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Massachusetts Water Resources Authority

MWRA Long-term CSO Control Plan

DEP Hearings on CSO Variances forLower Charles River and Alewife Brook/Upper Mystic River

July 18, 2007

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MWRA CSO Control Plan

• MWRA is implementing a Long Term CSO Control Plan (LTCP)

• LTCP consists of 35 projects

• Reduces average annual CSO volume by 85%, from 3.3 billiongallons to 0.5 billion gallons

• 94.5% of remaining volume will be treated

• $811 million cost (2007 dollars)

• Construction period 1996-2015; full verification by 2020

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Current Status of CSO Plan

• 19 of 35 LTCP projects are completed

• 6 projects are in construction

• Total spending thru Jun 07: $409 million

• Average annual CSO discharge volume reduced from 3.3billion gallons to 0.8 billion gallons.

• CSO impacts to water quality greatly reduced

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Reduced CSO Discharges

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CSO Volume/Impacts Reduced Dramatically

• Annual CSO volumes have already been reduced by 2.5 billion gallons(75% since 1988).

• By 2015, 94.5% of the remaining CSO flows will be treated.

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1988 1992 2002 2003 2004 2005 2006 2015

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Untreated Treated

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Dramatic Improvements In Bacterial Water Quality:Wet Weather

Average Enterococcus counts in Boston Harbor in wet weather

The lighter the blue, the better

1987-1998 (Before Secondary Treatmentand South System transfer)

1999 - 2005 (After Secondary Treatmentand New Outfall)

1999 - 2006 1987 - 1991

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Variances

• CSO Long Term Control Plan (LTCP) approved by DEP/EPA

• Projects, CSO control levels and schedules are included in FederalDistrict Court Order

• All projects and post monitoring will be complete by 2020

• DEP/EPA concluded it is not feasible to attain Class B WQS inCharles River and Alewife Brook/Mystic River prior to 2020

• DEP/EPA are committed to reissuing variances for Charles Riverand Alewife Brook/Mystic River through 2020

• Variance requirements are limited to implementing LTCP,estimating/reporting CSO discharges annually, and continuingMWRA receiving water monitoring.

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Variances

“DEP has agreed to issue to the MWRA, and the United StatesEnvironmental Protection Agency (EPA ) has agreed to approve, 5consecutive variances, up to three years duration each, of themandated water quality standards for the Charles River andAlewife Brook/Upper Mystic River. The variances will be grantedthrough the year 2020, and will require the MWRA to comply withthe CSO milestones and levels of control referenced in ScheduleSix as amended.”

Schedule Six Compliance Order Number 199, United StatesDistrict Judge Richard G. Stearns, dated May 8, 2006

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Charles River:A National Model For CSO Control

MWRA has already achieved significant reduction of CSO relatedimpacts to the Charles River:

• Much more flow to Deer IslandTreatment Plant.

• Sewer separation and hydraulicrelief projects completed.

• Upgrade to Cottage Farmfacility completed.

• System optimization and targetsewer separation projects wereadded to the plan and areunderway.

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Revised Charles River Plan

• Total of 9 projects (four added since last variance)

• Total capital cost $73.3 million (four new projects added morethan $20 million)

• Four projects complete, four in design, one to start design nextyear

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Lower Charles River CSO Locations and Projects

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CSO Treatment FacilitiesNew Disinfection and Dechlorination Systems

• Cottage Farm: New disinfection and dechlorination building

• Completed: Jan. 2000

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Stony Brook Sewer Separation

• Completed September 2006, onschedule

• Total cost: $45 million

• 99.7% reduction in discharges:

• Removed stormwater runoff fromneighborhood and MWRA sewersby installing 74,000 feet of newstorm drains serving 609 acres inJamaica Plain, Mission Hill andRoxbury

Before After

22 discharges 2 discharges

44.5 million gallons 0.13 million gallons

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Charles River CSO Control Plan

Floatables Control and Outfall Closings

• Outfalls closed: BOS032, BOS033, BOS028, BOS042, SOM010,MWR021 and MWR022

• Outfalls to be closed: BOS049; Cambridge is monitoring CAM009and CAM011

• Floatables control plans completed:

