sedimentation – Aquarius-Systems

Aquarius Harvesters Support Hydropower in Malawi

Tue, 19 Dec 2023 21:18:51 +0000

Nearly 95% of Malawi’s power is generated by hydropower on the Shire River, but sedimentation and weed infestation hinder efficiency. Today Millennium Challenge Corp Principal Deputy Vice President Kyeh Kim joined U.S. Embassy Lilongwe Ambassador Virginia Palmer to celebrate the commissioning and hand-over of two new weed harvesters by MCA-Malawi to the Electricity Generation Company Malawi Limited. These harvesters, manufactured and supplied by Aquarius Systems in Wisconsin, will help to improve the generation capacity of Malawi’s hydro-power plants.

Herbicide to Treat Elodea Kills Native Aquatic Vegetation

Wed, 29 Dec 2021 21:49:49 +0000

Elodea is a plant commonly found in aquariums that, if released in the wild, will dominate certain lake or river habitats, choking out native vegetation and altering the food web at all levels.

It increases sedimentation rate, allowing more sediment to settle out of the water. And it can decrease the dissolved oxygen concentration in the water because it is growing so rapidly and using up all of that oxygen. But it also just displaces native aquatic plants, which are good forage for a variety of waterfowl species.

In addition, elodea can ruin the clear-water habitat needed by grayling and spawning salmon, and give an advantage to ambush predators like northern pike.

Applications of aquatic herbicide fluridone have appeared to have worked, and there is no elodea visible in Lake Hood (Alaska) now, but the herbicides killed most of the other plant life in Lake Hood as well.

What Is Aquatic Weed Harvesting and What Results Should You Expect

Thu, 16 Dec 2021 22:21:51 +0000

What is Harvesting?

Operational Considerations for your lake.

Expected Results from a Weed Harvesting Program.

Most aquatic plant harvesting systems will cut and remove submersed plants to a depth of five or six feet. As this biomass is removed from the lake, the water is immediately ready for use and there are no restrictions on use of the area that might be experienced with herbicide or some biological control treatments.

Removal of this biomass prevents its eventual decay and settling to the bottom, helping to reduce sedimentation in the lake. There is some nutrient removal with harvesting too, as the nitrogen and phosphorous that is bound up in the plant exits the water body. Harvesting is usually not lethal, leaving behind an oxygen and possibly habitat producing plant, which may be desirable in some situations.

Many harvester managers have witnessed a reduction in nuisance plant growth after a few years of repeated harvesting. The plants showed signs of stress and came back thinner, lower growing, and more scattered than before. In some cases desirable plants were able to out compete the nuisance plant growth.

Kitsap Lake Uses Phoslock and Weed Harvesting to Reduce Algae Blooms

Fri, 05 Nov 2021 20:43:44 +0000

It’s a familiar sight to residents living on the shores of Kitsap Lake in Washington: each summer, around the beginning of June, a bright green algae begins to creep across the water. These blooms can be harmful to people and pets and have forced closures of Kitsap Lake and its beaches every year for the last five years

This year, a different approach was taken. Starting in June, contractors sprayed the lake with a compound called Phoslock, which helps remove phosphorous from the water. Then an aquatic vegetation harvester trawled across the south end of the lake, chopping down underwater weeds and hauling them to shore. The goal – to remove as much phosphorous from the lake as possible.

Sediment in the lake – from decomposing weeds, lawn fertilizer, stormwater runoff – produces excess phosphorous, which acts as fuel for algae blooms. Relatively few outflow points on the lake result in a slow turnover rate of water and poor nutrient cycling, according to a 2011 Kitsap Public Health District report.

The harvester removes plant life and opens the water up to circulation, allowing for the water to mix and more sunlight to reach the deepest parts of the lake

Benefits of Weed Harvesting for Water Quality and Nutrient Removal

Thu, 04 Nov 2021 18:04:26 +0000

Benefits of Weed Harvesting
Dr. Stephen J. Souza
Lake Hopatcong Commission Environmental Consultant

One of the most obvious management activities of the Lake Hopatcong Commission is the weed harvesting program. Some may view this as a simple “mowing” of the Lake. However, much more is accomplished than simply opening boating lanes and improving swimming. The harvested weeds represent a significant amount of biomass, and associated nutrients, that if not removed would otherwise add to the siltation of the Lake and contribute to its future eutrophication.

In its first three years of operation, because of the concerted, coordinated efforts of the Lake Hopatcong Commission, over nine million pounds of weeds were removed from the Lake. This could not have been accomplished without the state-of-art harvesting equipment and the dedicated staff of the Lake Hopatcong Commission. From a water quality perspective, the removal of this much weed mass is very important. The phosphorus associated with these weeds is roughly 1,200 pounds.

Although this may not sound like a lot, a single pound of phosphorus can support over 1,100 pounds of algae. Thus, through the weed harvesting efforts of the Lake Hopatcong Commission in New Jersey, phosphorus, that otherwise would be recycled through the Lake and fuel future weed and algae growth, is removed. This has a direct positive benefit to the long-term water quality of the Lake and the control of the Lake’s eutrophication. As such, the weed harvesting program contributes in more than the obvious way in the revitalization of the lake and the improvement of its water quality.