Delegated Action of the Executive Director
PROJECT NCPC FILE NUMBER DC Clean Rivers Project - Northeast 7625 Boundary Tunnel (Division J) Various Locations NCPC MAP FILE NUMBER Washington, DC 52.00(03.40)44453 ACTION TAKEN SUBMITTED BY District of Columbia Water and Sewer Approve as requested Authority REVIEW AUTHORITY Advisory Per 40 U.S.C. § 8722(b)(1)
The District of Columbia Water and Sewer Authority (DC Water) is implementing a Long Term Control Plan (LTCP), also referred to as the DC Clean Rivers Project (DCCR), to control combined sewer overflows (CSOs) to the District of Columbia’s (District) waterways. DCCR is comprised of a variety of projects to control CSOs, including both grey infrastructure (pumping station rehabilitations, targeted sewer separations, and underground storage/conveyance tunnels) and green infrastructure.
The Northeast Boundary Tunnel (NEBT) is an underground storage/conveyance tunnel that will increase the capacity of the existing sewer system and will reduce the frequency, magnitude and duration of sewer flooding and basement backups. Additionally, the NEBT will provide storage volume to effectively reduce CSO discharges to the Anacostia River by 98 percent. The NEBT portion of the DCCR will commence just south of Robert F. Kennedy (RFK) Stadium and terminate just west of the intersection of Rhode Island Avenue NW and 6th Street NW.
The tunnel will course in a northern direction along the west bank of the Anacostia River, beneath Langston Golf Course and then shift to the west along the southern limits of the U.S. National Arboretum and the Mt. Olivet Cemetery beneath Mt. Olivet Road NE. The proposed tunnel will be 23 feet in diameter, approximately 27,000 feet long, and constructed approximately 50 to 160 feet below the ground surface in geologic stratigraphy consisting of clays, sands and highly weathered bedrock. The entire length of the NEBT will be excavated by a tunnel boring machine and finished with a permanent concrete tunnel lining.
The entire tunnel and a majority of the components associated with the NEBT will be located below or flush with grade, similar to the existing sewer infrastructure. Manhole covers, grates, hatches, and other access features are designed to be flush with final grade. Out of the eight (8) sites constructed as part of the project, three (3) sites will involve significant changes above-grade. Those three sites and the proposed work are further described below. Commission Action Page 2 NCPC File No. 7625
W Street Site The W Street Junction Shaft (W Street Site) is located in an industrial area bound by W Street, NE to the north, Brentwood Road to the West, Amtrak rail yard and New York Avenue to the south and Montana Avenue to the west. The western portion of the site currently serves as the District Department of Public Works (DPW) salt storage and fleet management facility, while the District Department of Transportation (DDOT) occupies the western portion of the site for their Street and Bridge Maintenance fleet. Amtrak’s Ivy City Maintenance Facility and Commissary are located just south of the W Street Site.
The proposed facilities associated with the NEBT at the W Street Site include a below-grade junction shaft, below-grade ventilation channel, above-grade ventilation control facility, above- grade ventilation vault and a retaining wall. In order to construct the junction shaft and ventilation control facility (VCF), the existing site, which slopes moderately from the north to the south, will be graded to suit construction. Grading the site will require a retaining wall to be constructed at the northern edge of the site in order to stabilize the sloped wooded area that buffers the DPW and DDOT facilities from the residential properties located along W Street, NE. The retaining wall will vary in height from 4 feet to 27 feet depending on adjacent topography. The Ventilation Control Facility will be 6,000 square feet, and have a height of 32 feet. A green roof on the VCF, bioretention areas, dry swales, and tree plantings will mitigate site runoff.
Mount Olivet Road Site Another component of this project is located at the Department of Public Works West Virginia Avenue Maintenance Facility, located on Mount Olivet Road NE, adjacent to the Mount Olivet Cemetery. The project consists of an above-grade electrical cabinet and a transformer associated with the NEBT. These facilities will be located behind an existing chain link fence with privacy slats. The cabinet and transformer will be painted Bryant Park Green.
R Street, NW Site This project is located on a triangular park at the intersection of R Street, NW and Rhode Island Avenue, NW formerly Reservation 159. The proposed project site consists of two underground facilities: a diversion chamber and a drop shaft. The existing park will be reconstructed once the underground portion is completed. The reconstruction of the park includes some landscaping, relocating two traffic control utility cabinets, a two-and-half-foot high decorative iron fence, brick sidewalks, benches and a memorial plaque to a local community leader, Mother Cooper. All of these elements currently exist on the site and will be replaced, with the exception of the benches which will be new. Flush mounted panels and grates will be installed to access these underground facilities.
Analysis In December 2014 the Commission approved the preliminary site and building plans but also requested that the applicant provide information demonstrating how the project is addressing stormwater impacts at the W Street, NE site, which includes a large, paved area for vehicles. DC Water responded to the request in this submission and demonstrated that the stormwater retention and detention volumes achieved at the site exceed DOEE requirements. Commission Action Page 3 NCPC File No. 7625
The project will not adversely impact any federal interests and is not inconsistent with the Comprehensive Plan for the National Capital. As a District project on sites outside of the Central Area, NCPC is advisory in its review authority, and does not have an independent obligation to fulfill the requirements of National Environmental Policy Action or Section 106 of the National Historic Preservation Act.
The Coordinating Committee reviewed the proposal on November 9, 2016, and without objection, the Committee forwarded the proposed final site and building plans to the Commission with the statement that the proposal has been coordinated with all participating agencies, with the SHPO coordinating subject to archaeological monitoring being carried out within areas not evaluated during Phase 1 survey. The participating agencies were: NCPC; the National Park Service; the District of Columbia Office of Planning; the District of Columbia State Historic Preservation Officer; District of Columbia Department of Transportation; the General Services Administration; and the Washington Metropolitan Area Transit Authority.
* * *
Pursuant to delegations of authority adopted by the Commission on October 3, 1996 and per 40
U.S.C. § 8722(b)(1), I approve the final site and building plans for the DC Clean Rivers Project -
Northeast Boundary Tunnel (Division J) at various locations in Washington, DC.
// Original Signed // November 23, 2016 Marcel Acosta Date Executive Director