CTH Q is a rural, two-lane major collector highway that winds and twists its way through the hills of Grant County in southwestern Wisconsin, connecting the City of Fennimore with the Town of Hickory Grove. Approximately 0.6 miles of CTH Q near the Homer Road intersection were identified by the County as in need of improvement.

Former CTH Q alignment with the bridge in the distance and the quarry on the right.

This section of highway had back-to-back reverse curves with speed advisory signs and reduced sight distance due to surrounding rocky topography. Located on one of the curves was a substandard and deteriorating bridge structure over the Fennimore/Castle Rock Creek, built in 1958 and rated as in “serious condition.” These slow curves, reduced sight distances, and deteriorating bridge structure required updates.

Grant County was approved by the Wisconsin Department of Transportation (WisDOT) to receive funds through the Surface Transportation Program – Rural (STP-Rural), which allocates federal funds to improve roadways classified as major collector or higher, to address the safety and deficiencies of the CTH Q roadway and the Fennimore/Castle Rock Creek crossing. MSA was selected to provide design services for these improvements. Per STP-Rural requirements, the project was designed to meet WisDOT standards and reporting requirements.

Former CTH Q bridge.

To address the roadway safety concerns, CTH Q was realigned 200 feet east of the existing roadway, redesigning the horizontal curves to meet a 45-mph design speed. The realignment traversed through an abandoned quarry, which, compared to other roadway alignments considered, helped to minimize project length and the amount of rock cut. The new roadway profile was designed to balance cut and fill volumes as much as possible, with excess rock and excavated material used to fill in the floor and sides of the quarry, transforming and revitalizing the landscape. The Homer Road approach was also reconstructed to consolidate the local road from a split configuration of two intersections with CTH Q into one intersection located where the realigned highway passed through the old quarry.

Realignment of CTH Q also allowed the crossing of Fennimore/Castle Rock Creek to be relocated to a tangent section of the roadway, simplifying the structure design, and improving safety. The existing three-span haunched slab bridge was replaced with a single-span prestressed concrete girder bridge. The single-span design eliminated the need for a pier within the creek, helping to minimize environmental impacts. In addition to the structure design, care was given to the space below the structure. A Wisconsin Department of Natural Resources (WDNR) streambank easement is located along the Fennimore/Castle Rock Creek which allows public access for recreational use. A flat area was provided along the streambank for creek access and voids in the riprap under the bridge were filled with smaller select crushed material to provide a more walkable surface.

New CTH Q alignment with new bridge in the distance and quarry on the right.

At the northern end of the project, a natural spring and narrow, underwater cave system – explored by a few brave souls – is located adjacent to and underneath the roadway. The roadway in this area was deteriorating and sloughing towards the spring and creek. To avoid impacts to the creek and improve the long-term stability of the road, CTH Q was shifted 15 feet away from the spring, and special details were developed to enhance the roadway structure and minimize disturbance of the embankment. Low-impact rock blasting restrictions were also in place to minimize impacts to the cave system below the roadway. Rural curb and gutter was added to the project to further reduce impacts to adjacent embankments and periodic openings in the back of curb allowed water to enter shallow swales and receive natural treatment before entering the pristine waters.

The project was constructed in 2022.

New CTH Q bridge.