Shallow Lakes

 

The Shingle Creek Watershed Management Commission has developed a Water Quality Plan and Capital Improvement Program to address water quality concerns in the Shingle Creek Watershed. 

 

In support of these efforts, the State of Minnesota has provided funds for development of TMDLs for impaired waters in the Shingle Creek watershed, including excess nutrient impairments in lakes as well as chloride in Shingle Creek.  The results of the TMDLs will provide the scientific understanding and framework for selecting capital projects and management activities designed to bring the impaired waters into compliance with State water quality standards. 

 

However, not all of the projects will be capital in nature; rather, many of the activities will involve management of the natural systems for water quality, especially in shallow lakes. 

 

What is a Shallow Lake?  Generally, any lake that does not stay stratified throughout the summer season is a shallow lake.  MPCA defines a shallow lake as lakes with a maximum depth of 15 feet or less, or with 80% or more of the lake area shallow enough to support emergent and submerged rooted aquatic plants.

 

Shallow lakes have received considerable attention over the last decade as demonstrating unique characteristics from their deeper counterparts.  A healthy shallow lake has clear water and is dominated by native aquatic plants that provide habitat for fish and zooplankton.  Degraded shallow lakes demonstrate turbid waters dominated by algae.  Shallow lakes do not respond as readily to nutrient reductions, largely because of sediment and nutrient re-suspension from wind action, carp activity, and invasive nuisance plant species such as curly leaf pondweed. 

 

Understanding the ecology of shallow lakes is critical to developing TMDLs that are both appropriate and effective for restoring shallow lakes.  Recent studies suggest that restoration of a shallow lake may require more than simply reducing nutrient loads, but also may require biomanipulation, or changing the biological structure of the lake.  Either way, a healthy shallow lake will have a significant aquatic plant community that is often perceived as an inhibitor to recreation. 

 

Below are PDF versions of PowerPoint presentations given by Joe Bischoff of Wenck Associates regarding Shallow Lakes:

 

Shingle Creek Lake Nutrient TMDLs (February 2006)

Shingle Creek Lake Nutrient TMDLs (March 2006)

Shingle Creek Chloride TMDL (March 2006)