Combined Sewer Overflow Control
Program Annual Report 2003
Massachusetts Water Resources Authority

1. Introduction

2. CSO Progress and MWRA Commitment

3. Costs to Complete the Long-Term CSO Control Plan

4. Progress and Accomplishments in 2003

• 4.1 2003 Progress Highlights
• 4.2 Planning and Regulatory Review
  • Project Reassessments
  • Charles River CSO Variance
  • Alewife Brook/Upper Mystic River CSO Variance
• 4.3 Updating Sewer System Performance and Water Quality Assessments
• 4.4 Safeguarding CSO Benefits in the Long-term

5. Project Implementation

• 5.1 MWRA Managed Projects
  • North Dorchester Bay and Reserved Channel
  • Hydraulic Relief Projects at CAM005 and BOS017
  • East Boston Branch Sewer Relief
  • Fort Point Channel (BOS072-073) and BOS019 Storage Conduit
  • Chelsea Relief Sewers
  • Union Park Detention\Treatment Facility
  • Upgrades to Existing CSO Facilities

• 5.2 Community Managed Projects
  • South Dorchester Bay Sewer Separation
  • Stony Brook Sewer Separation
  • Neponset River Sewer Separation
  • Constitution Beach Sewer Separation
  • Dorchester Brook Conduit In-line Storage
  • Cambridge/Alewife Brook Sewer Separation

• 5.3 Region-wide Floatables Controls and Outfall Closing Projects
• MWRA Floatables Control at Outfalls MWR018-020
  and Outfall Closings at MWR021-022
• CSO Control at Outfall MWRA 010
• BWSC Floatables Control
• Cambridge Floatables Control
• Somerville Floatables Control

• 6. Key CSO Program Activities in 2004

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1. Introduction

The Massachusetts Water Resources Authority (“MWRA”) files this CSO Annual Report for 2003 in accordance with the Federal District Court Order in the Boston Harbor Case. Annual and quarterly CSO reports describe the progress of work to complete MWRA’s long-term CSO control plan relative to milestones in the Court-ordered schedule.

MWRA’s long-term CSO control plan was recommended in the Final CSO Facilities Plan and Environmental Impact Report (the “Facilities Plan/EIR”), which MWRA filed with federal and state regulatory agencies in August 1997. Together with certain plan modifications addressed in subsequent Notices of Project Change and Supplemental EIRs, it recommends 25 wastewater system improvement projects (see Figure 1) to bring CSO discharges at 84 outfalls in the metropolitan Boston area into compliance with the federal Clean Water Act and state Water Quality Standards.

Figure 2 summarizes the scope, schedule and benefits of the plan. The Facilities Plan/EIR received state and federal regulatory approvals in late 1997 and early 1998, respectively, allowing MWRA to move the projects into design and construction.

Figure 2: CSO Plan Summary

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Design and construction milestones for all of the projects are included in Schedule Six of the Federal Court Order in the Boston Harbor Case. Schedule Six calls for the CSO plan to be ful1y implemented by November 2008, although MWRA has reported to the Court that completion of certain projects will take longer due to implementation obstacles or new information questioning a project’s cost and benefit that typically have led MWRA to conduct project reassessments. Several project reassessments were underway in 2003, as MWRA also continued to design and construct other projects on schedule. MWRA expects to request changes to Schedule Six upon completing each reassessment and reaching agreement with the Court Parties. Those projects and the circumstances necessitating more time are reviewed in this report.

This annual report reviews planning, design and construction progress and accomplishments in 2003 and in the quarterly period December 16, 2003, to March 15, 2004. Like previous annual reports, it discusses issues that affect MWRA’s ability to complete the CSO projects on schedule and describes the efforts taken to move CSO control forward. In addition, this report looks ahead at the regulatory decisions, including water quality standards determinations, that must be made to finalize the CSO plan and allow MWRA to complete its CSO control obligations under the Court Order.

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2. CSO Progress and MWRA Commitment

It has been 16 years since MWRA assumed responsibbility for developing and implementing a long-term CSO control plan pursuant to a stipulation entered in the Federal Court case. Initial efforts by MWRA and the CSO communities that involved large-scale projects and system optimization measures resulted in major reductions in CSO discharge that set the baseline for development of a long-term control plan. The long-term plan, recommended by MWRA for regulatory approval in 1997, was one of the first in the nation to be guided by, and to conform to, the new National CSO Policy issued by the U.S. Environmental Protection Agency (EPA) in 1994, as well as Massachusetts’s revised CSO Policy and Guidance issued by the Department of Environmental Protection (DEP) in 1997. Complying with these revised policies necessitated extensive and expensive investigations by MWRA, including flow metering, water quality sampling, system inspections, detailed hydraulic modeling, and a full evaluation of CSO control alternatives over a range of control levels, costs and benefits (efforts MWRA continues to undertake in support of ongoing project reassessments and water quality standards reviews). The result of this work, MWRA’s long-term CSO control plan, evidenced the merits of the federal and state regulatory changes.

To date, MWRA has spent more than $230 million on planning, design and construction of the long-term CSO control plan.  With the cooperation of its CSO communities, MWRA has completed 14 of the 25 projects the plan recommends (see Figure 1 and Table 1).  Five additional projects are well into construction. Of the 84 CSO outfalls addressed in the plan, 21 have been closed to CSO discharges (of the total 35 outfalls recommended to be closed). CSO discharges to Constitution Beach and the Neponset River have been eliminated.

Improvements to MWRA’s wastewater transport and treatment systems since 1987, when MWRA assumed responsibility for developing and implementing a regional CSO control plan in the Federal Court Order, have produced huge reductions in CSO discharges with dramatic improvement in water quality in many areas (see Figure 3).  The wastewater system improvements, which include upgrading the Deer Island Treatment Plant and associated pumping stations, as well as completed CSO projects, have reduced average annual volume of CSO discharge (in a typical rainfall year) from 3.3 billion gallons in 1988 to 0.8 billion gallons in 2003, with 64% of the remaining overflow receiving treatment at MWRA’s five CSO facilities.

CSO impacts to water quality have been greatly reduced.  CSO discharges to South Boston beaches have been cut almost in half with the improvements to pumping capacity at Deer Island from 1989 to 2000. Water quality samples collected at Carson Beach in dry and wet weather in the period 1996-2000 show 94 percent compliance with swimming standards.  During the past two summers (2002-2003), of the 19 beach postings at Carson, only 5 were attributable to rainfall conditions that may have triggered a CSO  activation the remaining postings were either precautionary or occurred during dry or damp weather, when CSOs did not discharge (defined as rainfall exceeding 0.5 inch).

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For Boston Harbor, a decrease in wet-weather bacteria counts harbor-wide since the late 1980s (Figure 4) shows the cumulative effect of the Boston Harbor Project and CSO control projects.  The counts in the outer harbor are now at or below detection limits and well within the swimming standard even during wet weather.  Boston Harbor as a whole generally meets swimming standards.  However, bacteria counts remain elevated in some shoreline areas,embayments, the Inner Harbor and the rivers, particularly after heavy rain. 

