Pay Invoice
Pay Invoice
Client Name
City of Marion
Client Type
Project Type
Services Provided
Project Manager
Contact Craig German, PE
Structural Engineer

Donnelly Park (Boyson Trail) to Tower Terrace Road Multi-Modal Trail Link

Our environmental professionals check creek conditions near one of the bridge locations.

Having doubled in population over the past three decades, the Cedar Rapid’s suburb of Marion has been the dual beneficiary of a rapidly expanding metro area and the proliferation of trail networks springing up around the state. Multi-modal networks are a major draw for attracting new residents, as well as creating recreation and exercise opportunities for people of all ages and abilities. The recently completed 2.2-mile-long section of the Indian Creek Trail checks all those boxes.

Designed by the professionals with Snyder & Associates, this ten-foot-wide PCC trail was aligned to run adjacent to Indian Creek within the Marion city limits. The trail connects Boyson Trail in Donnelly Park to the newly constructed section of Tower Terrace Road on the north side of town, passing by Linn-Mar High School and Indian Creek Elementary School along the way. The trail was designed to utilize as many existing bridge and box culvert structures as possible along the alignment, with most of the necessary street crossings occurring below bridges.

Updated At-Grade Crossing, Prefabricated Bridges Utilized & Box Culvert Tunnel

One area that required an at-grade crossing was near the Linn-Mar Community Schools building. The heavy traffic along 29th Avenue posed risks to pedestrians attempting to cross without assistance. Our team recommended a High-Intensity Activated Crosswalk (HAWK) signal for this mid-block crossing. The signal will be activated and provide a safe crossing for both the trail users and pedestrians using the sidewalks.

With the flood events common in the area, the pedestrian bridges were designed to withstand most scenarios.

The trail corridor also includes three new prefabricated bridges. Our team designed the bridge abutments and coordinated with the supplier to ensure a product that will withstand high floodwaters that are consistent with the characteristics found in this floodplain. Hydraulics were analyzed to set the bridges at an appropriate elevation to provide clearance for small storm events which will also reduce maintenance costs associated with debris collection on and around the structures.

The Indian Creek Trail design team also worked closely with another team working on a joint bridge and roadway project crossing the trail alignment. This project included the construction of a large box culvert that was designed and sized to accommodate the trail passage. The extensive coordination between both teams successfully created a project that interlocked designs while creating clear boundaries for construction.

Accommodating Trail Alignment Creates Win-Win Scenario

Initial trail alignments were met with skepticism from several property owners in the area. They were mainly concerned with an alignment that too closely encroached on their property and showed some resistance to working with the city to accommodate the trail route. However, our team was able to work with the city and Linn-Mar Community Schools to create an alternative trail alignment that was beneficial to both parties while avoiding certain areas of conflict.

With the trail substantially completed in the fall of 2022, recreational and exercise enthusiasts now have another alternative to navigate through the Marion community, mostly separated from vehicle traffic. Better yet, countless students in the Linn-Mar School District have a safer alternative to travel to school by bicycle or walking. This critical trail connection has linked essential amenities for Marion residents and will most likely spur future connections as trail popularity continues to grow.