A New Mattress for Shannon County Stream Bed

Shannon County Road 401 leads from Eminence, Mo., southwest to Delaware. Along the way, CR 401 crosses Mahan Creek, a tributary to the Jacks Fork River. Part of the Ozark National Scenic Riverways, the Jacks Fork is considered an Outstanding Water Resource by the Missouri Department of Natural Resources. The low-water crossing at Mahan Creek consisting of natural stream gravel had to be repaired after every flood or high-water event. In addition, local residents would get vehicles stuck in the crossing due to the unstable nature of the gravel. This continual disturbance presented a large problem for the local residents and a maintenance headache for the county road crews and ultimately added to the gravel accumulation in the Jacks Fork River.

Common Interests Lead to Partnership

In the fall of 2009, Shannon County officials and Fisheries Division staff from the Missouri Department of Conservation met at the crossing to discuss the county’s continuous maintenance problems, as well as the resulting effects on stream health and water quality of Mahan Creek and the Jacks Fork River. Between the county commission’s concern for accessibility and safety for the local residents and MDC’s interest in maintaining healthy stream dynamics, a partnership was formed to address the problem.

A New Mattress for the Stream Bed

MDC staff was able to secure a grant from the Missouri Conservation Heritage Foundation (MCHF) through their Stream Stewardship Trust Fund to purchase materials for an articulating concrete mattress (ACM) crossing. An ACM is a series of concrete blocks cabled together to form a mattress. These mattresses can then be installed in the stream bed, providing a stable low-water crossing for vehicles. The design allows for the passage of sand and gravel over the crossing during high flow events while maintaining stability after flooding. In addition, the design of ACM allows for adjustment to the natural shifting and settling of the stream bed during high flows and provides a surface for aquatic organism passage as a low-water crossing.

New Solutions to Old Problems

The partner contributions of this project included funding for the ACM materials from the MCHF at just over $20,000, installation of the ACM crossing by the Shannon County Commission and engineering design and technical guidance from the Missouri Department of Conservation. Through the contributions of these three partners, the new crossing was installed in December 2010. This project is a good example of how the goals of different agencies and organizations can overlap to create strong partnerships and new solutions to old problems.

For More Information

The MCHF is a nonprofit, charitable organization that helps meet financial needs placed on natural resource conservation and conservation-related outdoor recreation. Since being founded in 1997, MCHF has allocated more than $9 million for conservation funding statewide. For more information about the Stream Stewardship Trust Fund or the MCHF visit their homepage.