Figure 3: Annual Overflow Volume Reductions

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Of the rivers tributary to BostonHarbor, the Neponset, Mystic Rivers and Alewife Brook continue to suffer from poorest bacterial water quality and show little change over the past ten years. Bacteria counts in these rivers are frequently elevated in dry weather and following light rainfall, indicating that dry weather pollution sources and stormwater are problematic in these areas.  The lower ends of the Mystic and Neponset Rivers frequently fail to meet standards in both wet and dry weather, even though CSO discharges in these areas are treated, have been eliminated or rarely occur. 

The Charles River, on the other hand, has shown dramatic improvement over the past decade in both wet and dry weather. Nowhere were CSO discharges more affected by improved pumping capacity at Deer Island than along the Charles River, where water quality has improved dramatically since monitoring began in the late 1980s.  Geometric mean bacteria counts in the Charles River decreased nearly 10-fold between 1989 and 2001(See figure 4), although water quality continues to be poor in wet weather at the Stony Brook (where MWRA and BWSC are constructing a sewer separation project to greatly reduce CSO discharges) and Laundry Brook (which is not affected by CSOs).

Figure 4: Charles River Data

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Shoreline water quality is highly variable and subject to numerous pollution sources typical in an urban harbor.  Carson and Constitution beaches have generally good water quality, with at least 90% of samples meeting standards. 

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3. Cost to Complete the Long-Term CSO Control Plan

The budget for MWRA’s CSO Program has grown considerably since the long-term CSO control plan was first proposed in the 1994 CSO Conceptual Plan and System Master Plan and approved in 1997-8. Project cost estimates (Table 2) have been affected primarily by site-specific conditions, construction requirements and impact mitigation measures identified during the preliminary design phase of each project.

The total cost of the CSO plan (planning, design and construction) has risen from $411 million when the Final CSO Conceptual Plan was issued in 1994, to $481 million when the Final CSO Facilities Plan and Environmental Impact Report was approved in 1997, to $645 million in MWRA’s Approved FY04-06 CIP (see Figure 5).  The latest cost estimate continues to carry a cost for the North Dorchester Bay and Reserved Channel projects ($229 million) based on the 1997 recommended plan, pending completion of the reassessment. It also carries the cost of the 1997 recommendation for hydraulic relief of the East Boston Branch Sewer. Revised project recommendations and regulatory decisions expected to be made in 2004 for South Boston, East Boston, and the Charles and Alewife/Mystic variances may significantly increase cost to MWRA and financial burden on its ratepayers.

Table 2.    Cost of CSO Plan

(1)  From MWRA approved FY04-06 Capital Improvement Program (CIP).

(2)  Based on the recommended plan in the 1997 Facilities Plan/EIR, now under reevaluation.

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MWRA spending on its CSO program from 1987 through calendar year 2003 exceeded $240 million. In 2003 alone, MWRA spent approximately $45 million in CSO control, with the bulk of spending on project construction, including the South Dorchester Bay and Stony Brook sewer separation work and the Union Park and East Boston contracts.  Annual spending has increased over the last few years and will continue to increase as more projects move into construction.  Spending is expected to peak in FY09, at $90.5 million, and continue through at least FY12.

Table 4:  CSO Program Spending

Note:  From MWRA’s approved FY 04-06 CIP.  MWRA’s fiscal year (FY) ends on June 30.

Numerous milestones are included in Schedule Six of the Federal District Court Order for commencement and completion of planning, design and construction of the 25 CSO projects.  Since 1994 when MWRA first proposed a new CSO control plan and implementation schedule, many CSO project scope and schedule changes have been proposed by MWRA and accepted by the Court Parties and the Court. As recommendations and regulatory decisions unfold in several key areas over the next year, MWRA expects more changes will occur.

MWRA believes that decisions from the project reassessments and variance reviews, as well as their total financial impact, should take into consideration current economic conditions and MWRA’s loss of debt service assistance, as well as the impacts on water and sewer rates.  While MWRA believes it is reasonable to continue on schedule with those CSO projects that clearly provide benefit commensurate with cost, it also believes that decisions on projects reassessments and related project schedules must take into serious consideration the overall cost of the program, the huge cost increases to date, escalating water and sewer rates and their economic impacts on MWRA ratepayers, especially the many ratepayers already suffering hardship.

Figure 5: Risk of Cost Increases

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MWRA plans to commence discussions with Court Parties on a review and revision of CSO project scopes, schedules and priorities as part of the process for the key, outstanding decisions that need to be  made for South Boston, East Boston and other areas.  MWRA’s purpose with these discussions is to move CSO control and water quality improvement forward on realistic and reasonable schedules, with a level of assurance that benefits will be commensurate with cost and with a consideration of the current and projected economic difficulties.  In this way, MWRA hopes to bring closure to the long-term CSO control plan which it committed to develop and implement under the 1987 stipulation in the Federal Court case.

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4.Progress and Accomplishments in 2003

4.1 2003 Progress Highlights

The following summarizes key accomplishments in 2003.  More information on each of these items is presented later in this report.

