Introduction

The Long Lake Creek Subwatershed is a 12.8-square mile drainage basin which outlets from Long Lake Creek to Tanager Lake on Lake Minnetonka.  The subwatershed is bisected by the waterbody of Long Lake which accommodates approximately 9.8-square miles (76%) of the total subwatershed drainage area.  Long Lake Creek serves as the outlet for Long Lake and primary conveyance of watershed drainage to Lake Minnetonka.

The 2007 MCWD Comprehensive Plan identifies an annual phosphorus concentration goal of 70 mg/L for Tanager Lake.  It is anticipated that Tanager Lake will be placed on the State Impaired Waters List in the future because of its poor water quality.  In order to meet loading goals, MCWD will need to reduce loading to the bay by 923 lbs. of phosphorus per year.  Opportunities to reduce external loads to Tanager include improving the quality of water from Long Lake, two proposed stormwater ponds along Long Lake Creek and a wetland restoration in a drainage area flowing to Long Lake Creek (the current project).  MCWD also has a broader interest in enhancing the corridor connection and quality of resources within the creek corridor flowing from Lake Minnetonka to Long Lake.

The MCWD Comprehensive Water Resources Management Plan identifies three wetland basins with moderate to high restoration potential along the Long Lake Creek Corridor.  Through MCWD Staff discussions with the City of Orono, a wetland complex was identified on property owned and operated by the City as a public golf course.  While the wetland area lies outside of the identified restorable basins, the restored wetland would be positioned directly upstream of the creek and riparian wetland areas.  A restoration project would enhance the resources on the project site and serve as a water quality improvement, providing bioretention and treatment to stormwater runoff from the golf course and surrounding drainage area prior to discharge downstream to the creek.  Given the public nature of the site, additional opportunities would be available for public education and outreach activities.  A graphic of the restoration site is included below:

Wetland Siting

Identification of geographic location on the property and size of restored wetland that maximizes external load reduction and where hydrology provides for adequate surface and/or groundwater flows to maintain wetland conditions in existing or altered topography.  Adequate technical analysis of runoff rate, path, timing of inflow/outflow, duration and frequency of ponding and saturation of existing and proposed conditions is required.  Wetland sites could either build/expand upon existing wetlands or be created in locations on site where conditions permit. Proximity to important natural resources within the subwatershed must be considered and high quality upland natural areas must not be negatively affected as a result of restoration of wetland features. 

Wetland Type

Wetland Type and Classification must be integrated into the other important natural resources planning throughout the site.  Considerations of vegetation species and wetland function must be evaluated in order to optimize the value of existing wetlands on site as well as the restored features.  Proposed restored wetlands on site should be representative of natural or historic wetland features within the area and should complement the vegetation types of high quality upland features on the site. Wetland vegetation must be selected relative to the hydrologic considerations cited above in analysis of wetland siting.

Upland Resources

Wetland buffers adjacent to restoration areas should be free and clear of exotic and invasive species and generally consistent with other natural features on the site.  Evaluation of existing and proposed site conditions must take into account the establishment and maintenance of buffer areas as well as restoration areas.  This effort must also include thoughtful considerations of existing site use and integrating sensitive resource features into the public use of the site. 

Feasibility Study Report

Further questions and concerns can be addressed by contacting MCWD Planner Michael Wyatt at (952)471-0590 ext. 204 or mwyatt@minnehahacreek.org.