Summer Vegetation (2024)

During the summer, there are a few concerns people may have about our lakes and vegetation. The first concern is the algal growth. The two main forms of algae we have are filamentous and planktonic. Filamentous algae is the long stringy algae that you can hold in your hand and may resemble a clump of hair. This algae usually grows on the lake bottom. Generally, filamentous algae grow early in the season, between March and May. Planktonic algae, also called phytoplankton, is microscopic and is what gives the lake water a greenish color. Once phytoplankton establishes itself in the water column, it shades out the filamentous algae. Phytoplankton is important as it serves as a food base for microscopic animals, which in turn, are food for juvenile fish. We have a well established water monitoring and fertilization program to keep the phytoplankton in a balance such that the water is neither too clear nor too murky.

The second concern is rooted vegetation. The two main types of rooted vegetation in our lakes are emergent and submerged. Emergent vegetation is rooted on the lake bottom and grow out of the water’s surface. The most abundant emergent plant in Bella Vista is water willow. This plant provides a great refuge for juvenile fish. However, it may grow into areas that inhibit boat launches or swimming areas. In this case, the best course of action is to pull the vegetation by hand. This leaves a clean area that is immediately usable. Using an herbicide will kill the plant, but the stiff stems remain. Submerged vegetation is rooted on the lake bottom but does not grow out of the water. Historically, the main submerged plants were two species of naiad, which were also great refuge for fish. However, an invasion of the parrot’s feather (Myriophyllum aquaticum, AKA watermilfoil) necessitated the heavy use of aquatic herbicides and grass carp. With the invasive plant species gone (to our knowledge), we are harvesting grass carp to encourage the re-growth of native submerged vegetation and are looking into ways to be proactive in bringing native vegetation back. When that occurs, we will continue to be willing to remove aquatic plants where they impede lake use.

Water willow; vegetation has been killed with herbicide, but the stem remains