McClure was contracted in August 2019 by the City of Decorah to prepare preliminary and final plans for the reconstruction of approximately 1.3 miles of roadway and improvements to storm sewer and construction of sidewalk. The work involves replacing all culverts and pipes, providing erosion control in a drainage ditch in limestone that is being eroded due to severe water flows and reconstructing the existing 24 feet roadway to a new 40 feet wide section with bike lanes on both sides within the available right of way. The City and Alliant Energy are also collaborating to install a joint utility trench under the roadway to place all overhead utilities underground. The project is a part of the SWAP funding and is proposed to be let by the Iowa DOT in April 2020 with check plans due to the DOT for review by December 2019 for a total project design duration of five months.
McClure was responsible for all aspects of the design from traffic studies, concept preparation, survey, geotechnical, preliminary and final geotechnical design, permitting, etc. McClure was also responsible for designing the drainage and stormwater system to address not only the additional stormwater due to a wider pavement surface but also the global stormwater and flooding issues that were being caused due to development in the surrounding area since the original road was constructed. This increased flow has caused severe erosion along ditch channels through limestone bedrock and created a significant drop of about 10 feet at a culvert outlet. To address these issues, project plans propose a series of gabion walls and erosion stone ditch protection. This erosion protection will continue for a length of approximately 600 feet along the drainage ditch to prevent further erosion and stabilize the ditch banks. Additionally, to avoid impacts to existing ROW, the 25 feet high embankment along this culvert is being proposed to be reconstructed as reinforced soil slope.
- Safety improvements – street lighting, rumble strips in the rural sections, flashing radar-controlled speed limit signs and a lowered speed limit throughout the corridor.
- Majority of the work will be performed under local detours with truck traffic diverted along a global detour.
- McClure was honored to receive a positive feedback from Christy Vanbuskirk, Local Systems Bureau project delivery coordinator for the plan quality for a project designed and delivered within five months.