ROCKVILLE, MD—A week ago, park managers began lowering Lake Needwood in Rock Creek Regional Park as the Montgomery County Department of Parks anticipates dredging the lake will begin this month, October.
“Lowering the water level in the lake will continue for a period of approximately two weeks—depending on weather—as the water level has to be lowered by about six (6) feet from the present elevation,” said Department of Parks Project Manager Stephen Reid. “The lake is being lowered now in order to allow more time for the sediment to dry out before dredging activities commence.”
Lake Needwood was built in the 1960s to provide flood control and recreational opportunities for the community. Over the past five decades, increased development within the Lake Needwood watershed resulted in increased stormwater runoff and associated erosion of urban areas. In addition, increased stormwater runoff produces higher stream flows. These larger stream flows produce greater stream bank erosion. These phenomenon ultimately result in greater amounts of sediment that is transported during storm events. As the storm flows enter the lake, the water is slowed down and the sediment is deposited within the lake.
For many years, the lake’s forebay and upper portion were regularly dredged to maintain sufficient capacity for the flood control, improved water quality and recreational use. However after 1990, due to funding constraints, the regular dredging operation was discontinued. The result was extensive silt accumulation, impacts to aquatic habitat and reduced recreational opportunities.
“Dredging increases the water depth, thereby improving recreational use and aquatic resources within the lake,” added Reid.
The Department of Parks hosted a public meeting in September 2007 on the preliminary engineering designs for dredging Lake Needwood and presented the project to the Montgomery County Planning Board in December 2007. Design and construction was funded in the FY 09-14 Capital Improvement Program.
The Montgomery County Council appropriated approximately $3.8 million for design and construction of the dredging project in 2008. This project is expected to be complete by June 2011 in time for the beginning of the next boating season.
Right now the Department of Parks is still reminding the public to avoid contact with the water at Lake Needwood and not to allow dogs or other pets to drink from or swim in the lake. This summer, the algal bloom in the lake was found to include Microsytis, and the toxin Microcystin—a toxic substance produced by blue-green algae (cyanobacteria). Water that contains Microcystin can cause minor skin irritation and gastrointestinal discomfort in humans and has been reported to result in health problems to animals that drink infected water.
“Dredging the lake might help with future algal blooms as the water quality will noticeably improve,” said Department of Parks Aquatic Ecologist Doug Redmond.
For more information and updates, visit www.MontgomeryParks.org.
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Media Relations Manager
Montgomery County Department of Parks