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GLARO Engineering: Projects

Engineering projects designed and implemented by DU's Great Lakes/Atlantic Regional Office engineering staff
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The projects featured on this page are a handful of examples of the diverse body of work that has been completed by GLARO's engineering staff to date. To see some of the unique structures designed and implemented by DU's engineers, see our Structures Gallery. If you would like more information on GLARO's engineering services, please visit the GLARO Engineering homepage or contact Warren Weirich at 734.623.2000.

Back Bay NWR Shoreline Protection
Back Bay NWR, VA
Rush Lake Stream Redesign
Rush Lake, WI
Back Bay Pool C Erosion Control
Back Bay NWR, VA

Tidal Interchange
Sachuest Point NWR, RI

Water Control
Structure Replacement

Erie NWR, PA

Active Water-Level Management
Big Marsh Lake, MI

Fish Point
Wildlife Area

Great Lakes Coastal Marsh, MI

Brancheau
Detroit River Intn'l Wildlife Refuge, MI

New Projects!
Coming soon

Structure rehab
Prime Hook NWR, DE



Shoreline Protection

Back Bay National Wildlife Refuge, Virginia

Challenge

Erosion. The Back Bay National Wildlife Refuge staff manages hundreds of acres at the refuge, including the eastern shore of Back Bay in southern Virginia. Due to predominantly southwestern winds coming across the bay, the eastern shore and the native vegetation had been eroding away. The bay also was threatening to compromise the refuge's boardwalk along the shore, and several storms already had damaged the refuge's pier and boat ramp to a point of disrepair that caused staff to close the ramp.

Analysis

The engineering staff of Ducks Unlimited's Great Lakes/Atlantic Regional Office performed a topographical survey along the shoreline area using a survey-grade total station. This was done to determine the bay elevations, relate them to the existing shoreline height and compare them to historical water elevation data. With this data a one-foot contour site map was created showing all visible features, including the bay floor contours.

Action

DU engineers worked with the refuge staff to develop a rock shoal design with little to no subaquatic vegetation impact. The shoal was designed at an elevation of 3.2 to be built out in the bay at three strategic locations to break up the fetch of the waves before they hit the shoreline. The plans also called for regrading the damaged shoreline to a 3:1 slope and placing revetment along the slope for further armoring. A new pier was designed with a H2 load rating, including a boat ramp for refuge use.

Delivery

With approved final design, cost estimates and proper permits in place, Ducks Unlimited prepared, bid, awarded and executed contract, providing construction management for the project.

 Back Bay NWR - Before
Back Bay NWR pier - BEFORE

 Back Bay NWR - Before
Back Bay NWR pier - AFTER

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Stream Redesign

Rush Lake, Wisconsin (with Wisconsin DNR)

Challenge

Rush Lake is the largest prairie pothole east of the Mississippi River and is home to the largest concentration of red-necked grebes in Wisconsin. It is located in both Winnebago and Fond du Lac counties and renowned for its waterfowl production. Rush Lake had been hunted heavily over the years, leaving behind a large concentration of lead shot in the unconsolidated bottom of the lake. In addition, the lake was virtually devoid of submergent vegetative growth and suffered from an overabundant population of carp.

Analysis

The engineering staff of Ducks Unlimited's Great Lakes/Atlantic Regional Office performed a topographical survey of the lake area and outlet creek using a Trimble GPS unit and a survey-grade total station. A contour map was developed using AutoCad Land Development software. With a completed study of the existing conditions, it was concluded that the water levels of the lake should be reduced to expose at least 50 percent of the lake bottom for two growing seasons to promote emergent and submergent vegetative growth, also causing a significant winter kill that would reduce the carp population. To execute this, the existing earth and wooden dam would need to be replaced. DU engineers developed a hydrological model using HydroCad showing that approximately 3000 feet of the outlet creek (Waukau) needed to be regraded to allow for proper discharge.

Action

Ducks Unlimited engineers worked with the Wisconsin DNR staff to develop a thorough stream redesign without impacting the surrounding vegetation, along with replacing two of the old existing culverts with bridges. Ducks Unlimited designed a sheet pile weir dam with six specially designed weir gates to aid in drawdown and water level management.

Delivery

With approved final design, cost estimate and proper permits in place, Ducks Unlimited prepared, bid, awarded and executed the contract, providing construction staking and construction management for the project.

