RES2020-23: Peak Flow Estimation in Urban Drainage Areas - PART 2

Peak Flow Estimation in Urban Drainage Areas

In 2024, the U.S. Geological Survey, in cooperation with the Tennessee Department of Transportation, updated the methods for predicting the magnitude and frequency of floods at ungaged locations on streams in urban areas in Tennessee. The study area included streamgages in urban areas in Tennessee, Mississippi, Alabama, Georgia, South Carolina, and North Carolina. Regression equations were developed to predict streamflows corresponding to the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual excedance probabilities (AEPs) and were incorporated into the StreamStats application. In generalized least-squares (GLS) regression, the base-10 logarithm of drainage area, the percentages of the streamgage basins in developed land use and the percentages of the streamgage basins in the Piedmont and Ridge and Valley level 3 ecoregions were statistically significant in explaining the variability in annual peak streamflows in the study area. Pseudo R-squared of the regression equations ranged from 0.86, or 86 percent, for the 0.5 and 0.2 AEPs (the 2- and 5-year floods) to 0.71, or 71 percent, for the 0.002 AEP (the 500-year flood). The average variance of prediction (in log base 10 units) ranged from 0.023 for the 0.2 and 0.1 AEPs to 0.05 for the 0.002 AEP. The average variance of prediction can be reported as a percentage of the predicted value, known as the standard error of prediction, which ranged from 35.8 percent for the 0.2 AEP (the 5-year flood) to 55.4 percent for the 0.002 AEP (the 500-year flood). Methods are presented for estimating annual peak streamflows for gaged locations, ungaged locations on gaged streams, and locations on ungaged streams.

• Record URL:
  • https://www.tn.gov/content/dam/tn/tdot/research/researchsummary/res2020-research-summaries/RES2020-23%20Peak%20Flow%20Esimation.pdf
• Supplemental Notes:
  • This is Part 2 from the U.S. Geological Survey (USGS).

Language

• English

Project

• Status: Active
• Funding: $225,000.00
• Contract Numbers:

  RES2020-23

• Sponsor Organizations:

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Managing Organizations:

  University of Memphis

  Center for Intermodal Freight Transportation Studies
  3815 Central Avenue
  Memphis, TN  United States  38152
• Project Managers:

  Peck, Wesley

• Performing Organizations:

  Tennessee Department of Transportation

  James K. Polk Building
  Fifth and Deaderick Street
  Nashville, TN  United States  37243-0349
• Principal Investigators:

  David Ladd, USGS

• Start Date: 20210401
• Expected Completion Date: 20210331
• Actual Completion Date: 20241231
• USDOT Program: Modeling and Analysis Tools
• Subprogram: Conditions and Performance Forecasting

Subject/Index Terms

• TRT Terms: Floods; Predictive models; Stream gages; Streamflow; Urban areas; Watersheds
• Geographic Terms: Tennessee
• Subject Areas: Data and Information Technology; Highways; Hydraulics and Hydrology;

Filing Info

• Accession Number: 01941869
• Record Type: Research project
• Source Agency: Tennessee Department of Transportation
• Contract Numbers: RES2020-23
• Files: RIP, STATEDOT
• Created Date: Jan 7 2025 10:28AM