8835b 06883570 LittleBlue River near Alexandria (Gilead),Nebraska 27 12 40 26 23 97 1,560 1,560 8835a 06883540 SpringCreek tributaryNebraskanear Ruskin, 49 06 40 12 49 97 2.11 2.03 8830 06883000 Nebraska LittleBlue River near Deweese, 58 19 40 59 03 98 979 984 8820 06882000Barneston,Blue River at Big Nebraska 10 3 40 16 35 96 4,447 4,450 8815 06881500Beatrice, NebraskaBlue River at Big 00 15 40 00 45 96 3,900 3,890 8814a 06881450NebraskaBeatrice,at Indian Creek 07 17 40 46 44 96 74.7 74.5 8812 06881200 NebraskaCreek near Wilber, Turkey 48 28 40 43 00 97 461 461 8810 06881000 NebraskaBlue River near Crete, Big 47 35 40 35 57 96 2,710 2,710 8808 06880800 Nebraska ForkBlue River near Dorchester, Big West 51 43 40 38 10 97 1,192 1,190 8807d 06880740Saronville,near School Nebraska Creek 58 34 40 24 57 97 89.4 87.0 8807c 06880730tributary SchoolHarvard,nearNebraska Creek #2 41 36 40 35 02 98 16.4 16.5 8807b 06880720Harvard,near SchoolNebraska Creek 48 35 40 04 03 98 51.5 49.6 Table B1.

APPENDIX B B-17 0.48 0.36 0.31 7.0 0.53 6.0 0.35 6.4 1.25 9.6 0.62 6.8 0.75 9.2 0.58 11.4 10.0 14.5 P60 MSS DF SR 0.192 0.104 0.241 0.061 0.611 0.186 0.196 0.094 0.266 0.072 0.217 0.071 0.315 0.439 0.229 0.081 0.889 0.341 0.12 0.15 0.13 0.12 0.11 0.08 0.14 0.11 0.15 0.12 0.18 0.36 0.14 0.16 0.16 0.19 0.13 0.14 PLP AWC inued 3.35 3.35 3.35 3.19 3.27 2.83 3.15 3.03 3.05 33.75 35.28 31.71 30.77 33.13 28.35 31.80 30.92 30.33 TTP MAP 1.39 0.794 1.45 0.900 1.24 1.18 1.25 0.787 1.51 0.980 1.75 0.838 1.21 0.654 1.47 0.951 1.43 1.39 SD CR Drainage-basin characteristics 9.0 7.4 5.6 8.0 17.1 43.9 10.3 78.5 48.5 99.1 55.1 111 110 BS 163 149 235 103 162 MCS 3.01 9.05 3.15 6.86 2.66 2.17 6.25 1.05 3.73 4.86 2.95 1.36 2.89 4.05 2.59 SF 22.2 19.8 18.6 RR 3.17 4.50 14.7 34 136 240 174 410 TDA CDA 3,290 ) 2 area total total (mi drainage drainage Published ) ’ ” ’ o ( Longitude ) ’ ” o ( Latitude Station name—remarks Selected drainage-basin characteristics for streamflow-gaging stations in Nebraska and for selected out-of-state stations--Cont out-of-state selected for and Nebraska in stations streamflow-gaging for characteristics drainage-basin Selected Station number ber Map num- 8883 06888300Louisville, Kansas Rock Creek near 53 15 39 47 22 96 128 136 8880 06888000Kansas Creek near Wamego, Vermillion 59 20 39 09 13 96 243 240 8872 06887200 KansasCreek near Manhattan, Cedar 30 15 39 47 33 96 13.4 14.7 8865 06886500 KansasCreek at Winkler, Fancy 19 28 39 54 49 96 174 174 8855 06885500Frankfort,Kansas River near Black Vermillion 3 41 39 15 26 96 410 410 8844 06884400Kansas LittleBlue River near Barnes, 32 46 39 29 51 96 3,324 3,290 8843 06884300 Kansas MillCreek tributarynear Washington, 47 48 39 29 00 97 3.20 3.17 8842 06884200 Kansas MillCreek at Washington, 50 48 39 20 02 97 344 345 8840b 06884005 Dry Branch tributary Nebraska near Fairbury, 40 02 43 97 10 14 4.51 4.50 Table B1.

B-18 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska /s) 3 peak WY and dis- and WY of maximum maximum of 1967 13,000 1991 13,300 1947 5,500 charge (ft 1947, record 1951–93 1953–70 1960 698 1948–93 1949–52 Period of of Period peak-flow for regulated streams streams for regulated —regional equation— Type and length length and Type (years) of analysis , square, miles; >, greater than;<,less than; #, number; 2 rmeability—Composite; HPS, High-Permeability—Standard; LP3S, HPS, High-Permeability—Standard; rmeability—Composite; nd Western; PS, peak stage; R, River; REG, regulated; peak South; PS, S, stage; River;nd R, Western; REG, e k discharge computed from regression equations might not agree with sed on the regression analyses, whichused unrounded values of drainage-basin /s, cubic feetsecond; per mi 3 Basin characteristicsincomplete and/or remarks and/or /s) for given recurrence interval (years) (years) interval recurrence given for /s) No basin characteristicsNo basin 2 3 <1 mi <1 TDA Basin Basin characteristic(s) outside of range for equations —N&W— Appears to require composite frequency analysis—see fig. 5 fig. analysis—see frequency composite require to Appears 7 36 79 175 285 660 889 1,260 —N&W— Peak discharge (ft discharge Peak 68 270 500 892 1,270 3,590 4,900 6,980 —N&W— 86 386 754 1,410 2,050 4,790 6,860 10,360 —N&W— 47 231 463 878 1,300 2,260 3,170 4,670 —N&W— 90 378 711 1,270 1,830 3,620 5,020 7,300 —N&W— 2 5 10 25 50 100 200 500 105 467 866 1,510 2,080 1,730 2,310 3,240 —N&W— 100 322 693 1,280 1,890 5,960 8,330 12,200 —N&W— 129 594934 1,120 2,090 1,960 3,090 2,700 4,650 1,880 6,010 2,550 7,560 3,640 9,340 12,040 —N&W— —N&W— 232 810 1,430 2,450 3,410 6,770 9,280 13,400 —N&W— 437 1,190 1,910 3,070 4,120 8,560 11,200 15,300 —N&W— 819 1,980859 3,000 2,040 4,490 3,050 5,860 4,590 9,370 5,920 12,000 15,800 9,510 12,060 15,900 —N&W— —N&W— 124 488 891 1,560 2,190 3,450 4,680 6,670 —N&W— PS 674 1,640 2,500 3,820 4,940 6,160 7,480 9,350 LP3W 18 1964–81 1968 4,050 PS 59 133 200 303 394 496 610 779 LP3W 10 1969–78 1969 270 PSPS 16 23 48 42 82 143 56 202 74 272 89 355 103 486 117 LP3W 137 25 LP3W 1956–80 25 1980 275 1956–80 1965 86 PS 849 1,190 1,390 1,630 1,800 1,950 2,100 2,290 LP3W 19 1956–74 1968 1,550 PS 113 595 1,380 3,290 5,720 9,320 14,500 24,500 LP3W 24 1955–78 1966 6,160 PS 24 146 358 895 1,590 2,610 4,080 6,910 LP3W 26 1953–78 1953 3,050 PS 36 174 378 834 1,370 2,100 3,080 4,840 LP3W 18 1953–70 1965 740 PS Insufficient data—zero flow of for 18 peaks 11 PS 55 395 1,020 2,650 4,760 7,910 12,400 20,800 LP3W 26 1953–78 1962 2,740 CR 682CR 2,380 64 4,450 1,100 8,470 12,700 4,430 18,100 18,400 24,900 44,700 36,400 96,800 193,000 433,000 LP3W 43 LP3W 11 1905, 1983–93 1991 8,270 CR 322CR 806 872 1,290 1,680 2,120 2,340 2,900 3,330 3,850 4,160 4,970 5,080 6,760 6,090 7,560 LP3W 75 LP3W 13 1931-44, 1949–61 1957 4,480 CR 1,190 2,260CR 3,130 <1 4,400 5,460 27 6,610 254 7,860 2,480 9,670 10,100 34,400 161,000 LP3W 360,000 34 LP3W 1931–43, 26 1953–78 1963 188 CR 20 154 418 1,160 2,200 3,850 6,340 11,400 LP3W 11 1969–79 1977 5,670 type Gage Gage Station name (station skew—skew relations generalized skew—peak-flow regional equations or remarks) or equations regional skew—peak-flow (-0.251—Skew map -0.399—N&W) (——— -0.210—Newnetwork stationN&W for analysis) (-0.415—Skew N&W map, -0.259—N&W) (-0.238—Skew N&W map, ——) (-0.319—Skew map -0.378—N&W) (+0.103—Skew map, N&W -0.192—N&W) (-0.257—Skew map, HP, N&W -0.254—N&W) N&W (-0.257—Skew HP, map, (-0.152—Skew N&W map, -0.163—N&W) (——— station new used as inadvertently station *Out-of-state -0.271—Newnetwork stationN&W for analysis) -0.282—N&W)(-0.395—Skew map analysis frequency composite require to Appears (——— ———) (——— -0.211—N&W) (——— -0.151—Newnetwork stationN&W for analysis) (-0.091—Skew map -0.148—N&W)(-0.091—Skew map (——— -0.241—Newnetwork stationN&W for analysis) (-.0372—Skew -0.333—N&W) N&W map, (——— -0.318—Newnetwork stationN&W for analysis) , total drainage area; trib, tributary; UR, upper Republican River; W, West; WY, water year;total,drainage ft area; trib, WY, tributary;UR, upper Republican West; River; W, TDA Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations streamflow-gaging for data frequency Peak-flow Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, and drainage areas drainage and stations, out-of-state selected for and Nebraska in stations streamflow-gaging for data frequency Peak-flow Station Station number ber Map num- 3822 06382200 Pritchard Draw near Lance Creek, Wyo. 3964a 06396490Cr near Harrison, Nebr. Warbonnet 3962 06396200Edgemont, Fiddle Cr near S. Dak. 3963 06396300 CottonwoodEdgemont,near Cr tribDak. S. 3997 06399700Ardmore, Dak. near S. Pine Cr 4437 06443700 Soldiers Cr near Crawford, Nebr. 4433 06443300 Nebr. Deep Cr near Glen, 4000 06400000 HatCr near Edgemont,S. Dak. 4008a 06400875Oelrichs, HorseheadDak.* S. Cr at 4432 06443200 White R trib near Glen, Nebr. 4439 06443900#2 near Crawford,Nebr. R trib White 4440 06444000 White R at Crawford, Nebr. 4450 06445000 Nebr. Cr near Whitney, R below Cottonwood White 4455 06445500Nebr. R near Chadron, White 4455a 06445530 Chadron Cr trib Park at Chadron near Chadron, Nebr. State 4455b 06445560 Chadron at Cr Chadron Park near State Chadron, Nebr. 4455c 06445590 Big Bordeaux Cr near Chadron, Nebr. Table B2. streams regulated for areas drainage and Table B2. [BB, Big Blue River Branch; Basin; Br, C&SC, Central and South-Central; CR, continuous record; Creek; Cr, Fk, Fork; HPC, High-P drainage areasfor regulatedstreams from Boohar andProvaznik (1996) except asnoted. Note:values ofgeneralized skew and pea values intable for stationsused in the development of the respective equations because table values forthose stations are ba characteristics andequation coefficients] log-pearson Type III with station skew; LP3W, log-Pearson Type IIIwithlog-Pearson weighted IIIwithstation log-pearsonType Northern skew; North; skew; N, Type LP3W, NE, Northeast; a N&W, Southeast; SE,

APPENDIX B B-19 /s) 3 peak WY and dis- and WY of maximum maximum of 1965 1,190 1967 13,700 charge (ft record 1956–80 1980 575 1962–93 1956–80 1977 970 1951–93 1938–40, 1939–40, Period of of Period peak-flow —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or /s) for given recurrence interval (years) No basin characteristics characteristics basin No 3 Basin characteristics Basin incomplete 1962–79 Some basin characteristics unreliable No basin characteristics No basin Dak. S. in is Gage itself Peak discharge (ft 85 329 617 1,140 1,660 1,590 2,040 2,760 —N&W— 2 5 10 25 50 100 200 500 248182200 566 433 1,020 543 841 1,220 926436 1,180 1,780290 1,640 1,000 1,560 2,190 2,380 742 1,590 2,040258 2,680 3,410 1,230 2,360 2,610 3,450 500 4,220 2,130 3,710 3,570 5,490 3,060 644 4,640 —HPS— 466 4,110 5,740 —HPC— 1,120 965 —N&W— 5,060 7,500 1,390 1,790 6,530 1,720 3,000 —HPS— 4,200 2,110 —N&W— 2,790 7,540 9,200 12,000 —HPS— —N&W— 120 562 1,100 2,050 2,960 2,640 3,680 5,430 —N&W— 809 1,820 2,810 4,470 6,050 9,690 12,200 16,000 —N&W— 1,4801,030 2,820 2,190 3,790 3,070 5,290 4,170 6,780 5,510 8,500 7,140 10,500 13,800 9,130 12,400 —HPS— —HPC— 1,030 2,8301,240 4,630 3,180 7,620 5,070 10,400 11,200 8,170 14,000 11,000 18,600 14,000 18,600 26,000 —N&W— —N&W— 1,850 3,820 5,380 7,670 9,560 11,700 14,600 18,800 —N&W— 2,7602,290 5,030 4,690 6,100 5,860 9,010 9,140 11,200 12,000 14,000 15,600 17,400 20,000 22,800 27,300 —HPS— —HPC— PS 38 53PS 62 72 78 Out-of-state station onlyfor used relation(s) skew 84 89 9515 LP3S 1960-74 1962 65 PS 24 127 280 616 998 1,510 2,170 3,310 LP3W 15 1956–70 1968 548 PS 686PS 1,310 1,810 2,540 3,130 Out-of-state station onlyfor used relation(s) skew 3,770 4,460 5,440 LP3W 25 1956–80 1962 3,300 CRCR 79 313 111 662 130 1,010CR 152 1,600 692 167 2,200 1,460 2,930 181 2,230 3,850 3,620 5,400 194 5,020 211 LP3W 6,830 34 9,120 LP3S 21 13,100 1960–93 1991 LP3W 1938–40, 1966 50 3,540 154 1944–93 1967 4,640 CR 46 174 378 925 1,710 3,050 5,290 10,600 REG 38 1956–93 1977 2,120 CR 188 409 618 964 1,290 1,670 2,130 2,860 LP3W 35CR 1932, 1,690 3,660CR 5,630 9,100 855CR 12,500 1,600 1,370 16,800CR 2,220 22,200 3,090 1,610 31,300 3,130 4,700 3,860 3,900 7,310 LP3W 6,060 4,760 9,690 48 9,760 12,500 5,700 13,200 15,700 7,080 1930–32, 17,400 20,600 22,300 30,100 LP3W LP3W 13 45 LP3W 36 1961–74 1949–93 1962 1960 2,840 1958–93 9,810 1960 15,700 type Gage PS, CR 866 1,690 2,360 3,330 4,150 5,030 5,980 7,340 LP3W 50 1944–93 1947 5,200 ) CR 149 352 639 1,360 2,360 4,070 6,960 14,000 REG 47 1947–93 1951 4950 2 ) CR 52 84 111 152 188 229 277 350 REG 35 1958–92 1959 181 2 Station name , approximately) 2 (station skew—skew relations generalized (455 mi skew—peak-flow regional equations or remarks) (——— ———) (——— +0.678—New*out-of-state stationHPS stationnew station for inadvertently network as analysis) used N&W +0.404—HPS, HPC, N&W) (+0.642—HP, (-0.283—Skew map, N&W ———) (——— +0.268—HPS, N&W) (+0.235—HP, N&W +0.018—HPS, HPC, N&W) (+0.235—HP, (——— -0.381—N&W) N&W +0.246—HPS, HPC, N&W) (+0.458—HP, NE N&W, (+0.033—Skewmap, HP, -0.034—N&W) (+0.090—Skew map, N&W -0.237—N&W)(+0.090—Skewmap, N&W (-0.379—Skew ———) map (——— ———) NE N&W, (-0.228—Skew map, HP, -0.041—N&W) (-0.089—Skew -0.173—N&W) map Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations for streamflow-gaging data frequency Peak-flow Station number ber Map Map num- 4480 06448000Dak. S. Tuthill, refuge near Cr above Lake 4492a 06449250 Spring Cr near St. Francis, S. Dak.* 4497 06449700Cr near Mission,Dak. Little S. Oak 4495 06449500RDak. near Rosebud, Little S. White 4491 06449100S. Dak. R near Vetal, Little White 4541 06454100Agate, Nebr.R at Niobrara mi (840 4545 06454500 Nebr.Box Butte Reservoir, R above Niobrara (1,400 mi 4475 06447500RS. near Martin, Dak. Little White 4497b 06449750 W Br Horse Cr Mission,near S. Dak. 4505 06450500Dak. R S. below White R, Little White 4536 06453600 Nebr. Ponca Cr at Verdel, 4540 06454000 line state Wyoming-Nebraska R at Niobrara 4464 06446400 S. Cr Cain Dak. trib at Imlay, 4465a 06446550Dak. S. Interior, trib near White R 4534 06453400 Nebr. Ponca Cr near Naper, 4535 06453500 Ponca Cr at Anoka, Nebr. 4460 06446000S. Dak. near Oglala, White R Table B2. Table streams--Continued regulated for areas drainage and

