Watershed planners are recommending that either the Odana Golf Course Pond or the Secret Pond storm water pond in the UW-Madison Arboretum be considered as potential sites for the addition of alum to capture phosphorous in storm water runoff. This according to October 17, 2013 meeting notes of the Wingra Watershed Plan Steering Team. The Wingra Watershed planning is a joint project of City of Madison Engineering Division and the Friends of Lake Wingra (FoLW)
The two sites in the Lake Wingra watershed are in addition to City of Madison Engineering Division plans to begin adding potassium aluminum sulfate to storm water that flows into a pond in the Arboretum near the intersection of Glenway and Monroe Streets. Aluminum sulfate injection into storm water flowing into the Marion Dunn pond is expected to being in 2014.
Wingra Watershed Aluminum Sulfate Application Sites
The Odana Pond and Secret Pond sites are among 25 strategies and projects for reducing phosphorous flow to Lake Wingra that were presented by Strand Associates at the October 17, 2013 steering team meeting. If all the projects were implemented it is estimated they would capture 761 pounds of total phosphorous.
The City’s plans to add aluminum sulfate to the Marion Dunn storm water pond in the Arboretum were reported on by this blog in earlier posts (click here for the original post in March, 2013 and click here for a follow-up post in June, 2013). The City’s plans are in response to federal and state mandates to develop a plan to reduce the total amount of it phosphorous discharges. Working with the Clean Lakes Alliance, the City and other partners in the Rock River Basin developed a plan to reduce the amount of phosphorous discharged by 50%. The U.S. Environmental Protection Agency (EPA) accepted the plan and the partners are now working to carry out its many moving parts.
A Concern With Phosphorus or Public Opinion?
According to the October 17, 2013 meeting notes, a recent draft study of Lake Wingra and its watershed conducted by the UW-Madison researchers calls into question the need for, and benefit to the Lake, of removing phosphorous at the Marion Dunn Pond site in the Arboretum. The draft “lake response model” which has not yet been released to the public, concludes that the main contributors of sediment and phosphorous to the Lake are: lake carp (80%); wind and waves (6%) and storm runoff (14%).
That the amount of phosphorous from storm water runoff going into the Arboretum pond is especially small was confirmed Madison staff engineer John Reimer, who was reported in an August 20, 2013 UW News Release as saying that ” . . . the neighborhood draining into the pond isn’t a particularly strong source of phosphorus.”
The UW News Release about the alum project went on, “Reimer doesn’t expect much noticeable change in Lake Wingra, because of the relatively small size of the pond’s watershed. His hope is for improvement of the pond water, a measure of the neighborhood’s comfort level with the alum system and an understanding of the feasibility of alum additions elsewhere in Madison.”
Alum Dosing Facilities Proposed Throughout Dane County
The City of Madison is not alone in its mission to reduce phosphorous. In fact, there are plans supported by the Clean Lakes Alliance to add several other Alum Dosing Facilities (ADF) sites across Madison and Dane County. The potential ADF sites were proposed by Strand Associates in a March, 2012 report to the Clean Lakes Alliance entitled Yahara Clean Implementation Plan. The 2012 Strand Report forms the technical basis of the “Yahara Clean Strategic Action Plan for Phosphorous Reduction”. Click here for a link to the Yahara Clean Strategic Action Plan for Phosphorous Reduction.
The other Madison and Dane County sites recommended by Strand Associates include:
- West Towne storm water pond
- Tiedeman Pond
- Pheasant Branch Creek (downstream of the Conservancy)
- Yahara River at Hwy 113
- Starkweather Creek
- Dorn Creek
- Six Mile Creek
- Yahara River at Tenney Park locks
One wonders why plans for the above aluminum sulfate dosing facilities (ADF) are already on the books, even before the Arboretum ADF project has begun, let alone before it has produced any results and data by which one could measure its feasibility, effectiveness, and the neighborhood’s response to it?