Manston Slough Water Resource Management and Wetland Restoration Project

More than a century after the drainage of Manston Slough in the late 1800s,
project partners set out to complete a large multi-use, comprehensive project that could achieve the goals of many different interests to restore the 6,000-acre historical basin in Wilkin County, Minnesota.

Background

The Manston Slough project was initiated after the Minnesota DNR (MnDNR) began looking at enhancing wetlands in the Manston Wildlife Management Area (WMA). After a thorough site review of the 6,000-acre project area, the watershed district decided that a larger, more comprehensive project would not only restore historic wetland water levels but could also provide additional flood control for area landowners.

The project area is located near the bottom of the beach ridge on very flat land. Runoff from the east drops quickly through the landscape upstream of the site, and then enters the Manston Slough area, spilling out of various waterways that drain into the basin. The state of Minnesota initially drained the area in the late 1800s with the construction of County Ditch 15.

The Project

To complete a project of this size, many partnerships were formed between agencies, local government, and landowners. Because of the potential for flood control, the NRCS and Ducks Unlimited encouraged landowners with property in the flood pool and wetland areas to sign up for the Wetland Reserve Enhancement Program. The District worked with more than 30 landowners to gain easements for the project.

Working from this base of collaboration, HEI supported partners by designing key project features, including:

A low-hazard classification dam with more than 4,000 acre-feet of storage
1,150 acres of wetland restoration
2,500 acres of new prairie converted from cropland
5.5 miles of new or improved conveyance systems for landowners
A water level control structure to manage wetland elevations
Upland watershed treatment to control erosion

Construction began in 2008 once funding and permits were secured. In 2015, at Minnesota’s Environmental Initiative awards, BRRWD, HEI, and their partners were recognized as the winners of the Partnership of the Year as well as the winners in the Natural Resources category for the efforts in the Manston Slough project. The project is an example of a large-scale collaborative success story that provides both flood control and wildlife benefits.

A preliminary cost-benefit analysis was conducted for the project.
The estimate of project costs was $3.1 million. Project benefits, expected to exceed $15 million, include:
Floodwater storage and retention and Buffalo Aquifer recharge.
Natural resource enhancement—1,150 acres of newly restored wetlands in addition to enhancement of existing wetlands.
Nutrient assimilation and sediment entrapment, resulting in improved water quality.
Improved nesting habitat for waterfowl and improved habitat for breeding, feeding, or cover purposes for other species.
Pre-settlement type wildlife benefits while providing flood control.

Project Details

Client: Buffalo-Red River Watershed District

Location: Wilkin County, Minnesota

Project Highlights

A preliminary cost-benefit analysis was conducted for the project.
The estimate of project costs was $3.1 million. Project benefits, expected to exceed $15 million, include:
Floodwater storage and retention and Buffalo Aquifer recharge.
Natural resource enhancement—1,150 acres of newly restored wetlands in addition to enhancement of existing wetlands.
Nutrient assimilation and sediment entrapment, resulting in improved water quality.
Improved nesting habitat for waterfowl and improved habitat for breeding, feeding, or cover purposes for other species.
Pre-settlement type wildlife benefits while providing flood control.