An ordinary least squares (OLS) technique was used with at-site flow-duration exceedance probabilities, from SWToolbox (Kiang and others, 2018), and 14 basin characteristics (basin perimeter, drainage area, maximum basin elevation, mean total annual reference evapotranspiration, groundwater head, length of longest flow path, minimum basin elevation, runoff-curve number, relief, ruggedness, slope ratio, percentage of hydrologic soil type B, available water capacity, and total length of streams in a basin) for 28 selected streamflow gaging stations in Puerto Rico to calculate regional flow-duration regression equations for ungaged stream locations. The final flow-duration regression equations were developed in R (R Core Team, 2019) using the “lm” function. Performance metrics were analyzed to determine drainage area, mean total annual reference evapotranspiration, and minimum basin elevation as the explanatory variables that provided the best results. This data release includes a SWToolbox_output_files folder that contains supporting data used to format the R input file, a FlowDuration_regression_models folder that contains .txt files showing the final regression models for the 99th, 98th, 95th, 90th, 80th, 70th, 60th, and 50th percent exceedance probabilities, and a FlowDuration_regression_model_plots folder that contains .pdf files showing supporting graphics output for the final regression models. References Cited:
Kiang, J.E., Flynn, K.M., Zhai, T., Hummel, P., and Granato, G., 2018, SWToolbox—A surface-water tool-box for statistical analysis of streamflow time series: U.S. Geological Survey Techniques and Methods, book 4, chap. A–11, 33 p., https://doi.org/10.3133/tm4A11. R Core Team, 2019, R—A language and environment for statistical computing: R Foundation for Statistical Computing, Vienna, Austria, accessed February 11, 2021, at https://www.R-project.org/.