About the Watershed

(excerpted form Study Report Chapter 2: Description of the Study Area)

A tributary to the Connecticut River, the Eightmile’s confluence with the Connecticut River is approximately eight miles upstream from the mouth of the Connecticut River at Long Island Sound, hence its name. This area was the focus of early industrialization in Connecticut but was spared intense maritime industrialization after World War II due in part to the restrictive and shifting sandbars at the mouth of the Connecticut River. The lower Connecticut River Valley which sits between the highly populated and densely developed areas surrounding Hartford, New Haven and New London is known for its rural character, relatively undeveloped landscape and hilly terrain, outdoor recreational opportunities and nationally and internationally recognized natural environment.

With over 150 miles of pristine rivers and streams and 62 square miles of relatively undeveloped rural land, the Eightmile River Watershed is an exceptional natural and cultural resource. The watershed contains large areas of unfragmented habitat, an array of rare and diverse wildlife, scenic vistas, high water quality, unimpeded stream flow, and significant cultural features. Most notable is that the overall Eightmile River Watershed ecosystem is healthy and intact throughout virtually all of its range.

The landscape of the watershed is characterized as one of low rolling hills and ridges separated by numerous small, narrow drainage corridors and hollows, and in places broader valleys and basins. Approximately 90% of the watershed lies in roughly equal portions within the three communities of East Haddam, Lyme and Salem, with the remaining 10% evenly split within Colchester and East Lyme. Because the East Lyme section of the watershed is almost entirely protected by state owned forest and the Colchester section is small and contains few tributaries, this study focuses on the portion of the watershed within East Haddam, Lyme and Salem.

In 2004 the combined population of the three main communities was 15,228, with 60% located in East Haddam, 27% in Salem and 13% in Lyme. With just 5,400 people living in the watershed itself, population density is very low at 87 people per square mile as compared to the overall statewide average of 700 people per square mile. The low density has contributed to a rural, bucolic countryside with scenic views, occasional farm fields and a transportation pattern that has not changed substantially since the peak of the local agrarian economy in the mid-19th century. In the latter half of the 20th century, population growth in Salem and East Haddam have outpaced the average State growth with Salem increasing in population size by six-fold over the same period of time.

With over 83% of the watershed in forest, wetland or water, the Eightmile hosts a rich diversity of natural communities and rare and significant plant and animal species. Comprised primarily oak-hickory and maple-ash vegetative communities, the forests of the Eightmile provide resource requirements for a multitude of significant bird, mammal and insect species.

Further detail of the natural resources in the Eightmile watershed is described below in Section 3.B.1 – “Outstandingly Remarkable Resource Values”.

With only 6% developed area, the watershed is made up of large un-fragmented habitat blocks supporting an abundant array of rare and diverse species. Substantial open space conservation has been achieved in the watershed. As of March of 2006 nearly 32% of the watershed (12,600 acres) has been permanently protected, including over 5,000 acres of state forest and park land as well as significant holdings by municipalities, local land trusts and The Nature Conservancy.

However, there has been significant pressure for and a trend toward development and forest conversion in the watershed as shown in Table 2.1. Strong economic growth in Hartford and southeastern Connecticut is driving the region’s economy and development trends.

Table 2.1 Land Cover changes between 1985 and 2002 as reported by the Center for Land Use Education and Research (CLEAR), UCONN.

Table 2.3: Land Use in the Eightmile Watershed compared to state-wide land use. Source: UCONN Center for Land Use Education and Research/*Consulting ecologist Bill Moorhead for the Study Committee.

See Map in Eightmile River Watershed Management Plan: Landcover


The town of Lyme makes up the southern third of the watershed and contains Hamburg Cove, the Eightmile River’s only navigable waterway. Lyme is the least populous of the three Watershed towns. The Town’s population actually peaked in 1800 on the strength of its maritime industries and then declined to only 546 residents by 1930 before beginning a 70-year trend of slow growth to 2,016 people in 2000. Lyme is the most isolated of the Watershed towns in terms of expressway access and is more than three towns removed from the regional employment centers of Groton, New London, and Norwich.

Since 1998, Lyme has been the most aggressive of the three principal watershed towns with respect to open space protection. Lyme has conserved approximately 40% of the Town overall with 1,724 acres (nearly 8%) of the Town protected in the last seven years alone.

East Haddam

East Haddam lies in the northwest section of the watershed and, at a population of 8,333, is the most populous of the three towns that comprise the Watershed. This was due initially to the industrialization and immigration of the 19th Century, and later due to the abundance of recreation opportunities and its access to jobs both inside and outside the region via Route 9. Devil’s Hopyard State Park lies within the Eightmile River Watershed in East Haddam and contains Chapman Falls, a locally known scenic and outdoor recreation area that attracts many visitors to the banks of the Eightmile.

