The water-hyacinth is one the most troublesome and difficult to manage aquatic weeds. It is resilient, spreads quickly, and difficult to get rid of. Fortunately there exist a variety of different tools to deal with it. You may have heard of a lake weed cutter, but there are also different types of harvesters and drag lines that can be used. In addition, there are different methods of dealing with the waste and disposing of it in such a way as to make sure it can't spread again. Here is an overview of the techniques and methods involved in mechanical lake weed control.
A harvester is a specific type of lake weed cutter machine that not only cuts vegetation, but collects it and stores it on board so it can be transported to a disposal site. They are one of the best machines for dealing with weeds efficiently, and come in a variety of models with different cutting swath widths. In addition, a harvester needs to be able to haul multiple tons because an acre of water hyacinth can weigh up to 200 tons.
A lake weed cutter specializes in the removal of surface vegetation, and is much more nimble compared to a harvester. In places where the area is obstructed by low hanging trees or bridges a cutter can fit easily. They also operate well in shallow water. After the weeds are cut they are then collected immediately for disposal or allowed to drift downstream or to the shoreline.
If disposing and transporting the sheer mass of cut weeds is too difficult or undesirable, it is possible to use a shredder. Aptly named, the machine shreds surface weeds finely enough that they sink to the bottom and decompose. While they are highly effective at clearing floating islands and tussocks, shredders can have adverse impacts and are not recommended under certain conditions. They cannot be selective about plants or animals in their way, and have disruptive effects if done during fish bedding or wildlife nesting periods.
For weeds that collect on the lake bed or far beneath the surface, a drag line is used. It works exactly like it sounds, dragging a large shovel that hauls plants to a set collection point. One variation of a dragline, called a track hoe, uses a claw-like shovel that can dig into the lake bed and pull weeds that a normal shovel cannot. In addition, draglines and track hoes can be mounted on barges to enable hauling to a separate disposal site.
Disposing of a large mass of harvested weeds is a tall order, especially when it weighs multiple tons and is heavily soaked. If wet material needs to be transported on the highway, a resource manager will usually use sealed dump trucks in order to prevent spillage. It can be spread out and dried before transportation, but this is a time consuming process and can be undesirable depending on the circumstances. Whatever option for disposal is chosen, multiple permits are required on both the state and federal level.
While there exists a variety of machinery that can be used in mechanical weed control, there are really only two stages. The first is removal by the use of a lake weed cutter or harvester, and the second is disposal. If done correctly, mechanical control can provide a clean alternative to the use of pesticides and chemical solutions.