Rush Lake dam before
BEFORE: A dam in a state of major disrepair and deterioration

Rush Lake dam after
AFTER: DU designed a sheet pile weir dam with six specially designed weir gates to aid in drawdown and water level management.

Rush Lake
One of two replacement bridges developed by DU and the Wisconsin DNR

Rush Lake stream before
BEFORE: A choked, overgrown stream at Rush Lake

Rush Lake stream after
AFTER: DU revitalized the stream, allowing for more abundant water flow and improving habitat quality along the riverbanks.

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Erosion Control

Pool C and Observation Pool, Back Bay National Wildlife Refuge, Virginia

Challenge

The Back Bay National Wildlife Refuge (NWR) staff manages hundreds of acres at the refuge, including several impoundments. Pool C is the storage and distribution unit for several other wetland impoundments. Over the years, the winds blowing across the impoundment caused varying water levels to damage the interior slopes. This damage spawned maintenance issues and concern over the integrity of the berm. Back Bay NWR staff contacted Ducks Unlimited to draft a comprehensive plan to reestablish a safe and maintainable slope for the unit.

Analysis

Ducks Unlimited performed a topographical survey using a survey-grade total station. A contour map was developed utilizing AutoCad Land Development software.

Action

Because the original berm had been built with an adjacent interior borrow, utilizing material from inside the unit would be costly. The refuge was under a separate contract and building a visitor observation building overlooking a nearby unit, so DU decided to enhance the observation unit with scrapes, potholes and channels and use the material to rebuild the interior slopes of Pool C. The design also called for 1,200 tons of riprap to be placed along the inside slope of Pool C, where the wind and waves could do the most damage, and 2,600 linear feet of erosion control matting.

Delivery

With approved final design, cost estimate and proper permits in place, Ducks Unlimited prepared, bid, awarded and executed the contract, providing construction staking and construction management for the project.

 Pool C Before
Back Bay NWR's Pool C - Before

 Pool C After
Pool C - After

 Pool C
Wetland created utilizing creative borrow

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Tidal Interchange

Sachuest Point National Wildlife Refuge Salt Marsh

Highlights of the Sachuest Point Salt Marsh restoration include dual 3x6 concrete pipe structures, which allow full tidal interchange between Narragansett Bay and the existing salt marsh. Along with a constructed channel, the refuge now has the capability to restore 29 acres back to high and low salt marsh.

The inaugural pulling of the first stop log and the guarded inlet to the impoundment

The Sachuest Point project from the air

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Water Control Structure Replacement

Erie National Wildlife Refuge, Pennsylvania

Challenge

An existing water control structure had failed in previous years, removing the ability to manage and maintain water levels for the Pool 4 impoundment. Water level manipulation is important for the refuge to meet their habitat goals.

Analysis

The engineering staff of Ducks Unlimited's Great Lakes/Atlantic Regional Office performed a site visit and acquired an electronic copy of an existing topographic survey to evaluate the existing site conditions. The existing water control structure consisted of two 10-foot-wide fixed crest half-round risers with 72-inch barrels. The risers and barrels separated at the joint due to forces from ice and waves. This failure had removed the managers ability to increase water levels in the impoundment. The goal of this restoration was to return water level management capability to the impoundment. The existing auxiliary spillway had sufficient capacity to pass the larger storm events.

Action

Ducks Unlimited engineers worked with the U.S. Fish and Wildlife Service to develop a concrete water control structure with two six foot by six foot cast in place concrete culverts. The water control structure has two stoplog bays on the face of the structure to allow for complete drawdown. The structure also has stoplog bays on the east and west sides of the structure to increase flow capacity when the impoundment is being managed at full service level.

Delivery

With approved final design, cost estimate and proper permits in place, Ducks Unlimited prepared, bid, awarded and executed the contract, providing construction management for the project.

Erie NWR Pool 4 - BEFORE
Pool 4 before


Erie NWR Pool 4 - AFTER
Pool 4 after 1
Pool 4 after 2

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Active Water-Level Management

Big Marsh Lake, Battle Creek, Michigan

The purpose of this project is to replace a dilapidated water control structure with a new one, and provide active water level management of Big Marsh Lake located north of Battle Creek, Michigan. The goal of this project is to re-establish 200 acres of quality wetland habitat for waterfowl and other wetland species. This will be achieved by replacing the non-functional water control structure with an improved one that will allow site managers to actively manage the wetland to promote aquatic plant growth and to mimic natural hydrologic regimes, which will benefit the primary objective of an increased diversity of wetland flora and fauna. A related objective of this project is to re-connect Big Marsh Lake to Ackley Creek, allowing for the passage of a diversity of fish species in and out of Big Marsh Lake.

