Regional Community Park & Trail Planning at Johnston’s Terra Lake Park

Transforming a Brownfield Site for Public Recreational Use

With neighboring communities on multiple sides, the City of Johnston understands the importance of utilizing every available space to accommodate and provide amenities for its exploding population. The Terra Lake Park project is a prime example of this forward-thinking outlook. This ambitious project transformed a decommissioned sanitary sewage lagoon into an eight-acre lake and community park with multiple connections to a regional trail network. The planners and engineers with Snyder & Associates worked in collaboration with the community and city leaders to establish the vision for the park and help bring it to completion. The park’s master plan development involved extensive public engagement efforts and numerous technical reviews to develop the desired park concept and plans. Foremost on the list of goals for the park location was the conversion of a 15-acre basin into an eight-acre recreational lake with a consistent pool elevation. This involved a thorough investigation and evaluation of the soil conditions at the site to ensure the safety of patrons, as well as the creation of a habitat that would support adequate fish stocking and native species protection and enhancement. Additionally, public input helped determine the importance of creating a regional park and the establishment of the park as a regional trailhead as critical components.

Providing Amenities to Create Destination Location

The completed Terra Lake Park offers impressive amenities, including a three-acre irrigated great lawn for concerts and games, an open-air civic shelter and amphitheater for large gatherings, a picnic pavilion, several smaller shelters, and a nature-themed circular playground that is handicap accessible. For further ease of accessibility, the park boasts over 220 parking stalls in two convenient locations, several multipurpose trail connections leading to regional trails to the south and west of the park, and an ADA-accessible fishing pier that puts anglers of all abilities right on the water’s edge. The use of large stones and a cascade water feature, along with numerous native plantings creates a pleasing and harmonious environment.

Addressing Site Challenges & Phased Construction Needs

Working on a former brownfield site, the design team was faced with numerous challenges over the course of the project. Foremost, the conversion of the former basin into a recreational lake required a sophisticated earthwork plan to harvest as much clay soils on site as possible. This allowed the construction of the clay liner and utilization of large amounts of sandy soils in the open space areas. Also, the construction and routing of the regional trail connections within the wetland and floodplain areas required significant planning and permitting. Under real-world conditions such as rain, localized flooding, and hydric soils, the trail alignment work required thoughtful creativity and meticulous design efforts. Project construction occurred in five distinct phases allowing similar construction activities to be bundled together into bid packages. This helped to reduce mobilization and project administration costs. During the first phase, the majority of the earthwork and lake construction was completed. The utilities were also located and a groundwater well was established. The second phase incorporated the building of the multi-use trails, parking lots, bioretention areas, and the addition of the permeable paver areas. Phase three brought in most of the architectural elements, including the restroom shelter, lakeside shelter, civic shelter, stone crossings, and the overlooks, while phase four consisted of the addition of the fishing pier. Wrapping up the project in the fifth phase was the construction of the circular playground with five different ADA-accessible play experiences. The strong emphasis on fishing and fish habitat allowed our team to work with the Iowa Department of Natural Resources (DNR) and Polk County Conservation to attract regional recreational programming support and park interest. The connection of the numerous multi-use trails to the park allows it to serve as a regional trailhead, which is a prominent park attraction. The park will host an installment of Johnston’s annual “Jazz in July” concert series along with other live music, charity, and community events. Through the reclamation of this former brownfield site, a community resource has been created, resulting in a higher quality of life for local residents and regional visitors. https://youtu.be/ttdEbnSkhNY