Gulf of Maine Coastal Program
Northeast Region

Restoration projects

Coastal wetlands

Rivers and streams

Coastal wetlands

Cascade Brook salt marsh restoration in Scarborough Marsh

Picture of Cascade Brook salt marsh restoration.
Cascade Brook salt marsh restoration. Credit: USFWS

Scarborough Marsh Wildlife Management Area, Maine's largest salt marsh (3,100 acres), has the greatest diversity of water-dependent birds statewide. However, barriers to tidal flow, undersized culverts, upland development, invasive plants, fill material and drainage ditches limit the Marsh's full biological potential.

Al 100-acre section of Scarborough Marsh became the focus of an ambitious restoration effort coordinated amongst federal, state and local conservation partners. In 1996, a 500-year flood destroyed the road crossing at the Old Blue Point Road, dumping large quantities of spoil material on two acres of downstream marsh, smothering native salt marsh vegetation and filling a tidal creek. In addition, 45 large piles of peat (ranging in size from one to 100 cubic yards) were ripped out of the marsh during the flood, floated downstream and came to rest on the surface of the marsh. Non-native Phragmites began aggressively invading the newly disturbed areas, threatening the natural resource values of the Cascade Brook salt marsh.

The Cascade Brook restoration porject, completed in early 2004, involved:

  • lowering the water control structure to increase tidal flow,
  • partially removing the underwater berm,
  • removing 5,000 cubic yards of spoil material on the surface of the marsh and in the intertidal creek,
  • removing all of the peat piles,
  • controlling the spread of Phragmites, and
  • pre-restoration monitoring and five years of post-restoration monitoring

Our Gulf of Maine Coastal Program office, along with partners at Natural Resources Conservation Service, Maine Department of Inland Fisheries and Wildlife, Friends of Scarborough Marsh and several environmental consulting firms -- provided uncounted hours of technical support needed to design the restoration work, plan the monitoring protocols, obtain permits, fundraise, conduct community outreach and coordinate partner activities.

Weskeag Marsh restoration projects

Photo of the Weskeag Marsh culvert installation.
Weskeag Marsh culvert installation. Credit: USFWS

Weskeag Marsh is one of the largest marshes in mid-coast Maine (1,000 acres) and ranks as one of the most productive shorebird roosting and feeding sites in the Muscongos Bay region. Four phases of salt marsh restoration work focusing on ditch plugging, and a fifth phase involving the removal of an undersized culvert, have been completed at Weskeag, with active involvement of our Gulf of Maine Coastal Program office, Natural Resources Conservation Service, Maine Department of Inland Fisheries and Wildlife, Ducks Unlimited, USFWS Partners for Fish and Wildlife Program and several environmental consulting firms. Restoration work involving plugging mad-made ditches to prevent excessive drainage and permit the re-establishment of permanent pool habitat on the marsh surface. Restoring salt marsh water levels helps attract many native species -- aquatic plants, invertebrates, fish, shorebirds, wading birds and waterfowl -- that depend on permanent pools of water on the high marsh. Replacement of the undersized culvert at Buttermilk Lane was funded by Maine Department of Transportation, with technical support from our Gulf of Maine Coastal Program staff and other partners.

Phragmites control and monitoring in Scarborough Marsh

Picture of biologists assessing non-native phragmites.
Biologists assessing non-native phragmites. Credit: USFWS

A non-native form of Phragmites is aggressively invading Scarborough Marsh, Maine's largest and most well-known salt marsh. Scarborough Marsh still retains a natural assemblage of salt marsh vegetation, pools and creeks, and it has recently been documented as the marsh with the greatest waterbird biodiversity statewide. However, Phragmites has the potential to eliminate native salt marsh vegetation, creating a monoculture of tall reeds that destroys salt marsh habitat values for many native fish and wildlife.

Phragmites first appeared in Scarborough Marsh about 25 or 30 years ago. Since then, it has aggressively invaded the Marsh, converting some areas into pure, dense stands of Phragmites up to 18 feet tall. Phragmites has expanded into previously pristine sections of the Marsh, and all partners involved in Scarborough Marsh restoration activiites recognize that Phragmites has the potential to overtake the Marsh. Some of the restoration activities Gulf of Maine Coastal Program and our conservation partners have already completed have halted the spread of Phragmites in a few sections of Scarborough Marsh, but parnters have now embarked on a Marshwide program to identify and then control the spread of Phragmites. For more information on Phragmites, read our five-page fact sheet, "Phragmites: Questions and Answers."

Rivers and streams

Somes-Ripple-Long Pond watershed fish passage restoration

Picture of the Somes Sound dam and fishway.
Somes Sound dam and fishway. Credit: USFWS

Four degraded fishways located at low-head mill dams no longer provided effective passage for diadromous (searun) fish in the Somes-Ripple-Long Pond watershed on Mt. Desert Island, Maine, adjacent to Acadia National Park. Without effective fish passage at the dams, annual native fish runs (alewife, blueback herring, American eel, sea lamprey) have declined dramatically. Without the fish, valued local traditions associated with the harvest of searun fish have also been lost. In 2006, the deteriorated fishways located at the first and third dams in the watershed were repaired. Work continues to monitor and evaluate fish runs at the two restored fishways, and to implement restoration projects at the two remaining degraded fishways. Once all four fishways are restored, conservation partners will have restored searun fish access to 1,032 surface acres of lake habitat and one mile of riverine habitat throughout the watershed. Bringing searun fish back has added benefits of attracting birds and other wildlife, increasing the biological vitality of the entire watershed.

