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County Executive's Office

County Partners to Target Top Pollutant Pipeline to Prevent Massive Amounts of Sediment From Entering Lake Mendota

November 18, 2013
Casey Slaughter Becker, Office of the County Executive (608) 267-8823 or cell (608) 843-8858
County Executive


$1.4 Million in Grants Recommended for Seven Projects to Curb Urban

Runoff Pollution Into Area Lakes 

The county, in partnership with the City of Madison and the University of Wisconsin – Madison is targeting the stormwater pipeline that releases the most sediment and trash into Lake Mendota, Dane County Executive Joe Parisi announced today.


The top outfall is on Willow Creek, an urban stream that extends from Whitney Way to the Lakeshore Nature Preserve at University Bay on the UW campus. The project is one of seven recommended by the county’s Lakes and Watershed Commission to receive a combined $1.4 million in Urban Water Quality Grant money in 2013. 


“Willow Creek empties into an iconic part of Lake Mendota, University Bay, home to picnic point, miles of pristine lakeshore, and host to a variety of outdoor water recreation,” said Parisi.  “By partnering to clean up this pipeline and others throughout the county, we’re protecting important natural resources for decades to come and improving the overall health of our lakes.”


Decades of untreated stormwater entering and traveling through Willow Creek has created a sediment island in University Bay so large that can be seen in aerial photos.  The outfall is estimated to release more than 38,000 pounds of sediment into the lake annually.


The county’s grant program helps build stormwater sediment basins to capture this sediment, trash, and phosphorus-laden debris such as yard or pet waste from urban areas that otherwise wash directly into lakes and streams when it rains. 


The basins capture the debris by giving it an area to ‘settle out’, preventing it from entering the water, and allowing for safe disposal at a later time.  Phosphorus is the main culprit that leads to smelly, unsightly lakes. 


“The urbanized area that drains to Willow Creek was developed decades prior to modern water quality practices, leaving us with few options for retrofitting storm water treatment systems. Providing treatment at this location is a perfect opportunity to capture trash and dirt from storm water before it reaches Lake Mendota, preventing further contributions to the “island” forming at the outlet of Willow Creek,” said Madison Mayor Paul Soglin.  “The city looks forward to partnering with Dane County, UW, and WDNR to help fund, design, permit, and build this project.”


“The State of Wisconsin including the Dept. of Administration, the UW System and UW-Madison have been working hard with our regional partners to help provide solutions to help improve the water quality of Lake Mendota,” said William Elvey, Associate Vice Chancellor for UW-Madison Facilities Planning and Management.  “The latest example includes an on-going, phased project consisting of new bio-retention facilities including swales and a large retention pond, all of which will significantly improve the quality of stormwater runoff into Lake Mendota.  This project alone represents a nearly $4 million investment of funds.”


In addition to building a sediment basin for Willow Creek, the project includes dredging the sediment island in the bay, and restoration of the Willow Creek shoreline into a native and stable condition.


This year’s recommended projects will help prevent more than 70,500 pounds of debris and 1,000 pounds of phosphorus from entering the lakes annually.  In addition to the Willow Creek outfall, the county will partner with Middleton, Monona, and Fitchburg to reduce urban runoff pollution with projects in those municipalities.  A full list of projects is attached.


For the first time ever in this year’s grant cycle, municipalities that contained one of the county’s top ten discharging pipelines, such as the Willow Creek outfall in Madison, were eligible to receive a 75% cost share from the county to address their runoff.


Since 2005, the county’s Urban Water Quality grants have helped fund projects totaling more than $5.3 million dollars that are estimated to have removed more than 400,000 pounds of debris since that time, and more than 760 pounds of phosphorus annually. 


One pound of phosphorus removed from the county’s watershed prevents 500 pounds of algae growth in area lakes.


The recommended projects are subject to final approval by the Dane County Board.  A resolution recommending the projects will be introduced at this Thursday’s meeting of the Dane County Board, and could be approved as early as the board’s December 5thmeeting.


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