Risks for Drinking Water Source Areas: Surface and Hydrogeologic Displays 24th Annual ESRI International User Conference Water Management and Rights Thursday, August 12, 2004 San Diego, CA Authors: James Sinnott, RTI International (presenter) William Cooter, RTI International Scott Guthrie, RTI International Jay Rineer, RTI International Roger Anzzolin, US EPA, Office of Ground Water and Drinking Water

Acknowledgements The work described in this presentation was funded by the U.S. Environmental Protection Agency under Contract 68-C-01-001 with Research Triangle Institute (RTI). RTI gratefully acknowledges this support. Disclaimer: Although the research described has been funded wholly or in part by the U.S. Environmental Protection Agency Contract 68-C-01-001 to Research Triangle Institute, it has not been subject to the Agency's review and therefore does not necessarily reflect the views of the Agency, and no official endorsement should be inferred. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. Disclaimer: In the interest of protecting certain types of information, and in accordance with EPA protocol, the GIS data displayed in the following images were rendered for display purposes only and do not accurately represent actual data from EPA’s spatial databases.

Presentation Outline Overview of the Drinking Water Mapping Application (DWMA) Georeferencing to the National Hydrography Dataset (NHD) Building Analytical Source Water Areas (SWAs) Relating SWAs to Potential Risks and Vulnerabilities Wellhead Visualization Tool

DWMA Overview A secure, ArcIMS-based geospatial application for US EPA Office of Ground Water and Drinking Water Enables queries of the Safe Drinking Water Information System (SDWIS/Fed) with other federal and state data Identifies potential risks and vulnerabilities to surface water and groundwater used for public drinking water Generates query driven maps and reports at a variety of spatial scales

Web Interface Header Frame (standard EPA template) Tab Frame Query Frame Map Frame Combines queries and maps Tab Frame Query Frame Map Frame

Driving the DWMA

Georeferencing to NHD Allows one to analyze upstream and downstream effects nationally >6,000 drinking water intakes >100,000 facility pipe discharges >9,000 combined sewer overflows

Source Water Areas (SWAs) Land areas that can contribute water and pollutants Surface water and ground water SWAs State defined SWAs not available nationally

Building Analytical Source Water Areas (SWAs) Analytical wellhead SWAs defined as simple 2 mile buffers Analytical surface water SWAs Created 15 mile upstream drainage network for each intake Built a “convex hull” around each drainage network

Analytical Surface Water SWA vs. State Defined Surface Water SWA

Relating SWAs to Potential Point Contamination Risks Superfund sites Hazardous waste sites Class I Underground Injection Control (UIC) wells

Relating SWAs to Non-Point Concerns Atrazine use (USGS) Nitrogen fertilizer sales (EPA) Recoverable manure nitrogen from confined livestock (USDA) All non-point data were related to counties which will be related to SWAs

Relating SWAs to Vulnerabilities Percent impervious cover Based on 1992 National Land Cover Dataset (NLCD) NLCD land cover categories were assigned degrees of impervious cover Weighted average impervious cover will be calculated for SWAs using ArcGrid

Relating SWAs to Vulnerabilities and Other Factors Presence of karst geology Population counts based on 2000 census data Disadvantaged communities based on median household income

Looking Below the Surface Well Visualization Tool generates a custom UIC well profile by clicking on a well Shows geology in area and all nearby wells Based on scalable vector graphics (SVG) WVT Tool Drinking Water Wells UIC

Looking Below the Surface Override database defaults for well profile values Enter a radius for the “Area of Investigation” Create a well visualization or a tabular report

Looking Below the Surface Generalized geology UIC wells Drinking water wells in area of investigation Hyperlinked to scanned formation images

Looking Below the Surface 5 section report: UIC wells, drinking waters wells, generalized geology, and salinity Hyperlinks to existing SDWIS reports where available SDWIS reports

Conclusions Creating analytically based source water areas and spatially relating them to potential contaminant risks, vulnerabilities, and other attributes is one way to facilitate national scale analyses for drinking water supplies Scalable Vector Graphics are a useful way to integrate surface views with subsurface views As more detailed data become available they can be incorporated into the DWMA database and used to improve the accuracy of the analyses For more information contact: Roger Anzzolin, US EPA Anzzolin.Roger@epa.gov James Sinnott, RTI International jsinnott@rti.org