The U.S. Geological Survey (USGS) and the Federal Highway Administration (FHWA) are currently cooperating in a national project to evaluate FHWA's highway-runoff quality planning model. The FHWA wants to update the 1990 FHWA highway runoff quality model to reflect changes in runoff quality and to address the importance of upstream recieving-water concentrations for assessing the potential effects of runoff in these recieving waters. The FHWA wants a catalog of existing studies and available data that can be used to quantitatively predict the potential for adverse effects from highway-runoff discharge. Information collected will be used to determine if available data are sufficient to characterize pollutant loadings and impacts attributable to highway stormwater runoff around the country. The new model will use monte-carlo methods to quantify the effects of precipitation characteristics, streamflow, estimated runoff quanity and quality, and best management practices on the probability distribution of recieving-water concentrations. This web page will provide a catalog of reports, and other information as it becomes available.

SELDM Model Overview (Presented to the Transportation-Research Board by FHWA)

FHWA Natural Environment Web Page

This effort is an update of the FHWA 1990 model, which is now available here

This effort is an offshoot of the National Highway Runoff Water-Quality Data and Methodology Synthesis

Project Products
  Note: The CD-ROM image files are large and need to be saved to the user's computer to be used. Right-click the link and use the save as option.

Granato, G.E., 2006, Kendall-Theil Robust Line (KTRLine--version 1.0)—A visual basic program for calculating and graphing robust nonparametric estimates of linear-regression coefficients between two continuous variables: Techniques and Methods of the U.S. Geological Survey, book 4, chap. A7, 31 p. Report On-Line Software On-Line

The KTRLine program may be used to calculate parameters for robust, nonparametric estimates of linear-regression coefficients between two continuous variables. The Kendall-Theil robust line was selected because this robust nonparametric method is resistant to the effects of outliers and nonnormality in residuals that commonly characterize hydrologic data sets. The slope of the line is calculated as the median of all possible pairwise slopes between points. The intercept is calculated so that the line will run through the median of input data. A single-line model or a multisegment model may be specified. The KTRLine software is a graphical tool that facilitates development of regression models by use of graphs of the regression line with data and the regression residuals. The user may individually transform the independent and dependent variables to reduce heteroscedasticity and to linearize data. The program plots the data and the regression line. The program prints model specifications and regression statistics to the screen and saves the results to a user-specified output file in a format suitable for use with other programs.

 

The KTRLine program was used as part of this project to develop water-quality transport curves, relations between TSS and suspended sediment concentrations for highway runoff, relations between watershed area and pre-storm streamflow statistics and relations between the total-impervious fraction and runoff coefficient statistics of highway sites and upstream basins.

Granato, G.E., Carlson, C.S., and Sniderman, B.S., 2009, Methods for development of planning-level stream-water-quality estimates at unmonitored sites in the conterminous United States: Washington, D.C., U.S. Department of Transportation, Federal Highway Administration, FHWA-HEP-09-003, 53 p. Report On Line (1.5 MB). Example Water-Quality Transport Curve Poster On Line (1.7 MB).

This report documents methods for data compilation and analysis of water-quality-transport curves that meet data-quality-objectives for order-of-magnitude planning-level estimates of stream-water quality at unmonitored sites in the 84 U.S. Environmental Protection Agency Level III nutrient ecoregions in the conterminous United States. The water-quality- transport curves developed in this analysis are intended for use with a stochastic data-generation algorithm, for use with a highway-runoff model designed to better quantify the risk of exceeding water-quality criteria as precipitation, discharge, ambient water quality, and highway-runoff quality vary from storm to storm. Transport curves are regression relations used to estimate constituent concentrations from measured or estimated water-discharge values. Three constituents, total phosphorus, total hardness, and suspended sediment, were selected for regression analysis to develop transport curves for each ecoregion. However, the data compilation and interpretation methods described herein may be used with other water-quality constituents. A total of 24,581 USGS surface-water-quality monitoring stations with drainage areas ranging from 0.002 to 1,140 square miles were identified in the conterminous United States and cataloged for retrieval of water-quality data. The number of paired water-discharge and water-quality samples for total phosphorus, total hardness, and suspended sediment concentrations was 246,403; 107,289; and 275,950, respectively. Examination of transport curves developed with these data indicate that these curves are appropriate models describing the underlying processes of washoff or dilution expected for each constituent, and that predictions made using these transport curves are comparable with published estimates for each water-quality constituent. All of the geographic information system files, computer programs, data files, and regression results developed for this study are included on the CD-ROM accompanying this report. The CD-ROM also contains a data directory with more than 1,876,000 paired discharge and water-quality measurements that include 21 other constituents commonly studied in highway- and urban-runoff studies.

Granato, G.E., and Cazenas, P.A., 2009, Highway-Runoff Database (HRDB Version 1.0)--A data warehouse and preprocessor for the stochastic empirical loading and dilution model: Washington, D.C., U.S. Department of Transportation, Federal Highway Administration, FHWA-HEP-09-004, 57 p. Report On Line (3 MB). Database-Design Map On Line (0.22 MB).

This report documents highway-runoff database (HRDB), which was developed to serve as a data warehouse for current and future highway-runoff data sets. The database can be used by transportation agencies and researchers as a data warehouse to document information about a data set, monitoring site(s), highway-runoff data (including precipitation, runoff, and event mean concentrations). The HRDB currently includes 37 tables with data for 39,713 event mean concentration (EMC) measurements (including over 100 water-quality constituents) from 2,650 storm events, monitored at 103 highway-runoff monitoring sites in the conterminous United States, as documented in 7 selected highway-runoff data sets. These data include the 1990 FHWA runoff-quality model data compilation and results from 6 other data sets collected during the period 1993–2005. The HRDB application, which is the graphical-user interface and associated computer code, can be used to facilitate estimation of statistical properties of runoff coefficients, runoff-quality statistics, and relations between water-quality variables in highway runoff from the available data. The database application facilitates retrieval and processing of the available data.

For questions, comments, additions or suggestions contact:
Gregory Granato