Hydraulics & Waterways
397012 - Improving Oxygen Conditions in the Lower Kinnickinnic River, Milwaukee River Estuary, Wisconsin
Wednesday, June 6
2:00 PM - 3:30 PM
Location: Regency Room
Robert Montgomery, Cottage Grove WI – Montgomery Associates: Resource Solutions LLC; Nick Hayden, Cottage Grove WI – Montgomery Associates: Resource Solutions LLC; Courtney Allen, Milwaukee WI – Milwaukee Metropolitan Sewerage District; Stacy Hron, Milwaukee WI – Wisconsin Department of Natural Resources
The Milwaukee Metropolitan Sewerage District and the Wisconsin Department of Natural Resources (DNR), with funding from the U.S. Environmental Protection Agency (EPA), are conducting an in-situ aeration pilot study as a part of ongoing activities to improve the ecological condition of the Kinnickinnic River as it enters the Milwaukee River Estuary. This work is within the designated Milwaukee River Estuary Area of Concern (AOC), which has been established to address a number of beneficial use impairments (such as degradation of benthos and degradation of fish and wildlife populations) that limit both ecological function and full use of the aquatic resource. The oversized nature of the Kinnickinnic River channel, which in the past was dredged to support navigation, low baseflows and backwater influences from Lake Michigan lead to long retention times within the reach. This reach also experiences complex hydraulic conditions including pronounced seiches at a frequency of about ten to twelve cycles per day. The biological communities here have been consistently found to be poorer than those both upstream and downstream, in large part due to extended periods of hypoxia through the whole water column.
Since September of 2016, we have conducted a number of tests using an array of floating mechanical aerators to increase dissolved oxygen levels in the river. Monitoring data was used to drive modeling to assess the increase in DO attributable to the aerators for each test. These results will be used to evaluate the feasibility and benefits of a permanent aeration system in this area. This presentation will describe the current conditions within the Kinnickinnic River and Milwaukee Estuary, potential restoration opportunities, the initial results of the aeration pilot tests and the next steps for restoring ecological function in this system.