Flooding issues in southwest Ann Arbor neighborhoods prompt $200K study
Photo courtesy of Bob Loukotka
The City Council voted 10-0 Monday night to approve an agreement with the Washtenaw County Water Resources Commissioner's Office to undertake a project to evaluate and identify opportunities for conveyance and stormwater improvements in a portion of the Malletts Creek Drainage District.
Photo courtesy of Laura Ent
The study is an answer to a previous council resolution passed in August that directed staff to negotiate such an agreement with the water resources commissioner.
Much of Malletts Creek is contained in underground piping that carries stormwater runoff from urbanized areas.
Jennifer Lawson, the city's water quality manager, said nearly 37 percent of the land surface draining to the creek is impervious, meaning liquid doesn't pass through it. As a result, stormwater frequently enters the creek too quickly, causing neighborhood flooding — including flooding of residents' basements — when it rains.
"These rain events also carry pollutants from impervious areas to the creek, lowering water quality," Lawson wrote in a memo to council.
Churchill Downs resident Ellen Fisher is asking the city to pay for nearly $25,000 in damages she incurred during a March 15 storm after her basement flooded. That storm also spawned the violent Dexter tornado.
Lawson said the the Malletts Creek Restoration Project of 2000 and the Malletts Creek Management Plan of 2007 both identify construction of stormwater control measures within the creekshed as a high priority to control water quantity and improve water quality during storm events.
Lawson said the improvements yet to be identified could include more stormwater detention, pipe upsizing and green infrastructure to improve overland flow issues.
Malletts Creek is an established county drain, and any work to study and evaluate the county drainage system falls under the jurisdiction of the water resources commissioner.
There was no discussion of the study by city officials at Monday night's meeting. Council Member Stephen Kunselman was absent.
While the city zeros in on the Churchill Downs and Lansdowne neighborhoods, it also is undertaking a citywide analysis of its stormwater drainage system following the March 15 storm that left neighborhoods flooded and home basements under water. The City Council took action in June to approve an $822,700 contract with CDM Michigan Inc. to complete the citywide analysis.
The city also has studied three condominium neighborhoods near Lansdowne and is recommending hundreds of thousands of dollars worth of stormwater detention improvements, but the city wants to have property owners pay for the improvements directly through special assessments.