Big Marsh Dam
Big Marsh Dam

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Fish Point Wildlife Area

Great Lakes Coastal Marsh, Michigan

The Fish Point Wildlife Area encompasses approximately 3,000 acres of Great Lakes coastal marsh. In 2009, two aging pump stations were replaced with one larger, more efficient pump and associated water distribution infrastructure. The new pump will allow managers to more effectively manage 680 acres of emergent wetlands in the wildlife refuge and 310 acres of seasonally flooded agricultural crops by manipulating water levels and wetland vegetation to meet the habitat needs of critical wildlife species, including waterfowl. 

Ducks Unlimited provided the survey, engineering design, contracting, bidding and construction management services to complete the coastal wetland enhancement at Fish Point Wildlife Area. Funding for this project was made possible through a North American Wetlands Conservation Act grant and a partnership between the Michigan Department of Natural Resources and Environment, Fish Point Wildlife Association and Ducks Unlimited.

In with the new: Structural installation at Fish Point Wildlife Area (top) and completed new, efficient pump (bottom).

Fish Point
Fish Point

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Brancheau

Detroit River International Wildlife Refuge, Michigan

The Brancheau tract was purchased by the United States Fish and Wildlife Service (USFWS) to be included in the Detroit River International Wildlife Refuge. The Brancheau tract was farmed prior to USFWS ownership and was artificially drained with tiles and ditches. In 2007, the USFWS, Waterfowl USA, Michigan Duck Hunters Association, Metropolitan Affairs Coalition, DTE Energy, the North American Wetlands Conservation Council and Ducks Unlimited (DU) partnered to restore wetlands on this property.

DU provided the engineering design, contracting, bidding and construction management services to restore 67 acres on this site. The project included breaking drain tiles and constructing a low-level berm to restore the hydrology to the site and prevent flooding of off-site locations. Water control structures were installed in the berm to facilitate wetlands management. With new infrastructure, managers can promote the establishment of native plant species that will provide high quality habitat for resident and migratory wildlife and control the invasion of invasive species such as phragmites.

The addition of the water control structure at Brancheau will help managers provide quality habitat for a variety of wildlife including resident and migratory waterfowl.

Brancheau
Brancheau

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Structure Rehab

Prime Hook National Wildlife Refuge, Delaware

Challenge

Staff at Prime Hook National Wildlife Refuge (NWR) in Delaware sought out Ducks Unlimited to facilitate a facelift for a deteriorating water control structure on a 1,500-acre freshwater wetland. The 11-bay structure was built in the 1970s and consisted of a combination of wooden stoplogs and flapgates to manage water levels while restricting tidal flow into the impoundment. The flapgates were inaccessible for repair and maintenance by refuge staff, and the narrow catwalk caused safety concerns.

Analysis

After an initial site visit and investigation, it was found the concrete structure was in good shape and only the water control portion needed to be addressed.

Action

Ducks Unlimited’s engineering team developed a unique retrofit for the existing water control structure. The original, inaccessible flapgates were replaced with individual aluminum flaplogs that serve the same function and can be accessed easily for maintenance and repair. The wooden stoplogs within each bay were replaced with an aluminum sliding weir gate that enables refuge staff to manage water levels to a greater degree of accuracy than previously possible. The sliding weir gate also has the unique ability to draw water from the top or bottom of the impoundment. The existing catwalk was widened and a railing was installed for the refuge staff’s safety. The catwalk also incorporates a locking system that restricts the general public from accessing the weir gate and flaplogs.

Delivery

With the ability to call upon their list of known skilled fabricators throughout the Great Lakes/Atlantic region, and ownership of the die for specially manufactured gates, Ducks Unlimited was able to solicit fabricators for their design. DU then bid and awarded a general contractor to replace the old water control components and build a new safer catwalk.

 Prime Hook NWR structure
The rehabilitated water control structure at Prime Hook NWR

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