Replacement of the Nahma Highway Bridge

New bridge protects resources while old bridge is re-used through partnership on Hiawatha

Story submitted by Rich Corner, Hiawatha's West Unit Hydrologist

The Co. Rd. 497 Bridge over the Sturgeon River was constructed in 1917 by the Joliet Bridge and Iron Company of Joliet, Ill. (Photo 1). It was a steel pony-truss style bridge, 94 feet long and 20 feet wide and carried one-way traffic. The bridge was closed in 1991 due to structural inadequacy and vehicle traffic was re-routed over a longer detour. Because the bridge was constructed to the standards of the time, it was somewhat narrower (bank to bank) than is now considered desirable and was causing bank erosion both upstream and downstream of the bridge (Photos 2 and 3). In 1997 the Nahma Township Board stated that they believed reconstruction of the bridge was important to the economic development of the Village of Nahma.

In spite of the economic and environmental incentives to replace the bridge, its replacement was not straight forward. The bridge had intrinsic historic, cultural, and scenic qualities and was located within a Wild and Scenic River Corridor. By virtue of its age and length (it was one of the longest pony truss bridges of its time) the bridge was considered to be historically significant. Additionally, locals were very fond of the structure for its aesthetic values.

The Delta County Road Commission, Delta County Conservation District, Hannahville Indian Community, and U.S. Forest Service (with input from the U.S. Army Corps of Engineers and USFWS) worked cooperatively to replace the structure while mitigating as many of the concerns as possible. Before removing the old structure, the U.S. Forest Service arranged for important architectural aspects of the original bridge to be preserved by a professional archival photographer. The bridge was replaced by a structure with longer span which, it is hoped, will lessen the bank erosion problems in the area. The new bridge, also a pony truss structure with "weathered steel" trusses, was specifically chosen to maintain the scenic qualities and context of the original bridge (Photo 4). Finally, the original structure was not discarded but rather has been used to enhance the scenic quality of the new Sweetgrass Golf Course, owned and operated by the Hannahville Indian Community. The 'Old Nahma Highway' bridge is now a highlight of the golf course where it provides access to the only true "island green" in the Upper Peninsula.