– Reduced activations at MWR010, MWR018, MWR019, MWR020and MWR023 to zero discharges in a typical year

– Completed underflow baffle installation at CAM005

• Floatables control plans underway: Cambridge to completefloatables controls at CAM007 and CAM017 by December 2007

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Charles River CSO Control Plan

Since last variance issued, 4 projects have been added to Long TermCSO Control Plan for Lower Charles River

• Brookline Connection/Cottage Farm Chamber Interconnection/GateControl

• Bulfinch Triangle Sewer Separation

• Brookline Sewer Separation

• Charles River Valley/South Charles Relief GateControls/Interconnections

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Charles River CSO Controls - Brookline Connection

• Reactivate a 54-inch pipeline under the Charles River and installgate controls, piped interconnection to Cottage Farm CSO facility

• Estimated Total Cost: $4.3 million

• Design Commenced: Sept. 2006

• Anticipated ConstructionNotice To Proceed: June 2008

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Brookline Connection/Cottage Farm InflowImprovements

MWRA commenceddesign Sept. 2006, onschedule.

Design contract: $1.3MTotal cost: $4.3M

Cottage Farmtreated discharges:

1997 goal: 7 activationsand 23.9 million gallons

New goal: 2 activationsand 6.3 million gallons

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Charles River: Bulfinch Triangle Sewer Separation

BWSC commenced design in August 2006, on schedule.

61 acres

Total cost:$4.4 M

Complete:July 2013

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Charles River: Brookline Sewer Separation

Town of Brookline commenced design in November 2006, on schedule.

72 acres

Total cost:$9 M

Complete:July 2013

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Alewife Brook/Upper Mystic River CSO Control

Long Term Control Plan for Alewife Brook/Upper Mystic River includes:

• Cambridge/Alewife Sewer Separation (CAM004 and CAM400)

• MWR003 Gate and Rindge Street Siphon Relief

• Interceptor Connection Upgrades

• Somerville Baffle Manhole Separation (completed 1997)

• Somerville Marginal CSO Facility Upgrade (completed 2001)

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Alewife Brook/Upper Mystic River BasinCSO Locations and Projects

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Alewife Brook Sewer Separation

• Multiple contracts to separate certain combined sewer/stormwatersystems and relieve local connections to minimize CSOdischarges into Alewife Brook

• Project delayed due to wetlands appeal

• Project will be bid and managed by the City of Cambridge, fundedby MWRA and Cambridge

• Estimated Project Value: $102 million

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Alewife Brook CSO Control PlanSewer Separation

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Alewife Brook CSO Control Plan - Cost

Significant cost increases have occurred:

• 1997 Facilities Plan/EIR: $13 M• 2001 Notice of Project Change: $74 M• 2004 Cambridge SSPDR: $94 M• Current cost to complete: $102 M

Continued schedule delays will increase cost burden

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Alewife Brook CSO Control - Status

• Sewer separation construction in Cambridge began 1998

• Work completed to date has reduced CSO activations from 63to 25 (typical year) and annual CSO volume from 50 milliongallons to 33 million gallons

• Significant design changes made in proposed stormwatersystem and wetland basin to address flooding concerns

• Remaining work delayed due to wetland appeals

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Alewife Brook CSO Control - Benefits

• Somerville Baffle Manhole separation: closed 4 Somerville CSOoutfalls

• Alewife Brook CSO Control Plan: will reduce CSO discharges to 7activations (89% reduction) with total annual volume of 7.3 milliongallons (85% reduction)

• Floatables control at all remaining CSO outfalls

• Due to non-CSO impacts (i.e. storm water, illegal connections,overland runoff, and other sources), a higher level of CSO controlwill not result in increased hours of Class B attainment.

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Upper Mystic River CSO Control

• Somerville Marginal CSO Facility Upgrade

– Upgraded disinfection, improved reliability and addeddechlorination

– Completed September 2001

• Other CSO outfalls to Upper Mystic River closed (SOM006and SOM007)

• LTCP goal for Upper Mystic River is 3 treated discharges in atypical year with an annual volume of 3.48 million gallons atoutfall MWR205A