USA: Dredging Project at Silver Lake Likely Delayed
Plans to dredge Silver Lake in Rehoboth Beach are moving forward, but officials say the choice of dredging equipment could delay the project until next summer.
Mayor Sam Cooper said the Department of Natural Resources and Environmental Control has approached Rehoboth Elementary School officials, seeking to use school property as a base of operations. Originally, plans called for basing the project on land at Silver Lake Park, but Chuck Williams, project manager of the department’s Shoreline and Waterway Management Section, said that’s no longer the case.
Cooper said state environmental officials are considering using Geotube technology to store dredge spoils. It’s a technology being used in dredging projects in Henlopen Acres and North Shores, in which sediment from the lake is pumped into a bag that filters sediment and sludge as water slowly drains out of the tube. The spoils are then removed for use as farm fertilizer.
Williams said the bags are 100 feet long and 35 feet wide; each bag holds 420 cubic yards of spoils.
Cooper said if the state decides to use Geotubes, it would delay the project until summer, when children are not using the school property.
Williams said the department is still considering the choice of dredge equipment. One factor is city efforts to protect the lake using vegetative buffers. Williams said the department initially considered staging a mechanical dredge in Silver Lake Park. But because new vegetation has been planted, it is not feasible to remove the plants and restore them afterward, Williams said.
Officials are now considering a hydraulic dredge, using Geotube for the spoils. Mechanical dredges are typically placed on the shoreline, whereas hydraulic dredges float on the water and pump the spoils to an offsite location. Cooper said the school is the most logical base of operations, because Silver Lake Park is too small to place the bags.
Williams said using a hydraulic dredge and Geotube is a much cleaner operation than mechanical dredging.
The bags are designed not only to filter the spoils, but to also treat the water so that it is clean when released back into the lake, he said.
DNREC officials have contacted Cape Henlopen School District about using the school, Williams said; initial talks have been positive, although no decision has been made.
The cost of the project has been estimated at $300,000. At least $200,000 will come from the state’s 21st Century Fund, a section of the state budget that funds long-term infrastructure projects.
Williams said the state will likely look for the remaining $100,000 once it knows whether the school site is available.
Cooper said city taxpayers are also expected to contribute to the project.
Press Release, October 8, 2012