Gray's Bay

The Minnehaha Creek Watershed District is in the process of revising rules, including Rule F: Shoreline Protection. In order to better promote water quality within the District, this rule will promote natural landscaping and stabilization along shorelines to a greater degree than the existing rule. The Lake Minnetonka Shoreline Restoration Project compliments this change by classifying the shoreline around the lake according to likelihood to erode, and by creating five demonstration sites of natural stabilization (bioengineering) to show homeowners and contractors how to work with a variety of shoreline conditions. The first of the five demonstration sites was completed in 2005 at the Headwaters of Minnehaha Creek at Grays Bay. The remaining four sites will be stabilized summer of 2009.

Gray's Bay

Project Completed Fall 2009.

Demonstration Sites - Installed Summer 2009

Excelsior Point, Excelsior

Centerview Park, Mound

Tanager Bridge, Orono

Tonka Bay City Hall, Tonka Bay

Background Information

The Minnehaha Creek Watershed District is in the process of revising rules, including Rule F: Shoreline Protection. In order to better promote water quality within the District, this rule will promote natural landscaping and stabilization along shorelines to a greater degree than the existing rule. The Lake Minnetonka Shoreline Stabilization Project compliments this change by classifying the shoreline around the lake according to likelihood to erode, and by creating five demonstration sites of natural stabilization (bioengineering) to show homeowners and contractors how to work with a variety of shoreline conditions.

The classification portion of this project accounts for three factors.

• Fetch – The distance from the far end of the lake to the point on the shore being classified, as measured along summer prevailing winds. Summer prevailing winds around Lake Minnetonka are generally southeast to northwest, so fetch on the southeastern shoreline is usually zero. The fetch is highest across large bays on the northwest shore. Higher fetch indicates higher erosive potential.
• Slope – The pitch of the land immediately adjacent to the shoreline. Greater slope indicates higher erosive potential.
• Soils – Soils are classified according to their erodibility by the USDA NRCS, among others. Sandier, less cohesive soils indicate higher erosive potential than clay and more cohesive soils.

MCWD combined each of these factors to classify all the shoreline of Lake Minnetonka into four categories – High, Potential, Low, and Sensitive.“ High” shoreline has the greatest potential for erosion, “Low” has the lowest, and “Potential” is indeterminate, meaning there were not enough data to classify it. “Sensitive” shoreline indicates the presence of a wetland.

The Headwaters of the Minnehaha Creek at Grays Bay already serves as one of the five demonstration sites.MCWD will construct the other four sites on a variety of site conditions, ideally one on each of the four classification categories. These publicly accessible sites will serve as examples to homeowners and contractors who wish to construct bioengineered solutions to erosion problems on shorelines. They will demonstrate a variety of techniques, from mixed hard and soft armoring (interspersing vegetation with rock or other durable shoreline protection) to pure vegetative solutions, with plants running from the waterline up several feet out of the water. MCWD will be directing anyone who asks about soft or green shoreline stabilization to these sites, and will encourage local municipalities to do the same.