Arm Brook Multipurpose Dam Planning

Westfield, MA

Arm Brook Multipurpose Dam Planning

Westfield, MA
  • Existing conditions survey and plan development
  • Subsurface exploration program
  • Seepage and slope stability evaluations
  • Hydrologic and hydraulic evaluations & reports (NRCS Criteria)
  • Dam break analyses
  • Environmental assessment
  • Economic assessment
  • Alternatives development
  • Public presentations

Pare recently completed a Supplemental Watershed Plan and Environmental Assessment (Plan-EA) for the 60-foot-high, high-hazard potential Arm Brook Multipurpose Dam which is located directly upstream and above the City of Westfield, MA. The project was performed for the U.S. Natural Resources Conservation Service (NRCS). The purpose was to identify feasible design alternatives to bring the dam into compliance with applicable design standards and to provide a planning tool to advance the project through final design. The project involved constant coordination with NRCS to ensure that the project was being completed to NRCS’s strict and stringent design standards and standard procedures.

The Plan-EA involved review of historical data files, utilizing publicly available data sources (i.e. LiDAR, assessor’s data, hydrology information, etc.), developing a detailed existing conditions survey plan of the entire dam site from the upstream limits of the impoundment to the first downstream road crossing, the completion of hydrological and hydraulic evaluations of the existing dam as well as the dam with the proposed rehabilitation project under both existing watershed conditions and the projected future watershed conditions. Utilizing GIS software, Pare developed detailed figures highlighting the areas and infrastructure most vulnerable to a potential dam breach event. Additional data, such as flooded roadways and flood depths at each structure center were determined using spatial geoprocessing.

Multiple versions of a full rehabilitation scope were developed along with other alternatives including Future Without Federal Investment and decommissioning. A detailed benefit cost analysis economic assessment was performed to identify the feasibility of each alternative.

Pare presented the project findings at televised public meetings held at the City of Westfield’s Town Hall with 50+ residents and Town officials in attendance.