About the project
The Town of Braintree, MA Division of Marine Fisheries (DMF), Fore River Watershed Association (FRWA) and private property owner Messina Enterprises have been working for several years to advance removal of the obsolete Armstrong (Hollingsworth) dam on the Monatiquot River, the main stem of the Fore River watershed. In December of 2016, MA Division of Ecological Restoration (DER) designated the project a provisional priority project and became a project partner.
A primary goal of dam removal is to restore access for diadromous fish to native habitat in the Fore River watershed. The feasibility of restoring anadromous fish, specifically river herring, is well-documented in the 2009 Feasibility Analysis for Restoring River Herring to the Fore River (Gomez and Sullivan 2009). The study evaluated obstacles to herring passage and demonstrated hydraulic and hydrologic feasibility for providing passage to the 180–acre Great Pond Reservoir. A dam rehabilitation project for the reservoir is currently being constructed and includes a fish ladder to provide access to the reservoir in anticipation of the downstream dam removal and passage improvements. Also, completed in 2016 was the Armstrong Dam Removal Feasibility Study which further advanced the analyses required for dam removal.
The 2016 Healthy Estuaries grant award from MassBays allowed the team to conduct additional feasibility tasks and advance the project to the design phase. With MassBays funding, the project team completed necessary sediment sampling of the impoundment behind the dam. A discussion of the sampling results is found in Chapter 7 of the Armstrong Dam Removal Feasibility Study (Gomez and Sullivan 2016).
Following review of the sampling results, MA Department of Environmental Protection (DEP) requested four more samples be taken around a “hot spot”. Based on their extensive experience with dam removal projects, DER staff advised the project team to postpone the additional sampling until the expected flow path of the river is better understood. To that end, the project team completed ground penetrating radar to better map the bedrock topography beneath the dam. This information will help further refine the hydraulic model and expected flow path of the river following dam removal. The findings of the ground penetrating radar investigation are described in a report by Hager GeoScience, Inc. DER will take the lead on conducting the additional sediment sampling requested by DEP.
The project is now poised to complete engineering and design for the dam removal. Final design and implementation is expected by 2020.