Dredging Impacts Study
Bay-Lake Region, WI

Grantee: Bay-Lake Regional Planning Commission
Basin Program Funds: $14,915
Non-federal Funds: $4,971
Project Duration: 09/1996 - 07/1998
Status: complete

Problem Statement
Each year thousands of cubic yards of silt and sediments are dredged from the many small commercial harbor and marina facilities located within the Wisconsin Bay-Lake region. It appears that the need to dredge is perpetual and that the environmental and economic costs of dredging are enormous.

Before channel treatment

The Wisconsin Bay-Lake region contains approximately 450 miles of shoreline, encompasses three designated Areas of Concern (Marinette, Green Bay, and Sheboygan), and includes 185 units of local government. A majority of these governmental units are located in watersheds that drain to Green Bay or Lake Michigan. Dredging has become a major issue in the region, as increasing amounts of sediment are transported through these watersheds and deposited into the many harbors and marina facilities located in the Bay-Lake region.

This study assessed the extent and cost of maintenance dredging of the more than 70 harbors and marinas in the Bay-Lake region, and the impact of these costs on the communities. The cost assessment developed data that was used to determine the economic impact of dredging. These data may, in turn, be applied as a basis to influence public opinion and policy regarding the need to enact and enforce comprehensive soil erosion and sedimentation controls, as well as the implement best management practices (BMPs) that will reduce the frequency and need for dredging.

The Bay-Lake Regional Planning Commission undertook an inventory of dredging activities within the Commission's coastal areas. The inventory included all dredging permits that had been issued within the study area by the Wisconsin Department of Natural Resources and the U.S. Army Corps of Engineers. The inventory was used to create a database containing information on dredging material and dredging costs. The material component of the database included a characterization of the materials dredged, quantification of the amount dredged and frequency of dredging, and a review of disposal options. The cost component included the engineering costs, permit and enforcement costs, dredging costs, and disposal costs. Investigators created a database using existing data on current and historic dredging activities in the region.

After the database was completed, investigators undertook an economic impact study. Data relative to the cost of upland streambank protection and policy and planning development, both general in scope and specific to the watersheds located within the Bay-Lake region, was compiled and analyzed. The cost to enact and enforce comprehensive soil erosion and sediment controls, and to implement best management practices was determined. The direct and indirect economic benefits of harbor facilities -- the Manitowoc and Kewaumee harbors -- was determined and analyzed by utilizing past planning documents.

After channel treatment

The Bay-Lake Regional Planning Commission completed An Inventory & Assessment of Dredging in the Bay-Lake Region, which was distributed to the Technical Review Committee of the Bay-Lake Regional Harbor Council. The information will also be disseminated through newsletter articles and reports to appropriate regional commissions and committees.

Contact: Martin W. Holden, (920) 448-2820


Great Lakes Commission des Grands Lacs.  2805 S. Industrial Highway, Suite 100.  Ann Arbor, MI  48104-6791.  phone: 734/971.9135.  fax: 734/971-9150.  projects.glc.org. Join the Friends of the Great Lakes GLIN Partner