Aquatic Vegetation Removal

Aquatic plants are an integral part of the aquatic environment and serve as important habitats for aquatic organisms. They also improve water quality. However, due to eutrophication of water bodies, increased aquatic vegetation often needs to be mowed or otherwise removed to enhance recreational opportunities and landscape values.

Machine mowing or removal of aquatic vegetation should be reported 30 days in advance to the regional Centre for Economic Development, Transport, and the Environment (ELY Centre) as well as the owner of the water area. Extensive mowing may require a permit from the Regional State Administrative Agency. When planning extensive mowing, a thorough vegetation survey should be conducted at the mowing site. If mowing is planned in protected areas, it should be coordinated with the authorities.

Thinning denser plant growth can improve water flow and enhance the living conditions for fish and bird populations. Timing is crucial when it comes to mowing aquatic vegetation. The most effective time for mowing is around the transition between July and August. If multiple mowing sessions are planned, the first mowing should be done just before the plants bloom in late June, followed by subsequent mowings every 3-4 weeks. The mowing should be designed so that vegetation patches and open water alternate. Keep in mind that particularly at the mouths of ditches, aquatic vegetation also helps retain nutrient loads from the catchment area, preventing them from entering the lake.

The cut plant material must always be removed from the water. Decomposing plant debris consumes oxygen and releases nutrients into the water, which can promote algal growth. Floating masses of vegetation in water also cause aesthetic problems, hinder recreational use, and often drift to someone else’s shoreline.

A designated site must be allocated for the disposed plant material to prevent its re-entry into the water body. Alternatively, the plant debris can be composted.

To facilitate mowing in the following summer, it is possible to mow reeds from the ice surface. The mowed vegetation can be burned or composted.