Finding the Right Balance of Aquatic Vegetation

Aquatic plants, whether invasive or native, can be described as either a mess or a resource.  Natural plant growth covers 20 – 40% of the water and includes a diversity of plants.   However, invasive plants such as Eurasian watermilfoil, hydrilla and water hyacinth quickly take over a lake covering 60% and sometimes 100% of the surface water. 

Tennessee Valley Authority is a corporate agency of the United States that provides electricity for business customers and local power distributors serving 9 million people in parts of seven southeastern states.  TVA maintains 29 power generating dams with reservoirs in addition to another 17 non-power dams that are used solely for flood control and recreation.  TVA is certainly no stranger to invasive species.

Management of invasive plants is necessary to keep the right balance between the diversity and density of plant growth. TVA has been managing invasive plants since the late 1950s, when it began to address the problem of milfoil. In the 1960s, TVA began to use helicopters to chemically eradicate weeds.

One of TVA’s management options is prevention. In some communities the spread of invasive plants have been prevented by quarantining boats on specific bodies of water to prevent transfer.

• Physical management including the use of mechanical weed harvesters or barriers such as plastic to prevent sunlight from reaching the plants.

• Biological methods include the introduction of grass carp to eat the weeds.

• Chemical management includes the use of herbicides to kill the weeds.

• Mother Nature is perhaps the most effective force in managing invasive plant growth. Many of the invasive weeds are susceptible to cold. The past few mild winters in the region might explain the increase of invasive plants on TVA waters.  

In a recent workshop on the issue of aquatic invasive species, over 200 people turned out to not only voice their concerns on the growing weed problem, but to learn how they can help in the management.


Learn More

Wisconsin’s Phosphorus Rule is Approved

In December, 2010 Wisconsin became the first state in the country to adopt phosphorus water quality standards for lakes, reservoirs, rivers, and streams.  The Environmental Protection Agency has approved Wisconsin’s revised rule as a revision to Wisconsin’s federally-approved National Pollutant Discharge Elimination System program under the Clean Water Act.

Under the new rules DNR determines the phosphorus discharge limits based on the condition and quality of a watershed.  Limits can vary depending on whether a waterway is already impaired by phosphorus, among other factors.

Already this summer, many Wisconsin lakes are experiencing algae blooms and excessive aquatic plant growth, both of which are fueled by phosphorus pollution.  The excess nutrients increase the populations of algae, which can multiply in waterways particularly when the water is warm and the weather is calm. 

Algae is typically not harmful to humans, however, some species produce toxins which can affect people by causing illness so swimming and other water activities should be avoided in areas where algal is present.  Blue-green algae blooms have been blamed for the deaths of many dogs which are more vulnerable because they often drink the contaminated water or swallow the algae as they clean their coats. 

Almost 175 Wisconsin waters are officially listed as “impaired” due to excessive phosphorus levels.  The new rules will help clean up those lakes and protect the others.  The new rule is in addition to a smaller effort from 2009 which restricted the sale of fertilizers containing phosphorus and banned the sale of dishwasher detergents with phosphorus.

Phragmites: Big Grass - Big Problem

A fairly dry winter with very little snowfall plus near drought like conditions this summer has lead to even more aquatic plants.  Another invasive species is quickly filling in exposed lake beds which are occurring due to historic low water levels.  Phragmites, the Common Reed, is a large perennial grass that can grow up to 20 feet tall, not only blocking shoreline views, but it reduces habitats for a variety of animals and competes with native plants for limited resources including habitat, food, and light.

Phragmites is found on every continent except Antarctica.  This colonial plant is capable of forming large stands or colonies arising from one or a few seeds or plant pieces.  These colonies form along the margins of streams and in marshes and ditches.  They form in brackish water and in mucky moist soil of exposed lakebed and coastal wetlands.  It will grow in damp ground, in standing water up to three feet deep, and even as a floating mat. 

The extensive reed beds can spread at sixteen feet or more per year by horizontal runners, which put down strong, deep roots at regular intervals.  The stems grow from six feet to twenty feet tall, with thick feathery plumes of seeds.  The tallest Phragmites plants are common in areas with hot summers and fertile growing conditions.  Eradication of Phragmites is not likely once it successfully invades an area, but with proper control methods and annual maintenance, native plant populations can be reestablished, wildlife and wetland habitat improved, and recreational opportunities restored.

