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7/26/2019 DC Water Northeast Boundary Tunnel - For General Release 2016 06
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DC CLEAN RIVERS PROJECT
Northeast Boundary Tunnel
a
nd
WMATA Coordination
Florida Avenue Site
District of Columbia Water and Sewer AuthorityGeorge S. Hawkins, General Manager
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Long Term Control Plan (LTCP) to: Relieve flooding in the Northeast
Boundary Area
Control combined sewer overflows to: Potomac River
Anacostia River
Rock Creek
Meet nutrient discharge limits ofChesapeake Bay Program
Schedule: 2005-2023
Implemented under a Federal Consent
Decree among: United States Environmental Protection
Agency (US EPA) United States Department of Justice (US
DOJ)
District of Columbia
DC Water
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Background
Project Snapshot
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Nannie MiningLocation
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Summer 2012 Storm Events: Surface Flooding
Rhode Island Metro
1st St NW
Flagler St NW
Rhode Island & T St NW
Rhode Island Between 1st & 2nd St
Rhode Island & T St NW
Rhode Island & 1st St NW
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1st & V St NW
Photo courtesy of: Greg Roberts
Photo courtesy ofhuffintonpost.com
Photo courtesy of myfox.com
Photo courtesy of myfox.com
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Photo source unknown
Photo source unknown
Photo source unknown
Photo source unknown
Photo source unknown
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Mayors Task Force
Overview
4 storms caused major
flooding: July 10, 18, 19
and Sept 2, 2012
Mayor formed Task
Force in Aug 2012
Task Force reportdelivered end of Dec
2012
Over 25 Recommendations:
Engineering Measures McMillan Stormwater Storage
First Street Tunnel
Northeast Boundary Tunnel
(NEBT)
Regulatory Code ChangesOperations &
MaintenancePublic
Outreach
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Mayors Task Force
Recommended Plan
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NORTHEAST BOUNDARY TUNNEL PROJECT A large, deep sewer tunnel that will increase the capacity of
the sewer system to current design standards and control
combined sewer overflow discharges to the Anacostia River Completion in 2023
MCMILLAN STORMWATER STORAGE PROJECT Repurpose McMillan Sand Filtration cells as stormwater
storage In-line storage in a sewer that runs along First Street NW 3.6 million gallons, Completed
IRVING STREET GREEN INFRASTRUCTURE PROJECT Construction of bioretention facilities along Irving Street NW
0.4 million gallons, Completed
2. MEDIUM-TERM
FIRST STREET TUNNEL PROJECT
Construction of a new tunnel under First Street NW Construction of diversion facilities to divert flows to tunnel 8 million gallons, Summer 2016
3. LONG-TERM
Construction of green infrastructure projects Installation of storm drains and a five-foot-wide storm sewer Backwater valve and rain barrel program
1. SHORT-TERM (NOT ILLUSTRATED)
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Significantly mitigate the frequency, magnitudeand duration of sewer flooding and basement
backups in the Northeast Boundary drainage
area
Control combined sewer overflow (CSO)
discharges to the Anacostia River, significantly
improving water quality
Minimize the nuisance and economic costs
associated with flooding
Reduce risks to human health
Greatly reduce the discharge of untreated
wastewater into the Districts receiving
waterbodies
Prevent deterioration of historic resources fromwater damage caused by flooding
Mayors Task Force
Benefits
CSO Reduction Project Timeline
CSO Overflow Volume
to Anacostia River
(mg/yr)
% Reduction from
Baseline
1996: Baseline: Without Inflatable Dams or Pumping Station Rehab 2,142
2008: After Inflatable Dams and Pumping Station Rehab 1,282 40%
2018: Blue Plains and Anacostia River Tunnels 407 81%
2023: Northeast Boundary Tunnel* 54 98%
CSO Reduction
* 2025 Consent Decree Deadline; Project accelerated due to Mayors Task Force recommendations.6
Flood Relief
SIG
NIFICANT
CSOREDUCTION
Capacity provided by Long-TermImprovements (NEBT)
Approx. capacity ofexisting system
Capacity provided by Medium-Term Improvements
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Northeast Boundary Tunnel
What is a Diversion Facility?
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Northeast Boundary Tunnel
Alignment and Chronic Flood Areas
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Northeast Boundary Tunnel
Phases of Work
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In order to accomplish the Mayors Task Force goals, construction work has beendivided into two distinct phases
Phase Description Start Finish
A Relocation of utilities (gas, electric, communication, water,
sewer, etc.) that conflict with permanent diversion facility
structures Typical linear trench-type utility work
Borings
Moving work areas
Short durations
May 2016 September 2017
B Construction of NEBT and diversion facilities along tunnel
alignment
Stationary work areas Long durations
September 2017 May 2023
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Northeast Boundary TunnelUtility Relocations
Anticipated Start of Construct ion
Washington Gas June 2016
Pepco June 2016
DC Water Contractor April 2017
BORING
LOCATION
BORING
LOCATION
EXISTING G2
BUS STOP
EXISTING G2
BUS STOP
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Northeast Boundary TunnelFlorida Avenue Construction Site
EXISTING G2
BUS STOP
EXISTING G2
BUS STOP
Anticipated Star t of Construction
DC Water Contractor Sept. 2017
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Why is the G2 Detour Required?
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Sidewalk and lane closures along the G2 route are required to complete the work
Currently, WMATA using same 40-ft buses from existing route. Forcing less direct
routing
40-ft buses will be replaced with 30-ft buses at next opportunity for garage
switchover (June 26), allowing more direct routing WMATA will increase rush hour frequency of buses to maintain capacity
Bus detour will remain through construction (2023) and will be reevaluated at that
time
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WMATA G2 Detour Phase 1
FLORIDA AVENUE
CONSTRUCTION SITE
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WMATA G2 Detour Phase 2
FLORIDA AVENUE
CONSTRUCTION SITE
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JUNE
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Washington Gas
Pepco
DC Water Borings
DC Water Utili ty Contractor
DC Water NEBT Contractor
20232016 2017 2018
Next Steps
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Continue public outreach throughout the project area
Relocate utilities in advance of construction: June 2016
NEBT Construction: September 2017 May 2023
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