• MWRA commenced the $40 million construction contract for the Union Park Detention/Treatment Facility in March, in compliance with Schedule Six. 
• MWRA also commenced the $5.5 million first construction contract for the East Boston Branch Sewer Relief project (outfalls BOS003-014) in March, in compliance with Schedule Six. 
• MWRA substantially completed its reassessment of engineering options for finishing the East Boston Branch Sewer Relief project and commenced discussions with EPA and DEP towards recommending a final plan. 
• MWRA completed its reassessment of CSO control alternatives for the South Boston beaches (North Dorchester Bay) and the Reserved Channel.  On April 14, 2004, the MWRA Board of Directors approved a recommended plan to include in the Supplemental Facilities Plan and Environmental Impact Report that MWRA will file with the Massachusetts Executive Office of Environmental Affairs’ MEPA Office by April 30, 2004.  The recommended plan includes a 17-foot diameter storage tunnel and ancillary facilities to effectively eliminate CSO discharges to North Dorchester Bay and collect separate stormwater in up to a one-year storm event.  It also includes construction of a new storm drain to redirect certain separate stormwater discharges to South Dorchester Bay to achieve a higher level of stormwater control along the beaches of North Dorchester Bay.  For Reserved Channel, the recommended plan proposes sewer separation to greatly reduce CSO discharges.  The estimated cost of the recommended plan, exclusive of site acquisition costs, is $257 million in 2004 dollars.
• MWRA completed its early design reassessment of the CSO storage conduit projects at outfalls BOS072 and BOS073 on the Fort Point Channel and at outfall BOS019 on the Little Mystic Channel. While MWRA confirmed the cost-benefit of the BOS019 storage plan, it filed a Notice of Project Change in June recommending that the Fort Point Channel storage project be replaced with a plan for sewer separation and system optimization that would exceed the 1997 CSO control goals at reduced cost and impact.  On February 27, 2004, the Court accepted an MWRA motion seeking to incorporate the project change into related milestones in Schedule Six. 
• Boston Water and Sewer Commission (“BWSC”) continued to make design and construction progress on the sewer separation projects it assumed responsibility for implementing, with construction activities reaching peak levels in 2003.  Construction progress on the South Dorchester Bay project has surpassed the Court-ordered progress level, and construction progress on the Stony Brook sewer separation project has quickly ramped up such that it will surpass the Court-ordered progress level in 2004.  During calendar year 2003 alone, BWSC incurred $29 million in MWRA eligible costs for design and construction of the CSO projects it is implementing, bringing total eligible spending to date for the BWSC projects to approximately $90 million. 
• MWRA and the City of Cambridge completed the MEPA review requirements for the revised Cambridge/Alewife Brook sewer separation project, allowing CSO control for Alewife Brook to move forward.
• In July, MWRA submitted the Final Variance Report for Alewife Brook and the Upper Mystic River to DEP, in accordance with conditions in the regulatory variance for CSO discharges to these waters. The report shows that higher levels of CSO control than the level provided by the revised plan for Alewife Brook sewer separation would not yield additional water quality improvement.  Information in the report is expected to be used by DEP to help make a water quality standards determination for the Alewife Brook and the Mystic River Basin.  MWRA expects DEP to make its determination by September 1, 2004, when the variance ends. 
• In January 2004, MWRA submitted its Cottage Farm CSO Facility Assessment Report to MEPA, EPA and DEP, in accordance with conditions in the regulatory variance for CSO discharges to the Charles River.  The report shows that construction of additional storage basins at MWRA’s Cottage Farm CSO Treatment Facility would not provide a water quality benefit, and it describes how planned sewer separation work and proposed optimization of MWRA’s wastewater system will further reduce CSO discharges to the Charles River.  The report also recommends that DEP extend the Charles River variance beyond the current end date of October 1, 2004, until the water quality benefits of ongoing and planned work to reduce CSO and non-CSO pollution are realized.
• In May, MWRA reported to EPA and DEP that data from a depth sensor it installed in the Boston Marginal Conduit in 2001 confirmed that CSO outfalls MWR018, 019 and 020 along the Charles River Esplanade rarely activate, as MWRA had predicted when it sought relief from floatables control requirements at these outfalls from EPA and DEP.
• In August, BWSC completed work to construct system optimization plans (SOPs) to lower CSO discharges to the Dorchester Brook Conduit, which drains to Fort Point Channel. The work involved the raising of an overflow weir and the installation of a new tide gate, which were recommended by MWRA and were part of the basis for the Court’s July 2001 decision to remove the Dorchester Brook Conduit In-line Storage project from the long-term CSO control plan and Schedule Six. 
• MWRA completed development of a new hydraulic model of its wastewater conveyance and treatment systems.  The new, state-of-the-art model replaces the model MWRA developed in 1992 that supported the past 11 years of CSO planning and design work.  The new model allows MWRA to conduct more efficient and more detailed system performance evaluations, including the impacts of system changes and the optimization of hydraulic capacity and operational control. 

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4.2  Planning and Regulatory Review

• Since late 1997 and early 1998, when EPA and DEP issued water quality standards determinations and CSO plan approvals, MWRA has conducted additional planning level investigations to support continuing regulatory review and remaining regulatory decisions.  These investigations fall into the following areas:
• Project cost and benefit reassessments,
• Charles River CSO Variance, and
• Alewife Brook/Upper Mystic River CSO Variance

In 2003, MWRA reassessed or revised the recommended CSO control plans for North Dorchester Bay and Reserved Channel, East Boston, Fort Point Channel and Alewife Brook.  Information on the progress of the reassessments and any project changes recommended by MWRA is presented in Section 5 for each project.

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Charles River CSO Variance

Figure 6: Recommended system optimization measures to reduce discharges at Cottage Farm CSO Facility

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The Charles River CSO variance, issued by DEP on October 1, 1998, originally covered a two-year period during which MWRA began to implement its 1997 CSO plan for the Charles River Basin and conduct additional water quality and CSO control evaluations.  By issuing the variance, DEP intended that the evaluations would provide more information to support its determination on water quality standards and the required level of CSO control for the Basin.  The variance was issued with the goals of minimizing CSO impacts in the short-term, reassessing the relative impacts of CSO and stormwater pollutant loadings to the Basin, evaluating the prospects for maximum water quality improvement through the control of non-CSO sources of pollution, and evaluating the cost and benefit of higher levels of CSO control at the recently upgraded Cottage Farm CSO facility (see page 40). 

In this timeframe, USGS embarked on an intensive water quality study of the Basin, in part funded and technically supported by MWRA, to assess non-CSO sources of pollution, especially urban stormwater, and the extent to which these sources could be controlled and attendant improvement in water quality could be achieved.  The improvements predicted under the USGS study would, in part, form a new baseline for determining the benefits of higher levels of CSO control.

Cottage Farm CSO Control Facility

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As all of the work related to the variance progressed, reasons to provide more time before making a long-term decision on water quality standards arose, and DEP extended the variance four times. The latest extension was issued by DEP in September, 2003, pushing out the end date of the variance to October 1, 2004. DEP’s reason for the latest extension was to provide ample opportunity for public and regulatory review of the new water quality information and a required report by MWRA on the performance and impacts of its upgraded Cottage Farm facility, as well as a DEP tentative determination on water quality standards that would follow.  This extension also allowed MWRA additional time to complete water quality sampling necessary to assess the performance of its Cottage Farm treatment facility upgrades and the impacts of the treated discharges on water quality in the Basin, prior to completing the Cottage Farm CSO Facility Assessment Report.

In 2002, USGS completed its work to identify a range of stormwater pollution reductions that could be achieved by implementing Best Management Practices (BMPs) in the watershed.  With this information, MWRA developed different modeling scenarios to assess the potential for water quality improvement in the Charles River with different levels of reduction of stormwater bacteria loading. In January 2003, MWRA met with DEP, EPA, CRWA and USGS to reach consensus on baseline bacteria concentrations in stormwater and the percent reductions to be used by MWRA in its evaluations on the benefits of higher level of CSO control at Cottage Farm.

In the fall of 2003, MWRA completed the water quality sampling program related to Cottage Farm and, in January 2004, it submitted the Cottage Farm CSO Facility Assessment Report to MEPA, EPA and DEP.  In addition to presenting an assessment of the treatment performance of the upgraded Cottage Farm facility, it also evaluated the cost, water quality benefits and environmental impacts of alternatives providing additional storage capacity at the facility or improving the hydraulic performance of its interceptor system.  Finally, the report presented an updated description of the recommended plan for CSO control for the Charles River and a preliminary economic impact analysis which MWRA plans to supplement with economic information it is now gathering. 