B-20 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska /s) 3 peak WY and dis- and WY of maximum maximum of 1962 3,230 1962 9,130 charge (ft record Period of of Period peak-flow 1962–71 1947–93 1968 616 1946–93 —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or /s) for given recurrence interval (years) (years) interval recurrence given for /s) 3 Possibly affected by irrigation Possibly affected Regulated after 1965 No basin characteristics Appears to Appears require analysis composite frequency Appears to Appears require analysis composite frequency Basin Basin characteristic(s) outside of range for equations —N&W— Appears to require composite frequency analysis—see fig. 5 fig. analysis—see frequency composite require to Appears Peak discharge (ft discharge Peak 29 131 266 535 822 1,060 1,400 1,940 —N&W— 28 72 118 204 292 404 547 792 26 LP3W <1 253 5,840 146,000>1,000,000 ————— ————— 26 LP3W 2 5 10 25 50 100 200 500 140 523 955 1,710 2,440 3,010 4,010 5,610 —N&W— 148 565 1,060 1,920 2,810 4,020 5,500 7,910 —N&W— 247 348 423 544 594 753 943 1,290 —HPS— 263 484 596 858 1,170 1,440 1,760 2,320 —HPS— 160 827 1,430 2,410 3,390 4,130 5,390 7,270 —N&W— 282299 394 340 475 427 556 388 567 474 712 573 886 688 1,170 869 —HPS— —HPC— PS 11 507 1,640 3,580 4,900 5,910 6,630 7,230 LP3S 18 1953–70 1965 3,300 PS 8 57 154 438 854 1,550 2,640 5,040 LP3W 26 1953–78 1953 2,000 PSPS 95 238 2 377 230 611 1,330 5,260 827 10,100 1,080 16,000 22,100 1,380 29,700 1,840 LP3S 13 LP3W 26 1953–65 1953–78 1958 1955 1,900 444 PS 25 367 1,430 5,900 14,500 32,100 66,000 156,000 LP3W 28 1951–78 1951 28,100 PS 34 73 102 136 160 182 202 226 26 LP3S 1953–78 1977 130 CR 278 327 362 409 446 485 526 583 LP3W 12 1982–93 1991 367 CR 64 102 128 160 183 206 228 256 LP3S 17 1958–74 1968 147 CR 761 2,210 3,810 6,740 9,670 13,300 17,800 25,300 REG 15 1950–64 1951 7,330 CR 436 546 629 748 846 952 1,070 1,240 LP3W 22 1962–81 1962 820 type Gage Gage ) CR 186 223 263 332 400 483 585 758 REG 47 2 contributes directly to surface runoff) directly contributes to surface contributes todirectly surface runoff) 2 2 ) CR 771 1,970 3,420 6,420 9,910 14,900 21,900 35,700 REG 48 1929–32, ) CR 193 385 748 1,980 4,320 9,670 22,100 67,100 REG 10 1931–42, , approximately), CR 2,470 3,720 4,730 6,240 7,550 9,020 10,700 13,200 REG 30 1946–93 1949 10,200 2 2 2 ) CR 1,890 3,020 3,870 5,050 6,020 7,060 8,170 9,760 REG 10 1948–57 1951 4,170 2 Station name , approximately, of, which aboutapproximately, 44 mi , approximately, of which about 200 mi approximately, , 2 2 (station skew—skew relations generalized (drainage (drainage notarea published) (600 mi N&W network analysis) (390 mi skew—peak-flow regional equations or remarks) or equations regional skew—peak-flow (——— -0.132—N&W) (——— -0.157—N&W) (——— ———) (——— -0.148—Newnetwork stationN&W for analysis) (——— +1.060—New station for HPS network analysis) (——— +0.559—New station for HPS network analysis) (-0.627—Skew N&W map, -0.249—Newstationfor (+0.714—N&W +1.071—HPS,HPC) (——— +0.250—New station for N&W network analysis) Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations streamflow-gaging for data frequency Peak-flow Station Station number ber Map num- 4563 06456300 Pebble nearCr Dunlap, Nebr. 4562 06456200 Pebble Nebr. nearCr Esther, 4559 06455900Dunlap, Nebr.near Niobrara R (1,580 mi 4577 06457700at Gordon, Nebr. Antelope Cr 4578 06457800 Antelopetrib near Gordon, Cr Nebr. 4590 06459000 Nebr.at Cody, Niobrara R (5,570 mi 4555 06455500 Nebr.Box Butte Reservoir, below Niobrara R (1,460 mi 4591a 06459175 SnakeNebr. R at Doughboy, 4609 06460900 MinnechaduzaKilgore, Cr near Nebr. 4615 06461500Sparks,near Nebr. Niobrara R (8,090 mi 4564 06456400 CottonwoodNebr. Cr near Dunlap, 4592 06459200 Snake R above Merritt Nebr. Reservoir, 4610 06461000Nebr. MinnechaduzaValentine, Cr at CR 193 364 523 793 1,050 1,370 1,760 2,410 REG 46 1948–93 1960 1,100 4572 06457200Alliance, Nebr. Cr near Berea 4575 06457500 Niobrara R near Gordon, Nebr. (4,290 mi 4565 06456500Hay Springs, near Nebr. Niobrara R 4595 06459500 Nebr.R near Burge, Snake CR 370 471 552 673 777 893 1,020 1,220 REG 30 1947–93 1963 3,170 Table B2. streams--Continued regulated for areas drainage and

APPENDIX B B-21 /s) 3 peak WY and dis- and WY of maximum maximum of 1983 9,600 1960 39,000 1955 27,400 1967 2,070 1962 9,650 1952 5,430 charge (ft record Period of of Period peak-flow 1953–83, 1986 1959–93 1938–93 1977–93 1955–93 1950–93 —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or /s) for given recurrence interval (years) 3 Basin characteristics incomplete characteristics Basin Appears composite to require analysis frequency Basin characteristic(s) outside of range for equations —N&W— Basin characteristic(s) outside of range for equations —N&W— Basin characteristic(s) outside of range for equations —N&W— Peak discharge (ft 81 387 803 1,590 2,460 5,290 7,810 12,200 —N&W— 12 66 158 383 670 2,280 3,360 5,260 —N&W— 2 5 10 25 50 100 200 500 811 1,540 1,870 3,950 5,220 6,760 8,610 11,700 —HPC— 810453 1,680295 969 2,070 816 1,170 4,100 1,420 2,260 6,630 2,570 2,870 8,500 3,790 10,700 3,600 6,540 14,400 4,450 8,480 5,830 11,600 —HPS— —HPC— —N&W— 264 840 1,530 2,780 4,160 6,590 8,890 12,600 —N&W— 469 1,440447 2,510 1,430 4,290 2,530 6,160 4,360 8,440 6,260 11,400 16,100 7,700 10,500 14,900 —N&W— —N&W— 501 1,370 2,320 4,020 5,730 8,970 11,800 16,300 —N&W— 726 1,700 2,700 4,460 6,190 8,380 10,600 14,000 —N&W— 1,110 2,510 3,880 6,210 8,420 10,900 13,900 18,400 —N&W— 1,020 1,820 2,150 4,520 6,820 8,970 11,600 16,400 —HPS— 3,280 7,490 11,400 17,900 23,700 30,400 39,000 50,600 —NE— 1,480 2,810 3,300 7,610 12,100 16,100 21,000 29,300 —HPS— PS 71 349 843 2,250 4,320 7,900 13,900 27,900 LP3W 19 1956–74 1962 747 PS 70 227 435 897 1,450 2,270 3,430 5,750 LP3W 11 1958–68 1962 640 PS 15 48 88 171 262 385 547 838 LP3W 11 1968–78 1973 150 PS 8 54 152 482 1,040 2,120 4,120 9,400 LP3W 21 1958–78 1964 833 PS 24 90 185 410 692 1,120 1,750 3,040 LP3W 11 1958–68 1965 294 CR 5,260 7,700 9,620 12,400 14,800 17,500 20,500 24,900 REG 30 1928–36, CR 383 677 954 1,430 1,900 2,480 3,200 4,450 LP3W 45 1963–75, CR 372 438 481 536 577 619 661 718 LP3W 12 1980–91 1983 507 CR 133 242CR 2,930 336 9,100 486 16,400 30,600 621 45,700 65,400 780 90,800 135,000 965 1,260 LP3W 43 LP3W 13 1951–93 1957 1980–92 68,600 1992 329 CR 596CR 1,420 528 2,280 1,150 3,830 1,770 5,400 2,840 7,400 3,890 9,910 5,190 14,200 6,790 LP3W 9,480 13 LP3W 1979–91 13 1981 1981–93 3,300 1990 2,140 CR 985 2,080 3,200 5,250 7,360 10,100 13,600 19,900 LP3W 44 1949–53, CR 699 1,560 2,410 3,850 5,230 6,910 8,930 12,200 LP3W 46 1939–40, CR 1,800 3,610 5,230 7,820 10,200 12,900 16,100 21,100 LP3W 36 1958–93 1962 9,280 type Gage , approximately), CR 5,390 8,430 11,400 16,600 21,800 28,600 37,200 52,300 REG 30 1938–40, , approximately) CR 2,340 3,710 4,980 7,110 9,170 11,700 14,900 20,300 REG 21 2 2 Station name , approximately), 2 (station skew—skew relations generalized analyses) (12,100 mi skew—peak-flow regional equations or remarks) (+0.707—HP, N&W +0.770—HPS, HPC, N&W) (+0.707—HP, (——— ———) (——— +0.254—Newanalysis) stationN&W network for (——— +0.578—New station for HPS and N&W network (——— +0.371—Newanalysis) stationN&W network for (——— +0.015—Newanalysis) stationN&W network for NE -0.39—NE) N&W, (-0.034—Skew map, HP, (——— +0.220—Newanalysis) stationN&W network for (+0.093*—Skew map, N&W, NE(+0.093*—Skewmap, N&W, +0.318—N&W) ofon original +0.564 equation based value NE *Revised, (——— +0.177—Newanalysis) stationN&W network for (——— +0.273—Newanalysis) stationN&W network for (+0.470—HP, N&W +0.528—HPS, HPC, N&W) (+0.470—HP, (+0.086—HP, N&W +0.126—N&W) (+0.086—HP, (+0.022—HP, N&W(+0.022—HP, +0.212—N&W) Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations for streamflow-gaging data frequency Peak-flow Station number ber Map Map num- 4620 06462000 Niobrara R near Norden, Nebr. (8,390 mi 4625 06462500 Plum Cr at Meadville, Nebr. 4633 06463300near Ainsworth, Sand Draw trib Nebr. 4632 06463200 Bone Cr trib #2 near Ainsworth, Nebr. 4630a 06463080 Long Pine Cr near Long Pine, Nebr. 4656a 06465680 Nebr. Cr near Verdigre, N Br Verdigre 4658a 06465850 Bingham Cr near Niobrara, Nebr. 4665 06466500 Nebr. Cr near Niobrara, Bazile 4654a 06465440Redbird,Nebr. Redbird Cr at 4655 06465500 Nebr.R near Verdel, Niobrara (12,600 mi 4653 06465300 Cr Camp near O’Neill, Nebr. 4653b 06465310 Cr near Redbird,Nebr. Eagle 4652 06465200 Honey nearCr O’Neill, Nebr. 4635 06463500 Nebr. Long Pine Cr near Riverview, 4645 06464500 S. Dak. Keya Paha R at Wewela, 4649 06464900 Nebr. Keya Paha R near Naper, 4650 06465000 Nebr. R near Spencer, Niobrara Table B2. Table streams--Continued regulated for areas drainage and

B-22 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska /s) 3 peak WY and dis- and WY of maximum maximum of 1965 1,480 1969 40,400 1953 10,900 1953 2,540 1953 4,980 1944 9,600 1960 4,210 1967 3,150 charge (ft record Period of of Period peak-flow 1962–93 1993 6,300 1972–80 1946–93 19841949–93 17,000 19571966–93 29,400 19931897, 18,900 1948–93 1926, 1934, 1949–69 1953–65, 1968–73, 1976–77 1953–65, 1967, 1969 1981–93 1989–93 1967–78 —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or /s) for given recurrence interval (years) (years) interval recurrence given for /s) No basin characteristicsNo basin characteristicsNo basin characteristicsNo basin characteristicsNo basin characteristicsNo basin characteristicsNo basin characteristicsNo basin characteristicsNo basin 3 Appears to Appears require analysis composite frequency Peak discharge (ft discharge Peak 92 367 665 1,140 1,550 1,980 2,410 2,990 11 LP3S 2 5 10 25 50 100 200 500 913 2,120 3,240 5,100 6,810 8,750 10,700 14,200 —NE— 180 465 762 1,290 1,820 2,460 3,340 4,520 —NE— 2,430 5,490 8,330 12,900 17,000 21,700 26,700 34,800 —NE— PSPSPS Out-of-stateusedskew only for relation(s) station Out-of-stateusedskew only for relation(s) station Out-of-stateusedskew only for relation(s) station PS 1956-78 1965 1956–80PS 945 1978 1956–70, Out-of-stateusedskew only for relation(s) station 120 Out-of-stateusedskew only for relation(s) station PS 74PS 360PS 813 1,910PS 3,290 Out-of-stateusedskew only for relation(s) station 5,340 Out-of-stateusedskew only for relation(s) station 8,290PS 14,100 Out-of-stateusedskew only for relation(s) station 379 LP3W 1,360 11 2,630 1968–78 5,300 1970 8,310 12,400 1956-78 928 17,900 27,900 1969 1956–80 3,200 1960 LP3W 1956–80, 14 920 1964–65, CR Out-of-stateusedskew only for relation(s) station CR Out-of-stateusedskew only for relation(s) station CR Out-of-stateusedskew only for relation(s) station CR Out-of-stateusedskew only for relation(s) station 1939–69, CR 3,340 7,240 10,800 16,400 21,500 27,300 34,000 44,300 LP3W 15 1979–93 1984 21,400 type Gage Gage CR, PSCR, PSCR, Out-of-stateusedskew only for relation(s) station PS,CR Out-of-stateusedskew only for relation(s) station Out-of-stateusedskew only for relation(s) station Station name (station skew—skew relations generalized skew—peak-flow regional equations or remarks) or equations regional skew—peak-flow (+0.184—N&W ———) ———) NE (-0.070—Skew N&W, map, (-0.169—N&W ———) (+0.008—Skew ———) map map(-0.112—Skew ———) (+0.337—Skew ———) map ———)(-0.348—Skew map (+0.027—Skew ———) map ———)(-0.389—Skew map ———)(-0.200—Skew map ———)(-0.308—Skew NE map, (-0.392—Skew map ———)(-0.392—Skew map (——— -0.006—New stationNE for network analysis) (+0.072—N&W ———) NE (+0.266—Skew———) map, N&W, NE (+0.107—Skew———) map, N&W, (——— -0.108—NE) (——— -0.002—New stationNE for network analysis) Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations streamflow-gaging for data frequency Peak-flow Station Station number ber Map num- 4788 06478800 Saddlerock S. Cr near Canton, Dak. 4788b 06478820 SaddlerockDak. Beresford, near S. Cr trib 4788c 06478840 Saddlerock Cr near Beresford,S. Dak. 4790 06479000 S. Dak. Wakonda, R near Vermillion 4815 06481500Sioux SkunkS. Falls, Dak. Cr at 4826a 06482610 Split Rock Cr at Corson, S. Dak. 4835 06483500 Iowa Rock Valley, near Rock R 4840 06484000Iowa at Hawarden, Dry Cr 5998 06599800 PerryCr near Merrill, Iowa 5999a 06599950 PerryCr near Hinton, Iowa 6000 06600000 Iowa City, Sioux Perry Cr at 38th Street, 4786a 06478690Dak. S. near Parker, R Vermillion W Fk 4669a 06466950 Cr near Crofton, Weigand Nebr. 4782a 06478260 NBr Dry Cr near Parkston, Dak. S. 4782b 06478280 S Br Dry Cr near Parkston, S. Dak. 4783 06478300 Dry nearCr Parkston, S. Dak. 4785a 06478518Nebr. James, Bow Cr near St 4785b 06478520 W Bow nearCr Fordyce, Nebr. Table B2. streams--Continued regulated for areas drainage and

APPENDIX B B-23 /s) 3 peak WY and dis- and WY of maximum maximum of 1953 45,500 1971 18,100 1965 29,800 charge (ft record Period of of Period peak-flow 1953, 1956–93 1956–93 1962 8,060 1946–93 1939–69 19621966–90 12,400 19841940–93 3,150 19541919–25, 21,000 1929–32, 1937–93 1940–69 1965 29,700 1942–93 19781940–93 20,800 1983 31,200 —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or /s) for given recurrence interval (years) No basin characteristics No basin characteristics No basin characteristics No basin characteristics No basin characteristics No basin characteristics No basin characteristics No basin characteristics No basin characteristics No basin characteristics 3 Peak discharge (ft 2 5 10 25 50 100 200 500 241412 598 924 954 1,370 1,560 2,080201 2,120343 2,710 534 2,780 3,430 734 3,440 4,240 892 1,070 4,660 5,460 1,550 1,610 2,200 2,100 —NE— —East— 3,010 2,640 4,370 3,270 5,870 4,200 —NE— —East— 504549 1,370 1,190 2,310 1,750 3,980 2,610 5,620 3,370 7,610 4,240 10,800 14,300 5,200 6,640 —NE— —East— 1,0101,260 2,640 2,610 4,310 3,730 7,160 5,430 9,8302,170 6,900 13,000 5,630 17,000 8,520 22,400 9,130 10,300 15,000 12,900 20,500 —NE— 26,800 —East— 35,100 45,600 —NE— 3,0805,900 7,000 11,000 10,500 14,900 15,900 20,400 20,600 25,000 25,800 29,700 29,500 34,700 38,400 41,600 —NE— —East— 2,970 5,760 7,930 11,100 13,700 16,600 19,600 23,800 —East— PS 409PS 765 1,320 1,060 3,850PS 1,500 6,530 298 11,200 1,880PS 15,700 2,300 694 21,100 1,920 2,770 27,600 1,060 4,310 37,700 3,460 1,640 6,360 2,170 9,380 LP3W LP3W 2,760 18 11,900 18 14,600 3,440 1950–67 17,500 1950–67 4,460 21,600 1954 1957 10,100 1,410 LP3W LP3W 29 38 1950–78 1951–78 1954 1957 2,150 14,200 PS Out-of-state station onlyfor used relation(s) skew PS Out-of-state stationfor only relation(s) used skew PS 615 1,220 1,710 2,430 3,020 3,660 4,340 1966–89 5,320 LP3W 1969 18 5,300 1950–67 1950 2,580 PS 602 1,220 1,730 2,490 3,140 3,850 4,620 5,740 LP3W 29 1950–78 1950 5,000 CR Out-of-state stationfor only relation(s) used skew CR 3,400 6,590 9,060 12,500 15,100 17,900 20,700 24,600 LP3W 73 1940, CR Out-of-state stationfor only relation(s) used skew CR Out-of-state stationfor only relation(s) used skew CRCR Out-of-state stationfor only relation(s) used skew Out-of-state stationfor only relation(s) used skew CR Out-of-state stationfor only relation(s) used skew CRCR Out-of-state stationfor only relation(s) used skew Out-of-state stationfor only relation(s) used skew type Gage Station name (station skew—skew relations generalized skew—peak-flow regional equations or remarks) (-0.089—Skew ———) map (——— -0.539—NE, East) (-0.312—Skew ———) map (——— -0.004—NE, East) (——— -0.236—NE, East) (-0.414—Skew -0.166—NE,NE East) map, (-0.230—Skew -0.388—NE,NE East) map, (-0.296—Skew ———) map (-0.598—Skew ———) map (-0.493—Skew ———) map (+0.014—Skew map ———) (-0.189—Skew ———) map (-0.054—Skew ———) map (-0.505—Skew ———) map (-0.458—Skew ———) map (——— ———) (——— -0.204—NE, East) Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations for streamflow-gaging data frequency Peak-flow Station number ber Map Map num- 6001 06600100 Floyd R at Alton, Iowa 6010 06601000Nebr. at Homer, Omaha Cr 6003 06600300Iowa near Struble, FloydBr R W 6006 06600600 Nebr. tribCr near Walthill, S Omaha 6007 06600700 Nebr. S Omaha Cr near Walthill, 6008 06600800 Nebr. Walthill, tribCr #2 near S Omaha 6009 06600900 S Nebr. Omaha Cr at Walthill, 6020 06602000 W Fk Ditch at Holly Springs, Iowa 6021a 06602190Lawton,Iowa Elliott Cr at 6024 06602400 Iowa Monona-HarrisonTurin, Ditch near 6066 06606600Correctionville,at Little Sioux R Iowa 6067 06606700 IowaKennebec, at Little Sioux R 6067b 06606790Iowa Cr near Alta, Maple 6072 06607200 Maple R at Mapleton, Iowa 6075 06607500 Iowa Turin, near Little Sioux R 6077 06607700Craig, Nebr. Cr near S Br Tekamah 6078 06607800 Nebr. Cr trib near Tekamah, S Br Tekamah Table B2. Table streams--Continued regulated for areas drainage and

