1. Drinking Water Mapping Application (DWMA) Demonstration
EPA GIS Workgroup Spring Meeting
May 15-18, 2007
Boston, MA
Authors:
Roger Anzzolin, US EPA, Office of Ground Water and Drinking Water
Bill Cooter, RTI International James Rineer, RTI International (presenter)

2. Presentation Outline Overview of the DWMA Data layers
Georeferencing to the NHD
Building Source Protection Areas (Wells and Intakes)
Demo

3. 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)
Identifies potential risks and vulnerabilities to surface water and groundwater used for public drinking water

4. Web Interface SDWIS Points Source Protection Areas (SPA) System Type
Population Served
Violations
Point Risks
Nonpoint Risks
Source Protection Areas (SPA)
% Impervious
Population in SPA
Karst/DOD/SSA
All the SDWIS Point Options

5. Driving the DWMA

6. 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

7. Source Protection Areas (SPAs)
Land areas that can contribute water and pollutants
Surface water and ground water protection areas
State defined SPAs not available nationally

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

9. Analytical Surface Water SPA vs. State Defined Surface Water SPA

10. NHDPlus derived SPAs
Distance
Time
Detached
Service based

11. Relating SPAs to Potential Point Contamination Risks
Superfund sites
Hazardous waste sites
Class I Underground Injection Control (UIC) wells
PCS
CSO
UST (MT,CO,AZ,TN,AL,SC)

12. Relating SPAs to Non-Point Concerns
Atrazine use (USGS)
Nitrogen fertilizer sales (USGS-EPA)
Recoverable manure nitrogen from confined livestock (USDA)

13. Relating SPAs to Vulnerabilities
Percent impervious cover
Based on 1992 National Land Cover Dataset (NLCD)
Weighted average impervious cover was calculated for SPAs using ArcGrid
Update will be based on NHDPlus summaries

14. Relating SPAs 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
Generalized geology
UIC wells
Drinking water wells in area of investigation
Hyperlinked to scanned formation images

17. Drinking Water Mapping Application (DWMA)
For more information contact:
Roger Anzzolin, US EPA
Bill Cooter, RTI International
James Rineer, RTI International