Mapping Public Water
Systems in California
Craig Wolff, M.S. Eng
CA Environmental Health Tracking Program (CEHTP)
Environmental Health Investigations Branch
CA Department of Public Health (CDPH)
Craig.Wolff@cdph.ca.gov http://ehib.org http://cehtp.org
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Leaks and GIS
Craig.Wolff@cdph.ca.gov http://ehib.org http://cehtp.org
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Environmental Health Tracking
National and statewide network that
integrates environmental and health data
to produce and make available information
that drives action to improve the health of
communities.
Craig.Wolff@cdph.ca.gov http://ehib.org http://cehtp.org
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Data Visualization Example
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Enhancing Data for Tracking
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Assist data owners in geo-referencing
Geocoding
 Collaborative feature editing
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Internet- and service-oriented architecture
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Drinking Water Service Areas
No complete electronic statewide service
area coverage, changes/time
 How does Tracking benefit?
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Better analysis capacity wrt population served
Other beneficiaries
Emergency mgmt community
 Water resource mgmt
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Craig.Wolff@cdph.ca.gov http://ehib.org http://cehtp.org
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Solution – Mapping Tool
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Funded by CDC Tracking and CA ODW
Collaborative Internet GIS application for
calculating water system service areas in CA
Harness existing Tracking resources
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Secure web portal & content mgmt system (hardware,
software, data)
Software development expertise
Geocoding tool
Collaborators/advisory (ODW, UC Davis ICE, ACWA,
CalEMA, CDC, USEPA, AWWA?)
Craig.Wolff@cdph.ca.gov http://ehib.org http://cehtp.org
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Role-Based Access

Provide customized workspace for users who have
varying levels of access/jurisdiction
1.
2.
3.
4.
Water system staff – read/write access to water system;
indicate completion
Water system wholeseller staff – read/write access to member
water systems; indicate completion
Regional engineer (LPA) staff – read/write access to all water
systems within district; verification
State engineer/admin staff – read/write access to all water
systems
Craig.Wolff@cdph.ca.gov http://ehib.org http://cehtp.org
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Existing Information
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GIS Files
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Manually gathered existing statewide, regional and local
coverages  system name match to attach pwsid, evaluate
linkage; ~600 PWS in existing dbs
Water utility staff uploads existing GIS files (KML or shapefile)
describing service area boundaries
Customer Information Database

Upload customer address table
Craig.Wolff@cdph.ca.gov http://ehib.org http://cehtp.org
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Geocoding
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CDPH has web-based geocoding tool
Batch geocodes ~250K records/hr. ~90% of
CWS have <10K connections (i.e. addresses)
Existing browser-based utility for uploading
address table and batch geocoding
Craig.Wolff@cdph.ca.gov http://ehib.org http://cehtp.org
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Geocoding (cont’d)
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Processing steps for “connection” address table:
1.
2.
3.
4.
5.
User uploads address table
Geocoding batch submitted
Geocoding results displayed on map
Point “cloud” inferred from geocoded points
Cloud polygon saved for additional editing
Craig.Wolff@cdph.ca.gov http://ehib.org http://cehtp.org
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Polygon Editing
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User edits nodes of boundaries
Backdrop: Google basemap, satellite imagery,
terrain; Or personal geodata (i.e. KML).
3 editing modes:
1.
2.
3.
Node: manual insert/drag/delete; snap to street
centerline optional
Path: New nodes inferred from “best” route
Buffer: Identify segment; Buffer to one/both sides of
street or to adjacent property boundary
Craig.Wolff@cdph.ca.gov http://ehib.org http://cehtp.org
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Place Point on Street
Closest Street
Found Automatically
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Delete Points
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Refine along Streets
Points Placed
on Street
Automatically
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Refine along Property Lines
Select Second
Point
Click GO
Select First
Point
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Outputs from Tool

Public use dataset
All boundaries available for download
 New edits posted daily to flat file (KML or
shapefile); archive of previous posts
 Real-time feeds available for mash-ups
(WMS, KML, JSON)
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Embeddable code snippets to include
maps on other websites
 Coupled with geocoding (point-in-polygon)
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Craig.Wolff@cdph.ca.gov http://ehib.org http://cehtp.org
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Timeline
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Major software development completed
Deployed and live  http://www.ehib.org/water
Pilot with interested water systems  NOW!
Role-based, sitewide finish-work (pending)
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Navigation
Organization
Documentation
Integration with geocoding by Summer 2011
Roll-out to all PWS by Winter 2012
Craig.Wolff@cdph.ca.gov http://ehib.org http://cehtp.org
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What We Need From You
Contribute  upload, geocode,
digitize/refine
 Help  feedback during pilot
 Use  export to your own GIS
 Web  incorporate maps on your website
(“Report a Leak”)
 Encourage participation by neighboring
water systems
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Craig.Wolff@cdph.ca.gov http://ehib.org http://cehtp.org
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