- Developed EAPs for 16 high hazard dams and 8 significant hazard dams
- Performed dam break simulation for 2 significant hazard dams
- Generated modern and easily understandable inundation mapping using GIS
Challenge
Aquarion Water Company needed Emergency Action Plans (EAPs) for 24 dams located in in Connecticut, New York and Massachusett. GZA has past experience with all of the project sites, and has conducted Phase I dam inspections, developed Inspection & maintenance plans, and/or performed hydrologic & hydraulic modeling on the project sites. GZA has previously performed dam breach analysis at 22 of the dams which will be used for this project.
Solution
This project also included dam break simulations for two dams located in Massachusetts. The dam break simulation was performed using HEC-RAS version 5.0.3. The sunny day and wet weather failure of each dam was modeled, and the resulting flood wave was routed along the downstream floodplain.
For the dams located in Connecticut, GZA developed EAPs that follow the format outlined by the State of Connecticut’s Dam Safety Programs EAP template. GZA developed EAPs that follow the format outlined in FEMA 64 for the remaining dams. The EAPs document roles and responsibilities, identification of emergency conditions, emergency repair guidelines, general evacuation procedures and procedures for exercising the EAP.
GZA also developed new inundation maps which clearly and concisely show the extent of the impact zone and timing effects of the flood wave as it propagates downstream. The inundation maps provide information about the maximum discharge, peak flood elevation and depth, flood wave arrival time, etc. The maps include the latest available color orthophotos, supplemented with roadway layers and select political and cultural features.
GZA also moderated an EAP orientation and tabletop exercise.
Benefit
GZA helped Aquarion Water Company strengthen emergency preparedness through modernized Emergency Action Plans, clear inundation mapping, and a tabletop exercise—providing practical tools to support coordinated emergency response and evacuation planning and help protect downstream communities