Phragmites is a very aggressive plant and outcompetes nearby vegetation for limited resources including habitat, food, and light.  It grows so tall and the thick feathery plumes shade out native vegetation and makes coastal shorelines and wetlands unfit for wildlife.  One study has determined that the plants growth have reduced suitable nesting habitat for several species of turtles by affecting nest temperature.

Control of Phragmites is more easily achieved in areas where growing seasons are short and plant growth is less vigorous.  Control methods include spraying herbicides, mowing, discing, bulldozing, crushing, shading, dredging, flooding, draining, burning, and grazing; although a combination of treatments is most effective.  After successful treatment, native plants will once again become established in these areas.

 The Aquarius Systems Swamp Devil can easily chop through the thick Phragmites.  This heavy duty shredder effortlessly plows through the stubborn growth while carving through the subsoil creating an open water channel up to three feet deep and eight feet wide.  An aquatic weed harvester can then follow behind collecting the chopped vegetation for disposal.  The Swamp Devil easily maneuvers in shallow environments such as wetlands and marshy aquatic areas. 

While not specifically designed for Phragmites removal one of Aquarius Systems customers has achieved success in reclaiming a pond from the over abundance of Phragmites.  An EH-220, one of our smaller aquatic weed harvesters, ran for six hours per day for six weeks to clear a 20 acre pond of Phragmites and other aquatic invasive species. 

 

Watch the Swamp Devil in Action

Read more about the EH-220 versus phragmites 

Dam Controversy: Remaking the Mekong

Located in Southeast Asia, the Mekong is the 7^th longest river in Asia and the Mekong basin is one of the richest areas of biodiversity in the world which includes 20,000 plant species, 430 mammals, 1,200 birds, 800 reptiles and amphibians, and over 850 fish species.  


This 646 pound Mekong giant catfish is a world record for
largest freshwater fish ever found.


The Mekong is home to some very large fish such as the giant river carp, which can grow up to 5 feet long and weigh 150 pounds; the Mekong Freshwater Stingray, which have a wingspan up to 15 feet; and the giant pangasius, Siamese giant carp, and the endemic Mekong giant catfish, all three of which can grow up to about 10 feet long and weigh 660 pounds.  All of these species and many others are in danger of extinction due to overfishing, as well as the decrease in water quality due to development and upstream damming. 

 

China has engaged in extensive dam-building on the river with three completed and another twelve in consideration.  All nations downstream and the environment will suffer.  Since the building of the first dam, many species have become endangered, water levels have dropped, and the fish caught are smaller and fewer than before the dam.  The Mekong which winds through Laos, Thailand, Cambodia, and Vietnam, is one of the last big untamed rivers in the world and nearly 60 million people depend on its rich fisheries for survival. 

The tiny village of Pak Lan in northern Laos may soon be disappearing and its people relocated.  A proposed dam will need to move it and 18 other nearby villages because they will be partially or fully submerged if the Xayaburi dam is built.  The dam will generate 1260 megawatts of power, which will earn the developer between $3 and $4 billion a year.  If the Xayaburi dam is built, it will set a precedent for 10 other hydropower dams proposed for the main stem of the river turning nearly 55% of the river into slow-flowing reservoirs. 

Fish are a staple of the diet in Laos and Cambodia, with around 80 per cent of the Cambodian population's annual protein intake coming from fish caught in the Mekong River system, with no alternative source to replace them.  There are 229 fish species whose spawning and migratory patterns would be affected by this mainstream dam.  Dams would also restrict the flow of water over agricultural areas linked to the river.  Some scientists say the environmental impact assessment (EIA) conducted for the builder is seriously flawed because it does not consider the wider effects of the dam. 

Road Construction to Reach Dam Site.

Over the opposition of environmental groups, such as International Rivers and the Cambodian and Vietnamese governments, the construction of the giant dam deep inside Laos, is continuing. The Thai government, who will benefit greatly by importing around 95% of the produced electricity, is defying an agreemtn by the Mekong River Commission Council to halt construction until a more complete study of the dam can be completed.

