Annual peak streamflow (peak flow) at a streamgage is defined as the maximum instantaneous flow in a water year. A water year begins on October 1 and continues through September 30 of the following year. This definition of a water year is used because it more closely follows seasonal weather patterns. Peak flows in Texas can range from zero flow in very dry basins to flows that cause flooding and can cause extensive damage. The USGS Texas Water Science Center (TXWSC) monitors streams with real-time streamflow gaging stations and manual measurements. Visit the links below for more information on our data and science.
Annual peak-streamflow frequency estimates are needed for flood-plain management; for objective assessment of flood risk; for cost-effective design of dams, levees, and other flood-control structures; and for design of roads, bridges, and culverts. Annual peak-streamflow frequency represents the peak streamflow for nine recurrence intervals of 2, 5, 10, 25, 50, 100, 200, 250, and 500 years. Common methods for estimation of peak-streamflow frequency for ungaged or unmonitored watersheds are regression equations for each recurrence interval developed for one or more regions.

PEAK FLOW SCIENCE CAPABILITIES
TXWSC has expertise in peak flow science applications, including, but not limited to:
- Marking and surveying high-water marks
- Determining peak discharge from indirect measurements
- Analyzing flood-peak magnitudes and their statistical probabilities at selected locations
- Collecting streamflow using continuous record gages, crest-stage gages, acoustic doppler current profilers, and flow meters.
- Computing annual peak discharge
Find out more about TXWSC flood-response science expertise in this printable information sheet.
LOOKING FOR PEAK STREAMFLOW DATA?
CURRENT PEAK FLOW SCIENCE
InFRM Flood Inundation Mapping
Post Hurricane Harvey Assessment
Projects related to peak flows are listed below.
InFRM Flood Inundation Mapping
Post Hurricane Harvey Assessment
Publications related to peak flows are listed below.
Application of at-site peak-streamflow frequency analyses for very low annual exceedance probabilities
Trend analysis and selected summary statistics of annual mean streamflow for 38 selected long-term U.S. Geological Survey streamgages in Texas, water years 1916-2012
Annual peak streamflow and ancillary data for small watersheds in central and western Texas
Regression equations for estimation of annual peak-streamflow frequency for undeveloped watersheds in Texas using an L-moment-based, PRESS-minimized, residual-adjusted approach
Summary of annual mean and annual harmonic mean statistics of daily mean streamflow for 620 U.S. Geological Survey streamflow-gaging stations in Texas through water year 2007
Effects of regulation on L-moments of annual peak streamflow in Texas
Peak-flow frequency for tributaries of the Colorado River downstream of Austin, Texas
Documented and potential extreme peak discharges and relation between potential extreme peak discharges and probable maximum flood peak discharges in Texas
Regional equations for estimation of peak-streamflow frequency for natural basins in Texas
Techniques to estimate generalized skew coefficients of annual peak streamflow for natural basins in Texas
Peak data for U.S. Geological Survey gaging stations, Texas network and computer program to estimate peak-streamflow frequency
Data and Tools related to peak flows are listed below.
Texas Water Dashboard
View over 850 USGS real-time stream, lake, reservoir, precipitation, water quality, and groundwater stations in context with current weather and hazard conditions.
Texas Water On-The-Go
“Water On-the-Go” is a map-based web application that gives people easy access to current conditions in streams across Texas. It was developed to help raise water awareness during floods and normal conditions. The mobile-friendly website offers three ways to view streamflow or other data, including using your phone’s GPS system.
- Overview
Annual peak streamflow (peak flow) at a streamgage is defined as the maximum instantaneous flow in a water year. A water year begins on October 1 and continues through September 30 of the following year. This definition of a water year is used because it more closely follows seasonal weather patterns. Peak flows in Texas can range from zero flow in very dry basins to flows that cause flooding and can cause extensive damage. The USGS Texas Water Science Center (TXWSC) monitors streams with real-time streamflow gaging stations and manual measurements. Visit the links below for more information on our data and science.
Annual peak-streamflow frequency estimates are needed for flood-plain management; for objective assessment of flood risk; for cost-effective design of dams, levees, and other flood-control structures; and for design of roads, bridges, and culverts. Annual peak-streamflow frequency represents the peak streamflow for nine recurrence intervals of 2, 5, 10, 25, 50, 100, 200, 250, and 500 years. Common methods for estimation of peak-streamflow frequency for ungaged or unmonitored watersheds are regression equations for each recurrence interval developed for one or more regions.
Sources/Usage: Public Domain. Visit Media to see details.Measuring floodwaters in Peach Creek at Highway 90 near Waelder, Texas. (Credit: Cassi Crow, USGS. Public domain.) PEAK FLOW SCIENCE CAPABILITIES
TXWSC has expertise in peak flow science applications, including, but not limited to:
- Marking and surveying high-water marks
- Determining peak discharge from indirect measurements
- Analyzing flood-peak magnitudes and their statistical probabilities at selected locations
- Collecting streamflow using continuous record gages, crest-stage gages, acoustic doppler current profilers, and flow meters.
- Computing annual peak discharge
Find out more about TXWSC flood-response science expertise in this printable information sheet.
LOOKING FOR PEAK STREAMFLOW DATA?
CURRENT PEAK FLOW SCIENCE
InFRM Flood Inundation Mapping
Post Hurricane Harvey Assessment
- Science
Projects related to peak flows are listed below.