Results of performance testing on the CSO facility indicated that the new disinfection and dechlorination systems perform well, with the facility effluent able to meet the limits in MWRA’s NPDES permit. Water quality sampling and modeling results indicated that the facility’s treated discharges do not elevate bacteria concentrations in the river.  The report showed that construction of additional storage capacity at the Cottage Farm facility would not be cost-effective and would not reduce the hours of violation of water quality standards primarily caused by other pollution sources, and described how planned sewer separation work and proposed optimization of MWRA’s wastewater system will further reduce CSO discharges to the Charles River.

MWRA’s report recommended that DEP further extend the Charles River variance beyond the current end date, and not consider changing water quality standards for the Charles River Basin until the water quality benefits of ongoing and planned work to reduce CSO and non-CSO pollution are fully realized.

The variance included other conditions on MWRA, BWSC and Cambridge.  One condition required MWRA to submit a summary of existing water quality data for the Basin. Staff of MWRA’s Environmental Quality Department are completing a report entitled CSO Receiving Water Quality Monitoring in Boston Harbor and Tributary Rivers, 1989-2001, which compiles and evaluates MWRA data for that 12-year period.  In January 2003, MWRA submitted a draft Charles River chapter of that report to satisfy this variance condition.

As noted earlier in this report, water quality in the Lower Charles River Basin has improved tremendously over the last decade, in part as a result of significant reductions in CSO discharges at the Cottage Farm facility and several other outfalls.  Greatly improved pumping capacity at the Deer Island Treatment Plant, improved sewer system operation and maintenance, and the implementation of projects under the long-term CSO control plan have contributed to the CSO reductions. The completed CSO projects include hydraulic relief at outfall CAM005; upgrade of the Cottage Farm facility; the closing of several outfalls by MWRA and BWSC; and the ongoing sewer separation work in areas along the Stony Brook Conduit, which is more than 50% complete.

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Alewife Brook/Upper Mystic River CSO Variance

The Alewife Brook/Upper Mystic River CSO Variance, issued by DEP on March 5, 1999, originally covered a three-year period during which MWRA was to implement its 1997 CSO plan and conduct additional water quality and CSO control evaluations, prior to DEP making a long-term decision on water quality standards and the appropriate level of CSO control for these receiving waters.  As with the Charles River Variance, DEP specified a number of conditions that the three CSO permittees -- MWRA and the cities of Cambridge and Somerville -- must fulfill, with the goals of minimizing CSO impacts, better assessing relative impacts of CSO and stormwater pollutant loads, and reevaluating CSO control alternatives for these receiving waters.  Among the original conditions, MWRA, Cambridge and Somerville were required to perform stormwater monitoring, and MWRA was required to conduct receiving water sampling and prepare a report reassessing the costs and benefits of higher levels of CSO control, using the new water quality data. This final variance report was intended to summarize and evaluate the information gathered during the variance process and reevaluate the recommended level of CSO control for Alewife Brook and Upper Mystic River. Once the variance report was complete and public comments were received, DEP would make its water quality standards determinations.

In May 2002, DEP extended the variance by 18 months, to September 2003.  The extension also postponed the deadline for submission of the final variance report discussed above by one year, to July 1, 2003. This time extension was necessary to allow Cambridge, Somerville and MWRA to complete required stormwater sampling. MWRA also noted that the extension would allow Cambridge and MWRA to complete the MEPA process associated with the revised Cambridge/Alewife Brook sewer separation plan prior to the variance period ending and DEP making its final determination on water quality standards.  MWRA submitted the report on July 1, and MEPA review of the revised sewer separation plan was completed a couple months earlier, in May 2003.  But in September 2003, DEP extended the variance period to September 1, 2004, its current end date, to provide ample opportunity for public and regulatory review of the water quality information collected since the variance began, the report prepared by MWRA and a tentative DEP determination on water quality standards that would follow.

MWRA submitted the Final Variance Report for Alewife Brook and Upper Mystic River to EPA and DEP on July 1, 2003.  The report presented MWRA and Cambridge’s final plan for Alewife Brook CSO control.  It also presented the results of MWRA’s updated evaluation of the cost and performance of CSO control alternatives offering higher levels of CSO reduction and an affordability analysis.  The report concluded that higher levels of CSO control would not reduce violations of water quality standards in Alewife Brook, and could cause widespread social and economic hardship in parts of MWRA’s service area. MWRA plans to supplement the affordability analysis in the report with information it is now preparing, and expects the additional information to be available by March 2004.

To facilitate public review of MWRA’s report and public input into the water quality standards decision-making process, DEP sponsored a forum on Alewife Brook water quality issues on September 23, 2003. DEP outlined the regulatory framework for the variance and future decision-making. Panelists from MWRA and the Mystic River Watershed Association presented water quality data and analyses. 

The 90-day public comment period on the Final Variance Report ended on October 31, 2003.  MWRA understands that the report and the public comments are now being reviewed by DEP to support its long-term decision on water quality standards and the appropriate level of CSO control for Alewife Brook and the Upper Mystic River, a decision DEP expects to make before the variance ends.

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4.3  Updating Sewer System Performance and Water Quality Assessments

In 2003, MWRA continued to perform hydraulic modeling and water quality sampling to assess updated sewer system performance, remaining CSO discharges and their impacts, and changing water quality conditions as CSO control is implemented.  A considerable amount of hydraulic modeling and water quality sampling was conducted to comply with the requirements of MWRA’s NPDES permit or the conditions of regulatory variances.  The permit requires MWRA to estimate the quantity of CSO discharge from active outfalls in every storm event occurring in the previous year.

An evaluation of the efficacy of CSO controls can be made by comparing discharges from year to year and relating them to what would be expected to occur in “typical year” rainfall conditions, which were the basis for the CSO control goals in the 1997 Facilities Plan/EIR.  From the modeling results, one can generally assess whether MWRA is “on track” towards realizing the predicted benefits of its CSO plan and associated investment.

To support the modeling work, MWRA deploys temporary flow meters in several targeted areas, on a rotating basis, to supplement data from dozens of permanent meters in the sewer system. The targeted areas where temporary meters were deployed in 2003 included the outfalls along North Dorchester Bay (to also support the South Boston CSO reassessment), the Charlestown Branch Sewer, downstream of outfall BOS019 (to also support value engineering for the BOS019 storage conduit), and outfalls BOS017, CHE003 and CHE008 (to also check the hydraulic benefits of the completed CSO projects affecting those outfalls).  For NPDES purposes, the meter data were used to verify the accuracy of the model in predicting system flows and CSO discharges, and to recalibrate the model if necessary.  In addition to using flow data from its own temporary and permanent meters, MWRA uses operational records from its headworks and CSO treatment facilities, as well as information collected by the CSO communities.

In addition to the NPDES related program, MWRA conducted hydraulic model assessments and water quality sampling in 2002 to support project reassessments in South Boston (North Dorchester Bay and Reserved Channel projects), East Boston (East Boston Branch Sewer Relief), and the Fort Point Channel and Charlestown areas (Fort Point Channel and BOS019 Storage Conduits) and to support the preparation of the variance reports for the Alewife Brook/Upper Mystic River and the Cottage Farm Facility.  These efforts are described in the variance and project sections of this annual report.  Overall, the hydraulic modeling and water quality sampling work performed in 2003 continued to provide updated assessments of CSO and water quality conditions, system-wide.

