DC Water First Street Tunnel Project EA Meeting_Boards 2013 04 24

7/30/2019 DC Water First Street Tunnel Project EA Meeting_Boards 2013 04 24

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FIRST STREET TUNNEL

ENVIRONMENTAL ASSESSMENT

DISTRICT OF COLUMBIA

WATER AND SEWER AUTHORITY

DC CLEAN RIVERS PROJ ECT

WELCOME

The purpose of tonights meeting is to present the proposed

project to the public; present project impacts as described in

the Environmental Assessment (EA); and gather public input on

the proposed project and the EA.

PUBLIC MEETING

APRIL 24, 2013

6:30 P.M. 8:30 P.M.


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What is a CombinedSewer Overflow or CSO?

DC Waters wastewater collection

system is comprised of 67% "separate"and 33% "combined" sewers.

Separate systems are comprised of twoindependent piping systems: one for"sanitary" sewage (i.e., sewage fromhomes and businesses) and one forstormwater.

Combined sewer systems convey bothsanitary sewage and stormwater in onepiping system.

During dry weather, sanitary wastescollected in the combined sewersystem are diverted to the Blue PlainsAdvanced Wastewater Treatment Plant.

The sanitary wastes are diverted at facilitiescalled regulators.

When the capacity of a combined sewer isexceeded during storms, the excess flow,which is a mixture of sewage andstormwater runoff, is discharged directlyinto the Anacostia and Potomac Rivers,

Rock Creek, or tributary waters.These discharges are referred to asCombined Sewer Overflow (CSO).

Release of this excess flow is necessary toprevent flooding in homes, basements,businesses, and streets.


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DC Clean Rivers Project

In 2005, DC Water began implementing the DC Clean Rivers Project to Reduce flooding in the Northeast Boundary Drainage area, which

includes the Bloomingdale and LeDroit Park neighborhoods; and

Control CSOs to the Anacostia River, Potomac River, and Rock

Creek

The DC Clean Rivers Project is required to be completed by 2025 by a

Federal Consent Decree.

The Anacostia River Projects,

part of the DC Clean Rivers

Project, include the construction

of a system of large-diameter

tunnels to store and/or convey

CSOs.

In 2010, the National Park

Service and DC Water prepared

an Environmental Assessment

Report to assess potential

impacts of the Anacostia River

Projects.

Groundbreaking Event for the DC Clean Rivers Project


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Four storms caused major flooding on J uly 10, 18, and 19, and September 2,

2012 in the Bloomingdale and LeDroit Park neighborhoods. In August 2012, Mayor Gray assembled the Mayors Task Force on the

Prevention of Flooding in Bloomingdale and LeDroitPark (Task Force),which included residents from the affected communities, governmentofficials, and DC Water representatives.

The Task Force was charged with advising the Mayor on the causes of andpotential actions to prevent flooding in Bloomingdale and LeDroitPark.

The Task Force developed a report submitted to the

Mayor in December 2012 that included a range ofrecommendations that could be implemented over theshort, medium, and long-term to reduce flooding.

Recommendations include:

Short-term Remedial Measures

Backwater Valve Program

Rain Barrel Program

Green Infrastructure Program

Medium-term MitigationStrategies

6 million gallons of CSO Storageat McMillan Sand Filtration Site

6 million gallons of CSO Storagein the First Street, NW Tunnel

Long-term Strategy

DC Clean Rivers Project a

system of tunnels and diversionsewers for the capture of CSOsto Rock Creek and theAnacostia and Potomac Riversfor treatment at DC WatersBlue Plains AdvancedWastewater Treatment Plant.

Mayors Task ForceFlood Relief Plan


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PURPOSE: Flood relief for

Bloomingdale and LeDroit Parkneighborhoods.

Approximately 18.5 feet in diameterand 2,700 feet long.

Provide storage for 6 million gallonsof CSO.

40 to160 feet below ground.

Diversion chambers would beconstructed to divert CSOs to thetunnel for storage when the capacityof the existing sewer is exceeded.

Drop shafts would be constructed toconvey CSOs to the tunnel fromexisting sewer above.

CSO would be held in the tunnel untilflows in the existing sewers subside.

Construction of the First Street Tunnel

and related facilities would occur fromOctober 2013 through June 2016.

FIRST STREETTUNNEL

Project Overview

Cross Section of the First Street Tunnel

First Street Tunnel Schematic and Inflows

Hydraulic Profile of the First Street Tunnel


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FIRST STREETTUNNEL

Project Benefits

Provide storage for an additional 6 million gallons of CSOto reduce flooding in the Bloomingdale and LeDroitParkneighborhoods.

Reduce the nuisance and economic costs caused byflooding.

Reduce risks to human health.

Prevent deterioration of historic resources from waterdamage caused by flooding.

Reduce untreated wastewater discharges into theAnacostia River.

A significant step toward a permanent solution to flooding inthe area.


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FIRST STREETTUNNEL

Environmental Considerations

Parking, traffic, and public transportation would be temporarily

disrupted during construction periods.

Construction activities would generate noise in sensitiveresidential areas.

Vibrations caused by construction activities would be aboveambient levels.

Emissions from construction equipment, fugitive dust, and

numerous vehicular trips to and from construction sites wouldhave effects on local air quality.

Construction may require temporary disconnection of utilitiessuch as water, gas, and electric.

Alteration of the McMillan Sand Filtration Sitewould affect a local historic resource.

McMillan Sand Filtration PlantIngersoll-Rand G290 GeneratorSource: www.mascus.com

Dump TruckSource: www.ritchiewiki.com

Samuel Gompers House2122 First Street, NW, Bloomingdale

Crane-Mounted Drill Rig


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FIRST STREETTUNNELConstruction Staging andAlternative Parking Locations


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FIRST STREETTUNNEL

Construction Staging Areas

Adams Street Diversion Chamber, Drop Shaft, and Staging Area

Channing Street Mining Shaft and Sewer Connection


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FIRST STREETTUNNEL

Construction Staging Areas

Thomas and First Street Temporary Pumping Station and Staging Area

V Street Diversion Chamber, Drop Shaft, and Staging Area


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FIRST STREETTUNNEL

Parking and Traffic Study

Traffic Study being completed in coordinationwith DDOT

Alternative Parking identified to offset temporaryparking impacts

DC Fire and EMS will be provided continuousaccess to all residences

City Services (such as Trash Collection, Mail, etc.)will continue

Alternative Parking During Construction(approximately 90 spaces)


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FIRST STREETTUNNEL

How to Comment

You can submit your comments several different ways.Choose the one that is easiest for you.

1) Online at http://www.dcwater.com/FirstStreetTunnelEA

2) Email comments to [email protected]

3) Fax comments to (202) 787-2297

4) Mail comments to:

DC Clean Rivers Project

c/o First Street Tunnel Project EADC Water and Sewer Authority

5000 Overlook Ave., SW

Washington, DC 20032

DC Water values and welcomesyour input on this project!

Please be sure to submit your comments no later

than May 15, 2013.

Documents

DC Water First Street Tunnel Project EA Meeting_Boards 2013 04 24