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H. C. Riggs

Publications and source records attributed to H. C. Riggs.

13 recordsLinked to original sources
USGS2007

The National Streamflow Statistics Program: A Computer Program for Estimating Streamflow Statistics for Ungaged Sites

The National Streamflow Statistics (NSS) Program is a computer program that should be useful to engineers, hydrologists, and others for planning, management, and design applications. NSS compiles all current U.S. Geological Survey (USGS) regional regression equations for estimating streamflow statistics at ungaged sites in an easy-to-use interface that operates on computers with Microsoft Windows operating systems. NSS expands on the functionality of the USGS National Flood Frequency Program, and replaces it. The regression equations included in NSS are used to transfer streamflow statistics from gaged to ungaged sites through the use of watershed and climatic characteristics as explanatory or predictor variables. Generally, the equations were developed on a statewide or metropolitan-area basis as part of cooperative study programs. Equations are available for estimating rural and urban flood-frequency statistics, such as the 1 00-year flood, for every state, for Puerto Rico, and for the island of Tutuila, American Samoa. Equations are available for estimating other statistics, such as the mean annual flow, monthly mean flows, flow-duration percentiles, and low-flow frequencies (such as the 7-day, 0-year low flow) for less than half of the states. All equations available for estimating streamflow statistics other than flood-frequency statistics assume rural (non-regulated, non-urbanized) conditions. The NSS output provides indicators of the accuracy of the estimated streamflow statistics. The indicators may include any combination of the standard error of estimate, the standard error of prediction, the equivalent years of record, or 90 percent prediction intervals, depending on what was provided by the authors of the equations. The program includes several other features that can be used only for flood-frequency estimation. These include the ability to generate flood-frequency plots, and plots of typical flood hydrographs for selected recurrence intervals, estimates of the probable maximum flood, extrapolation of the 500-year flood when an equation for estimating it is not available, and weighting techniques to improve flood-frequency estimates for gaging stations and ungaged sites on gaged streams. This report describes the regionalization techniques used to develop the equations in NSS and provides guidance on the applicability and limitations of the techniques. The report also includes a users manual and a summary of equations available for estimating basin lagtime, which is needed by the program to generate flood hydrographs. The NSS software and accompanying database, and the documentation for the regression equations included in NSS, are available on the Web at http://water.usgs.gov/software/.

Techniques and Methods↗
USGS1994

Nationwide summary of US Geological Survey regional regression equations for estimating magnitude and frequency of floods for ungaged sites, 1993

For many years, the U.S. Geological Survey (USGS) has been involved in the development of regional regression equations for estimating flood magnitude and frequency at ungaged sites. These regression equations are used to transfer flood characteristics from gaged to ungaged sites through the use of watershed and climatic characteristics as explanatory or predictor variables. Generally these equations have been developed on a statewide or metropolitan area basis as part of cooperative study programs with specific State Departments of Transportation or specific cities. The USGS, in cooperation with the Federal Highway Administration and the Federal Emergency Management Agency, has compiled all the current (as of September 1993) statewide and metropolitan area regression equations into a micro-computer program titled the National Flood Frequency Program.This program includes regression equations for estimating flood-peak discharges and techniques for estimating a typical flood hydrograph for a given recurrence interval peak discharge for unregulated rural and urban watersheds. These techniques should be useful to engineers and hydrologists for planning and design applications. This report summarizes the statewide regression equations for rural watersheds in each State, summarizes the applicable metropolitan area or statewide regression equations for urban watersheds, describes the National Flood Frequency Program for making these computations, and provides much of the reference information on the extrapolation variables needed to run the program.

Water-Resources Investigations Report↗
USGS1976

Flood characteristics of streams in Owyhee County, Idaho

Channel-width measurements were used to estimate annual peaks with a recurrence interval of 10 years at 79 sites in Owyhee County, Idaho, and adjacent areas. These discharges and those from 33 gaging stations are plotted on a map of the area. The map will allow the user to interpolate between sites. (Woodard-USGS)

Idaho↗
USGS1976

A simplified slope-area method for estimating flood discharges in natural channels

Discharge of a stream may be computed from the slope of the water surface, the cross-sectional area, and an estimate of channel roughness. This, the slope-area method, is widely used to compute flood peak discharges from high-water marks. Reliability of a computed discharge depends largely on the roughness coefficient, which must be estimated. This paper shows that results of comparable accuracy can be obtained from area and slope alone in natural channels; a roughness coefficient is not needed because roughness and slope are related. The estimating equation and suggestions for application of the simplified method are included.

Journal of Research of the U.S. Geological Survey↗
USGS1973

Storage analyses for water supply

This manual briefly describes various methods of storage analysis and recommends one method for use by the U.S. Geological Survey to produce draft-storage relations useful to planners and designers. The recommended method is described in detail.

Techniques of Water-Resources Investigations↗
USGS1973

Regional analyses of streamflow characteristics

This manual describes various ways of generalizing streamflow characteristics and evaluates the applicability and reliability of each under various hydrologic conditions. Several alternatives to regionalization are briefly described.

Techniques of Water-Resources Investigations↗
USGS1972

Low-flow investigations

This manual describes methods of defining the low-flow characteristics of streams, shows how certain basin characteristics influence the mean and variability of annual low flows, and recommends procedures for data collection, analysis, and reporting.

Techniques of Water-Resources Investigations↗
USGS1969

Mean streamflow from discharge measurements

Mean flow of a stream is usually computed from a continuous record of flow ai a gaging station. A less costly method consists of (1) estimating 12 individual monthly flows from one discharge measurement per month and a concurrent gaging station record on a nearby stream, using a different relation for each month, (2) computing the annual mean from the estimated monthly means, and (3) using a relation based on gaging station records to estimate the long-term mean from the one annual mean. An annual mean can be estimated within about 10 percent of its measured value even though both the gaged and ungaged streams are affected by diversions and have different runoff characteristics. The method has greatest utility in regions where mean runoff is not closely related to drainage area.

Idaho, Nevada, Washington↗
USGS1955

Floods in North Carolina, frequency and magnitude

Recorded annual flood stages and discharges at 144 gaging stations are listed. Also included are maximum known flood stages and discharges, both at gaging stations and at miscellaneous sites. Using the annual flood discharge at gaging stations a regional analysis of flood magnitudes and frequencies in the state was made. Results of the analysis are (1) a composite annual flood frequency curve for North Carolina (2) two composite seasonal flood-frequency curves for the State, and (3) curves for transferring the composite frequency curves to specific sites on the basis of location and drainage area. A summary shows the flood-frequency relationships, the method of determining flood frequency at a site, and the application of flood-frequency information to typical problems.

North Carolina↗