Here in Southeast Wisconsin, our rich alluvial soils are the result of glacial and erosive processes. But erosion obviously isn’t always a good thing. Silt and debris wash into bodies of water and give footing to aquatic, transitional, and land plants, causing land to encroach on water. Wave action and runoff combine to erode shoreline and choke waterways. In navigable waterways, dredging is often necessary to keep waterways open to boat traffic of different kinds. In other cases, dredging may be necessary to get rid of undesirable chemicals that have leached into sediment, or to restore access for boating traffic.
Weed control helps to maintain ponds and lakes, but sometimes dredging is necessary for restoration. Runoff and accumulation of organic and inorganic materials in ponds and lakes, including phosphates and related chemicals, can cause explosive plant growth that harms the environment and accelerates sedimentation. In many instances, the dredging process is very invasive. Typically, heavy machinery is moved to the water’s edge and materials extracted without much consideration for the ecological impact. Often getting heavy machinery to the water’s edge means clearing shoreline trees, brush, and plants. This can cause further erosion. Dredging by scooping with a backhoe or similar machine also disrupts desirable aquatic vegetation and animals, and in areas where lake or pond water is retained by clayey substrata, removal of that layer can also cause water to leak out of the lake or pond.
By contrast, EcoWaterway uses specialized watercraft designed to minimize environmental disturbance. Their pontoon-based Crisafulli-built Rotomite SD110 light dredging craft can enter water as shallow as 17 inches. Equipped with a 40 hp outboard and a 110 hp pump, it can get just about anywhere. A hydraulic ram extending from the bottom provides enough pressure to help scrape and remove compacted material that otherwise would require scooping. It can remove as much as 85 cubic yards of sludge solids per hour, down to a depth of 12 feet.