Open space preservation efforts since 1998 have conserved 892 acres of land in East Haddam. East Haddam also recently adopted a comprehensive soils based zoning scheme that has significantly increased the level of resource protection in the town.


Salem makes up the northeast third of the watershed and remains a rural community with a small Town Green and a small commercial center nearby. Early clearing of significant forest resources was followed by agriculture that was hampered by the varied terrain, which also restricted residential growth. Re-growth of the forest has occurred over most of the Town since the 1890’s. After a century of population decline, recent pressure for residential development has almost tripled the population in the past 35 years, so that the population is now higher than in colonial times (1,453 in 1970 to 3,858 in the 2000 census). Salem is the fastest growing of the three Watershed towns due to its location closest to employment opportunities in Norwich, Groton and New London as well as its direct access to Colchester and Hartford.

The Town itself has protected 161 acres of open space since 1998. In total, over 2000 acres has been protected by other non-profit and government entities. The Town of Salem is currently working on adoption of its Open Space Plan, to prioritize lands for protection. The Plan of Conservation and Development highlights the importance of preserving the Town’s rural character.

Fishways at dams are key components of enhancing our protected watershed spaces. They restore the passages between freshwater habitat and the ocean for migratory fish like Atlantic salmon (Salmo salar), American shad (Alosa sapidissima), alewife (Alosa pseudoharengus), blueback herring (Alosa aestivalis), sea lamprey (Petromyzon marinus), sea-run brown trout (Salmo trutta) and American eel (Anguilla rostrata). Many of these species access freshwater habitat to reproduce and their young use the habitat as a nursery area to feed and grow until they return to the ocean. Eels are the exception to this pattern. They reproduce in the ocean and migrate to freshwater to grow to maturity before they return to the open ocean to spawn. Fishways also expand the habitat available to non-migratory fish such as yellow perch, white suckers and catfish. When more habitat is available, more fish can reproduce and survive. More fish improve the “food chain” so more kinds of fish, birds and mammals can prosper with restored prey. Fish stocks in the oceans can prosper as well.

There are two fishways in the Eightmile River Watershed (see map), both in Lyme. These fishways are the “highways home” for migratory fish and the “back roads” for resident fish in the Watershed. The Moulson Pond Fishway provides a pathway around the first barrier in the Watershed, the Rathbun Dam, which is about 3 miles from the mouth of the River. The Ed Bills Pond Fishway provides a pathway around the second barrier, the Ed Bill’s Dam, which is on the East Branch of the Eightmile River about half a mile upstream of its confluence with the West Branch of the Eightmile. Upstream of these dams, the Eightmile River Watershed has high quality habitat essential for the survival of both migratory and resident fish species. The Lyme Land Conservation Trust (LLCT), with support from the Connecticut Department of Environmental Projection (CT DEP), operates both fishways April through June for spawning adult fish and again in October – November for spawning adult salmon and emigrating juvenile fish. The LLCT also maintains the fishways.

Moulson Pond Fishway

The Moulson Pond Fishway is located on private property and is not open to the public. It was constructed in 1997 through a partnership of interested parties. The LLCT and the Silvio Conte Fish & Wildlife Refuge of the U.S. Fish & Wildlife Service provided staff support and funding. The CT DEP/Inland Fisheries Division provided staff support and materials. The CT River Watershed Council, the Coastal Conservation Association of Connecticut, and private donors provided additional funding.

The Moulson Pond Fishway was designed to accommodate a water supply system that supported mills during the Eighteenth, Nineteenth, and Twentieth centuries and the aesthetic andpreservationist concerns of several private landowners. The Fishway makes use of a pre-existing millrace and tailrace (see schematic below). Water flows from the head pond through a gate that, until June 2007, opened up from the bottom of the millrace. The water continues in the millrace, which passes under a private residence and extends approximately 200 feet downstream to another former mill and now contains a small hydroelectric generating station. About halfway down the millrace, a concrete structure constructed in the side of the millrace provides the openings for water flow and fish passage. Upstream fish passage is provided through several sections of Alaskan steep pass. Attraction water is provided through a secondary weir that passes water down a buried pipe; this also provides a route for downstream passage of young salmon and herring. Water flowing down the steep pass and through the buried pipe converges at the head of an excavated, semi-natural channel (photo below). From there, water flows through a semi-natural section into an old abandoned tailrace, which, in turn, leads to the Eightmile River below the dam.

