This project was identified for flood mitigation in the FY 2018 work plan as a result of repeated flooding in the vicinity of Sunset Hills Road near Isaac Newton Square W in Reston. In February 2018, staff of the Stormwater Planning Division initiated the design of the project.
The project area was severely flooded during Tropical Storm Lee. This area does not have overland relief as the W&OD trail embankment is higher than the upstream area of concern. During large storm events, this embankment impounds flows that exceed the capacity of the historic Civil War culvert that is under the W&OD trail. A flood mitigation conceptual analysis was done in February 2016 which provided several options to mitigate flooding. The option selected balances the upstream flooding with the impact on a downstream golf course.
The primary goals of the restoration are:
Mitigate the frequent flooding on Sunset Hills Road and properties adjacent to pond number 913
Relieve the pressure on the W&OD trail embankment due to ponding of water upstream
Provide water quality benefits by upgrading the farm pond to a stormwater management facility on the golf course property
The project is located at the VDOT park and ride lot near the intersection of Sunset Hills Road and Isaac Newton Square W. This project starts from the VDOT park and ride and runs through the W&OD trail embankment to the downstream farm pond located in the Hidden Creek Country Club Golf Course.
Reduction in frequent flooding of Sunset Hills Road and properties adjacent to pond number 913
Improvement of water quality through the removal of Nitrogen, Phosphorous and Total Suspended Solids
Construction is expected to start in FY 2022.
Project Cost and Funding Source
Construction of the Sunset Hills Road Drainage Improvement Project is estimated to cost about $11 million. Stormwater projects are funded through the county Stormwater Service District.