Nine Mile Creek Watershed Improvement

A “dry pond” was transformed into a sustainable, living system that manages stormwater and fosters habitat.

The Langerdale detention basin in South Euclid, Ohio, is an on-line flood control basin draining 7.6 square miles in the Nine Mile Creek watershed. Built in the early 1960s as a traditional “dry pond,” the basin relegated the stream to a concrete channel. The basin included a system that allowed any overflow to flow directly down Langerdale Boulevard through a secondary spillway structure. Since its creation, the detention basin had overflowed twice, causing flooding to adjacent homes.

Recognizing the value of Nine Mile Creek as a tributary to Lake Erie and as a critical component of the community’s green infrastructure, the City launched an effort to restore this urban stream, beginning with a retrofit of the detention basin. Biohabitats worked closely with the City of South Euclid to develop a concept and ultimately a final design package to retrofit the basin. The design increased treatment and storage areas, introduced naturally vegetated wetland areas, restored the channelized drainage way to a natural channel, and created areas for aquatic habitat. To maximize the detention time of the first flush of runoff, Biohabitats designed a series of wetland pools separated by low crested earthen weirs. This approach was developed with the parallel goals of maximizing storage volume, augmenting aquatic habitat and minimizing long-term maintenance.

In 2008, the City completed construction of the basin, which required excavating 14,000 cubic yards of soil, installing 14 floodweirs and open-water pools, and planting five vegetation zones. The planting zones included aquatic bed and open water wetland, scrub-shrub emergent wetland, forested wetland, riparian deciduous forest and native mesic meadow.

TAGS

• Analysis+Planning
• Assessment+Monitoring
• Design
• Ecological Restoration