RES2020-23: Peak Flow Estimation in Urban Areas - PART 1

Peak Flow Estimation in Urban Areas

16. Abstract This project addressed the need for updating the existing peak flow equations for urban basins in Tennessee. After reviewing the current state of the art, the work reported herein focuses on unraveling the complex, interacting effects that non-stationary precipitation, evolving urbanization levels, and spatial patterns in land development, rainfall, as well as antecedent conditions, all have on the hydrologic response or urbanizing basins. Potential uncertainties and biases in the estimation of extreme rainfall quantiles (IDF-DDF values), due to the low density of weather stations and the use of totalized rainfall data, and in the frequency analysis of frequent floods, due to using annual maxima instead of partial duration (peaks over threshold) series, are also investigated. All urban basins in Tennessee have experienced growth in the amounts of developed areas in the past 20 years, and there is a significant increase in the frequency of extreme rainfall events in the region. Using rainfall data with the 15-minute resolution typically available in the U.S. introduces a negative bias that is highly variable across stations, while the low density of rain gauges increases the uncertainty in IDF-DDF values. We derive a novel urbanization index based on hydrologic connectivity that, in contrast with the traditional approach of using percentage of impervious area (IA), is able to reflect the hydrologic effects of different spatial distributions of urbanized patches within a watershed. This index outperforms IA when used as an explanatory variable in regression equations for predicting urban peak flows. A methodology to perform continuous hydrologic simulation with artificial neural networks is also proposed to investigate the effects of changing land cover, excluding concurrent effects of trends in precipitation.

• Record URL:
  • https://www.tn.gov/content/dam/tn/tdot/research/researchsummary/res2020-research-summaries/RES2020-23%20Peak%20Flow%20Esimation.pdf
• Record URL:
  • https://www.tn.gov/content/dam/tn/tdot/research/final-reports/2020-final-reports-and-summaries/2020-final-reports-and-sumaries/RES%202020-23%20Final%20Report%20Part%201%20U%20of%20M.21524.pdf

Language

• English

Project

• Status: Completed
• Funding: $253,517.50
• Contract Numbers:

  RES2020-23

• Sponsor Organizations:

  Federal Highway Administration

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

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Project Managers:

  Peck, Wesley

• Performing Organizations:

  University of Memphis

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

  Meier, Claudio

• Start Date: 20200701
• Expected Completion Date: 20230630
• Actual Completion Date: 20230630
• USDOT Program: Accountability
• Subprogram: Advanced Materials

Subject/Index Terms

• TRT Terms: Flow equations; Predictive models; Rainfall; Streamflow; Urban areas
• Geographic Terms: Tennessee
• Subject Areas: Data and Information Technology; Environment; Highways; Hydraulics and Hydrology;

Filing Info

• Accession Number: 01941867
• Record Type: Research project
• Source Agency: Tennessee Department of Transportation
• Contract Numbers: RES2020-23
• Files: RIP, STATEDOT
• Created Date: Jan 7 2025 10:19AM