Also in 2003, MWRA completed calibration and verification of its new wastewater system model that is already beginning to replace the hydraulic model MWRA has been using since 1993.  MWRA’s plans call for the new model, built from InfoWorks software, to completely replace the older sewer system model, which used EPA’s Stormwater Management Model (SWMM) software, in the near future.  MWRA will then use the InfoWorks model to perform all CSO related hydraulic modeling, including modeling to support the NPDES permit requirement described above.  MWRA plans to begin using the new model in 2004 for the NPDES work.

MWRA used the new model in 2003 to test hydraulic optimization scenarios at strategic wet weather facilities and in key subsystems and to evaluate certain operational strategies for extreme wet weather events, with the goal of maximizing wet weather flow conveyance and treatment capacity and minimizing system backups, flooding and overflows.

The new model provides a means to efficiently and accurately evaluate detailed and sophisticated system enhancements, including real-time control strategies.  For instance, MWRA took advantage of the higher technical sophistication of the model to evaluate system optimization strategies for lowering CSO discharges at the Cottage Farm Facility and to evaluate the CSO control benefits of increasing the pumping capacity at the Alewife Brook Pump Station.

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4.4  Safeguarding CSO Benefits in the Long-term

Another important activity in MWRA’s CSO control program is the review of proposed projects involving changes to the MWRA or community sewer systems or development in the service area.  Careful consideration must be given to the impacts of sewer system improvements and development projects to ensure that these projects will not compromise sewer system performance, the attainment of CSO control goals or the benefits of CSO control long into the future.

Through coordinated efforts with its CSO communities (Boston, Cambridge, Chelsea and Somerville) and with DEP, MWRA has reviewed large development plans (e.g. Environmental Notification Forms, Draft and Final Environmental Impact Reports) and worked with developers to ensure that project plans mitigate any potential for negative impacts to the sewer system.  Development projects typically increase the amount of wastewater flow to the community and MWRA combined sewer systems, which could increase the burden on the systems during wet weather and exacerbate system flooding and overflows. 

Communities typically require development projects to remove on-site stormwater flows from the combined sewer system where possible, or to prevent any increase in stormwater flows that must continue to drain to a combined sewer.  To offset the impacts of the additional sanitary flow that typically accompanies large-scale development, DEP, MWRA and the communities urge developers to remove, at an appropriate ratio (e.g. 2:1, 3:1 or 4:1), an amount of stormwater or infiltration (groundwater entering the pipes). The developer may accomplish this on the project site, by separating sewers and storm drains that were  previously combined, or the developer may perform work off-site to remove wet weather flows from a hydraulically related sewer system.  The result in either case is no net increase in wet weather overflows, at a minimum, or a net reduction in wet weather flows and overflows.  Such is the case with the construction of Boston’s Convention and Exhibition Center, which will remove a much greater amount of stormwater from the combined sewer system than it will add as new wastewater flow, which by itself will significantly reduce CSO discharges at several outfalls along the Reserved Channel and Fort Point Channel.  In 2003, major development projects reviewed by MWRA included the North Point projects in Cambridge and projects along the East Boston waterfront.  In all cases, developers have been cooperative, and measures to mitigate the impacts of new wastewater flows are included in their plans.

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5.   Project Implementation

This section defines the scope and schedule of each of the projects recommended in the long-term CSO control plan and describes progress made in 2003, project changes, if any, and key issues that may affect progress and compliance with Court established milestones.  Many of the 25 CSO projects recommended in the Facilities Plan/EIR were combined into design and construction packages, and that is how they are presented below.

5.1  MWRA Managed Projects

NORTH DORCHESTER BAY AND RESERVED CHANNEL

Pursuant to Schedule Six, MWRA was required to complete construction of the North Dorchester Bay Consolidation Conduit and the Reserved Channel CSO Facility by March 2003, and complete construction of the Reserved Channel Consolidation Conduit by March 2005.  After an extensive design effort that began in 1997, it became clear, in late 1999, that MWRA’s recommended plan could not be constructed. Community opposition to the siting of the large pumping and treatment facility that was key to that plan prevented MWRA from obtaining state legislation necessary to acquire access to the facility site, known as “Site J.”  In response, MWRA began the South Boston CSO reassessment in September 2001, with the objective of identifying a new plan for the control of CSO discharges in North Dorchester Bay and the Reserved Channel.

Reassessment – Phase I

MWRA’s reassessment first identified and evaluated the full range of technology options that might lead to a cost-effective plan that could gain public and regulatory acceptance.  In this “Phase I” of the reassessment, MWRA kept options open to the fullest extent, being careful not to prematurely place restrictions on engineering approach, level of CSO control, potential for adding separate stormwater control and siting. More than 160 alternatives to control CSO discharges were identified and reviewed, and they included hydraulic relief, treatment, storage, relocation, and sewer separation. Phase I evaluations culminated in early 2003 in a short-list of three preferred CSO control approaches for North Dorchester Bay:  interceptor relief for a 1-year level of CSO control, a soft ground or deep rock storage tunnel of varying diameters for a 2- to 25-year level of CSO control and a 13-foot storage/conveyance tunnel with a large pumping facility for CSO elimination.  All of these options were paired with sewer separation to control CSO discharges to the Reserved Channel.

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Reassessment – Phase II

Early in “Phase II” of the reassessment, MWRA placed emphasis on three key project objectives: 1) implementing CSO control in phases, 2) providing for future phases that could attain elimination or near-elimination of CSO discharges to the South Boston beaches and 3) minimizing impacts to the community during construction and in the long-term.  A phased approach would involve constructing CSO measures in a step-wise fashion to provide a high level of control in the near-term (1 year storm or higher); measuring interim system performance and receiving water improvements to confirm incremental benefits; and identifying future modules that could eliminate CSO discharges to the beaches.  The phased approach would provide a means to confirm water quality benefits commensurate with cost and to provide a more accurate understanding of the additional benefits that might be achieved through further expenditures and higher levels of control. These key objectives led MWRA to explore various modifications to the three CSO control options it carried from Phase I.

MWRA invested considerable effort during the spring and summer of 2003 to revise the interceptor relief option.  This option as originally defined in Phase I had the unique attribute of not requiring permanent aboveground facilities, but did not then include means to phase in higher levels of control, towards elimination.  With further engineering investigations, MWRA developed a modified interceptor relief option that would still not require aboveground facilities, at least in the near-term, would improve the near-term performance and would allow build-on towards elimination in the future.  This concept employed larger relief pipe diameters that would convey more flow to MWRA’s Columbus Park Headworks (and eventually Deer Island Treatment Plant) and prevent CSO discharges to the beaches up to the 2-year storm, while also allowing conveyance of larger flows to a large storage facility that might be constructed in the future to prevent CSO discharges in a 25-year storm.  The storage facility likely would comprise underground tanks, possibly located under a portion of Moakley Park, and an aboveground access and odor control building.