Throughout this restoration project, Gulf of Maine Coastal Program has provided key strategic advice to local, state and federal partners, helped plan the restoration project, provided advice in developing the wayside exhibit, and directed substantial funds from several nationally competitive grants to the project. GOMCP will continue working with partners from Somes-Meynell Wildlife Sanctuary, Maine Department of Marine Resources, USFWS Fish Passage Engineers, NOAA and other locally-based supporters.

Highland Lake fishway restoration

Picture of the restored Highland Lake dam and fishway.
Highland Lake fishway after it was restored. Credit: USFWS

In 1936, a dam built at the outlet of 640-acre Highland Lake in the Presumpscot River watershed cut off native sea-run alewives, as well as some American eel and sea lamprey from their historic spawning and nursery habitat. More than 50 years later, in 1988, Maine Department of Marine Resources constructed a concrete denil fishway at the dam to allow adult alewives to pass upstream to spawn in Highland Lake, and to allow adult and juvenile alewives to move downstream to the Gulf of Maine. When the new fishway was installed, alewife populations rebounded. However, after only eight years of operation, the old Highland Lake Dam breached in a massive flood, destroying the fishway and overwidening the downstream channel of Mill Brook in the process. Unfortunately, a new dam and fishway constructed in 2000 did not effectively pass alewives.

In 2006, after several years of planning and fundraising, the existing fish ladder was renovated, the Mill Brook stream channel was restored, and post-restoration monitoring is now ongoing. Gulf of Maine Coastal Program has been actively engaged in many aspects of this restoration project – coordinating with partners (Maine Department of Marine Resources, USFWS Fish Passage Engineers, town officials, environmental consulting firms, building contractors, and nearby residents), planning, designing, fundraising, conducting outreach, and monitoring, With fish passage restored from the ocean to Highland Lake, fisheries biologists expect that Highland Lake can now produce an estimated 150,000 adult and 1,000,000 juvenile alewives annually – all part of exciting, collaborative and multi-pronged efforts to bring the Presumpscot River watershed back to life after centuries of abuse dating back to the Industrial Revolution.

St. Croix River alewife interaction study

Picture of alewives.
Alewives. Credit: USFWS

In sections of downeast Maine, there has been a widely held, but scientifically unsubstantiated belief that alewife restoration interferes with a well-established and recreationally/economically significant non-native bass fishery. Unfortunately, the controversy has led to management decisions that have caused precipitous declines in alewife populations (see the next slide for an example), and has threatened to de-rail alewife restoration elsewhere in Maine. To resolve the controversy, Maine Rivers, a non-government conservation group, took the lead in hiring a fisheries scientist to conduct an objective review of existing scientific literature and carry out original research designed to fill knowledge gaps. The work, completed in 2006, is detailed in two reports that are both available on this website:

Together, these reports replace unsubstantiated claims with credible scientific information and provide documented evidence that native searun alewife do not outcompete non-native bass. This information should contribute to reasoned decision-making for future restoration and management decision-making in the St. Croix River watershed and beyond.

Gulf of Maine Coastal Program provided funding through the National Fish and Wildlife Foundation -USFWS Maine Habitat Restoration Partnership, as well as technical and biological support through our participation on a Scientific Advisory Committee. The Advisory Committee oversaw the design, implementation and distribution of the studies. The Committee included Maine Rivers, NOAA, Fisheries and Oceans-Canada, New Brunswick Department of Natural Resources, Maine Department of Marine Resources, Maine Department of Inland Fisheries and Wildlife, St. Croix Waterway Commission, Trout Unlimited, and Maine Atlantic Salmon Commission.

St. Croix River and Milltown Dam monitoring

Picture of the Milltown dam fishway trap.
Milltown dam fishway trap. Credit: USFWS

Fisheries biologists estimate that the St. Croix watershed on the Maine-Canada border may have once suported 14-38 million alewives and similar-looking blueback herring. However, in the 19th and early 20th century, when dams, water pollution and overfishing overwhelmed the river, the alewife population plummeted. With installation of fishways and water pollution controls in the 1970s and 1980s, the population of alewives began to rebound -- up to two milion adult alewives by the early 1990s. However, based on unsubstantiated fears of negative interactions between native alewives and non-native bass, the Maine Legislature (over the objection of the Canadian government, the St. Croix International Waterway Commission, Maine Department of Marine Resources, Trout Unlimited, Maine Rivers and others) mandated closure of the federally-funded Milltown Dam fishway at Woodland. In a few short years, the alewife run declined to a shadow of its former abundance. Only 900 fish returned in 2002, and today, a tiny remnant populations is being maintained with a small-scale trap and truck operation, managed by the Canadians.

The St. Croix International Waterway Commission, under agreement with Maine Department of Marine Resources and Canada's Department of Fisheries and Oceans, operates the Milltown Dam fishway and research trap on the St. Croix River during the spring alewife run. Gulf of Maine Coastal Program has provided funding from 2004 - 2007 to collect, analyze and submit data on the St. Croix River alewive population. The data clearly documents the precipitous decline in the alewife population, and will be essential in taking future steps to restore alewives in the St. Croix River.


Last updated: September 5, 2013

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