In 2009, MCWD water quality staff monitored for veligers, the larval stage of zebra mussels, in Lake Minnetonka. Veligers are microscopic and are not visible to the human eye in a lake or stream.

In 2010, MCWD water quality staff began monitoring for adult zebra mussels in Lake Minnetonka and in the 11 upper watershed lakes. Samplers were placed in late June 2010 and inspected in late July. No zebra mussels were found. A second inspection occurred in August 2010. Zebra mussels were found on samplers at Grays Bay, Wayzata Bay and Browns Bay samplers during the August inspection. The samplers in the upper watershed lakes were zebra mussel free. All the samplers were pulled from the lakes in September. The map below shows the bays on Lake Minnetonka and the Upper Watershed lakes where samplers were placed to monitor for zebra mussel presence.

A fish survey was conducted by Blue Water Science for MCWD on October 20-23, 2009 at four sites within the 22 mile Minnehaha Creek corridor.  The four sites surveyed were Grays Bay Pool, Meadowbrook Lake, Utley Pool, and then Lake Hiawatha.

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 were stabilized in summer 2009. 

The water conditions in 22 out of 26 Lake Minnetonka bays that were assessed in this study have conditions that can support moderate to optimal zebra mussel growth based on high calcium concentrations (used for shell growth) and moderate chlorophyll concentrations, which provide a suitable food source from algae. The lake bottom conditions (substrate) are dominated by sand out to the mudline, where sediments then transition to muck. This is not optimal for zebra mussels but will support moderate growth.

Bathymetry is the process of mapping the depths of a body of water. The data collected can be compiled into a topographic map or used in a number of other ways to help the Minnehaha Creek Watershed District chart water quality or other changes to a water body. Mapping has been completed at the following locations.