Emergent Vegetation Plays an Important Role in Lake Health

Emergent aquatic plants such as cattails, bulrushes, and sedges grow within the shallow margins, or "littoral zone", of most lakes in Minnesota. These plants improve water clarity as their roots stabilize the lakebed and take in nutrients. Their stems and leaves provide habitat both above and below the water, and they protect shorelines against the forces of wave action. Emergent plants often grow alongside other aquatic vegetation, collectively creating diverse habitat essential to lake health. 

Any Destruction of Emergent Vegetation Requires a Permit in Minnesota - Lakeshore owners often wish to remove emergent vegetation to improve their water access. Given the important role emergent vegetation plays in lakes, any removal of aquatic emergent plants requires a permit from the Department of Natural Resources. The permit process connects landowners with professionals to ensure that the extent of vegetation removal (and methods used to achieve it) minimize impacts to the lake. Learn more about aquatic plant regulations HERE.

When Does Emergent Vegetation Become Problematic? - Non-native species such as narrow-leaf and hybrid cattails often grow in dense monocultures that can outcompete native species. Habitat quality and recreation can be quickly reduced as these species spread across large areas of shallow water, but management efforts to remove them are often challenging and costly. When occurring in small clusters, these plants can still provide water quality benefits along shorelines where native emergent plants are absent. In either circumstance, any removal of emergent plants - even if non-native -  requires a permit.


Expectations for Living on a Lake - Aquatic vegetation is a natural and important part of lake and wetland systems. The abundance and types of plants present are largely driven by water depth and clarity. Many lakes in the north metro are shallow (less than 15 ft. deep) or are technically open-water wetlands. When paired with good water quality allowing sunlight to reach the bottom, these lakes usually contain abundant vegetation throughout. The alternative is poor water quality from disturbances such as excessive nutrients, which can  reduce aquatic vegetation and the fish and wildlife that depend on it. Learn more about shallow lake vegetation from this StoryMap produced by the Rice Creek Watershed District: Aquatic Plants: Guardians of our Shallow Lakes.

For more information contact Breanna Keith, Water Resource Specialist, at This email address is being protected from spambots. You need JavaScript enabled to view it..

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Shallow Lakes Don’t “Stink”

Okay – the decay of organic materials in oxygen-poor shallow waters doesn't smell great. While this can worsen when nutrient pollution triggers excess algae growth, it is an otherwise natural process. Odor is a small price to pay for the vast benefits we receive from shallow lakes and wetlands; they retain floodwater and pollutants present in runoff, recharge groundwater, and provide fish and wildlife habitat that supports bountiful opportunities for hunting, fishing, bird-watching, and other outdoor recreation.

For many, the word "lake" triggers a vision of clear and deep water ideal for swimming and boating. However, over 5,000 of Minnesota's lakes larger than 50 acres are actually shallow lakes that are less than 15 feet deep and dominated by wetland habitat. In shallow lakes, sunlight reaching the lakebed, combined with readily available nutrients, increases the growth of aquatic plants. Shallow water also allows for more abundant emergent vegetation such as bulrush and  cattails, which can extend well beyond the shoreline and even become dominant, especially during periods of drought. Mucky lakebed conditions are produced as large quantities of organic materials die, settle to the bottom, and decompose over time.

Shallow lakes can exist in one of two states: clear or turbid. Clear shallow lakes are dominated by submerged vegetation, which often grows densely and can reach the water's surface. These aquatic plants are a source of food and habitat for fish and wildlife such as amphibians, waterfowl, and invertebrates at the base of both aquatic and terrestrial food webs. On the flip side, turbid shallow lakes are dominated by algae, which clouds up the water and restricts the growth of submerged aquatic vegetation. Turbid lakes typically support fewer fish and wildlife due to the lack of habitat provided by aquatic plants. 

Depiction of a clear, plant-dominated shallow lake versus a turbid, algae- dominated shallow lake. Image credit: Martin Scheffer, 2001.

Many shallow lakes are impacted by human activity, particularly those that are on the receiving end of stormwater and agricultural drainage networks. However, even the most impacted shallow lakes  are still valuable and can surprise us, as the recent plant inventory of Highland Lake in Columbia Heights proved when an uncommon pondweed species was found.

Check out MNDNR Shallow Lakes Program for more information about shallow lakes. Also, here's a great video produced by Ramsey- Washington Metro Watershed District about Minnesota's shallow lakes.

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The Oxbows of the Rum River

The Rum River in Isanti County


When allowed to wander freely, rivers flowing throughout a gently sloped landscape form a snakelike meandering path. This occurs as the fastest moving waters erode banks along the outer bends, and slower moving waters deposit sediment along the inner bends. Over many years, these processes cause the meanders to curve more intensely, causing the river to eventually loop back onto itself and cut a straight path through the narrow slice of land that remains. Now disconnected from the river, the C-shaped meander scar is called an oxbow.

To watch these processes in action, check out this video: Why Do Rivers Curve?

A quick glance at aerial imagery reveals numerous oxbow wetlands alongside the Rum River. They are rich in plant and animal life, serving as a "nursery" for fish, invertebrates, and amphibians in their early life stages while providing habitat for countless migratory bird species. These oxbows also improve water quality and reduce flooding by capturing water and the contaminants it carries following large storm events.

To learn more about the importance of oxbow wetlands and their utility in water resource management, read the Nature Conservancy's article on the topic here: What is an Oxbow? 

Aerial photos of a Rum River meander in Ramsey captured in 1991, 2003, and 2021 (left-right). Notice the increasingly thin sliver of land at the base of the curve, which eventually transitions to a river cut-through.
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