Details:

Creators:
Timpson, Aaron J. ; Pomeroy, Christine A.
Timpson, Aaron J. ; Pomeroy, Christine A. Less -
Corporate Creators:
University of Utah. Department of Civil and Environmental Engineering
Subject/TRT Terms:
[+]
Flood Forecasting--Utah Floods Floods--Utah Forecasting Watersheds
Publication/ Report Number:
UT-10.11
Resource Type:
Tech Report
Geographical Coverage:
Utah
Corporate Publisher:
Utah. Dept. of Transportation. Research Division
Abstract:
Determining discharge in a stream is important to the design of culverts, bridges, and other structures pertaining to

transportation systems. Currently in Utah regression equations exist to estimate recurrence flood year discharges for

rural watersheds greater than 30 mi2, and the rational method is used for areas smaller than 0.5 mi2, however, there

are no good methods available to estimate discharges for rural watersheds that fall between the two approaches. To

solve this issue, flood frequency analyses were conducted for small rural watersheds with streamflow gaging station

data within the state of Utah to develop regression equations for estimating flood flows for mid-sized watersheds. The

watersheds selected range from 0.5 mi2 to 30 mi2, and have at least 10 years of annual peak discharges recorded by

the United States Geological Survey (USGS). Flood frequency analyses were performed in accordance with the

guidelines of Bulletin 17B (Interagency Advisory Committee on Water Data), using the USGS computer program

PeakFQ (Flynn et al 2006). Computed flood year streamflows were regressed against multiple parameters (watershed

geometries, soil characteristics, precipitation data, land use data, etc.) to estimate different recurrence flood year flows

(i.e. 2-, 5-, 10-, 25-, 50-, 100-, 200-, 500-year). Regression equations were developed for seven regions in the state of

Utah delineated according to hydrologic regions or climatic properties. Regression equations were developed in the

format of the rational method where the runoff coefficient was regressed against appropriate determined data: basin

characteristics, such as drainage basin area, max flow distance, sinuosity, composite curve number, saturated

hydraulic conductivity, and climatic characteristics including, the basin centroid 2-year 24-hour precipitation, and

basin centroid mean annual precipitation. The regression equations are presented within the document including

errors associated with the regression processes. This document also summarizes the procedures a user should follow

to use these equations in practice. Cautions are presented for the user to understand the limitations of the equations

and to facilitate more efficient design of channel crossings.


Format:
PDF
Funding:
09-9099
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:9ad12f0d8aec3664283c86739d68681769f68b2a7c7d40dfd226d06dd455b3f6
Download URL:
https://rosap.ntl.bts.gov/view/dot/18143/dot_18143_DS1.pdf
File Type:

Supporting Files

• No Additional Files

More +