Aquatic Weed Harvesting Restores Pond

Heard Pond became so heavily infested that the beauty and recreational value of it were lost.  Once flourishing with native water lilies Heard Pond had a reputation for great fishing and bird watching.  All gone, due to the lack of open water, nearly completely covered with water chestnut.

Water chestnuts are native to parts of Eurasia and Africa, but have been observed in North America since 1859.  Introduced as an ornamental plant, the water chestnut quickly forms dense floating mats which crowds out native vegetation.  Once established, it can reduce oxygen levels, increasing the potential for fish kills. An infestation will limit boating, fishing, swimming and other recreational activities.

This annual aquatic plant has a submerged stem which can reach up to 15’ in length while it’s fine roots anchor the plant in the mud.  Water chestnut produces flowers in June and then a produces a nut with 4 – ½” barbed spines which can cause injury while swimming.  The seeds can remain viable for up to twelve years although most will germinate within the first two.

In 2003, crews began harvesting the water chestnut on Wayland, Massachusetts’s Heard Pond.  Heard Pond is 85-acre pond that is almost completely surrounded by U.S. Fish and Wildlife land.  Originally from Eurasia, produces large seeds with barbed spikes and large leaves that can quickly cover the water’s surface.

That summer aquatic weed harvesters were put to work and removed 1.2 million pounds of the aquatic plant.  Then again in 2004 when 500,000 pounds were removed and yet again in 2005 with the removal of 192,000 pounds of water chestnut were harvested from the water and taken to compost.

Successive season harvesting saw a steady downward trend and by 2009 hand harvesting became the primary course of action with as few as 240 pounds collected in 2012.  Since water chestnut is an annual plant, seasonal harvesting is necessary to rid the lake of the millions of seeds that must have been in the water at the beginning of the whole lake harvesting process.  One unharvested plant can produce 20 to 30 seeds.

The native water lilies are in abundance on the shoreline and waterfowl have returned along with watercraft and people.  Heard Pond is once again the water jewel of Wayland.  Unfortunately water chestnut will never completely disappear from Heard Pond, but these previous years efforts have left Wayland officials with a small scale maintenance and management effort.

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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 

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: