U of M wordmark
website banner
A collaboration of the University of Minnesota's Remote Sensing and Geospatial Analysis Laboratory and Water Resources Center

navigation edge

 
website logo
 

 

 
   

Mapping Aquatic Vegetation

While lakes are well known for their recreational and aesthetic value, traditionally, society has considered wetlands as nuisances and problems that need to be cleaned up. Statewide, Minnesota has drained over half of the original wetlands (around 4.5 million hectares) for agricultural and development purposes, and many of the remaining wetlands are degraded.

A frequent cause of wetland degradation is increased storm water discharge resulting from changes such as increases in impervious surface area or installation of storm water systems in urban and suburban areas, as well as tiling and ditching systems in agricultural areas.  Changes in hydrology affect the water quality and quantity, and may severely impact the function of wetlands. When too many wetland plants are removed or impacted, water quality, wildlife, and fish populations can suffer. These plants are important because they help protect water quality, provide habitat for fish and wildlife, and provide economic and aesthetic opportunities.

aquatic veg map
   

Aquatic plants in lakes and wetlands are beginning to be recognized as important ecosystem features in need of protection. As a result of this greater appreciation for aquatic plants in wetland and lake environments, aquatic plant surveys and assessments are becoming part of routine monitoring efforts conducted by consultants, citizen groups, and state and local agencies. Aquatic plant diversity and abundance are important indicators of lake or wetland health, but accurate maps and data are difficult to acquire. Because ground-based mapping requires much time and human resources, only a small fraction of this large resource has been mapped by natural resource agencies.

The objective of our research is to evaluate using high-resolution satellite imagery to map and classify aquatic plant groups by resource management agencies. To date, we have evaluated the two forms of commercially available high resolution satellite data: IKONOS and QuickBird. To evaluate IKONOS imagery, we conducted an aquatic plant survey on Swan Lake in Nicollet County, Minnesota.

Swan Lake is a large (>3600 ha), “type-4” wetland meaning it is classed as a deep fresh water marsh with standing water and abundant emergent aquatic vegetation. To evaluate the use of QuickBird imagery for assessment of submergent aquatic plants in open water lakes, we conducted aquatic plant surveys of two lakes south of Lake Minnetonka.

Back to the top
Back to the top