Institute for Water Resources

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Value to the Nation

Environment: Activities



Smelt Hill Dam

In 2002 the Corps removed the Smelt Hill Dam from the Premsumpscot River near Falmouth, Maine. The removal of the dam will improve water quality, restore natural habitats and improve fish passages on the seven miles of river that run from Falmouth to Westbrook.

A variety of migratory fish including 14,000 shad, 150,000 alewifes, and 78,000 blueback herring will now be able to pass upstream. In addition, many small streams and feeder branches are now available for spawning and foraging. Wildlife also will benefit from the abundant food supply.

Most of the material removed from the dam, powerhouse and other structures was used on site to re-establish the right bank of the river. The removal project received a 2003 Partnership Award from Coastal America.


Cougar and Blue River Dams

Another recent project involved the Cougar and Blue River Dams, which are located in Oregon about 40 miles east of Eugene on the South Fork McKenzie River and Blue River. These dams are operated for flood control, navigation, irrigation, and power generation. Both were built in the 1960s, at a time when the environmental impact of dams was not well understood. In recent years, it has become clear that the system used for drawing water from the reservoirs has changed downstream water temperatures, making that stretch of the McKenzie less hospitable to spring chinook salmon and bull trout, now listed as threatened under the Endangered Species Act.

The Corps completed interim changes to the dams to address these concerns, and plan to implement a long-term solution to improve the rate of juvenile salmon passing through the dam to return to their spawning grounds in the ocean. On May 18, 2005, the intake tower at Cougar Dam became operational to provide temperature control on the South Fork and main stem McKenzie rivers in Oregon. In 2010 the Corps opened the Cougar Dam Adult Fish Collection Facility; returns of wild adult spring Chinook salmon to the trap range between 250 to 525, with similar expectations of equal returns in the future.




Lake Allatoona/Etowah River Watershed Study

The Corps is a key partner in the Lake Allatoona/Etowah River Watershed Study in Georgia, which is aimed at developing solutions to streambank and shoreline erosion, sedimentation, water quality, fish and wildlife habitat degradation, and other problems relating to ecosystem restoration and resource protection in the rapidly urbanizing 700,000-acre watershed.

Addressing these issues requires participation by other federal agencies, eight counties and numerous municipalities. The problems facing the watershed area are so widespread and varied in nature that no one approach at one location or set of actions by a single entity can provide the solution. The study is expected to produce an action plan for a coordinated effort to address these widespread challenges.




New Jersey, Lower Cape May Meadows

Located along the southern Atlantic coast of New Jersey, Lower Cape May Meadows is an internationally significant coastal wetland situated along the Atlantic flyway that provides a vital resting spot for shorebirds, birds of prey, and songbirds during their seasonal migration. This area also provides important habitat for residential birds, mammals and amphibians.

The Meadows has been severely impacted upon by shoreline erosion, resulting in the direct loss of beach and unique freshwater wetland habitat. In addition to the actual loss of habitat acres, the erosion resulted in degradation of the remaining freshwater wetland habitat through saltwater intrusion and topographical changes. These conditions significantly reduced the ability of the wetlands to support the wildlife and endangered plant species that reside there.

The Corps worked with other key agencies to undertake an ecosystem restoration project at Cape May, which was completed on June 15, 2007. The project included berm and dune restoration and improvements to the interior habitat. Interior habitat improvements included moving the existing shoreline seaward to reclaim 35 acres of eroded wetlands, eliminating 95 acres of nuisance Phragmites australis, planting 105 acres of emergent wetland vegetation, creating fish reservoirs, restoring water flow between ponds, creating 25 acres of tidal marsh, and installing two water control structures. Post-project activities include beachfill operations, which were completed in 2017, and periodic nourishment cycles.


Sagamore Marsh

Another recent Corps coastal project is the restoration of Sagamore Marsh in Massachusetts. The ecological value of this estuarine habitat had declined significantly over the years. The Sagamore Marsh Restoration project was designed to restore 50 acres of tidal marsh estuarine habitat at this site. The project replaced the original culvert with two 6-foot wide reinforced concrete box culverts under each road, installed electric sluice gates, and updated the man-made channel, deepening the channel and widened it from 4-feet to 12-feet.


Puget Sound Basin

The Corps also is working on a project to preserve and restore critical nearshore habitat in the Puget Sound Basin in Washington. Nine species listed as threatened or endangered inhabit this area. The Feasibility Report and Environmental Impact Statement for the Puget Sound Nearshore Ecosystem Restoration Project was completed in 2016. The project plan includes removing nearly 28,860 linear feet of tidal barriers, nearshore fill, and shoreline armoring and restoring the Duckabrush River Estuary, Nooksack River Delta, and North Fork Skagit River Delta. The project is projected to restore over 2,100 acres of degraded habitat and produce 716 average annual habitat units.




Central Valley Joint Habitat Venture

The Corps is proud to be one of the major partners in the Central Valley Joint Habitat Venture—a collaborative effort to protect and restore public and private wetlands and to secure adequate water to support 4.7 million migratory waterfowl in California. The valley has been identified as the most important waterfowl watering area along the Pacific Flyway.




Nueces River Basin

The Corps is helping to implement a watershed approach to control water flows in the Nueces River Basin in Texas. Water planning in Texas is decentralized to the regional level, so the Corps watershed approach provides a unique vehicle to address issues that cut across regions.

Competing upstream and downstream stakeholder groups have been convinced to cooperate in developing a plan that will seek to downplay rivalries and find mutually acceptable solutions that will help maintain water flows at appropriate levels to protect environmental habitats that house many endangered species.