DOI: 10.5066/p9b48p2w
title: Flood-frequency of rural, non-tidal streams in Louisiana and parts of Arkansas, Mississippi, and Texas, 1877-2016

description: The dataset includes flood-frequency data and related files for 211 streamgages operated by the U.S. Geological Survey (USGS) in Louisiana and parts of the surrounding states of Arkansas, Mississippi, and Texas as well as assembled explanatory variables (physical, climatic, and land-use characteristics of the basins).  The data in this release were used in generalized least-squares (GLS ) regression analyses (Stedinger and Tasker, 1985) to generate equations used to predict annual exceedance probabilities (AEPs) at ungaged locations on streams in the study area (Ensminger and others, 2021).  Flood-frequency analyses were conducted using annual peak-flow data from the 1877-2016 water years to estimate streamflows corresponding to the 0.5, 0.2, 0.1, 0.04, 0.02, 0.01, 0.005, and 0.002 annual exceedance probabilities (AEPs; otherwise known as the 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year floods, respectively).  USGS PeakFQ software, version 7.3 (Veilleux and others, 2014; Flynn and others, 2006) was used to conduct the flood-frequency analyses.  R software (R Core Team, 2017) was used to join the suite of explanatory variables with flood-frequency data.  A final list of 211 streamgages with flood frequency data and explanatory variables suitable for GLS regression was determined with several criteria and analyses in R (See methods in Ensminger and others, 2021). USGS weighted-multiple-linear regression software (WREG; Eng and others, 2009) implemented in R (Farmer, 2017) was used to perform generalized least-squares (GLS) regression. 

The files in this data release include:  1)  PeakFQ files, 2) GIS shapefiles; and a .csv file.  The PeakFQ files are peak-flow (&quot;LA_pkflows.txt&quot;), specification (&quot;LA_pkflows.psf&quot;), and export (&quot;LA_pkflows.EXP&quot;) files.  The GIS shapefiles include one of points representing the streamgage locations with attributes of USGS site information, flood-frequency estimates, and their variances (&quot;LApkflows.shp&quot;) and another of the study area boundary (&quot;StudyArea.shp&quot;).  The comma-separated values text file (&quot;LApkflows.csv&quot;) contains the attributes of the GIS shapefile &quot;LApkflows.shp&quot;.

References:

Kennedy, E.G., 1983, Computation of continuous records of streamflow, U.S. Geological Survey Techniques of Water Resources Investigations 03-A13, https://doi.org/10.3133/twri03A13.

Stedinger, J.R. and Tasker, G.D., 1985, Regional hydrologic analysis 1-Ordinary, weighted, and generalized least squares compared, Water Resources Research Volume 21, Number 9, https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/WR021i009p01421.

Flynn, K.M., Kirby, W.H., and Hummel, P.R., 2006, User's Manual for Program PeakFQ Annual Flood-Frequency Analysis Using Bulletin 17B Guidelines, U.S. Geological Survey Techniques and Methods Book 4, chap. B4, https://pubs.usgs.gov/tm/2006/tm4b4/tm4b4.pdf.

Eng, Ken, Chen, Yin-Yu, and Kiang, J.E., 2009, User's guide to the weighted-multiple-linear regression program (WREG version 1.0), U.S. Geological Survey Techniques and Methods Book 4, chap. A8, https://pubs.usgs.gov/tm/tm4a8.

Veilleux, A.G., Cohn, T.A., Flynn, K.M., Mason, R.R., Hummel, P.R., 2014, Estimating magnitude and frequency of floods using the PeakFQ 7.0 program, U.S. Geological Survey Fact Sheet 2013-3108, https://doi.org/10.3133/fs20133108.

Farmer, W., 2017, WREG:  USGS weighted-multiple-linear regression version 2.02.  R package version 2.02, https://github.com/USGS-R/WREG.

R Core Team, 2017, R:  A language and environment for statistical computing, R Foundation for statistical computing, Vienna, Austria, https://www.R-project.org/.

England, J.F., Jr., Cohn, T.A., Faber, B.A., Stedinger, J.R., Thomas, W.O., Jr., Veilleux, A.G., Kiang, J.E., and mason, R.R., Jr., 2019, Guidlines for determining flood flow frequency-Bulletin 17C, U.S. Geological Survey Techniques and Methods Book 4, chap. B5, https://doi.org/10.3133/tm4B5.