International Dredging Review

International Dredging Review
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IMS Aquatic Weed Harvester Destroying Totora in Laguna de Colta Ecuador

Local authorities in the municipality of Colta Ecuador recently purchased an IMS Model 5012 LP Versi-Dredge with 12-inch discharge newly-developed Razor Tooth Weedmaster Cutterhead aquatic plant harvester and interchangeable horizontal cutterhead.

The dredge was delivered in September where its launch was attended by Ecuador’s minister of environment.

The officials were faced with a vegetation problem in Laguna de Colta a recreational lake at 10825 feet above sea level that had become infested with totora (Scirpus californicus) over 40 percent of its area. The other 60 percent of the lake was full of submerged mats of vegetation that were literally strangling all aquatic life. Forty percent of the vegetation was five feet tall and 60 percent was nine feet tall.

The patent pending Razor Tooth cutterhead purchased by the municipality features a reinforced double razor system designed by Michael Young IMS technical sales manager and Ryan Horton global sales director that can cut the tall vegetation and thick root masses with less wear and bending of cutting teeth than previous models.

The local officials also needed a machine that could cut and pump the vegetation without the need for a re-handling barge. Most weed harvesters cut the weeds and store them in a hopper which must be periodically emptied on shore. The Weedmaster chops the weeds into three- to five-inch pieces and pumps them to the shore up to a kilometer (.6 mile) away using the dredge pump.

The Weedmaster cutterhead unit mounts directly to the pump inlet door. It measures nine feet wide and consists of a steel shroud and cutterbar with dual direct drive motors driving the cutter. The cutterbar is made of heavy wall tubing with reinforced razor teeth. The shroud contains two rows of static cutter blades that clean the main cutterbar as it rotates. It can remove floating vegetation such as hyacinths; submerged vegetation such as milfoil and hydrilla; and emergent and rooted vegetation such as cattails and reeds including nine-foot-tall reeds. It can even digest complex aquatic vegetation root systems to prevent re-growth.

After the vegetation is removed the horizontal cutterhead will be installed to remove the moderately-compacted silt mud clay sand small gravels and occasional rocks up to six inches to increase the lake depth to 10 to 15 feet overall. The dredge is pumping a maximum of 1665 feet with an elevation of 15 feet.

For this project the standard 325 HP diesel engine was upgraded to a 375 HP diesel engine to compensate for the high altitude of 10825 feet above sea level the highest elevation a Versi-Dredge has operated in the company’s 26-year history. Workers in the IMS plant were startled by the strength of the machine when it was turned on for testing.

The project will take several years to complete and will have restored health to a lake that had been in an advanced state of eutrophication.