B-24 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska /s) 3 peak WY and dis- and WY of maximum maximum of 1990 30,800 1987 4,440 charge (ft record Period of of Period peak-flow 1918–25, 1938–93 1966–77, 1979–90 1955–76 1965 2,980 —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or /s) for given recurrence interval (years) (years) interval recurrence given for /s) No basin characteristicsNo basin No basin characteristicsNo basin characteristicsNo basin 3 Dam on S Br Tekamah Cr after 1980 Cr after Dam on S Br Tekamah Peak discharge (ft discharge Peak 45 186 356 663 968 1,640 2,160 2,970 —N&W— 2 5 10 25 50 100 200 500 773436 1,990 1,060 3,220 1,640 5,310 2,600 7,260 3,500 9,520 4,560 12,200 16,100 5,810 7,760 —NE— —East— 494 983 1,390 2,110 2,730 3,520 4,450 5,910 —HPS— 152256 380 579 616 870 1,030 1,350 1,430 1,790 1,920 2,310 2,540 2,920 3,460 3,850 —NE— —East— 171253 438 566 719 847 1,220 1,310 1,720 1,730 2,340 2,220 3,270 2,790 4,420 3,670 —NE— —East— 379577 941 1,240 1,510 1,820 2,480 2,740 3,410 3,580 4,510 4,540 5,900 5,620 7,910 7,260 —NE— —East— 697888 1,710 1,880 2,710 2,720 4,420 4,040 6,030 5,230 7,940 6,580 10,400 13,800 8,090 10,400 —NE— —East— 384610 927 1,320 1,450 1,940 2,340 2,940 3,180 3,860 4,140 4,890 5,180 6,090 6,960 7,870 —NE— —East— 1,0601,750 2,480 3,620 3,780 5,140 5,830 7,390 7,640 9,290 9,670 11,400 11,100 13,600 14,700 16,800 —NE— —East— 1,480 3,210 4,560 6,400 7,930 6,370 7,610 9,450 —N&W— 1,1001,580 2,730 3,160 4,330 4,460 7,040 6,420 9,580 8,130 12,600 10,000 16,600 12,100 21,800 15,100 —NE— —East— PS 1,290 2,130 2,720 3,480 4,040 4,600 5,160 5,910 LP3W 18 1950–67 1963 4,560 PS 459 876 1,220 1,710 2,130 2,580 3,070 3,780 LP3W 16 1952–67 1960 1,700 PS 242 629 1,010 1,660 2,250 2,950 3,760 5,020 LP3W 28 1951–78 1957 1,580 PS 1,250 2,090 2,700 3,530 4,180 4,840 5,540 6,490 LP3W 25 1951–75 1960 3,620 PS 776 2,080 3,410 5,730 7,940 10,600 13,800 18,800 LP3W 29 1950–78 1960 9,250 PS 303 677 1,010 1,510 1,930 2,410 2,920 3,680 LP3W 11 1968–78 1971 800 PSPS Out-of-stateusedskew only for relation(s) station Out-of-stateusedskew only for relation(s) station 1952–90 1958 17,300 PS 42 162 326 667 1,050 1,550 2,220 3,380 LP3W 25 1960–84 1961 2,100 CR 745 1,390 1,940 2,770 3,510 4,340 5,290 6,740 LP3W 63 1931–93 1967 5,110 CR 1,740 3,730CR 5,330 7,550 9,300 11,100 12,900 Out-of-stateusedskew only for relation(s) station 15,400 LP3W 31 1950–89 1963 6,180 1940–93 1993 23,400 CR 1,400 2,890CR 4,110 5,860 7,290 8,810 Out-of-stateusedskew only for relation(s) station 10,400 12,700 LP3W 24 1946–69 1950 5,500 CR Out-of-stateusedskew only for relation(s) station type Gage Gage is probably is noncontributing—modified fromothers, Boohar and 1992) 2 Station name , of which 1,930 mi of which 1,930 , 2 (station skew—skew relations generalized analyses) (22,200 mi skew—peak-flow regional equations or remarks) or equations regional skew—peak-flow (——— -0.401—NE, East) (+0.286—HP, N&W +0.025—HPS, N&W) (+0.286—HP, (-0.583—Skew map, NE ———)(-0.583—Skew NE map, (-0.651—Skew map, NE -0.473—NE,(-0.651—Skew East) NE map, (——— -0.168—NE, East) (-0.299—Skew map, NE -0.205—NE,(-0.299—Skew East) NE map, (-0.152—Skew map, NE -0.180—NE,(-0.152—Skew East) NE map, (+0.213—Skew -0.322—NE,NEEast) map, (-0.343—Skew map ———)(-0.343—Skew map (-0.369—Skew map, NE -0.322—NE,(-0.369—Skew East) NE map, (-0.065—Skew map ———)(-0.065—Skew map ———)(-0.402—Skew map ———)(-0.065—Skew map (——— -0.250—NewEastnetwork stationNE for and (——— -0.159—N&W) Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations streamflow-gaging for data frequency Peak-flow Station Station number ber Map num- 6079 06607900 Nebr. Cr near Tekamah, S Br Tekamah 6775 06677500 Nebr. HorseCr near Lyman, 6085 06608500 Soldier R at Pisgah, Iowa 6080 06608000 Nebr. Cr at Tekamah, Tekamah 6086 06608600 Nebr. near Spiker, Cr New York 6087 06608700 Cr trib Nebr. Spiker, near New York 6088 06608800 Nebr. northCr of Spiker, New York 6089 06608900 Cr Nebr. east of Spiker, New York 6095 06609500 Boyer R at Logan, Iowa 6090 06609000at Herman,Cr Nebr. New York 6095b 06609560 Cr near Willow IowaSoldier, 6105 06610500 Iowa Bluffs, Council Indian Cr at 6106 06610600 Mosquito Cr at Neola, Iowa 6107 06610700 BigPapillionCr near Orum, Nebr. 6745 06674500 N Platte R state lineat Nebraska-Wyoming CR 2,410 4,140 5,810 8,730 11,700 15,400 20,200 28,500 REG 36 1929–93 1929 17,900 6524 06652400 Draw near Lost Springs, Watson Wyo. Table B2. streams--Continued regulated for areas drainage and

APPENDIX B B-25 /s) 3 peak WY and dis- and WY of maximum maximum of 1965 7,880 1968 3,440 1917 19,500 1909 27,500 1899 24,900 1917 20,100 charge (ft record *Non-recurrentflow anomaly Period of of Period peak-flow 1932–93 1933–92 1978 516 1970–78 1921–93 1916–18, 1920–93 1902–06, 1915–93 1932–93 —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or /s) for given recurrence interval (years) 3 Appears composite to require analysis frequency Basin characteristic(s) outside of range for equations —N&W— Peak discharge (ft 2 5 10 25 50 100 200 500 260171 455 312 562 374 671 430 784 531 955 646 1,150450 779 1,470346 715 987 495 —HPS— 868 623 1,200 —HPC— 694 1,410 1,780 865 2,220 1,060 2,950 1,300 1,660 —HPS— —HPC— PS 14 82 199 501 897 1,500 2,380 4,130 LP3W 9 1968, CR 183 263 325 415 491 576 669 809 REG 60 CR 204 307 399 545 681 843CR 1,040 353 1,350 522 LP3W 670 63 908 1931–93 1,130 1938 1,390 720 1,700 2,220 LP3W 62 1932-93 1949 1,770 CR 359 690 968 1,390 1,740 2,140 2,590 3,250 REG 31 1949–79 1952 1,610* CR 380 640 841 1,120 1,360 1,610 1,870 2,260 REG 48 1932–79 1977 1,160 type Gage contributes directly to surface runoff) directly contributes to surface runoff) directly contributes to surface runoff) directly contributes to surface runoff) directly contributes to surface runoff) directly contributes to surface runoff) directly contributes to surface runoff) directly contributes to surface runoff) directly contributes to surface 2 2 2 2 2 2 2 2 ) CR 332 671 1,010 1,590 2,180 2,910 3,840 5,430 REG 31 1949–79 1951 2,010 ) CR 98 236 468 1,170 2,340 4,700 9,470 23,900 REG 62 1921, 2 2 ) CR 769 1,310 1,720 2,300 2,780 3,280 3,820 4,590 REG 48 1932–79 1956 2,320 2 is noncontributing) 2 Station name , approximately, of which about 22,300 mi of which about 22,300 approximately, , mi of which about 22,700 approximately, , mi of which about 23,300 approximately, , mi of which about 24,700 approximately, , mi of which about 25,400 approximately, , mi of which about 25,900 approximately, , mi of which about 26,100 approximately, , mi of which about 26,300 approximately, , —modified from Matthai,1968) 2 2 2 2 2 2 2 2 2 , of which about 25 mi 2 (station skew—skew relations generalized (28,600 mi (30,900 mi (drainage not published) area (29,800 mi (16,900 mi (29,400 mi (drainage not published) area (362 mi (24,700 mi (24,300 mi (25,300 mi (26,700 mi skew—peak-flow regional equations or remarks) (+0.984—HP, N&W +0.988—HPS, HPC) (+0.984—HP, (——— +0.233—Newanalysis) stationN&W network for N&W +1.035—HPS, HPC) (+1.182—HP, Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations for streamflow-gaging data frequency Peak-flow Station number ber Map Map num- 6790 06679000Mitchell, Dry Spottedtail Nebr. Cr at (15.0 mi 6875 06687500Nebr. at Lewellen,Platte R N 6930 CR 06693000 3,500Platte, at NorthPlatte Nebr. R N 5,630 7,390 10,100 12,400 15,100 18,100 22,800 CR REG 2,640 36 3,860 1941–93 4,900 6,520 1968 13,500 7,980 9,690 11,700 14,900 REG 53 1895–1993 1909 29,600 6800 06680000 Springs Tub near Scottsbluff, Nebr. 6840 06684000 Nebr.Cr near Bayard, Willow Red mi (162 6850 06685000Bridgeport, Pumpkin Nebr. Cr near (1,020 mi 6870 06687000 Blue Cr near Lewellen, Nebr. 6876 06687600 Ash Hollow near Oshkosh, Nebr. 6910 06691000 near Sutherland,PlatteNebr. R N 6920 06692000 Nebr. Birdwood Cr near Hershey, 7600 06760000 Colo.at Balzac, S Platte R CR 2,360 3,390 4,280 5,700 6,990 8,520 CR 10,300 13,200 3,420 9,300 REG 16,400 53 31,400 48,600 1937–93 73,100 107,000 174,000 1971 9,090 REG 65 1916–80 1965 123,000 6905 06690500 Nebr. near Keystone, Platte R N CR 2,920 4,110 5,090 6,570 7,870 9,360 11,100 13,700 REG 53 1942–93 1983 9,470 6810 06681000 Cr near Winters Scottsbluff, Nebr. 6820 06682000Nebr. near Minatare,Platte R N CR 2,970 5,220 7,190 10,300 13,200 16,600 20,600 27,000 REG 36 1916–19, 6780 06678000 Sheep Cr near Morrill, Nebr. 6795 06679500Nebr. at Mitchell,Platte R N CR 2,180 4,170 6,150 9,660 13,200 17,800 23,600 33,900 REG 36 1901–11, 6845 06684500 at Bridgeport,PlatteNebr. R N CR 3,380 5,710 7,780 11,100 14,300 18,000 22,500 29,800 REG 36 1897–1900, 6860 06686000Nebr. at Lisco,Platte R N CR 3,180 5,190 6,950 9,760 12,400 15,400 19,100 25,000 REG 36 1916–17, Table B2. Table streams--Continued regulated for areas drainage and

B-26 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska /s) 3 peak WY and dis- and WY of maximum maximum of 1962 3,110 1921 35,600 1965 37,600 1968 4,560 1935 37,100 1962 1,600 1962 1,970 charge (ft –93 1983 14,700 record Period of of Period peak-flow 1951–70 1904–06, 1916–24 1906–07, 1948–93 1951–79 1914–15, 1917, 1921–93 1960–81 1981 158 1951–70 1951–78 —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or /s) for given recurrence interval (years) (years) interval recurrence given for /s) No basin characteristicsNo basin 3 Basin Basin characteristic(s) outside of range for equations —N&W— Basin characteristic(s) outside of range for characteristic(s) Basin equations Peak discharge (ft discharge Peak 28 153 342 749 1,210 1,910 2,760 4,210 —N&W— 74 323 654 1,320 2,030 3,640 5,130 7,670 —N&W— 2 5 10 25 50 100 200 500 116 468 914 1,770 2,660 3,830 5,320 7,790 —N&W— 143 519231 983 768 1,890 1,390 2,830 2,560 6,070 3,740 8,460 6,580 12,400 8,990 13,000 —N&W— —N&W— 393 1,150 1,980 3,490 4,970 6,940 9,200 12,800 —N&W— PS 95 618 1,610 4,430 8,430 15,000 25,200 47,100 LP3W 46 1947–48, PS 22 71 127 234 344 486 664 964 LP3W 27 1952–78 1962 435 PS 196 535 885 1,490 2,070 2,760 3,580 4,880 LP3W 20 1951–70 1962 2,320 PS Out-of-stateusedskew only for relation(s) station PS peaksflowdata—zero8 of 11 Insufficientfor 1968-78 1968 820 PS Out-of-stateusedskew only for relation(s) station 1960–84 1967 528 PS 159 722 1,540 3,390 5,560 8,610 12,800 20,400 LP3W 32 1947, PS 68 361 829 1,960 3,350 5,390 8,250 13,700 LP3W 24 1947, CR 2,870 7,970 14,000 25,900 39,000 56,700 80,500 124,000 REG 49 1902, CR 384 937 1,450 2,270 3,000 3,820 4,750 6,120 LP3W 32 1947–78 1947 2,800 type Gage Gage contributes contributes todirectly surface runoff) contributes todirectly surface runoff) contributes todirectly surface runoff) 2 2 2 ) CR 50 176 423 1,290 2,920 6,540 14,500 41,100 REG 29 1931, ) CR 195 924 2,200 5,770 11,000 20,000 35,000 70,200 REG 61 1932–92 1950 16,500 2 ) Staff 15,700 24,600 30,100 36,500 40,900 45,000 48,800 53,400 REG 8 1902, 2 2 ) CR 1,700 6,670 13,000 25,500 38,800 55,700 76,900 112,000 REG 30 1940–1969 1965 33,800 2 Station name —modified from Ugland and others, 1994) approximately), of , approximately, which about 51,400 mi of , approximately, which about 51,700 mi of , approximately, which about 51,600 mi 2 2 2 2 2 (station skew—skew relations generalized (56,200 mi (23,200 mi (24,300 mi (56,500 mi (56,300 mi skew—peak-flow regional equations or remarks) or equations regional skew—peak-flow (-0.010—Skew map -0.144—N&W)(-0.010—Skew map (-0.062—Skew map -0.144—N&W)(-0.062—Skew map (——— -0.145—N&W) (+0.090—Skew ———) map (——— -0.067—Newnetwork stationN&W for analysis) (-0.386—Skew map, HP, N&W ———) N&W (-0.386—Skew HP, map, (-0.279—Skew map -0.148—N&W)(-0.279—Skew map (+0.081—Skew -0.160—N&W) map (-0.434—Skew map -0.150—N&W)(-0.434—Skew map Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations streamflow-gaging for data frequency Peak-flow Station Station number ber Map num- 7673 06767300 Plumat Farnam, Cr tribNebr. 7672 06767200trib NPlumFk near Farnam, Nebr. Cr 7671 06767100 S Fk Plum Cr trib near Farnam, Nebr. 7648a 067648807650 area not published) (drainage Nebr. at Roscoe, Platte S R 06765000 at Paxton,Platte S Nebr. R CRmi (24,000 3,380 6,760 10,000 15,700 21,400 28,400 37,100 52,000 REG 11 1983 7660 06766000Nebr. at Brady, Platte R CR 3,430 7,090 10,900 18,000 25,400 35,100 48,000 71,100 REG 53 1938–93 1983 23,500 7640 06764000 Colo. at Julesburg, Platte S R 7665 06766500 Nebr.near Cozad, Platte R 7670 06767000near Lexington,Nebr. Platte R (61,300 mi CR 3,240 7,560 11,700 18,600 25,100 32,700 41,600 55,800 REG 52 1940–92 1983 21,500 7655 06765500Platte, at NorthPlatte Nebr. S R CR 2,330 6,920 12,500 23,800 36,400 53,800 77,200 120,000 REG 77 1897, 7619 06761900 Lodgepole Cr trib near Pine Bluffs, Wyo. 7625 06762500 LodgepoleCr at Bushnell, Nebr. (1,350 mi 7635 06763500 Lodgepole Cr near Ralton, Nebr. (3,310 mi 7632 06763200 Lodgepole Cr trib near Sunol, Nebr. 7626 06762600 Lodgepole Cr trib #2 near Albin, Wyo. 7674b 06767410 Plum Cr near Farnam, Nebr. 7675 06767500 Plum Cr near Smithfield, Nebr. 7674 06767400 N Plum Cr near Farnam, Nebr. 7680 06768000near Overton, Nebr. Platte R CR 5,270 9,250 12,800 18,700 24,100 30,700 38,600 51,400 REG 53 1915–93 1935 37,600 Table B2. streams--Continued regulated for areas drainage and

APPENDIX B B-27 /s) 3 peak WY and dis- and WY of maximum maximum of charge (ft record Period of of Period peak-flow —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or /s) for given recurrence interval (years) No basin characteristics No basin characteristics No basin characteristics 3 Appears composite to require analysis frequency Peak discharge (ft 14 45 77 131 184 243 311 419 —C&SC— 2 5 10 25 50 100 200 500 182 535 890 1,520 2,130 2,840153 3,630 334 4,890 477 —C&SC— 688 871 1,060 1,260 1,560 —C&SC— 11 53 111 231 364 540 765 1,150 —C&SC— 37 134 248 463 680 950 1,280 1,800 —C&SC— 39 155 298 577 866 1,230 1,680 2,410 —C&SC— 59 155 243 382 507 650 811 1,050 —C&SC— 96 306 534 941 1,3401,820 2,380 3,270 —C&SC— 13 55 115 7 232 357 519 722 1,060 —C&SC— Appears to requireforAppearsflow compositezero to analysis6 of 15 peaks frequency — 106 329 569 159 470 996 1,410 794 197 1,910 1,360 573 2,500 1,900 963 3,420 2,540 1,630 3,290 2,270 4,460 3,030 —C&SC— 3,900 5,250 —C&SC— —C&SC— 108 344 601 1,060 1,500 2,030 2,660 3,630 —C&SC— PS 168PS 428PS 117 666 371 189 1,030 648 606 1,340 1,140 1,060 1,680 1,600 1,860 2,050 2,160 2,630 2,570 2,820 3,530 3,840 4,590 LP3W 29 6,210 LP3W 1952–78 29 LP3W 27 1954 1952–78 790 1952–78 1958 2,390 1960 1,750 PSPS 10 20 37 78 67 147 124 277 179 408 245 568 323 760 444 1,060 LP3W 27 LP3W 27 1952–78 1952–78 1972 1978 100 194 PS 57PS 99 183 129 311 168 400 198 515 227 601 256 687 294 771 LP3W 28 883 1951–78 LP3W 1965 28 148 1951–78 1965 679 PS 24PS 102 37 203 126 404 225 613 400PS 876 567 1,200 45 1,710 765 177 994 LP3W 344 15 1,350 673 1951–65 LP3W 1,020 28 1958 1,450 1951–78 172 1,990 2,880 1958 479 LP3W 28 1951–78 1965 1,660 PS 85 345 673 1,300 1,950 2,750 3,720 5,260 LP3W 17 1951–67 1958 1,570 PS 13PS 66 18 144 66 317 122 515 222 787 320 1,140 1,780 436 572 LP3W 14 782 1965–78 LP3W 1968 28 243 1951–78 1958 208 CR 217CR 703 136 1,270 253 2,360 3,500 341 4,950 461 6,770CR 555 9,840 305 652 1,440 LP3W 23 750 3,100 6,790 1947–69 885 11,100 17,000 1947 25,000 LP3W 9,000 10 39,300 1949–58 LP3W 12 1958 1947–58 383 1947 8,000 type Gage contributes directly to surface runoff) directly contributes to surface runoff) directly contributes to surface runoff) directly contributes to surface 2 2 2 Station name , approximately, of which about 55,300 mi of which about 55,300 approximately, , mi of which about 52,500 approximately, , mi of which about 52,900 approximately, , 2 2 2 (station skew—skew relations generalized (57,300 mi (57,600 mi (58,100 mi skew—peak-flow regional equations or remarks) (-0.985—Skew -0.330—C&SC) map (-0.375—Skew -0.330—C&SC) map (-0.479—Skew -0.340—C&SC) map (-0.793—Skew -0.325—C&SC) map (-0.436—Skew -0.330—C&SC) map (——— -0.300—C&SC)(——— (——— -0.320—New station for C&SC network analysis) ———)(-0.480—Skew map ———) map (-0.114—Skew (——— ———) (+0.399—Skew map -0.320—C&SC) (-0.359—Skew -0.330—C&SC) map (——— -0.330—New station for C&SC network analysis) (——— -0.330—C&SC)(——— (-0.587—Skew -0.320—C&SC) map (——— -0.330—New station for C&SC network analysis) Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations for streamflow-gaging data frequency Peak-flow Station number ber Map Map num- 7708 06770800 R near Oconto, Nebr. Wood 7709 06770900at Oconto, Nebr. R Wood 7709b 06770910 R near Lomax, Nebr. Wood 7707 06770700 R near Lodi, Nebr. Wood 7702 06770200 Nebr. Platte R near Kearney, 7705 06770500 Platte R near Grand Island, Nebr.7706 06770600trib Nebr. near Lodi, R Wood CR CR 5,970 6,310 10,500 10,800 14,900 13,800 22,400 19,200 29,800 23,800 39,200 28,900 51,000 34,600 71,400 43,000 REG 12 REG 53 1982–93 1934–93 1983 23,700 1935 30,000 7685 06768500Nebr. Cr near Darr, Buffalo 7690 06769000Cr near Overton, Nebr. Buffalo 7691 06769100 Elm Cr trib near Overton, Nebr. 7693 06769300 Elm Cr trib #2 near Overton, Nebr. 7700 06770000 Platte R near Odessa, Nebr. CR 5,710 10,200 13,800 19,200 23,800 28,900 34,600 43,100 REG 53 1937–93 1983 22,900 7683 06768300 Cr Buffalo trib #2 near Nebr. Buffalo, 7684 06768400 W Buffalo Cr Buffalo,near Nebr. 7692 06769200 Elm Cr near Nebr. Sumner, 7695 06769500 Elm Cr near Overton, Nebr. 7682 06768200 Nebr. Cr at Buffalo, Buffalo 7681 06768100 Nebr. Cr near Buffalo, Buffalo East 7680b 06768050 Cr Buffalo trib #1 near Nebr. Buffalo, Table B2. Table streams--Continued regulated for areas drainage and

