RES2020-23: Updating equations for peak flow estimation in urban creeks and streams of Tennessee

Engineers need to predict flood magnitude for different frequencies (return periods) in order to design infrastructure, for management and zoning, for emergency response, and to understand channel instability and other environmental impacts. In cities, where the risk to lives and property is higher, the hydrological response can be non-stationary because of urbanizing trends, changes in extreme precipitation, and development of storm water control measures. As a result, Tennessee Department of Transportation (TDOT) proposed Research Needs Statement Number 25, which states that: “TDOT uses equations developed by the United States Geological Survey (USGS) to estimate peak flows through all structures with a drainage area greater than approximately 500 acres. Equations for urban areas have not been updated since 1984 and do not take advantage of updates in estimation techniques and an additional 30 years of observed flow data to increase accuracy. Tennessee is currently experiencing exponential urban growth and updating the equations will provide more accurate peak flows resulting in more accurate drainage structure design.” The overall problem in the case of Tennessee involves multiple aspects: Previous work on the topic is aged and existing equations do not consider non-stationarity in either land use or rainfall extremes; few cities have gaged urban watersheds, and all of these are located within only three of the five main physiographic zones within TN; number of stations, record lengths and the range of variability in watershed characteristics needed for traditional regression analyses are very limited; there is a need to disentangle the effects of urbanization trends from any potential changes in extreme precipitation, while predictive equations should explicitly incorporate both these drivers, so as to be useful in the future, and; TDOT requires an automated decision support tool for calculation of estimates of flood-flow frequency and magnitude in urban areas of TN. This proposal offers innovative approaches to better understand the hydrologic response of urbanizing watersheds in Tennessee, in order to obtain the best possible predictive equations for urban peak flows, in a context of limited streamflow information, both in time (short records) and space (few stations, that happen to be spatially clustered).

• Record URL:
  https://www.tn.gov/content/dam/tn/tdot/long-range-planning/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
• Contract Numbers:

  RES2020-23

  40100-07219

• Sponsor Organizations:

  Tennessee Department of Transportation

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

  Meier, Claudio

  Burnette, Dorian

  Ladd, David

• Start Date: 20190611
• Expected Completion Date: 20230228
• Actual Completion Date: 20240100
• USDOT Program: Transportation, Planning, Research, and Development

Subject/Index Terms

• TRT Terms: Equations; Estimating; Floods; Forecasting; Rainfall; Streams; Urban areas; Watersheds
• Geographic Terms: Tennessee
• Subject Areas: Hydraulics and Hydrology; Planning and Forecasting; Transportation (General);

Filing Info

• Accession Number: 01744428
• Record Type: Research project
• Source Agency: Tennessee Department of Transportation
• Contract Numbers: RES2020-23, 40100-07219
• Files: RIP, STATEDOT
• Created Date: Jun 29 2020 5:50PM