NORWALK RIVER WATERSHED

UPDATE NO. 2: DAMS ON THE NORWALK RIVER

 by Jessica A. Kaplan Watershed Coordinator
Norwalk River Watershed Initiative 

To early inhabitants, the Norwalk River Watershed was bountiful.  Native Americans found fertile soils and forests in the valley and an array of fish and shellfish from the river and the Long Island Sound.  Colonists also took advantage of the river and its productive watershed, clearing forests, planting corps in the fertile soil they found, and building dams to harness the river’s energy.  Grist mills, iron processing mills, lumber mills, and others lined the Norwalk River, using its flow to power machinery.  

Today, the Norwalk River no longer supplies power for manufacturing.  Rather, it is enjoyed for its recreational aspects, such as fishing and canoeing.  However, seven dams remain along the Norwalk River.  These are considered “run of river,” meaning that inflow into the impoundment equals outflow; the dams hold back very little water.  All of them do, however, impede fish migration and do not allow fish, such as alewives, blueback herring, the American eel, and brown trout, to migrate upriver.  Another problem is that these dams alter habitat by increasing water temperature, reducing dissolved oxygen, and providing refuge for warm water fish (such as chain pickerel and large mouth bass) that out-compete cold water fish (such as trout) where their ranges overlap.  Dams also provide detention time for the uptake of nutrients, which in turn promotes growth of plants and algae and results in eutrophication.  

Because of these problems, the Norwalk River Watershed Initiative has targeted three of the seven dams – Cannondale, Merwin Meadows, and Flock Process  – for action.  By the end of 2002, a fish bypass will be built at the Cannondale dam in Wilton, enabling fish to move easily further up the river.  Plans for breaching the dam at Merwin Meadows Park (also in Wilton), originally constructed as a swimming pool for the owner’s children, are now being developed by the Natural Resources Conservation Service (US Department of Agriculture) and other Initiative partners.  The first step, planned for the fall of 2002, is to sample and analyze the sediments behind the dam to determine whether they are contaminated.  Costs of removing and disposing of these sediments will determine whether removing the dam is feasible.    

In contrast to the Cannondale dam and the Merwin Meadows dam, which are easily visible, the Flock Process (or Winnipauk) dam is hidden from view.  It lies south of the Merritt 7 office complex and the Merritt Parkway where the Norwalk River parallels Main Street.  This dam is unusual because it is 22 feet high (much higher than any other dam along the river).  There is also a two-acre pond behind the dam.  A Metro North railroad track crosses the river on a trestle bridge approximately 200 feet downstream.  

The Flock Process dam was built before the mid-nineteenth century.  By the time of the Civil War, a factory manufacturing cloth for uniforms stood there; this building was an impressive stone structure noted for its beauty.  Today, if you look closely, stone remnants of this building can still be seen.

Two options are under consideration for the Flock Process dam, either completely removing it or partially removing it and installing a stone ramp or other fish passage.  Although the state environmental protection department favors complete removal, both options will be evaluated during the design phase.  The quantity of sediment to be removed and disposed of will affect the project’s overall cost; under the complete dam removal option, it is estimated that 6,000 cubic yards of sediment will have to be removed.  Habitat restoration up and down stream of the dam will also be included in the project.  The state is currently determining project feasibility and wants to begin engineering analysis and design in 2002.  The project promises to be challenging because of the river’s steep banks, the change in water levels, and the nearby railroad track.                  

Projects such as these three are integral to the Initiative’s basic philosophy of restoring and protecting the Norwalk River.  By restoring an unimpeded flow to the river, all watershed residents benefit for we can truly appreciate the river’s beauty as nature intended it – and as the earlier residents of our watershed enjoyed it.