The other two control options carried from Phase I, a storage tunnel and a conveyance tunnel with a large pumping facility, were combined into a phased concept.  The storage tunnel alone, with a modestly sized dewatering facility, would provide a 5-year level of CSO control in the near-term, defined primarily by the diameter of the tunnel and attendant storage capacity.  If a higher level of control in the future was warranted, a large pumping facility could be added to the tunnel to direct flows exceeding the storage capacity of the tunnel to a less sensitive water body, such as Reserved Channel.  In full build-out, this option was similar to the MWRA’s 1997 recommended plan. 

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By mid-2003, the two preferred control alternatives were defined as: 1) revised interceptor relief, with a 2-year level of CSO control in the near-term and future build-out to a large underground storage tank and odor control facility for a 25-year level of control in the long-term (see Figure 7), and 2) a 13-foot diameter storage tunnel,providing a 5-year level of CSO control in the near-term, with future build-out to a large 300 million gallons per pay (mgd) pumping station to allow conveyance of excess flows to the Reserved Channel for CSO elimination to the beaches (see Figure 8).  Again, these alternatives were paired with sewer separation for the Reserved Channel.

Both of these alternatives involved a phased approach to CSO control.  While the interceptor relief alternative offered an essentially fixed level of CSO control (two-year) in its initial phase, enlarging the tunnel diameter could significantly increase the level of initial CSO control provided by the storage tunnel. Given the challenges associated with implementing the second phase of either alternative if regulatory agencies and the Court required MWRA to meet the high level of CSO control provided by the previous “Site J” plan, MWRA recognized the value of

pushing the storage tunnel concept further, by exploring the potential for CSO elimination without the need for a large pump station in the future.  MWRA and its consultant devoted considerable effort in the fall of 2003 to evaluating the feasibility of a larger tunnel. The aim was to optimize the tunnel diameter and length to achieve sufficient storage volume to hold CSO discharges up to the 25-year storm, which MWRA believed would be functionally equivalent to elimination, given the capacity of the upstream collection system, and to minimize siting impacts, while minimizing geotechnical risks. 

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MWRA believes a 25-year level of control is functionally equivalent to CSO elimination because BWSC’s combined sewer system serving the South Boston neighborhood has a hydraulic capacity to collect and convey combined flows only up to a 25-year storm.  Higher flows caused by storms of greater magnitude (i.e. 50-year or 100-year) cannot be captured or conveyed by the BWSC system to the main interceptor or the outfalls.

These efforts yielded what MWRA now proposes as the preferred alternative: a 17-foot diameter, storage tunnel (Figure 9) that would provide enough storage to prevent CSO discharges even in a 25-year storm, or functional elimination. The storage tunnel would have a 10 mgd dewatering pump station at its downstream end, possibly within the entrance to Conley Terminal, and a ventilation and odor control building at its upstream end, near outfall BOS087 and the State Police building, where the 1997 plan had recommended a similar facility.  At a 25-year storm level of control, this alternative provides a level of control comparable to the 1997 project goal without the need for a large pumping and treatment facility discharging to Reserved Channel.

In November 2003, MWRA conducted an intensive review of the estimated costs of the remaining control alternatives, including a review of estimating methods, project assumptions, construction schedules, unit costs, risks and contingencies.  This assessment yielded updated cost estimates for the control alternatives, which were then used by MWRA staff in communications with the MWRA Board of Directors and the public. 

Periodically throughout Phase II, MWRA met with EPA, DEP, the State Office of Commonwealth Development, local and state elected officials, community residents, Save the Harbor/Save the Bay, the Conservation Law Foundation, The Boston Harbor Association, property owners, including Massport, and others to update them on the reassessment and remaining alternatives, in an effort to forge a plan that could gain consensus.  MWRA staff also conducted a public meeting in June 2003 and briefed the MWRA Board of Directors on several occasions. 

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Understanding Water Quality

One of the aims of the reassessment was to collect additional water quality data in North Dorchester Bay to update our understanding of the relative contribution of CSO and certain non-CSO pollutant sources. As described in some detail in previous reports to the Court, MWRA undertook a water quality sampling program, from September 2001 to December 2003.  During the two-year program, sampling crews mobilized 20 times and succeeded in collecting samples during four storms with confirmed CSO activations.  The data gathered from this considerable effort and expense has been useful in the water quality assessments.

For several reasons, MWRA expanded its capabilities to monitor CSO activations along the South Boston beaches in 2003.  EPA and DEP had urged MWRA to monitor CSO discharges, and MWRA was interested in verifying collection system model predictions with field data and the sampling crew could use information about the flow level in the regulators to supplement the forecast in deciding when to mobilize crews.  In the spring and summer 2003, MWRA installed temporary meters in three of the CSO regulators along the beach as part of our ongoing NPDES monitoring requirement.  In the fall, MWRA operations staff purchased and installed depth meters at all CSO regulators along the beaches.  Depth data from these instruments are useful in determining whether flow overtopped the weir and entered the outfall pipe. The depth of flow above the weir can be correlated with the depth of the tide, to determine the likelihood that a CSO discharge occurred (the level of the water in the regulator has to be above the weir, and above the tide, in order for a discharge to occur).  These new meters are equipped with telemetry and allow MWRA staff to monitor water levels during the course of a storm. 

Since the beginning of the reassessment, MWRA has shared information with the Science Advisory Committee (SAC), a group of regional scientists convened by Save the Harbor/Save the Bay to provide independent scientific input on water quality issues in North Dorchester Bay.  MWRA and its consultant made periodic presentations regarding water quality data and modeling to the SAC during 2003. 

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Stormwater Control

Throughout the reassessment, MWRA has stressed its obligation to develop and implement a plan that provides a high level of CSO control for the beaches.  As the reassessment progressed, it became clear that to reach consensus with the regulatory agencies and court parties and satisfy the commitments within the existing court order, the new recommended plan would have to provide some level of stormwater control.

Reasons for the original plan calling for the accommodation of separate stormwater control (i.e. low incremental cost and water quality benefits) have not changed.  Analyses of additional water quality data collected during the reassessment support earlier assumptions that separate stormwater and dry weather conditions in the CSO outfalls contribute to beach closings even more frequently than CSO discharges. In addition, EPA, the Conservation Law Foundation and the Federal Court have strongly urged MWRA to meet the water quality benefits of the original plan, including benefits derived from stormwater management.  In the most recent compliance order, dated February 20, 2004, the Court stated the following:

I share the concerns expressed by the United States and the Conservation Law Foundation with regard to the Authority’s lack of attention to the issue of stormwater discharge, which is an issue that should be addressed in addition to CSO control.

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Finally, MWRA believes that public acceptance will hinge on a plan that extends use of the large storage volume provided by the tunnel to the many storm events that do not cause CSO discharges but clearly contribute to beach closings.

