The Philadelphia Water Department is leveraging GIS to create a billing system based on the amount of impervious surface cover on commercial properties. Stormwater billing based on impervious surface area both distributes the cost of managing stormwater more equitably and creates incentives for property owners to implement best management practices for mitigating stormwater runoff on-site. The bill calculation is performed using a series of GIS models assembled using ArcObjects, python scripts and a geoprocessing queuing system. The resulting datasets are then made available to Water Department customers via an ArcGIS Server application. In addition to searching and mapping, the application supports the billing appeals process and enables users to calculate the estimated financial benefits of implementing stormwater mitigation activities. This presentation will showcase the Philadelphia Water Department application and outline the benefits and challenges of using GIS technology for stormwater management and impervious surface area calculations in urban environments.

1. Using GIS for Stormwater Billing and Impervious Surface Calculations Dana Bauer [email_address] Casey Thomas [email_address] www.phillystormwater.org

3. 10% Research Program Pro Bono Program Time-to-Give-Back Program Employee-focused Culture Projects with Social Value

4. Photo courtesy PWD

5. Photo courtesy PWD

6. Photo courtesy PWD

7. Maps courtesy Philadelphia Water Department/phillyH2O.org

9. EPA

10. EPA

11. Schuylkill River Regular Flow vs June 2006 Flood Photos courtesy PWD

13. CC image courtesy of Thomas Hawk on Flickr

14. CC image courtesy of JSmith Photo on Flickr

16. Some Bills Go Down Existing Charge = $ 4,702.82 New Charge = $ 120.24 Gross Area = 24,338 Imperv Area = 24,338

17. Some Bills Go Up Existing Charge = $ 377.23 New Charge = $ 2,496.42 Gross Area = 599,744 Imperv Area = 491,035

27. PhillyStormwater.org

29. Data, data, data

33. Geoprocessing

34. 550,000+ parcels

35. PWD Enterprise Geodatabase PWD Billing Database

36. Photo courtesy Philadelphia Tourism Board

37. Parcel Fact Sheet PDF

38. Appeals

39. Credit Opportunities Images courtesy PWD

42. Many Thanks! © Photo used with permission from Alphafish , via Flickr.com

43. Using GIS for Stormwater Billing and Impervious Surface Calculations Dana Bauer [email_address] Casey Thomas [email_address]