MTA Details Environmental Impacts Of Purple Line

Flickr photo by rootchopper Rendering via MTA

The Maryland Transit Administration’s Final Environmental Impact Statement (FEIS) on the Purple Line details the removal of trees around the Georgetown Branch Trail and expected displacement of homes and businesses.

The agency released the FEIS on Friday and is taking public comment on the document for the next 30 days.

Most of the 388 full or partial property acquisitions take place in Silver Spring, Langley Park and Prince George’s County. The focus locally has been on the effect the $2.2 billion, 16-mile light rail will have on the forested area of Rock Creek Park that today surrounds the Georgetown Branch Trail.

The MTA is proposing to build the system on the Trail right-of-way, a former rail bed purchased by Montgomery County in 1988.

The FEIS recognizes 416 acres of Rock Creek Park forest within 6,000 feet of the transit system’s Limit of Disturbance. The report says the light rail will impact 23.4 of those acres.

Reforestation will take place according to state guidelines. The final forest planting obligation for the project has not yet been determined — the FEIS says it will be negotiated between MTA and the Maryland Department of Natural Resources:

MDNR requires that forest mitigation sites be chosen either as reforestation or afforestation on site, which is preferred, or in close proximity to the project area, which is allowed with approval from MDNR, provided the sites are within the same watershed as the impacted area. If these options are not possible, MDNR may approve the use of forest conservation banks.

Forests and Specimen Trees Construction activities associated with utility relocations, implementation of sediment and erosion control practices, and clearing of staging areas would cause the removal of trees. Tree decline and/or mortality could occur due to significant critical root zone (CRZ) disturbance, tree limb damage, changes in soil moisture, and soil compaction as a result of grading operations and other construction related activities occurring near or adjacent to individual trees

The loss of trees around the Trail right-of-way is also addressed in the visual impact section of the report. Homeowners along or near the Trail will see their views significantly altered.

MTA will put together a Forest Conservation Plan, or something similar, during the design phase of the project.

Other changes in Bethesda include the displacement of three businesses, in converted single family homes along Montgomery Avenue, that will be displaced: Newtown Auto Body Shop, Design in a Day studio and Maloney Design Build.

Those properties will make way to the light rail and a proposed Traction Power Substation on Montgomery Avenue, about 1,600 feet east of Wisconsin Avenue next.

A .02-acre section of Elm Street Park in Chevy Chase will be needed during construction for access to the Capital Crescent Trail.

Negotiations with Columbia Country Club resulted in some small shifts in landscaping on the course, which is a historic property. The green on hole No. 14 will be shifted and MTA will construct terraced retaining walls on the north side of the Trail right-of-way line.

Noise mitigation has been another major concern of homeowners near and along the Trail.

The MTA says the design will include a minimum four-foot noise wall or retaining wall near residential areas between Bethesda and Rock Creek Stream Valley Park, the only section of the 16-mile system where that mitigation is planned.

The light rail vehicles will also have vehicle skirt panels to reduce noise at the track level and the traction power substations “will be designed in accordance with MTA design criteria intended to minimize the noise from transformer hum.”

Based on measurements from a spot at 4320 East-West Highway, two homes will experience vibration effects over the Federal Transit Administration’s criteria during construction of the project:

MTA will mitigate operational vibration impacts associated with the Preferred Alternative by evaluating and implementing specific materials and construction methods in the construction of the transitway, including using resilient fasteners, ballast mats, resiliently supported ties, or other vibration damping measures as deemed necessary.

See anything else interesting in the FEIS? Have thoughts? Leave them in the comments section below.

Rendering via MTA, Flickr photo via RootChopper

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