Data from 346 streamgages used in the development of regional regression equations for the estimation of magnitude and frequency of floods at ungaged locations in New Mexico

The U.S. Geological Survey (USGS), in cooperation with the New Mexico Department of Transportation, estimated the magnitude and frequency of floods corresponding to the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (AEPs; otherwise known as the 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year floods, respectively) for 346 selected streamgages in New Mexico and parts of Arizona, Colorado, Oklahoma, Texas, and Utah using data through water year 2020 in version 7.3 of USGS PeakFQ software (Veilleux and others, 2014; Flynn and others, 2006). An updated regional flood skew, -0.145, standard error 0.454, was computed for the study area and, when appropriate, was used to weight the at-site skew. The results of the frequency analyses and a suite of basin characteristics from the USGS StreamStats application (Ries and others, 2008) were used in generalized least-squares (GLS) regression in USGS Weighted Regression (WREG) software (Farmer, 2021; Eng and others, 2009) to generate equations that predict discharges corresponding to selected AEPs at ungaged locations on unregulated streams in the study area. The methods and results of the study are published in the primary publication (Tillery and others, 2026).

This dataset includes a table of site information and tab-delimited versions of Tables 1 and 2 in the primary publication. File "SiteInfo.txt" contains site information, statistically significant basin characteristics, results from at-site flood-frequency analyses and results of generalized least-squares (GLS) regression of at-site estimates of selected flood quantiles against available basin characteristics for the 346 selected streamgages. File "Table1.txt" lists, by flood region, the ranges of basin characteristics that were statistically significant in GLS regression. File "Table2.txt" contains the regression equations for each of the eight selected AEPs in each of the nine flood regions and performance metrics for the equations.