This report details the hydrologic analysis required as part of the ISO certification of the Town of Bridgton, Maine’s 23 dry hydrants. The purpose of this project is to evaluate whether the 23 dry hydrants within and adjacent to the Town of Bridgton meet the certification requirements under the Insurance Services Office’s (ISO) Public Fire Suppression Rating Schedule. The certification requires that the water source have the ability to flow 250 gallons per minute (gpm) for a two hour period under the 50-year drought condition. Thus under the 50-year drought condition each ponded source must have 30,000 gallons or 4,010 cubic feet of water available. At the time of this report Bridgton did not have any flowing water sources for dry hydrants.
The certification approach involves a site visit to each pond to locate the intake structure, determining the 50-year drought condition, and estimating the volume available for firefighting under the 50-year drought condition.
NHI prepared water budget analysis and storage analysis for each dry hydrant source, providing the Town with data on expected water flow availability under 50-year drought conditions.