The storage tunnel alternative has the capability to accept stormwater flows, but at the risk of reducing or otherwise compromising CSO control.  With the installation of control gates that could remain open during smaller storms to accept stormwater, but be closed when larger storm events are forecast to dedicate the tunnel to CSO control, the 17-foot diameter tunnel could accommodate all CSO and separate stormwater flows up to a one-year storm event while still providing a 25-year level of dedicated CSO control.  Under this plan, in a typical year there would be no CSO discharges or stormwater discharge to the beaches, compared with 21 CSO discharges and about 108 stormwater discharges now.

Recently, the Court Parties have asked MWRA to explore implementing a project, previously proposed by BWSC, to redirect separate stormwater from the BOS087 tributary area through an enlarged stormwater drain along Morrissey Boulevard and discharge it to South Dorchester Bay at an existing stormwater outfall near the entrance to the University of Massachusetts campus.  Modeling indicates that outfall BOS087 accounts for about half of the separate stormwater entering North Dorchester Bay.  By redirecting this stormwater, the 17-foot tunnel may be capable of controlling separate stormwater discharges to North Dorchester Bay in up to a five-year storm event, as provided in the previously approved plan. It is anticipated that this work would be managed by BWSC and funded by MWRA.  MWRA would need to evaluate the performance and operation of the new stormwater outfall in an effort to reduce the volume of stormwater discharges from this outfall to South Dorchester Bay and agree jointly to implement any feasible optimization strategies with BWSC.

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Recommended Plan Summary

On April 14, 2004, the MWRA Board of Directors voted to approve a recommended plan for CSO control for North Dorchester Bay and the Reserved Channel.  The recommended plan, which will be presented in the SFP/EIR, shown in Figure 10.  It comprises the following components:

• 17-foot diameter, 2.1 mile storage tunnel mined beneath Day Boulevard with a pump station at Conley Terminal and odor control facility behind the State Police building near outfall BOS087.
• Operable gates at outfalls BOS081 through BOS086 to allow the tunnel to collect separate stormwater in most storms.
• A 12x12-foot storm drain along Morrissey Boulevard to divert stormwater from BOS087 to Patten’s Cove in South Dorchester Bay.
• Relocation of separate stormwater from Pleasure Bay to the Reserved Channel through outfall BOS080.
• Sewer separation of a 355-acre area north of East Fourth Street that is tributary to the four Reserved Channel outfalls.

The recommended plan will provide a 25-year level of CSO control and 5-year level of separate stormwater control for North Dorchester Bay, eliminate stormwater discharges to Pleasure Bay, and reduce CSO discharges to the Reserved Channel from 37 to 3 times in a typical year.  The redirection of some separate stormwater flows to South Dorchester Bay will add about 15% additional stormwater flow to the Bay in a typical year compared to the volumes entering South Dorchester Bay through existing stormwater outfalls and through outfalls BOS088, BOS089 and BOS090, which are being converted to storm drains with the sewer separation work underway by MWRA and BWSC in South Dorchester Bay.

The estimated capital cost of the recommended plan, exclusive of site acquisition costs, is $257 million in 2004 dollars.

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Remaining Challenges and Next Steps

The reassessment’s evaluation of a full range of control alternatives, in parallel with intensive discussions with interested parties, has yielded an alternative for CSO control for the South Boston beaches and Reserved Channel that is consistent with MWRA’s obligations under the Clean Water Act and the Federal Court Order, provides substantial environmental benefit for the region and appears to have public acceptance. MWRA believes that the 17-foot storage tunnel is the best option for attaining the goals of eliminating CSO discharges to the beaches and minimizing impacts to the community.

MWRA recognizes that any recommendation requires a fine balance among competing interests. Obtaining all necessary approvals and agreements to construct the project remains a challenge. Concurrence from EPA and DEP that a 25-year level of CSO control is the functional equivalent of elimination is necessary.  Private and public property owners and abutters in those areas where facilities are proposed must be prepared to accommodate the necessary construction impacts and permanent facilities.  The community and its elected officials must be prepared to support the project, including the necessary Article 97 legislation.

MWRA held a public meeting on March 8, 2004, to present and discuss the new recommended plan, prior to submitting the SFP/EIR to MEPA. At this time, MWRA anticipates there will be a 60-day MEPA comment period to provide an opportunity for thorough public and agency review following submission of the SFP/EIR on April 30, 2004.  MWRA will continue coordinating with regulatory agencies and other interested parties and plans to hold another public meeting during the MEPA comment period.

Issues related to long-term operation of the other facilities, including stormwater management strategies, will require coordination among various responsible parties and regulatory agencies.

MWRA understands that, in parallel with MEPA’s environmental review process, EPA and DEP will conduct their regulatory reviews of the project’s compliance with the requirements of the Clean Water Act and national and state CSO policies. MWRA’s recommended plan offers the functional equivalent of CSO elimination to the beaches and does not seek a change to water quality standards for North Dorchester Bay. With EPA and DEP concurrence on this matter, a Use Attainability Analysis would not be necessary.

Once the MEPA and regulatory review processes are successfully completed, MWRA will then renegotiate design and construction milestones with court parties for incorporation into Schedule Six of the Federal Court Order, replacing the 1997 plan milestones.

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HYDRAULIC RELIEF PROJECTS AT CAM005 AND BOS017

This contract combined two localized hydraulic relief projects, one in Cambridge to minimize CSO discharges at outfall CAM005, which discharges to the Charles River Basin, and the other in Charlestown to minimize CSO discharges at outfall BOS017, which discharges to the Lower Mystic River. In Cambridge, the 24-inch, 40-foot long dry weather connection between the CAM005 regulator and MWRA’s North Charles Metropolitan Sewer, adjacent to Mt. Auburn Hospital, was relieved with a new 54-inch connection. In Charlestown, 190 feet of 36-inch pipe was installed in Sullivan Square to divert two BWSC combined sewers to a more direct connection with MWRA’s Cambridge Branch Sewer, thereby relieving the original dry weather connection from the BOS017 regulator.  In addition, a 10-foot long restriction between the Charlestown and Cambridge Branch Sewers, adjacent to Sullivan Square, was eliminated.  This last improvement was intended to lower hydraulic grade lines in the Charlestown Branch Sewer during wet weather, possibly relieving CSO overflow conditions upstream at outfall BOS019.

MWRA completed construction of these two projects in 2000.

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EAST BOSTON BRANCH SEWER RELIEF

This project calls for relief of the MWRA interceptor system serving most of East Boston, to minimize CSO discharges to Boston Harbor and Chelsea Creek through outfalls BOS003-014.

