Outcomes and Conclusions
The creek naturalization project improved 0.3 miles of creek bed in Bryan Park, located in the heart of Bloomington’s downtown residential area. By establishing native plants along the creek bed, the project enhanced aquatic and terrestrial habitat in the park, and increased wildlife viewing and educational opportunities for park visitors. Biodiversity has noticeably improved as the new flora support more varieties of songbirds, pollinators and stream macro-invertebrates. Citizen scientist volunteers have monitored and tracked these species successes through Hoosier Riverwatch and the Bloomington Adopt-A-Stream program. Furthermore, for many years the creek had suffered from increasing sediment loads, dead zones and high sun exposure. This project corrected bank erosion, improved water quality in the creek and increased availability of shaded habitat. Since the completion of the project, the native vegetation has been able to hold the banks more effectively than turf during heavy storm events. Indeed, after the project was completed in 2007, it successfully managed a large flood just one year later in 2008.
Overall maintenance required for the creek shrunk and shifted such that it reduced mowing and thus fossil fuel use, and cost, in the park. The Department of Parks and Recreation maintains the improvement area along with some community volunteers. Maintenance requirements include invasive species removal, weeding, trimming existing plants, planting new plants, mulching and monitoring stormwater drainage.
Additional naturalization projects underway in Bloomington include a five-acre prairie planting funded through the Indiana Department of Natural Resources and U.S. Fish and Wildlife Services. The site was planted in 2018 with the goal of creating new, drought-resistant habitat for wildlife and native plants.
Challenges
While overall creek bed maintenance time and costs have decreased, maintenance requirements remain a challenge for the City. Aspiring for a biodiverse, herbaceous creek bed and eliminating mowing shifted the requirements to more hands-on tasks. The City has experienced mixed success in using volunteers to assist. Other challenges have included invasive species crowding out desired plants and winter-time aesthetics.
Lessons Learned
Project manager Steve Cotter said, "If I had to do it all over again, I would have incorporated trees into the vision from the outset and focused on selectively guiding the succession of the creek bed foliage rather than maintaining specific native plants. Initially we had only planned to plant wildflowers, grasses, and sedges. Cultivating a long-term herbaceous riparian zone for 0.3 miles of creek bed was an unrealistic goal without annual burning or mowing.”