B-28 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska /s) 20 3 peak WY and dis- and WY of maximum maximum of 1947 20,000 1952 2,440 1978 1983 1,290 1962 3,200 1957 10,400 1947 41,000 1947 930 1905 44,100 charge (ft record Period of of Period peak-flow 1947–80 1958, 1961-64 1946–93 1953–70 1968–75 1968–75 1951–78 1911–15, 1911–15, 1928–93 —regional equation— Type and length length and Type (years) of analysis 2 <1 mi <1 TDA and/or remarks and/or /s) for given recurrence interval (years) (years) interval recurrence given for /s) 3 Peak discharge (ft discharge Peak 2 5 10 25 50 100 200 500 504 799 971 1,350 1,580 2,000 2,510 3,340 —HPS— 456589 648 684 767 832 929 850 961 1,040 1,210 1,260 1,500 1,520 1,990 1,940 —HPS— —HPC— 331 447 527 638 637 808 1,010 1,350 —HPS— 1,990 3,060 3,3902,2802,220 4,600 3,570 3,300 5,080 4,040 4,000 6,350 5,520 4,660 7,830 6,060 5,930 10,500 7,630 7,440 9,490 9,260 —HPS— 12,500 12,200 —HPS— —HPC— 2,4402,800 3,840 4,220 4,4903,530 5,240 6,170 5,760 6,6604,460 6,810 7,020 8,570 7,330 8,620 9,750 10,9003,780 9,180 10,800 11,000 13,700 6,340 13,000 14,300 14,000 18,400 12,400 14,800 17,500 17,500 19,000 23,200 21,000 —HPS— 23,900 —HPC— 28,800 32,000 38,700 —HPS— 55,600 —HPS— —HPS— 6 20 33 56 76 101 129 173 —C&SC— 27 125 260 545 858 1,270 1,800 2,700 —C&SC— 33 143 290 591 918 1,340 1,880 2,790 —C&SC— 579 1,340 2,020 3,080 4,010 5,050 6,210 7,900 —C&SC— 476 1,100 1,640 2,480 3,210 4,020 4,900 6,200 —C&SC— 589 1,340 2,000 3,010 3,880 4,850 5,910 7,450 —C&SC— PS 3 8 11 17 22 27 33 42 LP3W 27 1952–78 1962, PS 65 131 184 258 317 379 444 533 LP3W 28 1951–78 1972 218 PS 5 49 187 719 1,630 3,290 6,110 12,500 LP3W 28 1951–78 1951 585 PS 78 335 675 1,360 2,090 3,020 4,180 6,100 LP3W 29 1947, CR 722 887 1,020 1,200 1,350 1,510 1,700 1,960 LP3W 48 1946–93 1989 2,160 CR 505 1,440 2,460 4,270 6,060 8,270 11,000 15,300 LP3W 35 1923, CR 318 447 559 736 897 1,090 1,310 1,670 LP3W 27 1967–93 1983 1,160 CR 555 1,340 2,040 3,110 4,020 5,020 6,100 7,650 LP3W 28 1949–76 1967 4,050 CR 1,450CR 1,830 2,120 1,820 2,530 2,240 2,860 2,540 3,220 2,970 3,620 3,320 4,200 3,690 4,090 LP3W 4,660 9 LP3W 1952–56, 20 1941–60 1946 2,990 CR 541 680 789 948 1,080 1,230 1,390 1,640 LP3W 49 1932, CR 354 731 1,030 1,460 1,810 2,160 2,540 3,050 LP3W 40 1954–93 1967 1,630 CR 1,780CR 2,260 2,630 3,030CR 3,160 4,780 2,930 3,610 6,380CR 4,940 4,090 9,010 3,660 6,870 11,500 4,620 8,220 10,200 14,600 5,400 13,100 13,500 18,300 22,200 17,600 24,500 31,700 22,800 LP3W 44,400 20 31,800 LP3W 61,000 56 90,700 1937–38, LP3W 17 1938–93 LP3W 25 1956–64, 1947 18,500 1941–58, type Gage Gage contributes contributes todirectly surface runoff) 2 Station name , approximately, of , approximately, which about 54,600 mi 2 (station skew—skew relations generalized (59,300 mi skew—peak-flow regional equations or remarks) or equations regional skew—peak-flow (——— +1.083—HPS) (——— -0.350—C&SC) (——— +1.112—HPS) (-0.214—Skew map -0.340—C&SC)(-0.214—Skew map (——— +1.016—HPS, HPC) (+0.044—Skew -0.330—C&SC) map (——— +1.021—New station for HPS network analysis) (+1.619—HP +1.118—HPS, HPC) (+1.619—HP+1.118—HPS, (-0.537—Skew map -0.340—C&SC)(-0.537—Skew map (+1.032—HP+0.943—HPS) (——— +0.918—HPS) (+0.507—HP+0.458—HPS (-0.715—Skew ———) HP map, (——— +1.004—HPS, HPC) (-0.285—Skew map -0.325—C&SC)(-0.285—Skew map (-0.568—Skew map -0.325—C&SC)(-0.568—Skew map Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations streamflow-gaging for data frequency Peak-flow Station Station number ber Map num- 7755 06775500at Dunning, Nebr. MiddleLoup R 7710 06771000Nebr. near Riverdale, R Wood 7759 06775900 Dismal R near Thedford, Nebr. 7715 06771500near Gibbon, Nebr. R Wood 7775 06777500 Middle Nebr. Loup R at Walworth, 7776 06777600 Lillian CrNebr. trib Brokennear Bow, 7770 06777000near Milburn, MiddleNebr. Loup R 7765 06776500 Dismal R at Dunning, Nebr. 7720 06772000Nebr. near Alda, R Wood 7790 06779000 Middle Loup R at Arcadia, Nebr. 7800 06780000 Middle Loup R at Rockville, Nebr. 7825 06782500 Nebr. at Ravenna, Loup S R 7826 06782600Nebr. Mud Br Cr trib near Broken Bow, S 7780 06778000 Nebr. at Sargent, MiddleLoup R 7778 06777800 Lillian CrNebr. trib Walworth, near 7777 06777700 Lillian Nebr. Cr near Broken Bow, 7740 06774000Nebr.near Duncan, Platte R CR 7,970 13,300 17,600 24,300 30,200 36,800 44,500 56,200 REG 53 1896–1909, Table B2. streams--Continued regulated for areas drainage and

APPENDIX B B-29 /s) 3 peak WY and dis- and WY of maximum maximum of 1945 1,500 1967 2,680 1947 72,000 1962 10,100 charge (ft record Period of of Period peak-flow 1951–78 1979–93 1903, 1929–93 1952–93 —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or /s) for given recurrence interval (years) 3 Appears composite to require analysis frequency Appears composite to require analysis frequency Peak discharge (ft 83 144 378 1,110 2,130 3,420 5,270 8,970 —HPS— 2 5 10 25 50 100 200 500 208 608 1,020 1,730 2,430 3,240 4,140 5,590 —C&SC— 856984 1,510 1,610 1,860354 1,950 2,620 2,770 662501 3,300457 3,420 4,110 855 920 4,200 751 5,080 1,320 1,160 5,130 6,660 1,870 917 1,600 6,620 2,340 1,120 2,120 —HPS— 2,910 1,340 2,620 —HPC— 3,850 1,600 3,200 1,900 4,160 —HPS— 2,370 —HPS— —HPC— 981 2,700 4,490 7,710 10,900 14,500 18,600 25,200 —C&SC— 6,350 10,800 21,700 32,300 39,300 54,900 74,600 109,000 —HPS— 3,1203,860 5,640 7,070 7,390 9,620 11,100 15,400 14,000 20,300 17,900 26,500 22,500 34,200 30,000 47,200 —HPS— —HPC— 2,4002,910 4,400 5,370 5,600 6,930 8,100 10,900 10,400 14,100 13,100 18,000 16,300 22,800 21,400 30,700 —HPS— —HPC— 58 220 417 796 1,190 1,680 2,280 3,260 —C&SC— 1,690 3,840 5,860 9,070 11,900 15,100 18,700 24,000 —C&SC— 84 350 707 1,450 2,260 3,310 4,660 6,940 —C&SC— 117 449 869 1,710 2,590 3,710 5,110 7,430 —C&SC— 437 1,170 1,920 3,160 4,320 5,660 7,210 9,570 —C&SC— 10,400 17,600 25,600 34,000 38,500 49,800 63,100 86,300 —HPS— 245 764 1,340 2,390 3,420 4,680 6,170 8,540 —C&SC— 103 455 950 2,010 3,190 4,750 6,760 10,200 —C&SC— PS 30 184 441 1,070 1,850 2,970 4,520 7,410 LP3W 29 1945, PSPS 23 106 70 256 386 696 874 1,370 1,980 2,590 3,260 4,710 5,000 9,970 7,290 11,300 LP3W 30 LP3W 17 1951–77 1951–67 1956 1,790 1956 1,550 PS 356 967 1,570 2,550 3,440 4,450 5,590 7,290 LP3W 24 1953–78 1965 1,450 PS 119 471 922 1,820 2,770 4,000 5,540 8,100 LP3W 20 1951–70 1966 2,360 PS 220 740PS 1,320 684 2,370 1,160 3,390 1,490 4,610 1,920 6,030 2,230 8,250 2,540 2,850 LP3W 17 3,260 1951–67 LP3W 17 1962 1,780 1951–67 1957 1,820 CR 866CR 1,910 3,100 2,870 7,070 11,200 4,420 18,700CR 5,830 26,400 7,480 36,300 759 48,900 9,380 1,390 70,900 12,300 1,870 2,520 LP3W LP3W 50 64 3,030 3,560 1944–93 1947–93 4,110 1947 1947 4,860 50,000 27,000 LP3W 19 1967–70, CR 8,350 14,500 20,100 29,400 38,300 49,200 62,500 84,600 LP3W 71 1895–99, CR 1,420 1,890CR 2,260 476CR 2,810 3,270 601 597CR 3,780 694 810 4,350 2,750 823 5,210 4,210 985 5,470 1,250 929 LP3W 7,480 1,480 1,040 57 9,330 1,750 1,170 11,500 1937–93 2,050 1,350 14,100 2,520 1983 18,400 3,210 LP3W 16 LP3W LP3W 53 44 1978–93 1941–93 1936–38, 1983 1964 801 1,790 CR 306CR 1,250 5,250 2,480 10,200 5,010 15,500 25,400 7,750 36,000 11,300 50,300 15,900 69,500 23,700 105,000 LP3W LP3W 14 33 1980–93 1937–69 1981 1966 3,460 37,600 type Gage Station name (station skew—skew relations generalized skew—peak-flow regional equations or remarks) (+0.148—Skew map -0.340—C&SC) (——— -0.330—C&SC)(——— (+0.592—HP +0.420—HPS) (——— -0.350—C&SC)(——— (+0.456—HP +0.266—HPS) (——— -0.296—New station for C&SC network analysis) (-0.183—Skew -0.273—C&SC)NE map, (+0.632—HP +0.684—HPS) (——— +1.020—HPS) (+1.223—HP +1.028—HPS, HPC) (+0.720—HP +0.938—HPS, HPC) (+0.615—HP +1.047—HPS, HPC) (-0.210—Skew +0.318—C&SC)NE map, (+0.997—HP +0.898—HPS, HPC) -0.336—C&SC)(——— -0.364—C&SC)(——— (——— -0.324—New station for C&SC network analysis) Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations for streamflow-gaging data frequency Peak-flow Station number ber Map Map num- 7829 06782900 Mud CrNebr. trib Brokennear Bow, 7828 06782800 N Br Mud Nebr. Cr at Broken Bow, 7827 06782700 Nebr. Cr at Broken Bow, S Br Mud 7835 06783500 Mud Nebr. Cr near Sweetwater, 7840 06784000 Nebr. Michael, St. R at S Loup 7847 06784700 nearCr Farwell, Turkey Nebr. 7848 06784800 nearCr Dannebrog, Turkey Nebr. 7850 06785000Nebr. Paul, St. R at Middle Loup 7870 06787000 Calamus R Harrop,near Nebr. 7875 06787500 Calamus R Burwell,near Nebr. 7885 06788500at Ord, Nebr. Loup R N 7860 06786000 Nebr. at Taylor, Loup R N 7892 06789200 Davis Cr trib #2 near North Loup, Nebr. 7890 06789000at Scotia, Nebr. Loup R N 7891 06789100 Davis Cr trib near North Loup, Nebr. 7893 06789300 Davis Cr near North Loup, Nebr. 7889a 06788988North Nebr. near Loup, Mira Cr Table B2. Table streams--Continued regulated for areas drainage and

B-30 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska /s) 3 peak WY and dis- and WY of maximum maximum of 1993 5,600 1966 129,000 1896 90,000 1966 64,700 1947 4,000 charge (ft record Period of of Period peak-flow 1980–93 1944–93 1899, 1903, 1929–93 1941–93 1958–93 —regional equation— Type and length length and Type (years) of analysis 2 < 1 mi TDA and/or remarks and/or /s) for given recurrence interval (years) (years) interval recurrence given for /s) 3 Basin characteristic(s) outside of range for characteristic(s) Basin equations —C&SC— although coded as such from 1937. No basin characteristics Peak discharge (ft discharge Peak 2 5 10 25 50 100 200 500 591666 1,260 1,570 1,890 2,540 2,870 4,300 4,390 6,070 5,520 8,270 6,860 12,600 9,050 16,700 —HPS— —NE— 154 387 628 1,060 1,480 1,990 2,730 3,700 —NE— 734 1,710 2,620 4,140 5,530 7,170 8,980 11,900 —NE— 270531937 498 848 1,900 671 1,010 2,810 1,720 4,400 886 2,050 5,970 1,180 2,450 7,940 1,460 11,700 2,920 1,790 15,400 3,690 2,320 —NE— —HPC— —HPS— 499 1,260 2,040 3,390 4,690 6,260 8,530 11,300 —NE— 2,110 4,560 6,940 11,000 15,000 19,900 29,300 38,100 —NE— 1,8502,050 3,4201,830 3,600 6,410 4,090 7,900 9,520 6,330 10,100 12,900 10,200 14,700 17,300 13,900 20,700 22,800 18,400 28,600 32,100 26,600 42,800 34,700 —HPS— —HPC— —NE— 4,2005,360 7,500 9,820 10,300 14,400 15,100 21,900 18,700 29,600 24,000 39,400 30,000 51,700 40,600 72,800 —HPS— —HPC— 1,190 2,770 4,240 6,640 8,840 11,400 14,300 18,800 —NE— 1,890 3,500 5,770 8,500 11,300 14,800 19,200 26,400 —HPS— 1,580 3,680 5,740 9,270 12,700 16,800 23,800 31,000 —NE— stations below Loup R Power Canal, peak flows are not considered regulated, 29 118 231 455 691 994 1,370 1,990 —C&SC— 1,430 3,540 5,640 9,140 12,300 16,000 20,200 26,600 —C&SC— 325 993 1,730 3,070 4,380 5,970 7,860 10,800 —C&SC— 265 855 1,530 2,770 3,990 5,490 7,280 10,100 —C&SC— 469 1,360 2,310 3,990 5,590 7,520 9,770 13,300 —C&SC— 258 932 1,770 3,430 5,150 7,340 10,000 14,500 —C&SC— Based on comparativeunregulatedBasedof analysis on and regulated periodsfor of record PS 137 238 316 426 516 612 715 863 LP3W 11 1968–78 1969 485 PS 218 823 1,550 2,930 4,310 6,010 8,050 11,300 LP3W 28 1951–78 1957 2,220 PS 68 283 570 1,160 1,810 2,660 3,750 5,600 LP3W 27 1952–78 1966 1,340 PS 527 1,610 2,800 4,940 7,040 9,600 12,700 17,600 LP3W 27 1952–78 1966 12,800 PS 1,050 2,600 4,100 6,540 8,770 11,400 14,300 18,800 LP3W 17 1951–67 1966 12,800 PS 172 680 1,340 2,690 4,160 6,090 8,560 12,800 LP3W 16 1952–67 1966 4,700 PS 887 2,710 4,750 8,530 12,300 17,100 23,000 32,700 LP3W 31 1948–78 1966 35,000 CR 946 1,980 3,050 5,010 7,040 9,710 13,200 19,400 LP3W 23 1945–53, CR 14,000 26,700 39,400 62,300 85,700 116,000 155,000 225,000 54 LP3S 1929–32, CR 2,240 4,800 7,410 12,100 17,000 23,200 31,200 45,300 LP3W 53 1941–93 1950 21,200 CR 738CR 1,200 5,630 10,800 1,530 16,300 1,940 26,600 2,250 37,500 52,300 2,560 72,000 2,860 108,000 3,270 LP3W 69 LP3W 11 1896–97, 1948–58 1958 1,720 CR 2,710 5,880 9,310 15,900 23,000 32,600 45,500 69,500 LP3W 54 1932, CR 620 1,090 1,550 2,370 3,210 4,300 5,700 8,200 LP3W 45 1945–53, type Gage Gage

