Magnitude and Frequency of Floods in the Coastal Plain Region of Louisiana, 2016

Scientific Investigations Report 2024-5031
Prepared in cooperation with the Louisiana Department of Transportation and Development
By: , and 



To improve flood-frequency estimates for rural streams in the Coastal Plain region of Louisiana, generalized least-squares regression techniques were used to relate corresponding annual exceedance probability streamflows for 211 streamgages in the region to a suite of explanatory variables that include physical, climatic, pedologic, and land-use characteristics of the streamgage drainage area. The resulting generalized least-squares models can be used to estimate selected annual exceedance probability streamflows for rural ungaged locations in the Coastal Plain region of Louisiana. For the 211 streamgages in the Coastal Plain region of Louisiana and surrounding States, annual peak-streamflow data available through the 2016 water year were used in this study. Two unique flood regions, the Mississippi Alluvial Plain and Coastal Plain, were identified as separate hydrologic regions based on statistical evaluation and significance of categorical variables representing the regions regressed against the 1-percent annual exceedance probability streamflow (the 100-year flood). Regional regression equations for estimating annual exceedance probability streamflow for the Mississippi Alluvial Plain region have been previously published; therefore, the purpose of this study was to generate updated regional regression equations for the Coastal Plain region of Louisiana. The final regression models used drainage area and channel slope as explanatory variables based on performance metrics.

Suggested Citation

Ensminger, P.A., Wagner, D.M., and Whaling, A., 2024, Magnitude and frequency of floods in the Coastal Plain region of Louisiana, 2016: U.S. Geological Survey Scientific Investigations Report 2024–5031, 18 p.,

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Annual Peak-Streamflow Data
  • Basin Characteristics
  • Ordinary Least-Squares Regression
  • Determination of Flood Regions
  • Generalized Least-Squares Regression Equations
  • Application of Methods
  • Summary
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Magnitude and frequency of floods in the Coastal Plain region of Louisiana, 2016
Series title Scientific Investigations Report
Series number 2024-5031
DOI 10.3133/sir20245031
Year Published 2024
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Lower Mississippi-Gulf Water Science Center
Description Report: viii, 18 p.; 2 Data Releases
Country United States
State Arkansas, Louisiana, Mississippi, Texas
Online Only (Y/N) Y
Google Analytic Metrics Metrics page
Additional publication details