Technical Description:
• Open Bottom Aluminum Box Culvert
• Span: 23-ft.
• Rise: 6-ft. 1-in.
• Length: 49.5 ft.
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Michigan’s Natural River Program is a river protection effort administered through the State’s Department of Natural Resources (DNR) office and was developed to preserve and protect its unique river system. There are 16 designated Natural River systems in Michigan which includes the tributaries to the mainstreams. The long-standing program was developed to "preserve, protect and enhance our state's finest river systems for the use and enjoyment of current and future generations.”
Big Cannon Creek is a designated natural river and tributary to the Manistee River as part of the Upper Manistee River Watershed. The existing dual 5.6' span x 3.7' rise corrugated metal pipe culvert crossing at Military Road had exceeded the useful service life and the outdated design practice was no longer acceptable through Michigan Department of Environment and Great Lakes and Energy (EGLE), the review and approval agency for structure replacement. Single or multiple culvert designs were an economical solution throughout the early and mid-1900s, but there was little attention paid to the long-term impact of the water course, the surrounding drainage area and the limitations of fish passage. The new structure needed to recreate the natural water course to improve the 28.3 square mile drainage area, reestablish a natural water path for fish passage and allow for new clearance access for canoeing and kayaking.
One of today’s key design practices is the requirement of the new structure to be designed to span the full width of the bank, or the width of the stream that corresponds with the depth where water fills the main channel prior to overflowing. For the Military Road crossing, the width of the bank was approximately 22' with rise limitations of 8' from streambed to road grade. As an added challenge, EGLE requested the new structure clear span the creek to limit construction-related impact and improve fish passage.
Early on in the design, engineers at Contech Engineered Solutions worked closely with local engineering firms and agencies in Northern Michigan to design a clear-span structure solution that addressed foundation design, long-term scour-counter measures, and met the span-rise requirements for a given crossing by combining aluminum structures with a light-gage metric sheeting cofferdam. Contech offers 143 standard aluminum shapes spanning up to 35' with varied rise options. For any given crossing, multiple aluminum solutions can be identified when considering EGLE design requirements, combined with a required hydraulic open area, and height of cover limits.
The inclusion of a steel sheet pile cofferdam allows for the contractor to complete construction without impacting the water course with temporary diversion methods or draw-down pumping. The 10' long cofferdam sheeting also acts as a spread foundation improvement and scour countermeasure protecting the structure design during the largest storm events.
The Kalkaska County Road Commission (KCRC), the project's owner, teamed with Trout Unlimited's Michigan chapter to address the challenges at Military Road, which included limited funding and careful timing of the installation. Due to Contech's previous experience working with Michigan's road agencies and non-profit organizations to replace structures along natural waters, the team met with Contech to review product options and concepts.
After evaluating the options, the team decided that an open bottom 23' span x 6'-1" rise Aluminum Box Culvert (ALBC) was the best replacement solution. Designed to MDOT HL-93 modified live loading requirements, the 49.5' long structure included an integral aluminum headwall and wingwall end treatment package. The entire structure replacement was completed for less than $200,000 including paving, guardrail and approach.
“Natural rivers have constant and significant flow where any approach used to manage the water creates a costly addition to the contract and impacts the aquatic environment,” noted Katie Monroe with Prein & Newhof. “Working over the creek, rather than in the creek, is an economical approach while accelerating the project construction cycle."
Technical Description:
• Open Bottom Aluminum Box Culvert
• Span: 23-ft.
• Rise: 6-ft. 1-in.
• Length: 49.5 ft.
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