Old County Road Bridge

Welch Comer was selected by Benewah County and LHTAC for the Old County Road Bridge design on Carpenter Creek Road across the St. Maries River in Fernwood. Design was completed in 2013 and the project began construction in 2014. The project had several interesting challenges, including the following:

Channel Scour: To counteract the effects of scour in the narrow channel, the pier walls were designed to extend 15 feet below the river bed, which required a cofferdam, dewatering, and wetland mitigation.    

No Detour: No detour was available for Carpenter Creek and the horizontal curve beyond the end of the existing bridge did not meet current design standards. The design team solved both problems by realigning the curve and shifting the bridge alignment thereby eliminating the need for a detour.

Waterline: The waterline on the bridge was critical for water supply to Fernwood and the Fernwood Water & Sewer District had no means to fund the replacement of the line. Welch Comer worked with the District, LHTAC, and DEQ to fund the water line replacement.  

 

Our Services

Project Stats

Construction Cost:
$2.8 Million

Completion Year:
2013

Carpenter Creek Road remains open during construction of the new bridge.
Riprap was required to protect against scour, which also required 404 permitting.
Carpenter Creek Road remains open during construction of the new bridge.