“The GIS map of Service Calls to the Fire Department for flooded basements that occurred during storms Irene and Lee has been a useful tool for the Engineering Division. The map allowed us to visually identify areas of Town where there was a concentration of calls. These areas are now being investigated to determine if the storm sewer system has capacity or other deficiencies that contributed to the flooding that was experienced. The information was also given to the MDC to use in the evaluation of the sanitary sewer system.”

– Thomas Silva, Civil Engineer II (Town of West Hartford)

Tropical storms Irene (8/27/11 – 9/1/11) and Lee (9/8/11 – 9/10/11) had a powerful impact across New England, bringing down power lines, flooding homes and roads, and causing water and wind damage to trees and buildings that affected millions of residents and businesses. Municipal fire, police and engineering department staff worked relentlessly to clear streets, protect public safety and respond to calls for assistance. They also put GIS to work to help report on and analyze the damages.

After the storms passed through the region, the West Hartford Fire Department needed a map of affected properties to support the Town’s application to the State for grant funding through the Federal Emergency Management Agency’s (FEMA) Hazard Mitigation Grant Program. Qualifying municipalities and properties are eligible for federal funding to help pay for storm damage repairs and measures to reduce future storm damage. Mapping affected locations and properties was important to Fire Chief, Gary Allen, so that he could assist FEMA with their eligibility assessment efforts.The Town’s Engineers, Dave Kraus and Tom Silva, also wanted this information mapped in order to identify potential storm sewer problems, whether it be clogged pipes or system capacity issues. Mapped data helped the Engineering Department to see areas of concentration or spatial patterns of storm impact, which helped them to focus their efforts in evaluating the adequacy of storm sewers and determining if any may require future investigation that may lead to system improvement projects.

Creating the Maps

The Fire Department created three spreadsheets of addresses from calls to the dispatch center: water calls from Irene, water calls from Lee, and “wires down” calls from Irene. AppGeo modified the spreadsheets to format addresses for a geocoding process that calculates the geographic locations (coordinates). To do this, AppGeo created a Town Address Locator using the Town’s address point and street centerline GIS layers as the geographic source to which a written address can be matched in order to pinpoint the address location on a map. When all the addresses from the Fire Department were mapped as points, the Engineering Department staff, with the assistance of an AppGeo Project Manager, created an impact area map (polygons) through “heads up digitizing” in order to represent the extent of locations of known basement flooding, house flooding, drainage channel erosion, and road flooding.