2 Station name , approximately, of which about, approximately, 5,620 mi 2 (station skew—skew relations generalized contributes directly to surface runoff) (14,320 mi skew—peak-flow regional equations or remarks) or equations regional skew—peak-flow (——— ———) (——— +0.677—HPS, NE) (——— ———) (-0.449—Skew map, NE -0.374—C&SC)(-0.449—Skew NE map, (+0.458—HP+0.450—HPS,HPC, NE) (——— -0.333—Newnetwork stationC&SC for analysis) (+1.196—HP+0.849—HPS,HPC) (+0.122—Skew -0.238—NE,NEC&SC) map, (——— -0.260—NE, C&SC) (——— -0.258—NE, C&SC) (——— -0.302—NE, C&SC) (——— +0.664—HPS, NE) (+0.924—HP+1.016—HPS,HPC, NE) (——— -0.226—NE, C&SC) Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations streamflow-gaging for data frequency Peak-flow Station Station number ber Map num- 7939a 06793995 Skeedee Cr trib near Genoa, Nebr. 7935 06793500Loretto, Nebr. Beaver Cr at 7894 06789400North Nebr. of Loup, Davis Cr southwest 7940 06794000Nebr. Genoa, Beaver Cr at 7895 06789500Cotesfield, Nebr. Davis Cr near 7905 06790500Paul,Nebr. near St. NLoup R 7906 06790600 Nebr. Spring EastBrnear Wolbach, Cr trib 7907 06790700Brayton,at Nebr. W Br Spring Cr 7908 06790800 Nebr. Wolbach, near W Br Spring Cr 7909 06790900Nebr. Wolbach, Cr at Mary’s 7930 06793000 Loup R near Genoa, Nebr. 7920 06792000 Cedar R Fullerton,near Nebr. 7915 06791500 Cedar R Spalding,near Nebr. 7911 06791100 Spring Cr near Cushing, Nebr. Table B2. streams--Continued regulated for areas drainage and

APPENDIX B B-31 /s) 3 peak WY and dis- and WY of maximum maximum of 1966 119,000 1987 5,640 1987 1,510 1987 14,100 1963 20,900 1967 16,900 1966 14,500 1990 8,000 charge (ft record Period of of Period peak-flow 1933–78 1961–72, 1978–93 1978–93 1960–93 1968–78 1940–93 1969 1978–93 —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or /s) for given recurrence interval (years) No basin characteristics 3 although coded as such from 1937. Appears composite to require analysis frequency Basin characteristic(s) outside of range for equations —NE— Peak discharge (ft 2 5 10 25 50 100 200 500 343 785 1,250 2,090 2,920 3,920 5,590 7,580 —NE— 428459 964 1,050306 1,220 1,670636 2,000 2,800 726 1,620 3,270 1,130 3,930 2,750 4,000 5,340 2,110 4,900 4,860 3,870 7,950 7,150 10,700 6,240 10,100 4,960 17,100 6,270 22,600 —HPS— —NE— 8,440 —NE— —HPS— 252 572 908 1,490 2,060 2,740 3,640 4,980 —NE— 1,2301,470 2,830 3,250 3,530 5,060 4,920 8,200 7,370 11,300 8,740 15,000 10,300 21,800 12,800 28,700 —HPS— —NE— 1,8002,280 4,180 5,040 5,280 7,810 7,790 12,600 11,800 17,200 14,200 22,900 17,000 33,600 21,300 43,800 —HPS— —NE— 1,8002,760 3,700 6,760 7,400 10,900 12,600 18,200 19,200 25,200 26,300 33,700 35,100 49,100 50,200 63,600 —HPS— —NE— 1,010 2,300 3,400 5,050 6,450 7,970 9,670 12,100 —East— 3,1802,940 6,920 6,350 9,730 9,670 13,900 15,300 19,800 20,600 24,400 27,100 29,900 38,500 38,500 49,900 —HPS— —NE— 2,440 5,470 8,150 12,300 16,000 20,000 23,200 30,300 —NE— 2,930 5,720 7,860 10,900 13,300 16,000 15,900 20,900 —NE— stations below Loup R Power Canal, peak flows are not considered regulated, 17,700 31,000 43,800 67,700 80,700 106,000 137,000 188,000 —HPS— Based Based on comparative analysis of unregulated and regulated periods of record for PS 464 979 1,400 2,020 2,530 3,070 3,640 4,440 LP3W 11 1963, CR 16,400 31,000 44,700 67,800 90,000 117,000 151,000 206,000 LP3W 67 1895–1915, CR 1,000 1,950CR 2,740 292CR 3,910 1,240 659 4,900 3,120CR 1,010 6,000 5,190 1,570 7,200 487 9,080 2,090 8,960 1,200 13,200 2,710 18,600 1,960 LP3W 3,420 25,600 3,360 11 37,900 4,540 4,800 1983–93 6,660 LP3W LP3W 47 1984 9,030 11 13,100 2,500 1947–93 1979–89 LP3W 1962 1987 38 7,500 948 1947–53, CR 344CR 656 1,840 4,100 935 6,260 1,380 9,880 1,790 13,300 2,280 17,400 2,850 22,300 30,100 3,760 LP3W LP3W 78 19 1932–58, 1962–64, CR 4,430 8,560 12,000 17,300 21,800 26,800 32,500 40,800 LP3W 61 1897–1903, CR 1,730 5,160 8,860 15,400 21,800 29,500 38,700 53,300 LP3W 19 1950–67, CR 141CR 1,400 327 3,500CR 515 5,800 523 849 9,800 1,140 13,900 1,180 19,100 1,680 1,600 25,600 2,500 36,800 2,100 3,210 3,000 4,010 LP3W 33 4,880 LP3W 18 6,170 1961–93 1976–93 1971 LP3W 15,200 12 1987 1967–78 574 1977 1,830 CR 1,520 2,810 3,770 5,050 6,030 7,020 8,030 9,400 LP3W 80 1947–75, type Gage contributes directly to surface runoff) directly contributes to surface 2

2 Station name , approximately, of which about 6,230 mi of which about 6,230 approximately, , mi of which about 57,800 approximately, , 2 2 (station skew—skew relations generalized contributes directly to surface runoff) directly contributes to surface (15,200 mi (70,400 mi skew—peak-flow regional equations or remarks) (——— 0.000—Newnetwork stationNE for analysis) (-0.149—Skew +0.330—HPS,NE map, NE) +0.202—HPS,NE) (+0.205—Skewmap, NE (+0.202—HP +0.645—HPS) (——— ———) (——— +0.263—HPS,(——— NE) (+0.045—Skewmap, NE +0.066—HPS, NE) (-0.163—Skew map, NE -0.005—HPS, NE) (——— -0.331—New station for East network analysis) (——— NE) +0.118—HPS, (——— -0.179—New station for NE network analysis) (——— -0.250—NE) +0.233—NE)(——— (-0.451—Skew -0.380—NE)NE map, Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations for streamflow-gaging data frequency Peak-flow Station number ber Map Map num- 7969b 06796978Emmet, Holt Cr near Nebr. 7975 06797500at Ewing,Nebr. Elkhorn R 7980 06798000at Ewing,Nebr. S Fk Elkhorn R 7969a 06796973 Elkhorn R near Atkinson, Nebr. 7983 06798300 Nebr. Clearwater, Clearwater Cr near 7985 06798500at Neligh, Nebr. Elkhorn R 7945 06794500 Loup R at Columbus, Nebr. 7990 06799000at Norfolk, Elkhorn Nebr. R 7947a 06794710 Nebr. Bone Cr near David City, 7991 06799100 N Fk Elkhorn R near Pierce, Nebr. 7991b 06799190near Cornlea, S Fk Union Cr trib Nebr. 7950 06795000Grove, Nebr. Cr at Newman Shell 7990b 06799080 Nebr. Foster, Cr near Willow 7955 06795500Nebr. Cr near Columbus, Shell 7960 06796000Bend,at North Nebr. Platte R CR 27,500 46,200 61,800 85,600 107,000 130,000 158,000 200,000 REG 45 1949–93 1960 112,000 Table B2. Table streams--Continued regulated for areas drainage and

B-32 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska /s) 3 peak WY and dis- and WY of maximum maximum of 1993 28,400 1944 100,000 1971 3,020 1944 35,000 1993 130,000 charge (ft record Period of of Period peak-flow 1950–93 1899-1903 1911–15, 1929-93 1967–78 1952–93 1989–93 —regional equation— Type and length length and Type (years) of analysis 2 < 1 mi TDA and/or remarks and/or /s) for given recurrence interval (years) (years) interval recurrence given for /s) 3 Appears to Appears require analysis composite frequency Basin outside ofBasin characteristic(s) range for equations —NE— Unregulatedafterof regulated1963; prior 1964 basin 30 percent to Unregulatedafterof regulated1962; prior 1967 basin 31 percent to Peak discharge (ft discharge Peak 2 5 10 25 50 100 200 500 447 999 1,490 2,290 3,010 3,800 4,220 5,720 —NE— Appears to require composite frequency analysis No basin characteristics 2,140 4,870 7,170 10,500 13,400 16,500 19,900 24,700 —East— 6,8901,590 14,800 20,900 3,860 29,200 6,040 35,600 9,640 42,300 13,000 49,100 16,800 58,400 21,300 28,300 —East— REG 29 7,820 14,500 18,900 24,100 27,700 31,000 34,000 37,600 REG 132 5,870 12,200 17,4006,160 24,800 11,900 30,900 16,100 37,400 21,900 38,900 26,300 50,500 30,900 29,200 38,100 —NE— —NE— 2,490 5,6707,870 8,5605,140 16,300 13,000 10,800 26,200 16,800 16,2003,730 37,800 21,000 24,800 51,300 7,880 23,500 32,800 66,000 11,200 30,900 42,100 83,300 16,100 56,500 111,000 20,000 72,800 24,200 —NE— 24,800 —HPS— 32,400 —NE— —NE— 3,750 7,400 10,200 14,000 17,100 20,400 19,900 26,000 —NE— 8,940 18,400 26,600 39,600 51,100 64,400 81,500 104,000 —NE— 12,500 25,100 44,600 65,900 87,600 116,000 150,000 206,000 —HPS— PS 10 92 262 741 1,390 2,400 3,850 6,670 LP3W 10 1968-78 1972 500 PS 330 1,150 2,180 4,300 6,640 9,800 13,900 21,400PS LP3W 12 60 1965, 188 344 658 1,000 1,470 2,100 3,220 LP3W 11 1968–78 1975 225 CR 1,770 4,180 6,380 9,820 12,800 16,200 20,000 25,500 LP3W 25 1969–93 1993 8,480 CR 4,040 9,550 14,300 21,100 26,700 32,500 38,600 47,000 LP3W 54 1950–93 1950 67,000 CR 8,750 16,500 22,300 30,200 36,300 42,500 48,800 57,300 LP3W 101 1908, CR 6,830CR 14,100 20,000 6,090 28,600 11,300 35,500 15,200 43,000 20,300 50,800 24,300 61,700 28,300 32,300 37,600CR LP3W 28 12,200 23,000 LP3W 1966–93 54 32,000 45,200 1971 1940–93 56,500 36,900 69,000 1971 82,700 25,200 103,000 LP3W 113 1881, CR 2,070CR 6,740 11,200 12,200 21,600 22,600CR 30,300 33,300 43,200 7,270 46,879 54,100 14,700 63,805 66,200 21,100 92,090 79,600 30,700 99,300 38,900 LP3W 48,000 15 58,100 LP3W 33 73,000 1979–93 1961–93 1990 LP3W 15,100 15CR 1967 44,000 1979–93 2,930 5,520 1991 27,900 7,460 10,100 12,100 14,200 16,300 19,200 LP3W 43 1944, type Gage Gage )) PS PS 503 994 958 1,610 1,330 2,000 1,860 2,480 2,300 2,820 2,780 3,130 3,290 3,430 4,030 3,810 REG 17 REG 17 1958–78 1957–78 1958 1958 3,300 2,570 2 2 ) PS 1,230 1,960 2,540 3,390 4,100 4,900 5,790 7,120 REG 17 1958–78 1967 3,370 2 ) 2 Station name , from state base maps, scale—100,000)state maps, from base , 2 (station skew—skew relations generalized (84,200 mi skew—peak-flow regional equations or remarks) or equations regional skew—peak-flow (-0.205—Skew -0.313—East) SE map, (——— -0.548—East) (——— ———) (-0.400—Skew map, NE -0.370—NE)(-0.400—Skew NE map, (——— ———) (-0.454—Skew map, NE -0.318—NE)(-0.454—Skew NE map, (+0.080—Skew -0.107—HPS,NENE) map, (——— -0.143—NE) -0.061—HPS,(-0.202—Skew NE) NE map, (——— -0.163—NE) (——— -0.088—New stationNE for network analysis) -0.406—NE)(-0.288—Skew NE map, (——— station for +0.112—New NE network analysis) Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations streamflow-gaging for data frequency Peak-flow Station Station number ber Map num- 8035b 06803510 Little Salt Cr near Lincoln, Nebr. 8032 06803200Nebr. Lincoln, Antelopeat 48th Street, Cr (7.14mi 8030 06803000 Nebr. at Roca, Salt Cr 8035 06803500Nebr.at Lincoln, Salt Cr (685 mi 7995 06799500Uehling,Nebr. Logan Cr near 7998a 06799850Nebr. Schuyler, Pond Cr near 7994b 06799450 Nebr. Pender, Logan Cr at 8005 06800500 Nebr. Elkhornat Waterloo, R 7992a 06799230 Unionat Madison, Nebr. Cr 7993a 06799350 Point, Elkhorn Nebr. R at West 7993b 06799385Nebr. at Scribner, Pebble Cr 7994a 06799423 N Logan Cr near Laurel, Nebr. 8000 06800000Nickerson, Nebr. Maple Cr near 8003a 06800350 ElkhornNickerson,trib Nebr. near R 8033 068033008034Nebr. Lincoln, Antelopeat 27th Street, Cr 06803400 (10.6mi Antelope Cr at Lincoln, Nebr. (12.1 mi 8010 06801000Nebr.near Ashland, Platte R CR 43,900 64,700 79,900 101,000 117,000 135,000 153,000 180,000 REG 30 1929–53, Table B2. streams--Continued regulated for areas drainage and

APPENDIX B B-33 /s) 3 peak WY and dis- and WY of maximum maximum of charge (ft record 1946–69 1950 14,500 Period of of Period peak-flow —regional equation— Type and length length and Type (years) of analysis 2 <1 mi TDA and/or remarks and/or /s) for given recurrence interval (years) No basin characteristics 3 Appears composite to require analysis frequency Unregulatedpriorregulated to 1962; 20 percent of basin after 1967 Peak discharge (ft 2 5 10 25 50 100 200 500 325 743 1,130 1,770 2,370 3,080 3,910 5,200 —East— 780 1,840 2,770 4,200 5,440 6,830 8,380 10,700 —East— 437 1,080842 1,690 2,130 2,660204 3,330 3,560 5,230 610316 4,610 1,040 6,940 5,820 921 1,790 8,920 7,700 1,550 11,200 2,530 14,700 2,620 3,460 —East— 3,670 4,590 —East— 4,950 6,450 6,510 9,040 —East— —East— Appears to require composite frequency analysis frequency composite require to Appears characteristics No basin 3,420 7,550 11,000 16,000 20,200 24,700 29,600 36,700 —East— 6,580 13,700 19,400 27,300 33,700 40,500 47,600 57,600 —East— 1,250 3,1905,990 5,000 14,200 7,880 21,600 10,500 32,900 13,500 42,900 16,900 54,200 22,200 67,100 86,400 —East— —East— 2,330 5,230 7,640 11,200 14,100 17,400 20,800 25,800 —East— 1,660 3,6501,100 5,270 2,540 7,6202,830 3,760 9,570 6,080 5,550 11,700 8,690 13,900 7,070 12,400 17,100 8,730 15,500 10,500 18,700 13,100 22,100 —East— 26,900 —East— —East— 13,400 31,600 45,900 65,000 79,200 93,100 106,000 123,000 REG 26 PSpeaks Insufficient data—flowsunknown for all 11 1968-78 ------PS 1,010 2,200 3,220 4,740 6,030 7,430 8,950 11,100 LP3W 17 1962–78 1978PS 2,800 475PS 1,100 600PS 1,690 1,840 2,620PS 77 3,250 3,450 5,940 102PS 270 4,410 8,710 5,500 386 517 12,300 643 7,150 16,700 1,030 2,590 766 24,300 1,610 5,220 1,580 LP3W 10,800 2,390 84 2,500 LP3W 17,100 84 3,430 3,780 25,800 5,310 37,200 1950–78 5,500 57,600 1950–78 1959 8,640 1959 4,040 LP3W 12,000 84 LP3W LP3W 84 84 1951–78 1950–78 1959 1951–78 5,000 1959 1959 21,600 4,640 PS 1,420PS 4,350 1,330 7,380PS 2,780 12,400 1,560 17,000 3,960 4,440 22,000 5,650 27,900 7,320 7,020 36,400 12,100 8,470 16,400 LP3W 21,400 9,990 135 27,000 12,100 35,400 1951–78 LP3W 1963 LP3W 79 15,900 77 1950–67 1951–78 1963 1963 13,800 81,400 PS 245 453 607 814 974 1,140 1,300 1,520 LP3W 29 1950–78 1963 923 CR Out-of-state stationfor only relation(s) used skew CR 2,950 6,170 8,890 13,000 16,400 20,200 24,300 30,200 LP3W 24 1970–93 1987 23,300 CR 4,200 9,400 14,100 21,200 27,400 34,400 42,000 53,400 LP3W 150CR 1950–93 17,900 1963 32,000 77,400 41,700 54,000 63,000 71,600 80,000 90,600 LP3W 21 1947–67 1963 87,000 CR 1,680 4,690 7,690 12,700 17,200 22,400 28,300 37,100 LP3W 25 1969–93 1989 12,900 CR 11,700 24,900 36,100 52,800 67,000 82,400 99,200 123,000 LP3W 11 1952–93 1984 46,800 type Gage contributes directly to surface runoff—from Boohar and others, 1992) and runoff—from Boohar directly contributes to surface 2 ) 2 Station name , approximately, of which about 71,000 mi of which about 71,000 approximately, , 2 (station skew—skew relations generalized (85,800 mi skew—peak-flow regional equations or remarks) (——— -0.183—New station for East network analysis) (-0.023—Skew ———) map (——— -0.253—East) -0.113—East) (-0.004—SkewSE map, (+0.014—Skew map, SE -0.127—East) map, (+0.115—Skew SE -0.077—East) -0.080—East)(-0.055—SkewSE map, (-0.100—Skew map, SE -0.111—East) -0.135—East)(——— (+0.405—Skew map -0.273—East) -0.414—East)(——— (-0.104—Skew -0.438—East) map (+0.018—Skew map* -0.345—East) development forequation*Should been used of SE have (-0.528—Skew map, SE -0.329—East)(-0.528—SkewSE map, -0.440—East)(-0.524—SkewSE map, (-0.128—Skew ———) map (——— ———) Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations for streamflow-gaging data frequency Peak-flow Station number ber Map Map num- 8060 06806000Bartlett,Iowa Cr near Waubonsie 8055b 06805510Nebr. Cr near Gretna, Buffalo 8035e 06803540Nebr. Cr near Alvo, Dee 8035f 06803555 Salt Cr at Greenwood, Nebr. (1,050 mi 8041 06804100 Silver Cr near Cedar Nebr. Bluffs, 8042 06804200 Silver Cr near Colon, Nebr. 8043 06804300tribCr Nebr. Silver near Colon, 8044 06804400 Silver Cr trib at Colon, Nebr. 8045 06804500 Silver Cr at Ithaca, Nebr. 8050 06805000 Salt Cr near Ashland, Nebr. 8055 06805500at Louisville,Nebr. Platte R CR 46,600 76,700 98,400 127,000 150,000 173,000 197,000 229,000 REG 41 1953–93 1993 160,000 8035d 06803530 Rock Cr near Ceresco, Nebr. 8037 06803700 Nebr. trib near Weston, Cr Wahoo Fk N 8039 06803900 Nebr. Cr at Weston, N Fk Wahoo 8040 06804000 Nebr. Ithaca, at Cr Wahoo 8035c 06803520 Cr near Stevens Lincoln, Nebr. 8036 06803600 nearCr Prague, Nebr. N Fk Wahoo 8035g 06803570Nebr. near Weston, Dunlap Cr trib Table B2. Table streams--Continued regulated for areas drainage and

