Lake Kittamaqundi Debris Removal/Dredging/Dewatering

Lake Kittamaqundi is a man-made 27-acre reservoir created in 1966 during the development of the Columbia Housing complex in Maryland. The lake served a dual purpose as a recreational feature and a low-cost primary catch basin for water runoff from Wilde Lake into the Little Patuxent River. In the fall of 2010, CASHMAN began this 60,000-yd³ pond dredging and dewatering project, completing it in November 2011. As sediment built up over the years since the lake's creation, the depth of the lake had become reduced. This dredging effort focused on restoring the lake to the original depths, reinforcing the banks, and creating two new peninsulas to enhance water flow. The Columbia Association chose CASHMAN for its proven skills in dewatering and its ability to tackle some of the toughest dredging projects. After the pond was initially cleared of all debris, CASHMAN used a variety of dewatering techniques prior to sending dredged material to be used in landfill closure and mine reclamation projects.


PROJECT HIGHLIGHTS 

• CASHMAN dredged ~48,000 yd³ of sand, silt, and stone from the lake to a specified depth using a hydraulic dredge as a part of an overall environmental restoration. 
• The firm dredged and pumped ~8,000 yd³ of material into geotextile tubes to create ~1.28 acres of wetland habitat within the lake and ~.4 acres of upland peninsula to reshape the lake. 
• The 40,000 yd³ of dredged material was pumped 4,000 feet to an upland processing area where it was dewatered using a combination of hydrocyclone separators and geotextile tubes. 
• Filtered return water was pumped to the lake for discharge, meeting specified water quality limits established by the Maryland Dept. of the Environment and USACE. 
• Dewatered sediment was characterized and beneficially reused in a mine reclamation project. 
• Installed ~295 linear feet of imbricated rip-rap along the Little Patuxent River to stabilize the area and reduce overflow between the river and lake.