There are problems with storm-water runoff in the city of Decorah, but there also are solutions, Bailee McClellan, of the University of Iowa’s School of Urban and Regional Planning, told the Decorah City Council Monday night.
Over the last two semesters, University of Iowa students and faculty, through the University of Iowa’s Iowa Initiative for Sustainable Communities (IISC), have teamed with community partners in Decorah and Winneshiek County to work on 11 projects, ranging from storm water management planning for the city of Decorah, to multiple studies on the potential impact of frac sand mining in Winneshiek County.
McClellan and Vanessa Fixmer-Oraiz talked to the Council about the storm water study Monday, and several other presentations were given during a public event at Luther College Tuesday afternoon and evening.
For the past nine months, the members of the IISC have been studying storm water management planning and financing for Decorah.
“Iowa used to be tall-grass prairies. Now its rooftops, streets and parking lots and all that water doesn’t have a place to go,” McClellan explained of the storm water issue.
Decorah needs to establish a storm water utility ordinance, she said.
“Decorah needs to take a proactive approach to storm water management by creating a systematic strategy and sustainable funding source.
“We recommend adopting this plan, which creates a storm water utility fee and guidelines for implementing effective storm water best management practices,” McClellan said.

Ponding
While the flood control levee did a “great job” of protecting the city from flooding during the 2008 flood, McClellan said there was a lot of ponding along the levee and that water had to be pumped back into the river. She said the city’s proximity to the Upper Iowa River and creeks considered “impaired water bodies” by the Iowa Department of Natural Resources due to the presence of mercury and bacteria is another reason to address storm water.
Fixmer-Oraiz said the IISC study identified five locations around the city where public projects could mitigate storm water runoff: Locust Road, the West Side, Heivly Street area, Old Dry Run Creek corridor and the Northeast Redevelopment area (former Wapsie Produce).

A bioswale project is recommended along Locust Road, including enhanced storm water infiltration, native plantings and signage/trail connection. Bioswales are landscape elements designed to remove silt and pollution from surface runoff water.

Bioretention cells are proposed for Decorah’s West Side. The cells remove contaminants and sedimentation from storm water runoff. Storm water is collected into the treatment area which consists of a grass buffer strip, sand bed, ponding area, organic layer or mulch layer, planting soil and plants. The IISC recommendation includes rain garden curb cut-ins, storm water infiltration, native plants and signage.

A Heivly Street parking project calls for reduced impervious areas, bioswales to capture impervious area runoff, permeable pavement, retrofitted parking lots and taking advantage of redevelopment plans to add infiltration practices.
Solutions proposed for the Dry Run Creek area include two “pocket parks,” public easements, bioswales and stream buffers, permeable paver lots and signage.

Proposed solutions for the Northeast Redevelopment Area include using an ordinance to require on-site detention, public access to a stream, stream beautification and an urban connection to Trout Run Trail.

Utility fee
McClellan said based on the research conducted in the study, a monthly storm water utility of $5 per residence is recommended to cover infrastructure maintenance, public projects, private cost share and education/community engagement.
She said there would be exemptions for low-income residents or those who have rain gardens or other projects on their property.
McClellen summarized key recommendations for the city: Adopt the storm water management plan, adopt the utility fee, adopt proposed storm water ordinances and establish a storm water management committee.
Mayor Don Arendt and Council members thanked the students for their work on the proposal. Council member Chuck Lore, chair of the Council’s utility committee, scheduled a committee meeting for Monday, May 18, at 6:30 p.m. to discuss the recommendations made by the IISC study.