Read More

Capturing and Using Rainwater from Rooftops

Capturing Rainwater from Rooftops Can Alleviate Nation’s Water Woes

As America’s expanding urban areas struggle with major water supply shortages and runoff pollution problems, capturing rainwater from rooftops provides a tremendous untapped opportunity to increase water supply and improve water quality, according to a recent analysis on Capturing Rainwater from Rooftops by the Natural Resources Defense Council (NRDC).

By capturing hundreds of millions of gallons of rainfall, residents of these communities would obtain inexpensive onsite water supplies for non-potable uses, such as yard watering and toilet flushing, and would lower energy costs associated with treating and delivering drinkable-quality water.  It would also reduce the street litter such as styrofoam, plastic, and paper; yard waste such as grass clippings , tree trimmings, and leaves; and pet waste that gets washed into local waterways during the rainfall.

The NRDC report illustrates opportunities for capturing, treating and supplying harvested rainwater for non-potable purposes in Atlanta, Ga.; Austin, Texas; Chicago, Ill.; Denver, Colo.; Fort Myers, Fla.; Kansas City, Mo.; Madison, Wis.; and Washington, D.C. Several success stories also demonstrate the effectiveness of rooftop rainwater capture for new construction in New York, N.Y., and redeveloped buildings in Santa Monica, Calif.

The report comes as the U.S. Environmental Protection Agency is in the process of updating its national standards for controlling runoff pollution from new development and existing paved areas. NRDC encourages the agency to adopt national standards for on-site stormwater retention that will increase green infrastructure approaches such as rainwater harvesting. As a result, communities can effectively transform polluted runoff flowing to our waterways into captured rooftop rainwater used as an on-site water supply resource.

Weed harvesters as workboats - WorkBoat.com

Weed harvesters as workboats
By WorkBoat Staff
11/15/2011

As we've been following efforts by folks such as those along the Cuyahoga River to establish greenery along previously dead rivers, perhaps opening them to more passenger vessel traffic as people again see these rivers as something they'd like to ride along, our attention was grabbed by a class of workboats that specializes in this area. 

Such as those made by Aquarius Systems, who recently posted a video of their latest delivery. If nothing else, they're kind of cool looking:

 

 

A Success Story - Lake Minnewawa Weed Harvesting

In the 1970’s, Lake Minnewawa was so choked with weeds that residents could no longer enjoy the lake.  Boating was impossible and water clarity and phosphorous levels were awful.  A group of concerned residents decided they needed to do something to save the lake and on December 15, 1977 as association was formed calling itself Save Minnewawa Association.

In 1982 the association purchased their first weed harvester and trailer, which was replaced in 1994 by a larger, but used 1987 Aquarius Systems 620 harvester, that is still in use today.  The association does not receive state funds to run the harvester; it is financed by membership, business, and other local group donations along with fund raisers.  The work required to run the machine is immense and there are a lot of donated hours by board members and volunteers to keep the equipment running.

Three months out of the year the harvester runs five days a week about 8 hours a day (weather permitting) to maintain the 4,500 acre lake.  Not all of the lake gets cut either, there are designated no cut areas established by the DNR and certain native plants aren’t cut like lily pads, wild rice, and bulrush.  Since the harvester has been in use not only has the amount of weeds decreased, but water clarity has significantly increased as well.

A big reason for this is because there are fewer weeds dying in the lake and decomposing to the bottom.  If the vegetation is left to rot, the nutrients in it that have been absorbed from the water are released back to the water column and become nutrients for the next weed growth or algae bloom. But something far worse occurs; as the vegetation decays, it uses up the oxygen at the bottom which affects fish as well as native plants.  The weeds contain a huge amount of phosphorous which is being removed along with the weeds, the more phosphorous in a lake, the more algae growth, therefore the lower water clarity.

Some people in the area don’t believe in the weed harvester and feel that cutting the weeds leads to more growth, but Steve Olson, LMA board member disagrees.  “If that were the case, then they would have never needed to harvest here in the first place.”  Other people have suggested controlling the weeds with chemicals instead of the harvester, but the cost is very prohibitive with a price tag of half a million dollars compared to the $25,000 a year it takes to run and maintain the weed harvester.

With the aid of the Aquarius Systems weed harvester and 18 years of sufficient lake improvements, Save Minnewawa Association officially changed their name in 1995 to Lake Minnewawa Association (LMA).