Sawmill Brook Watershed Projects
Central Pond Restoration Studies and Plans
Funded by a grant from the Massachusetts Municipal Vulnerability Preparedness program
This project is a continuation of the earlier studies performed for Sawmill Brook and has been focused on restoration options for the Central Pond area of Sawmill Brook and how to best stabilize its bank -- both the failing pond walls on the east side of the pond and stabilization methods for the western side of the pond.
Consultants presented three options for the pond restoration to the public and to the Board of Selectmen--all included removal of the existing tide gate which is necessary for the replacement of the Central Street bridge/culvert that runs between Sawmill Brook and the Harbor. The final decision was to allow the stream to flow naturally without creating any artificial impoundments and aid the restoration by adding salt marsh plantings on the edges of the pond area.
The intent is to also replace the failing walls on the eastern side of the pond area and create natural banks on the western side.
The benefits of the bridge/culvert replacement and this project include a reduction of flooding of upstream properties to School Street, enhancement of fish passage for Rainbow smelt and other species in such a way that is both ecologically sensitive and aesthetically pleasing. Creating public access will also be included in final plans.
The next step is to secure the required permits to perform the work. The Town is now actively seeking grant money to fund this effort.
For more details see: SM Brook, Central Pond MVP Action Grant FINAL RPT
Sawmill Brook Culvert Tide Gate Removal and Stream Restoration Feasibility Study now complete!
Funded by a grant from the Massachusetts Environmental Trust
The Sawmill Brook Feasibility studies funded by the Massachusetts Environmental Trust have been finalized. The purpose of these studies was to determine whether the tide gate at Central Street could be safely removed without negative impacts to upstream properties. The study contains detailed surveys and calculations required to make this determination. In addition, it includes sediment quantification and characterization to inform the restoration effort for the lower reaches of the stream between Central Street and Norwood Avenue.
The resulting studies (completed at the end of June 2018) will allow the Town to begin the next steps to create designs for Central Pond in conjunction with the bridge (culvert) project on Central Street. This will move the Town closer to its goal of remediating future flooding in the lower reaches of Sawmill Brook and restore this area for Rainbow smelt spawning habitat and to benefit other wildlife species.
Read the documents here:
- Sediment Characterization and Flushing Studies
- Sawmill Brook Hydrologic Monitoring and Flushing Studies
The funding that MET provides through their grant program is generated entirely through the sales of the state’s three environmental license plates. These are the only specialty plates that exclusively fund environmental initiatives.
The Town of Manchester is grateful to MET for supporting this project. Please consider purchasing one of their environment plates to support these grants which will provide $506,344 worth of funding this year to 15 communities, state-wide. Click here for more information.
Culvert Analysis, Green Infrastructure Study and Impacts of Climate Change
Funded by a grant from Massachusetts Coastal Zone Management
Manchester experiences frequent flooding and water quality impairment in the Sawmill Brook Watershed (PDF). Both issues are exacerbated due to a combination of hydraulic restrictions from culverts and the Center Street tidal dam, stormwater runoff from developed areas, a highly channelized stream system and poor infiltration conditions. Flooding and water quality problems will be magnified in coming years due to climate changes and expansion of impervious areas from future development.
This project compliments the FEMA Hazard Mitigation Plan Enhancement Project (funded by FEMA and administered by MEMA). The project will incorporate potential impacts of climate
change on critical sectors in town into the hazard mitigation plan.
Learn more at: FEMA Hazard Mitigation Plan Enhancement.
Sawmill Brook Studies and Documents
- Eval of Locations for Flood Mitigation (PDF)
- Eval of Locations for Flood Mitigation Append (PDF)
- Manchester Coastal Resiliency Forum Presentation (PDF)
- Manchester Conceptual Design Summary Sheets (PDF)
- Manchester Planning Level Designs (PDF)
- Sawmill Brook Culvert Study Scrapbook (PDF)
- Sawmill Brook Flood-prone Areas (PDF)
- Sawmill Brook Opportunities for Flood Mitigation (PDF)
- Sawmill Brook Stream Crossing Evaluation (PDF)
- Sawmill Brook Watershed Map (Downtown Area) (PDF)
- Sawmill Brook Watershed Map (PDF)