USGS

Flood Frequency and Storm Runoff of Urban Areas of Memphis and Shelby County, Tennessee

U.S. Geological Survey, Water-Resources Investigations Report 84-4110

by Braxtel L. Neely, Jr.

This report is available as a pdf below


Abstract

Techniques are presented for estimating the magnitude and frequency of peak discharges and storm runoff on streams in urban areas of Memphis, Tennessee. Comprehensive regression analyses were made in which physical characteristics of streams were related to flood characteristics at gaging stations. Equations derived from the regression analyses provide estimates of peak discharges and storm runoff volumes with recurrence intervals of 2 to 100 years on streams that have drainage areas less than 20 square miles. The regression analyses indicated that size of drainage area and condition of channel (paved or unpaved) were the most significant basin characteristics affecting the magnitude and frequency of floods in urban streams.

Data from 27 gaging stations each with 8 years of record were used in the analyses. Flood frequency at each gaging station was computed from calibrated parameters in a rainfall-runoff model.

Techniques are also presented for estimating discharge hydrographs for individual floods by using the unit hydrograph, lag time, and rainfall excess.

Table of Contents

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