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The $2.5 Million Dam

Dam plans for Royal Lake updated.

County, state and federal officials working on the construction plans for reinforcing Royal Lake’s auxiliary spillway want to make sure nearby residents have a place to walk, run and bike before they begin tearing up the current trail around the lake.

Royal Lake is used as a recreational and exercise place for residents of the Braddock area. But that exercise haven is about to go through a major renovation. At a meeting, Tuesday, June 26, at Bonnie Brae Elementary School, officials told the crowd of about 20 people about updated plans for the construction on the lake and dam, which includes changing the trail around the lake.

“In 1999, the county completed a study that showed that during the passage of significant storm events there was a possibility of the dam failing,” said Dipmani Kumar, project manager for the Fairfax County Department of Public Works and Environmental Services (DPWES) Stormwater Planning Division.

A FLOOD CONTROL DAM holds the water behind the dam so that floodwater can be released slowly, in amounts that match the capacity of the stream, she said. The spillway is what there is if a flood occurs and water overflows the bank that is not accommodated into that concrete structure. Now, the dam has many deficiencies, said Supervisor Sharon Bulova (D-Braddock).

The state, federal and county governments and the Northern Virginia Soil and Conservation District worked together to create a citizens task force of people in the communities that surround the lake, Bulova said. The community worked with staff to address their main concerns, including the loss of trees and the maintenance of the trail before and after the construction is over.

The federal government has been a major partner in the planning and executing of the spillway rehabilitation, she said. The government has agreed to pay 65 percent of the costs, with the county paying 35 percent.

“This is a very good deal,” Bulova said. “We are now able to move the project forward with their funds.”

The construction — costing an estimate of $2.5 million — is said to begin in the spring of 2008, Donald Rissmeyer, associate at A. Morton Thomas and Associates Inc. (AMT) said. AMT is a consulting group of engineers working with the county and federal government on this project.

Before the main construction takes place, a new, six-foot-wide paved trail will be built around the park, Rissmeyer said. The construction of the new trail is an improvement to the old, but also ensures that residents will have path to walk and bike on while the current trail is torn up during the process of installing Articulated Concrete Blocks (ACBs), he said.

ACBs are concrete blocks placed underneath the grass with holes in it so grass can be grown through the openings or on top of the whole structure, Rissmeyer said. The ACBs are a good alternative to concrete walls, which are open to the potential of vandalism, he said. The construction will also increase the width of the spillway from 100 feet to 115 feet to convey the Probable Maximum Flood safely, and will raise the training dikes to protect the townhouses from flooding. This will attempt to eliminate the need to cut down trees.

AFTER THE PROJECT is over, experts will be brought in to take out the invasive species in the woods and work on their reforestation, Rissmeyer said.

“Every concern has been more than addressed, it’s been addressed well,” said John Harris, chair of the Kings Park West Royal Lake spillway task force.

Researchers also found out that if there is a flood and the water overflows the set spillways, the water could erode the soil, causing the spillway to breach. There are townhouses in the direct path of the water and are one of the reasons for the action taken by the county and federal government, she said.

National Resources Conservation Services (NRCS) developed a rehabilitation platform for Royal Lake cooperatively with the Royal Lake citizens’ task force, Kumar said.

“This is an excellent example of state and county government working with concerned citizens,” he said. “They’ve really been attending to the concerns of the community.”