B-34 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska /s) 3 peak WY and dis- and WY of maximum maximum of 1956 3,430 1976 1,200 1950 30,300 1947 55,500 charge (ft 1971 1986 record 1949–93 1987 40,800 1950–78 1929–93 1922–23, Period of of Period peak-flow —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or Basin characteristics incomplete /s) for given recurrence interval (years) (years) interval recurrence given for /s) No basin characteristicsNo basin No basin characteristicsNo basin No basin characteristicsNo basin 2 3 <1mi TDA Peak discharge (ft discharge Peak 2 5 10 25 50 100 200 500 509 1,350 2,140 3,380 4,480 5,740 7,160 9,310 —East— 885 2,210 3,390 5,190 6,740 8,480 10,400 13,200 —East— 256 599 923 1,470 1,990 2,600 3,230 4,470 —East— 806 1,950 2,970 4,500 5,840 7,330 8,980 11,400 —East— 1,270 3,050 4,600 6,930 8,940 11,200 13,600 17,200 —East— 6,320 13,200 18,600 26,200 32,300 38,680 45,600 55,100 —East— 2,930 6,460 9,380 13,700 17,200 21,100 25,300 31,400 —East— 2,930 6,7201,908 9,860 4,360 14,400 18,100 6,420 22,000 9,4006,020 26,300 11,900 13,200 32,200 14,600 18,900 17,500 26,900 21,600 33,400 —East— 40,200 47,300 —East— 57,100 —East— 14,100 29,000 40,300 55,500 67,300 79,400 91,700 108,000 —East— PS 1,830PS 4,640 1,210 7,310 2,260 11,600 15,400 3,070 19,800 4,180 24,600 5,060 31,900 5,980 LP3W 6,920 22 8,220 1950–67 LP3W 1951 22 6,390 1950–67, PS 1,310 3,230 4,990 7,750 10,100 12,800 15,800 20,000 LP3W 29 1950–78 1950 9,500 PS Out-of-stateusedskew only for relation(s) station 1953–84, PSPS Out-of-stateusedskew only for relation(s) station Out-of-stateusedskew only for relation(s) station 1953–90 1973 1953–90 2,110 1973 3,700 PS 2,360PS 6,010 281 9,450 14,900 622 19,700 25,200 924 31,200 40,100 1,390 1,790 LP3W 2,240 96 2,740 3,470 1947, LP3W 29 1950–78 1967 1,570 PS 529 1,190 1,800 2,760 3,620 4,610 5,730 7,420 LP3W 11 1968–78 1973 3,200 PS 710 1,710 2,610 4,000 5,200 6,520 7,970 10,060 LP3W 29 1950–78 1963 4,210 PS 3,400PS 6,980 1,900 9,860PS 4,980 13,900 17,200 199 7,850 20,600 12,300 24,100 420 16,200 29,000 20,400 609 25,000 31,500 LP3W 890 18 1,130 LP3W 18 1,390 1950–67 1,670 1950 47,600 1950–67 2,080 1950 16,000 LP3W 29 1950-78 1950 1,280 CR 5,660 15,500 25,100 40,700 54,800 70,700 88,500 115,000 LP3W 44 1950–93 1993 65,100 CR Out-of-stateusedskew only for relation(s) station CR Out-of-stateusedskew only for relation(s) station CR 7,300CR 14,400 15,800 20,200 37,900 28,600 56,800 35,400 84,400 42,700 107,000 50,500 130,000 154,000 61,500 188,000 LP3W LP3W 140 140 1950–69 1950–93 1950 1950 225,000 164,000 type Gage Gage Station name (station skew—skew relations generalized skew—peak-flow regional equations or remarks) or equations regional skew—peak-flow (——— -0.275—East) (——— -0.317—East) (-0.398—Skew -0.323—East) SE map, (-0.254—Skew map ———)(-0.254—Skew map (-0.377—Skew -0.367—East) SE map, (+0.030—Skew ———) map (+0.314—Skew ———) map ———)(-0.617—Skew map (-0.575—Skew SE map, -0.286—East) ———)(-0.303—Skew map (-0.244—Skew map ———)(-0.244—Skew map (——— -0.155—New stationEastnetwork for analysis) (-0.064—Skew -0.323—East) SE map, (——— -0.438—East) (——— -0.469—East) (-0.406—Skew map ———) (-0.374—Skew -0.479—East) SE map, (-0.182—Skew map -0.457—East)(-0.182—Skew map Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations streamflow-gaging for data frequency Peak-flow Station Station number ber Map num- 8064 06806400Elmwood, Cr at Nebr. Water Weeping 8064b 06806420 Stove Cr near Elmwood, Nebr. 8064c 06806440at Elmwood, Stove Cr Nebr. 8077a 06807720Iowa, MiddleSilver Cr near Avoca, 8065 06806500Union, Nebr. Cr at Water Weeping 8077b 06807760 MiddleSilver Iowa Cr near Oakland, 8077c 06807780 Iowa MiddleTreynor, Silver Cr at 8085 06808500at Randolph, Iowa W Nishnabotna R 8064d 06806460 Nebr. Water, Weeping Cr at Water Weeping 8064e 06806470Nebr. Water, Cr trib near Weeping Water Weeping 8100 06810000 Nishnabotna R above Hamburg, Iowa 8100b 06810060 Honey Cr near Peru, Nebr. 8101 06810100 Hoopertrib near Palmyra, Cr Nebr. 8102 06810200 Hooper Cr near Palmyra, Nebr. 8103 06810300 Cr near Syracuse, Nebr. Wolf 8104 06810400 Little Nemaha R trib near Syracuse, Nebr. 8115 06811500at Auburn, Nebr. LittleNemaha R 8105 06810500 Little Nemaha R near Syracuse, Nebr. Table B2. streams--Continued regulated for areas drainage and

APPENDIX B B-35 /s) 3 peak WY and dis- and WY of maximum maximum of 1964 430 1973 7,200 1993 4,640 1942 16,300 1973 71,600 charge (ft 1993 record 1969–79 1973–78 1972–90 1957–89 1959 1,220 1944–93 1989–91, Period of of Period peak-flow —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or /s) for given recurrence interval (years) No basin characteristics 3 Appears composite to require analysis frequency Peak discharge (ft 303527 58 62 51 87 77 77 139 173 124 217 214 174 278 260 243 351 315 336 474 400 511 —HPS— —HPC— —UR— 2 5 10 25 50 100 200 500 910587 1,960 1,600 3,820 3,440213 8,560242 10,600 14,700 17,100 452 20,900 557 26,500 28,900 874 39,600 42,700 892 64,600 1,640 1,510 2,740 2,170 —HPS— —HPC— 3,750 3,020 5,030 4,140 7,200 6,150 —HPS— —UR— 262 609 934 1,470 1,990 2,590 3,300 4,410 —East— 1,350 3,750 6,400 11,300 16,400 22,900 31,100 44,900 —UR— 7,020 15,000 21,400 30,300 37,400 44,800 52,6004,730 63,300 10,700 15,600 22,600 —East— 28,300 34,500 41,100 50,400 —East— 11,400 23,500 32,900 45,600 55,500 65,800 76,300 90,500 —East— 18,800 38,400 53,200 72,700 87,800 103,000 119,000 139,000 —East— PSPS Out-of-state stationfor only relation(s) used skew Out-of-state station onlyfor used relation(s) skew PS 190PS 1966–91 771 1987 3,080 1,550 3,180 5,000 Out-of-state stationfor only relation(s) used skew 7,440 10,600 16,200 LP3W 11 1968–78 1973 1,050 1959–67, PS Out-of-state stationfor only relation(s) used skew 1952–87, CRCRCR Out-of-state stationfor only relation(s) used skew CR Out-of-state stationfor only relation(s) used skew 1,360 4,980 Out-of-state stationfor only relation(s) used skew CR 9,890 20,600 234 33,300CR 51,400 513 76,400 26 124,000 809 1,360 44 LP3W 1950–76 62 1,950 1974 63 2,720 1949–71, 4,700 1932–93 3,730 96 1950–76 1935 5,560 50,000 1965 130 3,460 LP3W 173 63 229 1931–93 327 1947 2,110 LP3W 53 1941–93 1948 140 CRCR Out-of-state stationfor only relation(s) used skew 6,920CR 12,500 18,700 16,500 31,900CR 21,600 41,000 21,000 25,400 52,400 33,700CR 29,200 60,600 42,000 32,900 9,390 68,600 52,000 37,700 17,400 76,500 59,000 23,300 86,500 65,600 31,400 71,900 LP3W 37,700 79,800 44,100 LP3W 1922–70, 50,600 LP3W 59,500 1949–93 100 1973 1953–93 21,400 LP3W 1982 21 1941, 59,500 1953–73 1973 35,000 type Gage contributes directly to surface runoff) surface to directly contributes 2 Station name , approximately, of which about 20 mi of which about 20 approximately, , 2 (station skew—skew relations generalized (23.6 mi skew—peak-flow regional equations or remarks) (-0.183—Skew ———) map (+0.270—Skew map ———) (-0.607—Skew ———) map (-0.026—HP -0.099—HPS,HPC, UR) (+0.487—HP +0.516—HPS, UR) (+0.728—HP +1.078—HPS, HPC, UR) (-0.691—Skew ———) map (-0.431—Skew ———) map (+0.027—Skew map ———) -0.501—East)(-0.485—SkewSE map, -0.501—East)(-0.266—SkewSE map, (——— -0.180—New station for East network analysis) (-0.634—Skew ———) map (-0.470—Skew map, SE -0.497—East)(-0.470—SkewSE map, (+0.050—Skew map -0.387—East) (-0.065—Skew ———) map Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations for streamflow-gaging data frequency Peak-flow Station number ber Map Map num- 8160 06816000Oregon, Mo. Mill Cr at 8210 06821000 Jenkins Br Mo. at Gower, 8230 06823000 N Fk Republican R at Colorado-Nebraska state line 8235 06823500Nebr. Cr near Haigler, Buffalo 8200 06820000 White Cloud Cr near Maryville, Mo. 8215 06821500 ArikareeNebr. R at Haigler, 8240 06824000 Rock Cr at Parks, Nebr. CR 38 71 107 177 254 361 509 795 REG 53 1941–93 1965 493 8118a 06811875 Iowa Snake Cr near Yorktown, 8130 06813000 at Fairfax, Mo. R Tarkio 8137 06813700 Kansas Seneca, near trib Cr Tennessee 8140 06814000 nearCr Seneca, Kansas Turkey 8145 06814500 N Fk Big Nemaha R at Humboldt, Nebr. 8155b 06815510 Nebr. Cr near Falls City, Temple 8155c 06815550 Staples Br near Burlington Junction, Mo. 8150 06815000 Nebr. City, Falls R at Big Nemaha 8155 06815500Nebr. at Verdon, Muddy Cr 8117a 06811760 near Elliott, R Iowa Tarkio Table B2. Table streams--Continued regulated for areas drainage and

B-36 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska /s) 3 peak WY and dis- and WY of maximum maximum of 1956 5,560 1935 200,000 1935 190,000 1962 12,900 1935 50,000 1935 103,000 1958 19,600 charge (ft record 1951–93 1946–93 1937–46 1970–78 1947–93 1951–75 1938–93 1902–06, 1931–32, Period of of Period peak-flow —regional equation— Type and length length and Type (years) of analysis

2 and/or remarks and/or /s) for given recurrence interval (years) (years) interval recurrence given for /s) 3 Basin characteristic(s) outside of range for characteristic(s) Basin equations —UR— Basin characteristic(s) outside of range for characteristic(s) Basin equations —UR— Noncontributing drainage area known to exist, but amount unknownNoncontributing but amountarea known to exist, drainage Peak discharge (ft discharge Peak 2 5 10 25 50 100 200 500 975 2,190 3,940 8,830 15,600 21,600 29,300 42,300 —HPS— 762 2,130 3,600 6,260 8,900 12,200 16,200 22,800 —UR— 581457 1,240334 1,090 2,400 798 2,270 4,560 1,280 5,180 7,560 2,160 7,820 10,400 11,400 3,060 13,900 16,100 20,000 4,210 24,600 5,670 —HPS— 8,190 —HPC— —UR— 512 1,520 2,650 4,680 6,600 9,070 11,800 16,600 —UR— 3,0303,120 6,730 9,200 12,200 16,000 27,100 28,800 45,600 41,900 63,900 58,400 86,900 78,800 126,000 113,000 —HPS— —UR— 1,140 3,000 5,060 8,950 13,000 18,300 25,100 37,000 —UR— 2,770 8,620 15,200 27,400 39,500 54,400 72,400 101,000 —UR— PS 289 701 1,110 1,810 2,470 3,270 4,230 5,760 LP3W 13 1966–78 1977 1,800 PS 299 582 824 1,200 1,520 1,890 2,300 2,920 LP3W 9 1962, CR 265 516 729 1,050 1,330 1,640 1,990 2,510 LP3W 10 1941–50 1949 626 CR 4,800 11,400 17,900 29,000 39,600 52,400 67,900 92,800 LP3W 120 1929–35, CR 1,090CR 2,870 4,850 3,580 8,630 8,270 12,600 12,100 17,900 17,300 24,800 21,400 36,900 25,500 29,600 34,900 LP3W 167 LP3W 110 1895, 1935, CR 1,380 3,510 5,660 9,350 12,900 17,100 22,200 30,300 LP3W 26 1951–76 1975 13,000 CR 271 648 1,060 1,830 2,650 3,730 5,150 7,680 LP3W 44 1950–93 1956 3,030 CR 416 1,550 3,080 6,410 10,300 15,800 23,400 37,600 LP3W 13 1966–78 1972 15,200 type Gage Gage contributes directlyto surface runoff) contributes directlyto surface runoff) contributes directlyto surface runoff) contributes directlyto surface runoff) contributes directly runoff) contributes to surface 2 2 2 2 2 contribute directly to surface runoff. However, these values do not reflect latest do not reflectrevision of 721 mi values these contributeHowever, to surface directly runoff. revision latest ofvalues do not reflect these However, runoff. directly contributes to surface 2 2 contributes directly to surface runoff) directly contributes to surface 2 Station name , approximately, of which, aboutapproximately, 2,100 mi of which, aboutapproximately, 3,690 mi of which, aboutapproximately, 3,940 mi mi, of which 859 mi 1,110 aboutwhichof , approximately, of which, aboutapproximately, 1,590 mi to (total) drainage area in Boohar and others (1995); a revised value of contributingpublished.)not(1995);ofa revisedwas in Boohar and othersarea drainage value to (total) drainage area 2 2 2 2 2 2 2 , approximately, of which about 421 mi approximately, , of which about 790 mi approximately, , 2 2 (station skew—skew relations generalized (1,300 mi (8,620 mi (519 mi (8,200 mi (2,630 mi 1,140 mi to (total) drainage area in Boohar and others (1995); a revised value ofin Boohar and othersdrainage revised (1995);to (total)contributingwas value area not published.) a drainage area (1,050 mi (930 mi (2,990 mi skew—peak-flow regional equations or remarks) or equations regional skew—peak-flow (——— ———) (——— +0.002—HPS, UR) (——— -0.090—Newanalysis) stationUR network for (——— -0.090—Newanalysis) stationUR network for (+0.057—HP+0.413—HPS,UR) (——— -0.523—UR) (-0.096—Skew map -0.090—UR)(-0.096—Skew map (+0.353—HP+0.359—HPS,HPC, UR) (——— -0.100—Newanalysis) stationUR network for Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations streamflow-gaging for data frequency Peak-flow Station Station number ber Map num- 8345 06834500 Nebr. Cr near Wauneta, Stinking Water 8340 06834000Palisade, Frenchman Nebr. Cr at CR 604 1,080 1,540 2,320 3,090 4,060 5,260 7,310 REG 43 1895–96, 8310 06831000 Frenchman Cr below Champion, Nebr. CR 388 878 1,370 2,220 3,060 4,110 5,400 7,560 REG 22 1935–56 1940 2,850 8280 06828000 Republican R at Max, Nebr. 8285 06828500 Republican R at Stratton, Nebr.8295 06829500 Republican R Nebr.at Trenton, 8297 06829700Nebr. ThompsonCanyon near Trenton, CR 2,480 CR 5,640 8,920 366 14,900 20,900 791 28,700 1,290 38,700 55,900 2,330 3,560 REG 5,340 44 7,920 13,100 1950–93 1962 REG 26,800 40 1935, 8281 06828100Cr near Max, NBr IndianNebr. 8245 06824500 Republican R at Benkelman, Nebr. 8250 06825000 S Fk Republican R near Idalia, Colo. 8255 06825500 Landsman nearCr Hale, Colo. 8315 06831500 Frenchman Cr near Imperial,Nebr. CR 160 387 668 1,280 2,820 3,120 4,750 8,150 REG 53 1941–93 1960 2,340 8325 06832500Nebr. Frenchman Cr near Enders, CR 352 460 524 599 650 699 745 804 REG 43 1946–93 1953 763 8350 06835000 Cr near Palisade, Stinking Nebr. Water 8275 06827500 S Fk Republican R near Benkelman, Nebr. CR 1,310 4,380 7,930 14,500 21,100 29,400 39,300 55,500 REG 44 1903–06, 8351 06835100 Bobtail nearCr Palisade, Nebr. 8355 06835500Culbertson, FrenchmanNebr. Cr at CR 741 1,660 2,520 3,890 5,140 6,580 8,230 10,800 REG 43 1931–93 1935 15,000 Table B2. streams--Continued regulated for areas drainage and

