DREDGING UPDATES

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Hello, I’m excited to be your new chair of the ESR (Ecosystem Restoration) Committee, otherwise known as the Dredging Committee. I’d Like to thank Paul Kling for his many years of service as the Chair of this committee and all of the work that he and this committee have done since 2003. Before I talk about what we are doing right now and in the future, there’s so much history and information that is crucial to be aware of in order to have an understanding of what has already been done and what needs to happen in order to proceed with a full-blown dredging project. The committee has been working towards dredging since the late 2000s – securing a permanent disposal site, dewatering sites, sediment sampling, researching and connecting with the right people at the DNR. The hurdle that has consistently held us back is the level of nitrogen in our muck, which is at approximately 15 parts per million and the DNR will not allow us to dump the sediment on any land if it exceeds 9.7 ppm. We must show from a large enough muck sample size that the nitrogen level will naturally dissipate to a consistent level of 5 ppm after the water has been removed. The other issue we have faced is the cost of getting these samples, dewatering, and testing in a manner that is acceptable to the DNR. There are many grants given out by the DNR and through government programs every year, but for the most part that money is given for projects that prevent or stop erosion, not for removal of sediment that is already in lakes or rivers. That brings us to where we are now – our current proposal for a test pilot dredging project which would take place throughout the entire boating season of 2021 consists of constructing A 2700 yd.³ holding pond on the DNR land north of Conservancy Bay where 400 cubic yards of dredged sediment would go through the process of denitrification in order to achieve nitrogen and ammonia levels acceptable by the State of Wisconsin. Of Course there’s a great deal of design, permitting, and testing is that goes into this process. Should the nitrogen and ammonia levels be acceptable by the DNR, the plan would be to then propose to our riparian owners the dredging 500,000 yd.³ of sediment/muck from the waterway. If all goes well the full-scale dredging project would begin in 2022. Financing, grants, donations, and riparian owner costs for that project will all be tasks of the committee to work on over the next twelve months.

Grant Horn, FMP

Return to Navigation Access and Hydraulic Management 

Ecosystem Restoration Dredging Project Update

September 24, 2019 – The DNR mandated a 2-year pilot study to include proof of concept to dredge and dewater 7,000 cubic yards removed from conservancy bay in year 1, with land spreading in year 2. This is basically a science project to see if we can do it. Information collected during this pilot study would determine the feasibility of the process and if successful, form the basis for engineering, plans, permits, bidding, and funding needed for the removal and disposal of the remaining material. Bidding for the pilot project was done in September. The one bid we received was for $1,999,750. Project management, contingencies and overhead push the budget to $2,325,000. The committee is not recommending proceeding with this proposal. Because this portion of the project did not go as expected, the pilot project will not happen as mandated by the DNR. Our efforts will shift from the anticipated contract negotiations to streamlining the project to eliminate unnecessary expenses and bring it back at a reasonable cost. The DNR will have to come up with a simpler, cheaper way to do the pilot (science) project to determine the feasibility of land spreading.

Annual Report

DNR Small Scale Dredging Permit

Updated May 26, 2019 – There is a small scale dredging general permit available from the DNR for riparian land owners for the navigational dredging of man-made impoundments (GP20), that was issued on September 27, 2018. It allows for the removal of up to 50 cubic yards of material per year from a waterway for the purposes of navigation. There are specific eligibility standards as well as a self-certification that an applicant is required to complete as part of the process which addresses the type of material being dredged.

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