Since the first dam at this location was built in the early Eighteenth century, enough alewife and blueback (collectively river herring) spawned and used nursery habitat in the stretch of river between Hamburg Cove and the dam to maintain their populations. Thus when the fishway was first opened on March 30, 1998, river herring began using it to expand their migration from the Atlantic Ocean through Long Island Sound, up the Connecticut River, through Hamburg Cove to spawning grounds in the Eightmile River Watershed.

Since 1998, dedicated volunteers have monitored the fishway daily between early April and late June and estimated the fish using the fishway. The results of the monitoring effort suggested two things. First, the numbers of herring using the fishway were declining, which was similar to the decline in herring seen all along theAtlantic Coast. Second, that when the hydro unit was drawing water to generate electricity, the fish had difficulty negotiating the increased water velocity through the submerged opening of the water control gate.

By 2004 water leaking from the millrace around the concrete structure had undermined the steep pass, and the LLCT was concerned that the side of the millrace could fail, damage the fishway and private property, and interrupt the effort to restore migratory fish to the Eightmile River Watershed.

To ensure the continued effectiveness of the Moulson Pond Fishway to pass fish, the LLCT and the CT DEP decided to repair the leaks and replace the water control gate. The leaks were repaired in September 2005 by injecting foam similar to Great Stuff ® into the unconsolidated soil along the bank of the millrace. When the foam solidified the leaks stopped.

The water control gate that opened up from the bottom was replaced in June 2007 with a pivoting “butterfly valve” that left the entire water column available for both water flow and fish passage. With this gate, water velocities will be lower and the fish will not have to swim next to the bottom to negotiate their migration upstream. For the first time in 2007 we used an underwater camera to record fish passing through the water control gate between 7 pm and midnight every night. We did this because we wanted to determine how fish reacted to different water velocities and we manipulated the velocities by having the gate open all the way and half way. We haven’t viewed all the video tapes, however when I checked the tapes to make sure there was a viewable image, I noted that on several dates, when no fish were seen by volunteer monitors in the fishway during the day, several fish were recorded passing through the gate. This suggests that we have been underestimating the number of fish using the fishway. We plan to repeat this next year and would like to have the underwater camera image available realtime on the internet.

The repairs and the gate replacement were funded by: Long Island Sound Study and National Fish and Wildlife Foundation with funding support from US Fish and Wildlife Service, National Oceanic and Atmospheric Administration, and the Shell Marine Habitat Program, Long Island Sound Fund administered by the CT DEP and individual donors. Volunteers also provided services to the effort.

Ed Bill’s Pond Fishway

Ed Bill’s Pond Fishway is located on private property, through an easement donated to the LLCT by the late June Maynard. It can easily be seen from the bridge on Salem Road that crosses the East Branch of the Eightmile River (see photos below and top of story). This bridge is about 0.2 mi from Rt. 156/Hamburg Rd. The fishway was constructed in 2000 with support from CT DEP, CT River Watershed Council, Corporate Wetlands Restoration Partnership – Boehringer & Ingelheim, Fish America Foundation in cooperation with National Oceanographic and Atmospheric Administration, LLCT, Pfizer, Inc., private donors, Town of Lyme, US Fish & Wildlife Service, US Environmental Protection Agency and the USDA, Natural Resource Conservation Service.

The first few years that the Ed Bill’s Pond fishway operated we didn’t expect to see any spring migrating river herring, shad or salmon. This was not surprising because several years would be required for fish populations to expand into the reaches of the Eightmile River between the Moulson Pond Fishway and this one. To “jump start” the migratory fish restoration CT DEP fisheries biologists stocked several hundred herring caught in Latimer Brook into Ed Bill’s Pond annually between 2001 and 2006; they also transferred shad into the Pond from the Connecticut River. School children in the area have been raising and releasing salmon fry into the Eightmile River for several years as well. Occasionally volunteer monitors wouldobserve some of these herring or shad in the pond above the dam. Volunteers also reported seeing trout jumping into the falls at the base of the dam and an increasing number of fish eating birds inthe area of Ed Bill’s Pond. During the 2007 migratory season the CT DEP fisheries biologists were unable to transplant any fish into Ed Bill’s Pond. Volunteers were delighted to observe herring in Ed Bill’s Pond this year – these fish are the first known to have reached this pond on their own since the early Eighteenth century!

For more information or to volunteer to monitor these fishways or to set up the Moulson Pond Fish camera for internet access please contact LindaBiota “at” Comcast “dot” net.

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