APPENDIX B B-37 /s) 3 peak WY and dis- and WY of maximum maximum of 1947 30,000 1960 5,890 1955 1,650 charge (ft record 1961–93 1955–93 1946–86 1958–60, Period of of Period peak-flow —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or /s) for given recurrence interval (years) No basin characteristics No basin characteristics 3 Peak discharge (ft 211 493 782 1,300 1,820 2,470 3,300 4,720 —UR— 2 5 10 25 50 100 200 500 571 1,530 2,540 4,340 6,110 8,310 11,000 15,400 —UR— 353 1,030506 1,770365 3,070 970 714 1,940 4,280 1,660 3,310 5,810 2,630 4,920 7,480 3,970 10,300 6,800 5,780 9,180 8,160 13,300 —UR— 12,500 —HPS— —HPC— 566639 874 1,820618 1,980 3,120 1,960 5,740 5,510 3,450 9,310 7,940 6,170 15,000 11,000 23,200 14,800 8,870 39,300 21,200 12,200 16,200 22,600 —HPS— —UR— —UR— 337 911 1,510345 2,560302280 3,570 621 499 4,810 1,080 701295 6,290 958 2,390 1,150 867 8,690424 2,180 3,830 1,960 1,480 1,250 3,220 5,450 2,780 2,580 2,160 4,590 —UR— 7,560 3,840 3,640 11,300 3,800 6,380 5,180 4,950 5,450 9,570 7,490 6,520 —HPS— 7,480 9,040 9,970 —HPC— —UR— 14,100337 —UR— 983406 —UR— 1,670 1,160 2,890 1,960 4,070 3,400 5,500 4,800 7,200 6,530 9,910 8,620 12,000 —UR— —UR— PS 728PS 2,330 18 4,260 8,080 93 12,200 17,600 214 24,700 37,100 509 880 LP3W 19 1,430 2,210 1952–70 3,720 1956 11,200 LP3W 27 1952–78 1967 731 PS 131 317PS 491 206 772PS 504 1,020 141PS 860 1,320 1,600 1,640 637 503 2,460 2,140 1,360 1,800 3,700 2,990 3,490 5,460 LP3W 4,920 7,010 33 8,940 11,000 7,620 16,400 11,300 1961–93 23,700 18,100PS LP3W 28 36,800 1968 148PS LP3W 900 27 LP3W 1951–78 652 19 240 1962 1,370 2,650 1952–78 789 1952–70 2,920 1969 1,420 1956 3,370 4,710 2,600 8,660 7,170 3,800 10,500 16,300 5,280 7,090 LP3W 10,100 29 LP3W 28 1952–70 1959 2,080 1951–78 1951 2,810 CRCR Insufficient data—zero or unknown flows for 6 of 12 peaks 341 846 1,420 2,560 3,800 5,510 7,820 12,100 1966–77 LP3W 1968 33 530 1961–93 1972 4,020 CR 392 929 1,440 2,280 3,060 3,970 5,020 6,660 LP3W 52 1935, CR 161 332 475 686 863CR 1,060 768 1,260 3,200 1,560 6,540 13,710 LP3W 21,800 33 32,900 47,500 1961–93 73,600 1965 LP3W 712 101 1951–76 1967 7,140 type Gage contributes directly to surface runoff) 2 contributes directlyto surface runoff) contributes directlyto surface runoff) contributes directlyto surface runoff) 2 2 2 Station name , approximately, of which about 6,220 mi of which about 6,220 approximately, , 2 approximately, of which approximately, about 320 mi of which approximately, about 405 mi , approximately, of which about 351 mi of approximately, , 2 2, 2, (station skew—skew relations generalized (361 mi (740 mi (12,240 mi (820 mi skew—peak-flow regional equations or remarks) (+0.311—HP (+0.311—HP +0.476—HPS, HPC, UR) (——— -0.100—New station for UR network analysis) (——— -0.120—UR)(——— (——— -0.130—UR)(——— (-0.279—Skew ———) map (-0.634—Skew -0.130—UR) map (-0.264—Skew ———) map (+0.869—HP +0.638—HPS, HPC, UR) (+0.310—Skew map -0.130—UR) -0.130—UR)(——— (-0.362—Skew map, HP -0.058—HPS, UR) -0.150—UR)(——— (+0.151—Skew map -0.140—UR) Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations for streamflow-gaging data frequency Peak-flow Station number ber Map Map num- 8365 06836500 Driftwood Cr near McCook, Nebr. CR 554 1,420 2,380 4,180 6,090 8,580 11,800 17,500 REG 48 1946–93 1950 4,740 8373 06837300Nebr. Cr above Hugh Butler Lake, Willow Red 8375 06837500Cr near McCook, Nebr. Willow Red CR 111 145 201 310 365 427 496 600 REG 32 1941–47, 8371 06837100 Nebr. Willow, Cr near Red Ash 8370 06837000 at McCook, Nebr. Republican R CR 1,480 2,730 3,620 4,770 5,630 6,480 7,320 8,400 REG 39 1931–32, 8360 06836000 Blackwood nearCr Culbertson, Nebr. 8396 06839600 Frazier Cr near Maywood, Nebr. 8397 06839700 Frazier Cr trib Maywood,near Nebr. 8385a 06838550Nebr. Bartley, Dry Cr at 8390 06839000 Medicine Cr at Maywood, Nebr. 8392 06839200 Elkhorn Canyon near Maywood, Nebr. 8394 06839400Maywood, Elkhornof Canyon southwest Nebr. 8395 06839500 Brushy Cr near Maywood, Nebr. 8398a 06839850Curtis,of Fox Cr north Nebr. 8399 06839900Nebr. Canyon near Curtis,Cut Fox Cr above 8380 06838000 Nebr. Cr Red Willow near Red Willow, 8382 06838200at Indianola,Nebr. Coon Cr CR 269 564 861 1,390 1,920 2,610 3,470 4,970 REG 32 1940–93 1947 30,000 Table B2. Table streams--Continued regulated for areas drainage and

B-38 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska /s) 3 peak WY and dis- and WY of maximum maximum of 1986 10,800 1951 3,340 1951 4,430 1944 10,600 1965 3,800 charge (ft record 1978–93 1978–93 1960–70 1944–72 1961–88 1951–72, 1961–70, 1951–58, 1946–53, Period of of Period peak-flow —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or /s) for given recurrence interval (years) (years) interval recurrence given for /s) 3 Appears to Appears require analysis composite frequency Out-of-stateusedskew only for relation(s) station Peak discharge (ft discharge Peak 2 5 10 25 50 100 200 500 538 1,470 2,440 4,160 5,820 7,830 10,200 14,100 —UR— 218 573502 1,400 942 2,370314 1,590 4,120 2,230 879 5,860 3,020 1,500 8,020 3,980 2,540 10,700 5,550 15,000 3,590 4,870 —UR— 6,420 —UR— 8,940 —UR— 243 634 1,040 1,740 2,410 3,240 4,220395 5,830 1,070 1,790 —UR— 3,070 4,330418 5,890 1,070 7,790 10,900 1,740 2,920 4,070 —UR— 5,490 7,200 10,000 —UR— 389 1,120 1,890 3,250 4,560 6,150 8,030 11,000 —UR— 691 1,770 2,900 4,890 6,860 9,300 12,300 17,200 —UR— 1,000 2,770 4,660 8,010 11,300 15,300 20,200 28,000 —UR— 1,040 2,830 4,740 8,150 11,500 15,600 20,600 28,700 —UR— PS 320 742 1,120 1,700 2,210 2,780 3,390 4,300 LP3W 28 1951–78 1952 1,560 PS Out-of-stateusedskew only for relation(s) station 1957–89 1979 3,450 PS 287 737 1,200 1,990 2,770 3,700 4,830 6,650 LP3W 37 1957–93 1957 2,680 PS 342 621 837 1,140 1,380 1,630 1,900 2,280 LP3W 33 1957–89 1975 880 CR 522 1,680 3,020 5,530CR 8,120 1,100 11,400CR 2,790 15,400 22,100 4,500 364 7,450 LP3W 10,300 721 26 13,700 1,010 17,800CR 1,410 24,300 1950–74 1,740 1951 303 LP3W 5,230 2,080 1,250 39 2,440 2,550 2,950 5,300 1947, 8,390 LP3W 12,600 16 18,100 27,800 1978–93 1993 LP3W 34 1,040 1960–93 1975 5,310 CR 866 2,510 4,386 7,970 11,700 16,600 22,900 33,800 LP3W 33 1929–32, CR 1,350 2,780 4,040 5,970 7,670 9,580 11,700 15,000 LP3W 48 1937–72 1966 9,500 CR 446 1,110 1,780 2,950 4,070 5,430 7,060 9,700 LP3W 40 1929–32, type Gage Gage CR, PS 429 1,130CR, PS 1,820 772 2,970 2,050 4,030 3,440 5,250 6,000 6,650 8,630 12,000 8,790 16,200 23,500 LP3W 34 LP3W 96 1951–58, 1947, contributes contributes todirectly surface runoff) contributes todirectly surface runoff) 2 2 contributes directly to surface runoff) directly contributes to surface runoff) directly contributes to surface 2 2 Station name approximately, of which about 7,780 mi of which about 7,780 approximately, mi of which about 8,880 approximately, 2, 2, approximately, of which about 530 mi approximately, of which about 655 mi approximately, 2, 2, (station skew—skew relations generalized (14,460 mi (770 mi (900 mi (15,580 mi skew—peak-flow regional equations or remarks) or equations regional skew—peak-flow (+0.149—Skew -0.140—UR) map (-0.341—Skew map -0.140—UR)(-0.341—Skew map (——— -0.150—UR) (——— -0.210—UR) (+0.027—Skew ———) map -0.050—UR)(-0.041—Skew map (+0.035—Skew -0.140—UR) map (——— -0.140—UR) (+0.224—Skew -0.050—UR) map (-0.058—Skew map -0.080—UR)(-0.058—Skew map (-0.134—Skew map -0.050—UR)(-0.134—Skew map (-0.026—Skew map -0.050—UR)(-0.026—Skew map (-0.884—Skew map ———)(-0.884—Skew map Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations streamflow-gaging for data frequency Peak-flow Station Station number ber Map num- 8399b 06839950Nebr. Canyon near Curtis, Cut 8440 06844000 Muddy Cr at Arapahoe, Nebr. 8442a 06844210Cr at Edison, Nebr. Turkey 8448 06844800 S Fk Sappa Cr trib Goodland,near Kansas 8449 06844900 S Fk Sappa Cr near Achilles, Kansas 8415 06841500 Mitchell Cr above Harry Strunk Lake, Nebr. 8435 06843500 Republican R at Cambridge, Nebr. CR 1,800 3,350 4,690 6,700 8,600 10,700 13,100 16,800 REG 32 1946–93 1947 160,000 8400 06840000at Curtis, Fox Nebr. Cr 8405 06840500 Dry nearCr Curtis, Nebr. 8410 06841000Nebr. Lake, Harry Medicine Strunk Cr above CR 1,430 3,600 5,960 10,400 15,000 21,000 28,600 42,200 REG 44 1950–93 1967 11,600 8425 06842500Nebr. Medicine Lake, Strunk Cr below Harry CR8445 384 06844500 Nebr. 539R near Orleans, Republican 665 8558450 1,020 06845000 Sappa 1,210 Cr near Oberlin, Kansas 1,430 CR 1,760 2,470 4,580 REG 44 6,240 8,570 10,500 1950–93 12,500 1960 14,600 1,300 17,600 REG 32 1948–93 1948 40,600 8451 06845100Kansas Norcatur, Long Br Draw near 8452 06845200 Nebr. Sappa Cr near City, Beaver 8460 06846000Ludell, Kansas Beaver Cr at 8462 06846200Kansasnear Ludell, Beaver Cr trib Table B2. streams--Continued regulated for areas drainage and

APPENDIX B B-39 /s) 3 peak WY and dis- and WY of maximum maximum of 1993 2,200 1955 1,100 1950 3,150 1950 12,200 1967 1,750 1966 43,400 1983 7,800 charge (ft 1959, record 1991–93 1962–78 1978–93 1978–93 1967–78 1946–93 1961–93 1962–89, 1963–75, 1962–75, Period of of Period peak-flow —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or /s) for given recurrence interval (years) 3 Appears composite to require analysis frequency Appears composite to require analysis frequency Out-of-state station onlyfor used relation(s) skew Peak discharge (ft 2 5 10 25 50 100 200 500 133 355 563 905 1,220 1,580 1,970 2,580 —C&SC— 438 815 1,100 1,500 1,830 2,180 2,550 3,080 —C&SC— 955 2,470177 4,050 6,870 495522 9,650 1,350 821 13,100 2,210 1,380 17,300 3,720 24,100 1,900 5,210 2,510 7,030 —UR— 3,240 9,240 4,360 12,900 —UR— —UR— 688 1,730 2,810 4,770 6,730 9,180 12,200 17,300 —UR— 1,350 2,970 4,450 6,760 8,770 11,000 13,500 17,200 —C&SC— 380 1,010 1,640 2,680 232 3,630 776 4,740 6,000 1,410 369 7,910 2,590 3,770 920 5,230 155 1,440 —C&SC— 6,990 319 9,810 2,260 445 3,000 625 —C&SC— 3,830 214 775 4,770 457 937 657 6,170 458 1,110 1,360 958 888 1,220 —C&SC— 1,500 1,220 —C&SC— 1,820 1,700 2,280 2,090 2,510 2,960 —C&SC— 3,600 —C&SC— PS 634 1,190 1,610 2,190 2,650 3,130 3,620 4,290 LP3W 37 1948–53, PS 218 480PS 702 154PS 1,030 1,300 460 352PS 1,600 777 878 1,910 253PS 1,310 1,360 2,360 481 1,810 389 2,120 2,390 LP3W 2,770 656 878 26 3,050 3,500 1,310 894 4,040 4,300 1,960 1948–56, 1,080 5,450 2,520 1,270 LP3W 18 3,130 1,470 LP3W 3,800 1,740 18 1953–70 4,770 1958 LP3W 1953–70 26 1,290 LP3W 1957 26 1,670 1953–78 1953–78 1957 1957 907 2,040 PS 217 510PS 802 1,310 1,800 Out-of-state stationfor only relation(s) used skew 2,390 3,120 4,310 LP3W 37 1957–93 1975 4,300 1957–91 1957 620 PS 562 1,150 1,640 2,350 2,940 3,590 4,280 5,270 LP3W 12 1941,1960, CR 507 1,110 1,600 2,330 2,920 3,540 4,200CR 5,120 1,900 LP3W 3,920 38 5,580 8,000 1948–56, 10,000 12,100 14,400 17,700 LP3W 38 1949–56, CR 674 1,490 2,270 3,580 4,820 6,320 8,100 11,000 LP3W 31 1963–93 1972 8,880 CR 439 1,100 1,810 3,090 4,390 6,040 8,110 11,600 LP3W 48 1946–93 1960 7,940 CR 319CR 1,160 736 2,230 2,360 4,430 4,350 6,830 8,380 10,000 12,800 14,200 18,800 21,600 26,800 41,000 LP3W 57 LP3W 50 1937–93 1983 1944, 9,510 type Gage contributes directly to surface runoff) directly contributes to surface 2 ) CR 978 2,200 3,540 6,100 8,870 12,600 17,600 26,800 REG 39 1948–53, 2 Station name , approximately, of which about 13,590 mi of which about 13,590 approximately, , 2 (station skew—skew relations generalized (20,820 mi skew—peak-flow regional equations or remarks) (-0.412—Skew -0.290—C&SC) map (-0.221—Skew -0.280—C&SC) map (-0.133—Skew -0.300—C&SC) map -0.300—C&SC)(——— -0.300—C&SC)(——— (-0.459—Skew -0.300—C&SC) map (-0.262—Skew -0.300—C&SC) map (-0.302—Skew -0.290—C&SC) map (——— -0.050—UR)(——— -0.060—UR)(——— (-0.435—Skew ———) map (——— -0.280—New station for C&SC network analysis) (+0.560—Skew map ———) (-0.234—Skew -0.050—UR) map -0.050—UR)(——— Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations for streamflow-gaging data frequency Peak-flow Station number ber Map Map num- 8500 06850000 Nebr. at Naponee, Cr Turkey 8502 06850200 Cottonwood Cr near Bloomington, Nebr. 8510 06851000at Franklin, Center Cr Nebr. 8511 06851100 W Br Thompson Cr at Hildreth, Nebr. 8512 06851200 W Br Thompson Cr Hildreth,near Nebr. 8513 06851300 W Br Thompson Cr trib near Hildreth, Nebr. 8514 06851400 W Br Thompson Cr Upland,near Nebr. 8515 06851500at Riverton, Thompson Nebr. Cr 8520 06852000 Nebr.at Amboy, Cr Elm (39.2 mi 8476 06847600 Prairie KansasDog Cr trib at Colby, 8479 06847900Kansas above Keith Sebelius Lake,Cr Prairie Dog 8482 06848200tribCr Prairie near Norton, Kansas Dog 8495 06849500Nebr. below Harlan County Dam, Republican R CR 1,330 2,390 3,300 4,710 5,970 7,420 9,090 11,700 REG 41 1953–93 1957 4,320 8496 06849600 nearCr Holdrege, Turkey Nebr. 8465 06846500 Cr Beaver at Bluffs, Cedar Kansas 8470 06847000 Nebr. Cr Beaver near City, Beaver 8475 06847500 Sappa Cr near Stamford, Nebr. Table B2. Table streams--Continued regulated for areas drainage and

B-40 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska /s) 3 peak WY and dis- and WY of maximum maximum of 1935 225,000 1941 15,000 1951 55,200 1951 91,900 1935 3,920 1973 1,900 charge (ft record 1950–93 1957 29,200 1932–93 1957–89 1945–93 1942–57 1957–89 1968–78 1928–32, Period of of Period peak-flow —regional equation— Type and length length and Type (years) of analysis 2 <1 mi <1 TDA and/or remarks and/or /s) for given recurrence interval (years) (years) interval recurrence given for /s) 3 Peak discharge (ft discharge Peak 2 5 10 25 50 100 200 500 968 1,950 2,840 4,210 5,300 6,460 7,730 9,540 —BB— 130 336 562 1,150 1,470 1,810 2,180 2,710 —BB— 1,490 2,8001,910 3,990 3,300 5,7703,430 4,610 7,130 7,180 6,300 10,100 8,590 7,800 14,600 10,200 18,100 12,400 9,400 21,900 11,100 25,900 13,600 31,600 —BB— —BB— —BB— PS Out-of-stateusedskew only for relation(s) station 1941, PS Out-of-stateusedskew only for relation(s) station 1957–90 1964 1,780 PS Out-of-stateusedskew only for relation(s) station 1957–89 1957 1,500 PS Out-of-stateusedskew only for relation(s) station 1957–93 1987 760 PS 317 594 814 1,130 1,390 1,660 1,960 2,380 LP3W 11 1968–78 1974 945 PS 626 1,160 1,580 2,160 2,630 3,120 3,640 4,370 LP3W 12 1963, CR Out-of-stateusedskew only for relation(s) station 1955–93 1973 15,800 CR 192 433 655 1,010 1,330 1,710 2,130 2,790 LP3W 40 1939–78 1959 970 CR Out-of-stateusedskew only for relation(s) station 1952–93 1957 23,300 CR Out-of-stateusedskew only for relation(s) station 1950–93 1951 12,900 CR Out-of-stateusedskew only for relation(s) station 1908, 1935, CR Out-of-stateusedskew only for relation(s) station 1919–25, CR Out-of-stateusedskew only for relation(s) station 1934–38, CR 1,690CR 2,990 1,450 4,010CR 3,010 5,450 3,230 4,350 6,630 6,770 6,360 7,900 9,810 8,100 14,400 9,260 10,000 18,300 11,200 12,100 22,700 15,300 27,500 LP3W 34,500 30 LP3W 40 LP3W 1964–93 40 1965 1954–93 10,700 1957 1954–93 10,100 1957 15,300 type Gage Gage contributes contributes todirectly surface runoff) 2 does not contribute1995)to surface does directlyand others, runoff—fromBoohar 2 Station name , approximately, of , approximately, which about 14,560 mi mi of which about 7,500 , 2 2 (station skew—skew relations generalized (Includes record for Republican R near Guide Rock, 06853000,(Includesfor 1950-1984) near Guide Rock, record Republican R (22,030 mi (22,400 mi skew—peak-flow regional equations or remarks) or equations regional skew—peak-flow (+0.476—Skew ———) map (-0.229—Skew map ———)(-0.229—Skew map (+0.401—Skew ———) map (-0.224—Skew map ———)(-0.224—Skew map ———)(-0.217—Skew map (+0.222—Skew ———) map (-0.198—Skew map ———)(-0.198—Skew map Kansas (-0.095—Skew ———) map (-0.010—Skew map ———)(-0.010—Skew map ———) map (+0.117—Skew (-0.216—Skew map ———)(-0.216—Skew map (——— -0.159—BB) (——— -0.137—BB) (-0.180—Skew -0.161—BB) SE map, (-0.222—Skew -0.162—BB) SE map, (——— -0.239—BB) Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations streamflow-gaging for data frequency Peak-flow Station Station number ber Map num- 8538 06853800 Kansas Burr Oak, Rock Cr near White 8531 06853100 Nebr. Beaver Cr near Rosemont, 8530a 06853020 Republican R at Guide Rock, Nebr. 8535 06853500Nebr. R near Hardy, Republican CR 3,860 6,780 9,500 14,100 18,500 CR 24,000 4,850 30,800 42,300 8,490 11,700 16,700 REG 21,200 41 26,600 32,900 42,800 REG 41 1903–15, 8561 06856100 Kansas Cr near Talmo, West 8568 06856800 Moll Cr near Green, Kansas 8710 06871000 N Fk Solomon R at Glade, Kansas 8715 06871500 Kansas Bow Cr near Stockton, 8726 06872600Bellaire, Kansas Oak Cr at 8730 06873000 S Reservoir, Fk Solomon R above Webster 8733 06873300Kansas Ashnear Stockton, Cr trib 8735 06873500 S Fk Solomon R at Alton, Kansas 8745 06874500 East Limestone Cr Ionia,near Kansas 8805c 06880590 N Br W Fk Big Blue R tribNebr. at Giltner, 8799 06879900at Surprise, Nebr. Blue R Big 8800 06880000 LincolnCr near Seward, Nebr. 8805 06880500at Seward, Nebr. Blue R Big 8805b 06880508 PlumNebr. Cr near Seward, Table B2. streams--Continued regulated for areas drainage and

