Presentation: Studying Stream Restoration at the Highland Pond Preserve, 4/1/2021
Sally Harold – RiverWork, LLC
Steve Gephard – Fisheries Biologist
Frequently Asked Questions
What’s happening at the dam?
The Middlesex Land Trust, the owner of the dam and surrounding land, received a federally-funded grant to hire an engineer to study the site and develop a plan for removing the dam to restore the natural hydrology and habitat of this reach of Sawmill Brook. These actions would enhance the health of the stream and allow upstream passage of migratory fish.
Will the dam be removed?
This grant does not pay for the actual removal. The final result of this project will be a plan. This plan will inform the land trust what a dam removal project would entail and provide a snapshot (produced with photo renderings made by the engineer) of what the system could look like with the dam removed.
What kind of information will the engineer provide?
The engineer will determine how the property would be impacted if the dam is removed. The engineer will determine how large of an opening in the dam would be necessary in order to pass a 100-year storm. (It may be possible to retain a portion of the dam.) The engineer will also determine how much sediment needs to be removed from the historic stream channel and where that sediment might be deposited somewhere on the property. The study will measure the bathymetry (the underwater topography) of the impoundment and determine whether some pond area will remain after the dam is gone.
Why is the land trust interested in removing the dam?
Dam owners have legal responsibilities and liabilities associated with dam ownership. Maintenance and inspections cost a lot of money as long as the dam remains. This is a burden on the non-profit land trust. As an organization dedicated to protection of natural areas and species, the land trust is interested in restoring a free-flowing stream, as it was 200 years ago. The ecological benefits of such are many. There are over 4,000 dams in Connecticut and most, like Highland Pond Preserve Dam, are no longer serving any useful purpose. Yes, the pond is pretty, but as it ages, it is becoming more and more choked with vegetation and sediment. It often suffers from low oxygen levels in the water and creates an environment that is more supportive of non-native invasive species, than our native species.
When will the dam be removed?
The engineering design project will likely take more than a year and this grant does not support any next steps. There is no specific date in mind to remove the dam. The land trust will seek additional grants to pay for dam removal and stream restoration after the plan is completed and the costs are known. If the land trust were able to complete the plan and secure additional funds, the earliest the dam would be removed is likely the summer of 2023.
How do I learn more?
Look for the next community meeting for the most up-to-date information on the engineering findings and recommendations. To find out more, contact David Brown, Executive Director, or call the Land Trust office at (860) 343-7537.