InFRM Flood Inundation Mapping
The purpose of this flood inundation mapping effort will be to meet the needs of real-time emergency managers by bridging the gap between the NWS's river forecasts and FEMA's available hydraulic modeling and mapping.Post Hurricane Harvey Assessment
In the immediate aftermath of Hurricane Harvey related flooding, the USGS Texas Water Science Center and the Federal Emergency Management Agency (FEMA) initiated a cooperative study to evaluate the magnitude of the flood, determine the probability of occurrence, and map the extent of the flood in Texas. - Publications
Publications related to peak flows are listed below.
Filter Total Items: 14Application of at-site peak-streamflow frequency analyses for very low annual exceedance probabilities
The U.S. Geological Survey (USGS), in cooperation with the U.S. Nuclear Regulatory Commission, has investigated statistical methods for probabilistic flood hazard assessment to provide guidance on very low annual exceedance probability (AEP) estimation of peak-streamflow frequency and the quantification of corresponding uncertainties using streamgage-specific data. The term “very low AEP” impliesTrend analysis and selected summary statistics of annual mean streamflow for 38 selected long-term U.S. Geological Survey streamgages in Texas, water years 1916-2012
In 2013, the U.S. Geological Survey (USGS) operated more than 500 continuous streamgages (streamflow-gaging stations) in Texas. In cooperation with the Texas Water Development Board, the USGS evaluated mean annual streamflow data for 38 selected streamgages that were active as of water year 2012. The 38 streamgages have annual mean streamflow data considered natural and unregulated. Collected annuAnnual peak streamflow and ancillary data for small watersheds in central and western Texas
Estimates of annual peak-streamflow frequency are needed for flood-plain management, assessment of flood risk, and design of structures, such as roads, bridges, culverts, dams, and levees. Regional regression equations have been developed and are used extensively to estimate annual peak-streamflow frequency for ungaged sites in natural (unregulated and rural or nonurbanized) watersheds in Texas (ARegression equations for estimation of annual peak-streamflow frequency for undeveloped watersheds in Texas using an L-moment-based, PRESS-minimized, residual-adjusted approach
Annual peak-streamflow frequency estimates are needed for flood-plain management; for objective assessment of flood risk; for cost-effective design of dams, levees, and other flood-control structures; and for design of roads, bridges, and culverts. Annual peak-streamflow frequency represents the peak streamflow for nine recurrence intervals of 2, 5, 10, 25, 50, 100, 200, 250, and 500 years. CommonSummary of annual mean and annual harmonic mean statistics of daily mean streamflow for 620 U.S. Geological Survey streamflow-gaging stations in Texas through water year 2007
Analysts and managers of surface-water resources have interest in annual mean and annual harmonic mean statistics of daily mean streamflow for U.S. Geological Survey (USGS) streamflow-gaging stations in Texas. The mean streamflow represents streamflow volume, whereas the harmonic mean streamflow represents an appropriate statistic for assessing constituent concentrations that might adversely affecEffects of regulation on L-moments of annual peak streamflow in Texas
Several techniques exist to estimate annual peak-streamflow frequency for streamflows that have recurrence intervals ranging from 2 to 500 years for natural (unregulated) drainage basins in Texas. Unfortunately, such techniques have limited applicability in regulated basins. There are numerous regulated basins throughout Texas, which has more than 7,000 dams that are identified by Texas Natural RePeak-flow frequency for tributaries of the Colorado River downstream of Austin, Texas
A procedure to estimate the peak discharge associated with large floods is needed for tributaries of the Colorado River downstream of Austin, Texas, so that appropriate peak discharges can be used to estimate floodplain boundaries and used for the design of bridges and other structures. The U.S. Geological Survey, in cooperation with the Lower Colorado River Authority, studied flood peaks for streDocumented and potential extreme peak discharges and relation between potential extreme peak discharges and probable maximum flood peak discharges in Texas
The U.S. Geological Survey, in cooperation with the Texas Department of Transportation, conducted a study of extreme flood potential for Texas. Potential extreme peak discharges, derived from the relation between documented extreme peak discharges and their contributing drainage areas, can provide valuable information concerning the maximum expected peak discharge that could occur at a stream siteRegional equations for estimation of peak-streamflow frequency for natural basins in Texas
Peak-streamflow frequency estimates are needed for flood-plain management; for objective assessment of flood risk; and for cost-effective design of dams, levees, other flood-control structures, roads, bridges, and culverts. Peak-streamflow frequency represents the peak discharges for recurrence intervals of 2, 5, 10, 25, 50, and 100 years. The U.S. Geological Survey, in cooperation with the TexasTechniques to estimate generalized skew coefficients of annual peak streamflow for natural basins in Texas
This report presents two techniques to estimate generalized skew coefficients used for log-Pearson Type III peak-streamflow frequency analysis of natural basins in Texas. A natural basin has less than 10 percent impervious cover, and less than 10 percent of its drainage area is controlled by reservoirs. The estimation of generalized skew coefficients is based on annual peak and historical peak strPeak data for U.S. Geological Survey gaging stations, Texas network and computer program to estimate peak-streamflow frequency
About 23,000 annual peak streamflows and about 400 historical peak streamflows exist for about 950 stations in the surface-water data-collection network of Texas. These data are presented on a computer diskette along with the corresponding dates, gage heights, and information concerning the basin, and nature or cause for the flood. Also on the computer diskette is a U.S. Geological Survey computer - Web Tools
Data and Tools related to peak flows are listed below.
Texas Water Dashboard
View over 850 USGS real-time stream, lake, reservoir, precipitation, water quality, and groundwater stations in context with current weather and hazard conditions.
Texas Water On-The-Go
“Water On-the-Go” is a map-based web application that gives people easy access to current conditions in streams across Texas. It was developed to help raise water awareness during floods and normal conditions. The mobile-friendly website offers three ways to view streamflow or other data, including using your phone’s GPS system.