APPENDIX B B-41 /s) 3 peak WY and dis- and WY of maximum maximum of 1993 12,400 1984 55,100 1941 57,700 1969 25,100 1992 32,600 charge (ft record 1958–93 1906–93 1929–93 1975–93 1975–92 1919–25, Period of of Period peak-flow —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or /s) for given recurrence interval (years) No basin characteristics 3 Peak discharge (ft 65 502 874 1,620 2,130 2,710 3,360 4,370 —BB— 99 468 943 1,970 2,740 3,650 4,720 6,460 —BB— 2 5 10 25 50 100 200 500 303 924122 1,520 429506 2,900 1,300 3,810 793 2,120 1,480 4,840 3,570 1,980 6,020 4,600 2,570 7,820 5,760 3,250 7,050 4,320 —BB— 9,000 —BB— —BB— 106 292 496 957348 1,250 1,580 939568 1,570 1,930 1,310933 2,830 2,460 2,070 1,810 3,690 3,390 2,730 4,650 —BB— 4,360 4,000 5,730 5,450 5,110 7,350 6,650 6,340 8,460 7,700 —BB— 9,760 —BB— —BB— 6,370 13,100 18,1003,300 25,300 5,910 31,3001,630 8,400 37,600 3,070 11,400 44,500 14,400 54,200 4,450 17,600 5,990 21,200 7,690 26,500 —BB— 9,560 11,600 —BB— 14,700 —BB— 3,370 6,510 9,180 13,000 16,100 19,400 23,000 28,200 —BB— 4,140 8,260 13,000 24,5005,760 31,000 38,100 11,700 17,000 45,900 27,200 57,300 33,900 41,200 —BB— 49,200 60,700 —BB— 10,600 20,200 27,30012,900 36,400 23,200 44,900 30,700 54,100 39,300 64,000 48,300 78,200 58,100 68,600 83,600 —BB— —BB— PS 1,530 2,810 3,760 5,060 6,080 7,120 8,190 9,650 LP3W 34 1960–93 1973 5,700 PSPS 42 263PS 215 774 488 166PS 1,330 1,150 388 518PS 2,340 1,970 1,330 3,340 594 3,170 19 2,140 4,580 4,880 922 3,490 6,070 8,160 36 1,220 4,760 8,500 1,550 6,250 LP3W 49 1,930 19 7,990 LP3W 2,510 26 10,700 68 1952–70 LP3W 1961 84 1953–78 LP3W 26 19 1961 999 101 2,690 1953–78 1952–70 120 1961 1960 1,120 146 3,720 PS LP3W 11 161 386 1968–78PS 1968 602PS 81 52 955 231PS 334 1,280 1,660 680 682 325PS 1,170 2,090 1,430 1,000 790 2,050 2,770 2,290 1,770 1,520 2,920 3,460 3,170 2,120 LP3W 3,990 5,020 4,580 12 3,000 5,290 7,830 6,330 3,740 7,380 8,480 1967–78 4,540 LP3W 12,000 1976 18 5,410 LP3W 1,660 28 LP3W 6,660 19 1953–70 1965 1952–78 LP3W 19 1960 1952–70 765 1,870 1960 3,690 1952–70 1960 3,220 CR 3,460CR 6,720 6,000 9,450CR 11,700 13,500 16,200 2,430 17,000 22,700 5,220 20,900 28,000 25,200 7,710CR 33,700 31,400 11,600 39,800 8,900 15,100 48,400 19,300CR LP3W 19,000 28,200 103 23,500 13,700 LP3W 41,600 30,300 24,000 124 53,000CR 31,500 65,400 1950, 41,600 4,220 LP3W 78,900 1945–93 49,400 34 98,500 8,560 1950 57,300 27,600 12,400 65,500CR 18,400 1960–93 LP3W 76,500 127 6,190 23,700 1984 29,700 11,800 33,000 LP3W 16,500 36,600 1902–03, 127 23,600 47,100 29,700 36,400 1903, LP3W 44,000 41 55,200 1951–72, LP3W 34 1959–72, type Gage Station name (station skew—skew relations generalized skew—peak-flow regional equations or remarks) (——— -0.166—BB)(——— -0.311—BB) (-0.495—SkewSE map, -0.205—BB)(-0.345—SkewSE map, (-0.056—Skew map, SE -0.148—BB)(-0.056—SkewSE map, -0.155—BB)(-0.018—SkewSE map, -0.158—BB)(——— (——— ———) -0.180—BB)(——— -0.189—BB)(-0.385—SkewSE map, (-0.249—SkewSE map, -0.225—BB) (+0.000—Skew map, SE -0.010—BB) -0.189—BB)(——— map, (+0.115—Skew SE -0.046—BB) -0.146—BB)(——— -0.182—BB)(-0.213—SkewSE map, -0.165—BB)(——— -0.157—BB)(——— (——— -0.140—BB)(——— Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations for streamflow-gaging data frequency Peak-flow Station number ber Map Map num- 8812 06881200 Nebr. nearCr Wilber, Turkey 8814a 06881450 Nebr. Cr at Beatrice, Indian 8815 06881500 Big Blue R at Beatrice, Nebr. 8807b 06880720Cr near Harvard, School Nebr. 8807c 06880730 School Cr trib #2 near Harvard, Nebr. 8807d 06880740Cr near Saronville, SchoolNebr. 8807e 06880775 Cr Beaver trib Henderson,near Nebr. 8808 06880800 W Fk Big Blue Nebr. R near Dorchester, 8810 06881000 Big R nearBlue Crete, Nebr. 8820 06882000 Big Blue R at Barneston, Nebr. 8830 06883000 Nebr. Deweese, R near Little Blue 8835a 06883540trib Nebr. Spring near Ruskin, Cr 8835b 06883570AlexandriaR near Little (Gilead), Nebr. Blue 8836 06883600Nebr. Edgar, near S Fk Big Sandy Cr 8837 06883700Davenport,nearNebr. S Fk Big Sandy Cr 8838 06883800Carleton,near Nebr. S Fk Big Sandy Cr 8839 06883900Hebron,near Nebr. S Fk Big Sandy Cr 8807a 06880710 School Cr trib near Harvard, Nebr. Table B2. Table streams--Continued regulated for areas drainage and

B-42 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska /s) 3 peak WY and dis- and WY of maximum maximum of 1992 54,000 1968 2,000 1903 73,000 1972 24,000 1915 38,500 charge (ft 1903, 1951, record 1957–93 1974–89 1929–57 1975–89 1954–85 1929–56, 1957–72, 1922–25, 1936–46, Period of of Period peak-flow —regional equation— Type and length length and Type (years) of analysis and/or remarks and/or /s) for given recurrence interval (years) (years) interval recurrence given for /s) No basin characteristicsNo basin No basin characteristicsNo basin 3 Peak discharge (ft discharge Peak 2 5 10 25 50 100 200 500 275 777 1,330 2,370 3,150 4,040 5,050 6,610 —BB— 450 1,150 1,890 3,370 4,480 5,720 7,100 9,160 —BB— 302 816 1,390 2,280 3,100 4,040 5,120 6,800 —BB— 3,110 6,090 8,860 12,600 15,900 19,500 23,600 29,600 —BB— 7,960 15,700 22,300 33,500 41,700 50,700 60,500 74,700 —BB— 4,880 9,630 13,600 18,600 23,700 29,300 35,400 44,200 —BB— 7,460 15,900 21,900 27,500 35,300 43,800 53,100 66,700 —BB— 3,730 7,3201,630 10,400 13,200 3,420 17,000 5,150 21,200 7,260 25,900 32,900 9,630 12,300 15,300 —BB— 19,900 —BB— 12,800 22,900 31,000 42,300 52,400 63,300 75,200 92,300 —BB— PS 308 738 1,140 1,790 2,380 3,050 3,810 4,960 LP3W 11 1968–78 1977 1,370 PS 225 697 1,180 1,980 2,690 3,490 4,380 5,670 LP3W 11 1968–78 1973 1,270 PS Out-of-stateusedskew only for relation(s) station PS 543 1,140 1,670 2,510 3,260 4,110 5,090 6,580 LP3W 37 1957–93 1983 2,500 PS 1,560 3,610 5,510 8,560 11,300 14,500 18,100 23,600 LP3W 37 1957–93 1972 8,800 CR 3,990 9,380 14,600 23,200 31,300 40,900 52,200 69,900 LP3W 14 1980–93 1984 21,900 CR 8,500 17,400 25,100 37,100 47,500 59,400 72,800 92,900 LP3W 73 1908–15, CR 5,100 8,610 11,200 14,700 17,500 20,300 23,300 27,300 LP3W 34 1960–93 1993 14,600 CR 13,700 23,500 30,900 41,300 49,700 58,500 67,900 81,100 LP3W 36 1958–93 1973 53,700 CR 7,800 16,200CR 23,300 34,200 43,500 53,900 65,400 Out-of-stateusedskew only for relation(s) station 82,300 LP3W 41 1953–93 1959 38,300 1918–60 1951 77,800 CR 6,120 10,800 14,400 19,500 23,600 28,000 32,600 39,300 LP3W 35 1954–73, CR Out-of-stateusedskew only for relation(s) station 1915, CR Out-of-stateusedskew only for relation(s) station 1959–90 1968 20,000 type Gage Gage PS,CR Out-of-stateusedskew only for relation(s) station Station name (station skew—skew relations generalized skew—peak-flow regional equations or remarks) or equations regional skew—peak-flow (——— -0.051—BB) (——— -0.181—BB) (-0.040—Skew -0.070—BB) SE map, (——— -0.473—BB) (-0.101—Skew map ———)(-0.101—Skew map (-0.342—Skew map -0.130—BB)(-0.342—Skew map -0.110—BB) map (+0.117—Skew (-0.155—Skew map -0.080—BB)(-0.155—Skew map (-0.176—Skew map -0.150—BB)(-0.176—Skew map ———) map (+0.118—Skew (-0.076—Skew map ———)(-0.076—Skew map (-0.148—Skew map -0.110—BB) (-0.148—Skew map (-0.273—Skew map -0.120—BB)(-0.273—Skew map ———)(-0.090—Skew map (-0.067—Skew map ———)(-0.067—Skew map Peak-flow frequency data for streamflow-gaging stations in Nebraska and for selected out-of-state stations, stations, out-of-state selected for and Nebraska in stations streamflow-gaging for data frequency Peak-flow Station Station number ber Map num- 8839b 06883940 Big Sandy Cr at Alexandria, Nebr. 8839c 06883955 Little Sandy Cr near Ohiowa, Nebr. 8840 06884000 Nebr. near Fairbury, LittleBlue R 8840b 06884005 Nebr. trib Dry near Fairbury, Br 8841 06884100 MulberryKansasnear Haddam, Cr trib 8842 06884200 Kansas Mill Cr at Washington, 8843 06884300 Kansas Mill Cr trib Washington, near 8844 06884400 Kansas near Barnes, LittleBlue R 8855 06885500 near Frankfort, R Kansas Black Vermillion 8860 06886000 Big Blue R at Randolph, Kansas 8845 06884500 Little Kansas Blue R at Waterville, 8865 06886500 Kansas Fancy Cr at Winkler, 8872 06887200 Kansas Cr near Manhattan, Cedar 8880 06888000Kansas Cr near Wamego, Vermillion 8883 06888300 Kansas Rock Cr near Louisville, Table B2. streams--Continued regulated for areas drainage and

APPENDIX B B-43 APPENDIX C—GRAPHS OF COMPOSITE PEAK-FLOW FREQUENCY CURVES FOR SELECTED STATIONS

APPENDIX C C-1 2,000 10,000

4475 LITTLE WHITE RIVER 7,000 4495 LITTLE WHITE RIVER 1,000 NEAR MARTIN, S. DAK. 5,000 NEAR ROSEBUD, S. DAK. 4,000 700 3,000 500 400 2,000 300

200 1,000

700 100 500 400 70 300 50 40 200 30

20 SECOND PER DISCHARGE, CUBIC FEET PEAK ANNUAL 100 99 98 95 90 80 70 60 50 40 30 20 10 5 2 1 99 98 95 90 80 70 60 50 40 30 20 10 5 2 1 20,000 5,000 4,000 4505 LITTLE WHITE RIVER BELOW 4592 SNAKE RIVER ABOVE MERRITT 3,000 10,000 WHITE RIVER, S. DAK. RESERVOIR, NEBR. 2,000 7,000 5,000 4,000 1,000 3,000 700 2,000 500 400 300 1,000 200 700 500 400 100 DISCHARGE, IN CUBIC FEET PER SECOND IN FEET DISCHARGE, CUBIC 300 70 200 50 99 98 95 90 80 70 60 50 40 30 20 10 5 2 1 99 98 95 90 80 70 60 50 40 30 20 10 5 2 1 15,000

10,000 4635 LONG PINE CREEK NEAR RIVERVIEW, NEBR. 7,000 5,000 4,000 3,000

2,000

1,000

700 500 400 300

200 150 99 98 95 90 80 70 60 50 40 30 20 10 5 2 1 ANNUAL EXCEEDANCE PROBABILITY, IN PERCENT EXPLANATION

Composite frequency curve Annual maximum peak flow

Figure C1. Composite peak-flow frequency curves for selected Nebraska and South Dakota streamflow-gaging stations in the White and Niobrara River Basins with average soil permeability of the top 60 inches of more than 4 inches per hour.

C-2 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska 5,000 5,000 4,000 4,000 6870 BLUE CREEK 6920 BIRDWOOD CREEK 3,000 3,000 NEAR LEWELLEN NEAR HERSHEY 2,000 2,000

1,000 1,000

700 700 500 500 400 400 300 300

200 200

100 100

70 70 50 50

10,000 20,000

7,000 7765 DISMAL RIVER 7775 MIDDLE LOUP RIVER 5,000 AT DUNNING 10,000 AT WALWORTH 4,000 7,000 3,000 5,000 2,000 4,000 3,000

1,000 2,000

700 500 1,000 400 700 300 500 200 400 DISCHARGE, IN CUBIC FEET PER SECOND PER IN CUBIC FEET DISCHARGE, 300

100 200 99 98 95 90 80 70 60 5040 30 20 10 5 2 1 99 98 95 90 80 70 60 50 40 30 20 10 5 2 1 20,000 20,000

7780 MIDDLE LOUP RIVER 7860 NORTH LOUP RIVER 10,000 AT SARGENT 10,000 AT TAYLOR

7,000 7,000 5,000 5,000 4,000 4,000 3,000 3,000

2,000 2,000

1,000 1,000 700 700 500 500 400 400 300 300

200 200 99 98 95 90 80 70 60 5040 30 20 10 5 2 1 99 98 95 90 80 70 60 50 40 30 20 10 5 2 1 ANNUAL EXCEEDANCE PROBABILITY, IN PERCENT EXPLANATION

Composite frequency curve Annual maximum peak flow

Figure C2. Composite peak-flow frequency curves for selected Nebraska streamflow-gaging stations in the North Platte and Platte River Basins with average soil permeability of the top 60 inches of more than 4 inches per hour.

APPENDIX C C-3 10,000 50,000 40,000 7,000 7875 CALAMUS RIVER 7885 NORTH LOUP RIVER 30,000 5,000 NEAR BURWELL AT ORD 4,000 20,000 3,000

2,000 10,000

7,000 1,000 5,000 4,000 700 3,000 500 400 2,000 300

200 1,000

700 100 500

100,000 150,000

70,000 7890 NORTH LOUP RIVER 100,000 7905 NORTH LOUP RIVER AT SCOTIA NEAR ST. PAUL 50,000 70,000 40,000 50,000 30,000 40,000 20,000 30,000

20,000 10,000

7,000 10,000

5,000 7,000 4,000 5,000 3,000 4,000 2,000 3,000 DISCHARGE, IN CUBIC FEET PER SECOND FEET CUBIC IN DISCHARGE, 2,000 1,000 1,500

10,000 30,000

7,000 7915 CEDAR RIVER 20,000 7940 BEAVER CREEK 5,000 NEAR SPALDING AT GENOA 4,000 10,000 3,000 7,000 2,000 5,000 4,000 1,000 3,000

700 2,000 500 400 1,000 300 700 200 500 400 100 300 99 98 95 90 80 70 6050 40 30 20 10 5 2 1 99 98 95 90 80 70 6050 40 30 20 10 5 2 1 ANNUAL EXCEEDANCE PROBABILITY, IN PERCENT EXPLANATION

Composite frequency curve Annual maximum peak flow Figure C3. Composite peak-flow frequency curves for selected Nebraska streamflow-gaging stations in the Platte River Basin with average soil permeability of the top 60 inches of more than 4 inches per hour.

C-4 Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska 100,000 500 400 70,000 8215 ARIKAREE RIVER 8235 BUFFALO CREEK 300 50,000 AT HAIGLER NEAR HAIGLER 40,000 200 30,000

20,000 100 70 10,000 50 40 7,000 30 5,000 4,000 20 3,000

2,000 10 7 1,000 5 700 5,000 500 4,000 8350 STINKING WATER CREEK 400 3,000 NEAR PALISADE 300 2,000 200

1,000 100 700 70 500 50 400 40 300 30 200 20

100 DISCHARGE, IN CUBIC FEET PER DISCHARGE, IN CUBIC FEET PER SECOND 10 99 98 95 90 80 70 60 50 40 30 20 10 5 2 1 70 50 99 98 95 90 80 70 6050 40 30 20 10 5 2 1 5,000 5,000 4,000 4,000 8373 RED WILLOW CREEK ABOVE 8390 MEDICINE CREEK 3,000 3,000 HUGH BUTLER LAKE AT MAYWOOD 2,000 2,000

1,000 1,000 700 700 500 500 400 400 300 300

200 200

100 100

70 70 50 50 99 98 95 90 80 70 60 50 40 30 20 10 5 2 1 99 98 95 90 80 70 6050 40 30 20 10 5 2 1 ANNUAL EXCEEDANCE PROBABILITY, IN PERCENT EXPLANATION

Composite frequency curve Annual maximum peak flow

Figure C4. Composite peak-flow frequency curves for selected Nebraska streamflow-gaging stations in the Republican River Basin with average soil permeability of the top 60 inches of more than 4 inches per hour.

APPENDIX C C-5