The Virginia Department of Environmental Quality (DEQ) on Jan. 25 filed with the Virginia State Corporation Commission its comments on Virginia Electric and Power’s (Dominion Energy Virginia) application for a certificate of public convenience and necessity involving the proposed Idylwood-Tysons 230-kV project in Fairfax County, Va.
As noted in the filing, Dominion proposes to:
- Build the new single-circuit, underground, 230-kV Idylwood-Tysons Line #2175, to run about 4.3 miles from the company’s existing Idylwood substation to the existing Tysons substation
- Rebuild the Tysons substation using gas insulated substation equipment to accommodate a six-breaker 230-kV ring bus within the existing property boundaries
- Install new gas insulated line terminal equipment at the Idylwood substation for the new Line #2175 installation
- Perform relay work at the Reston substation
Dominion identified six underground alternatives, with the proposed route being “Underground Alternative 05,” the DEQ said.
The proposed route would extend north from the Idylwood substation, through means of open trenching, for about 0.3 mile, crossing Shreve Road, the DEQ said. The route would then turn west at the Washington and Old Dominion Railroad Regional Park and follow Line #202 along the park, crossing under I-66, the Washington Metro Area Transit Authority Orange Line and I-495, until reaching Gallows Road through means of horizontal directional drilling (HDD) (two parallel drill paths) for about 0.6 mile.
The DEQ added that the route would then turn north at Gallows Road, where the remainder of the route would be built within the public road rights of way (ROWs) for about 3.4 miles by means of open trenching.
The route would follow Gallows Road and cross Leesburg Pike, just before Gallows Road intersects with Old Courthouse Road, the DEQ said, adding that after crossing over Leesburg Pike, where Gallows Road transitions into International Drive, the route would then turn northwest, crossing over Chain Bridge Road, continuing along International Drive.
The route then turns east onto Spring Hill Road, west along Tyco Road, and end at the Tysons substation, the DEQ said.
The Department of Historic Resources (DHR) recommends the alternatives with the least lasting impact be pursued, the DEQ said, adding, “Alternatives 01 and 02 are the only options that will have no visual, post-construction impact on architectural resource DHR ID #053-0276, which is eligible for the Virginia Landmarks Register (VLR) and the National Register of Historic Places (NRHP).”
While the impact of the proposed line does not significantly impact any character defining features that make #053-0276 eligible for listing, impinging upon the open setting/feeling of the corridor could cause more significant cumulative impacts if additional work, not currently in the scope, is done in the corridor, the DEQ said.
Recommendations regarding historic and archaeological resources include that the company should complete an archaeological survey in accordance with DHR guidelines prior to construction of any SCC-approved alternative with special consideration of recorded sites.
The DEQ also noted that its Office of Wetland and Stream Protection (OWSP) states that wetland areas and stream corridors have been identified within the project. The DEQ said that it recommends, for instance, that wetland and stream impacts be avoided and minimized to the maximum extent practicable, and that the company should maintain 100-foot buffers along either side of streams.
Of natural heritage resources, the DEQ noted that the Long Branch Stream Conservation Unit (SCU) is located downstream from the project site and has a biodiversity ranking of B4, which represents a site of moderate significance. Threats to the significant aquatic natural community and the surrounding watershed include water quality degradation related to point and non-point pollution, water withdrawal, and introduction of non-native species.
The DEQ added that the DCR Division of Natural Heritage states that the current activity would not affect any documented state-listed plants or insects.
To minimize adverse impacts to the aquatic ecosystem as a result of the proposed activities, the company should implement and strictly adhere to applicable state and local erosion and sediment control/storm water management laws and regulations, establishment/enhancement of riparian buffers with native plant species and maintaining natural steam flow.
The DEQ also said that the Virginia Department of Game and Inland Fisheries (DGIF) does not currently document any listed wildlife or designated resources under its jurisdiction from the project area. Therefore, DGIF does not anticipate the project to result in adverse impacts upon such species or resources.
Among other things, the DEQ added that recommendations include for the company to coordinate with the U.S. Fish and Wildlife Service regarding potential impacts upon federally listed threatened northern long-eared bats associated with tree removal.