GLARO Engineering Projects
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.
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 pier - 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.
BEFORE: A dam in a state of major disrepair and deterioration
AFTER: DU designed a sheet pile weir dam with six specially designed weir gates to aid in drawdown and water level management.
One of two replacement bridges developed by DU and the Wisconsin DNR
BEFORE: A choked, overgrown stream at Rush Lake
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.
Back Bay NWR's Pool C - Before
Pool C - After
Wetland created utilizing creative borrow
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TYPE OF PROJECT
Wightman Lake Restoration, Stueben Township, Illinois
Challenge
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Analysis
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Delivery
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TYPE OF PROJECT
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TYPE OF PROJECT
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TYPE OF PROJECT
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Challenge
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Analysis
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Action
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Delivery
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STRUCTURE REHAB
Prime Hook National Wildlife Refuge, DE
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.
The rehabilitated water control structure at Prime Hook NWR
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