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Application of the North Carolina Stochastic Empirical Loading and Dilution Model (SELDM) to Assess Potential Impacts of Highway Runoff


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Weaver, J.C., Stillwell, C.C., Granato, G.E., McDaniel, A.H., Lipscomb, B.S., and Mullins, R.M, 2021, Application of the North Carolina Stochastic Empirical Loading and Dilution Model (SELDM) to Assess Potential Impacts of Highway Runoff: U.S. Geological Survey data release,


In 2013, the U.S. Geological Survey (USGS) in partnership with the U.S. Federal Highway Administration (FHWA) published a new national stormwater quality model called the Stochastic Empirical Loading Dilution Model (SELDM; Granato, 2013). The model is optimized for roadway projects but in theory can be applied to a broad range of development types. SELDM is a statistically-based empirical model pre-populated with much of the data required to successfully run the application (Granato, 2013). The model uses Monte Carlo methods (as opposed to deterministic methods) to generate a wide range of precipitation events and stormwater discharges coupled with water-quality constituent concentrations and loads from the upstream basin and highway [...]

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NC-SELDM_Catalog_v1.0.xlsx 5.04 MB application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
NC-SELDM_Catalog_ReadMe.txt 5.43 KB text/plain
model-archive_Contents_ReadMe.txt 18.53 KB text/plain
model-archive_modelgeoref.txt 505 Bytes text/plain
Agency_logos_combined.png thumbnail 99.01 KB image/png


The purpose of this USGS data release is to publish NC SELDM streamflow and water-quality statistics developed from three series of multiple model simulations completed (one each) for the Blue Ridge, Piedmont, and Coastal Plain regions in North Carolina. These simulations were completed as part of an "NC SELDM phase 2" project from 2019 to 2021 between the USGS South Atlantic Water Science (Raleigh, North Carolina office) and the NCDOT (Hydraulics Unit). The phase 2 project was completed as a follow up to the NC SELDM project conducted from 2015 to 2019 by USGS and NCDOT (Weaver and others, 2019). Results summarized from the simulations completed for this project were used to develop an NC_SELDM_Catalog (Microsoft Excel spreadsheet) for NCDOT and others’ usage during the transportation design process to determine stormwater treatment goals, defined as the potential level of Best Management Practices that may be needed for treatment of highway runoff at a stream crossing. The data release also serves as a model archive for the (1) input and output files developed and generated for the purposes of the multiple NC SELDM simulations and (2) the R scripts developed for processing and summarizing the simulation output files for this project. The R scripts were developed using the R statistical language (


The Stochastic Empirical Loading and Dilution Model (SELDM) simulations and the NC_SELDM_Catalog documented in this model archive were prepared by the U.S. Geological Survey (USGS) in cooperation with the North Carolina Department of Transportation (NCDOT) and the Federal Highway Administration (FHWA). The USGS, NCDOT, and FHWA reserve the right to revise these model results and the NC_SELDM_Catalog pursuant to further analysis and review. These model results have been used by the USGS and are released on condition that the USGS, NCDOT, or FHWA may not be held liable for any damages resulting from their use. Information and numerical methods used in this study are attributable to the cited works. Copyright protection under Title 17 is not available for any work of the U.S. Government (17 USC §105).

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DOI doi:10.5066/P9LCXHLN

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