1. 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

2. Acknowledgements
The work described in this presentation was funded by the U.S. Environmental Protection Agency under Contract 68-C 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 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.

3. 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

4. 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

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

6. Driving the DWMA

7. 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

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

9. 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

10. Analytical Surface Water SWA vs. State Defined Surface Water SWA

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

12. 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

13. 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

14. 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

15. 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

16. 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

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

18. 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

19. 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
James Sinnott, RTI International