The current plan, recommended in the 1997 Facilities Plan/EIR, calls for replacing, relieving or rehabilitating a total of 24,750 feet of existing interceptor sewers using a combination of construction methods, including open cut, pipe bursting, microtunneling, and pipe repair or relining.  MWRA issued a Notice to Proceed for design services in March 2000, in compliance with Schedule Six.  Design plans call for three construction contracts to complete the project.  The first contract involves rehabilitation of portions of the existing East Boston Branch Sewer with cured-in-place-pipe liner. The second contract involves installation of a new sewer interceptor along Condor, East Eagle and Border Streets using microtunneling methods, and the third contract replaces and upgrades interceptors in upstream areas using “pipe bursting” methods.

In its April 26, 2002, “Special Report Concerning Construction of Interceptor Relief for BOS 003-014,” MWRA reported to the Court that it would move forward with the first construction contract, involving pipeline rehabilitation that was necessary to safeguard the structural integrity of the existing system and offer some hydraulic benefit for CSO control.  MWRA also reported, however, that it could not move forward with design of the remaining construction contracts pending a full project reassessment and, therefore, would not be able to meet the September 2005 milestone for completion of construction. MWRA determined that the reassessment was necessary to determine how it should complete the project in light of preliminary design information showing that the hydraulic relief would provide lower CSO control performance than estimated in the Facilities Plan/EIR and would cost significantly more. 

Design efforts continued on the rehabilitation contract, which called for relining the main trunk sections of MWRA’s East Boston Branch Sewer, and in March 2003, MWRA commenced this construction contract, meeting the milestone for commencement of construction in Schedule Six.  The work, which in addition to the relining includes changes to certain structures that have compromised hydraulic capacity, is scheduled to be completed by June 2004.

MWRA commenced the project reassessment in June 2003.  The scope included updating baseline hydraulic conditions; assessing the feasibility of improving existing system performance during wet weather; developing CSO control alternatives involving combinations of hydraulic relief, sewer separation and flow diversion; evaluating the alternatives for cost, CSO control performance and impacts; recommending a cost-effective plan; and preparing a MEPA Notice of Project Change if appropriate. 

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Results of the Reassessment

First, the baseline conditions in the sewer system model were updated to represent the current configuration of the sewer system along with any confirmed near-term improvements, including CSO outfall and regulator repairs by BWSC, limited sewer separation work planned by BWSC, construction work by the Central Artery Project and Massport, approved private development plans, and the MWRA relining contract mentioned above.  Under baseline conditions, the number of CSO discharges at the most active outfall dropped from the previously estimated 37 per year in the 1997 Plan to 31 per year in the new baseline estimate.  The total annual volume of CSO discharge from all 10 outfalls in East Boston dropped from 45 million gallons to 41 million gallons.

The reevaluation also considered the potential for improving the performance of the facilities and pipelines that carry East Boston flows to the Deer Island Treatment Plant.  These facilities include the Caruso Pump Station in East Boston, the Winthrop Terminal facility and the Chelsea Creek Headworks.  This review did not find new opportunities for improving the performance of these facilities beyond the benefits of currently planned work.  Although planned improvements to the Winthrop Terminal facility will increase transport capacity and allow Caruso Pump Station to pump at a slightly greater rate, this increase in capacity has little effect on flows and overflows in East Boston, where ability to convey wet weather flows is currently limited not by the pump station but by the conveyance capacities of the East Boston pipes delivering flow to the station.

In addition, the reassessment compared the cost and benefit of a total of 20 CSO control alternatives involving hydraulic relief, sewer separation and flow diversion.  Other CSO control technologies, such as storage or treatment, that were evaluated and rejected in the 1997 Plan were not deemed cost-effective, primarily because the outfalls are dispersed throughout East Boston. 

MWRA received the draft reassessment report in November 2003.  The report confirms that the current interceptor relief project (Figure 11), at a total estimated capital cost of $59 million, about twice the cost estimate in the 1997 Facilities Plan/EIR, would reduce CSO discharges from 31 to 6 in a typical year and reduce annual discharge volume from 41 million gallons to 8.6 million gallons, compared to the 1997 plan goals of 5 activations and 4.0 million gallons.  It is important to note that while the current hydraulic relief plan does not meet the 1997 goals, which were the basis for regulatory approvals of the plan and for new CSO discharge limits in the BWSC and MWRA NPDES permits, the current plan’s performance is consistent with the predicted performance in the 1994 CSO Conceptual Plan and System Master Plan, which was the original basis for the milestones in Schedule Six.

The reevaluation report also shows that the current interceptor relief project with the addition of sewer separation in the Jeffries Point and Maverick Square areas (Figure 12), at a total capital cost of $74 million ($15 million more than the current plan and about $44 million more than the 1997 cost estimate), is the lowest cost alternative to attain the higher CSO control goals in the 1997 plan.  Adding more areas of sewer separation beyond the Jeffries Point and Maveri

ck Square areas to the plan would not result in significantly higher levels of control and would add considerable cost.  Full sewer separation, in lieu of the interceptor relief project, while yielding the highest level of control (4 activations and 1.0 million gallons annual volume), would cost $105 million, and would not come close to eliminating CSO discharges.  This is primarily due to the configuration of the downspouts and drains in much of East Boston, which makes it difficult to separate the storm flows from the sewer system.

MWRA also evaluated constructing a new siphon across the Chelsea Creek (see Figure 13), to relieve the East Boston system by transferring some of its flows to MWRA’s North Metropolitan Sewer and Chelsea Creek Headworks, thereby bypassing the Caruso Pump Station and the main trunk sewer in East Boston and eliminating the need for the proposed hydraulic relief tunnel along Condor Street.  The results showed this alternative not to be cost-effective, since flow diversion would not increase the level of control or reduce project cost compared to options that build on the current interceptor relief project, i.e. sewer separation. This finding and the predicted performance of area-wide sewer separation mentioned above essentially confirm the cost-effectiveness of the current hydraulic relief plan.

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Regulatory Review

On November 26, 200

3, MWRA met with EPA and DEP to present and discuss these results.  At the meeting, EPA and DEP staff recommended incorporating the decision-making process on this project into a broader discussion involving other CSO projects, including South Boston, the Charles River and Alewife Brook.  To that end, MWRA agreed to meet with EPA and DEP to discuss this and other CSO projects prior to recommending a final plan for East Boston.

In the first quarter of 2004, MWRA performed additional analyses with the hydraulic model in an attempt to optimize the combination of hydraulic relief and sewer separation technologies for East Boston, in response to questions raised by EPA and DEP staff.  The feasibility of closing certain outfalls with the various alternatives was also evaluated.  MWRA is now finalizing the reevaluation report, and plans to discuss the additional evaluation results with EPA and DEP with the goal of selecting a preferred plan.

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FORT POINT CHANNEL (BOS072-073) AND BOS019 STORAGE CONDUIT

This design contract combined two CSO storage projects, one at Fort Point Channel in South Boston and the other adjacent to the Little Mystic Channel in Charlestown.  At Fort Point Channel, the 1997 Facilities Plan/EIR recommended constructing a 10-foot diameter, 1,500-foot long conduit along A Street in South Boston using tunneling methods, to capture and store CSO flows from outfalls BOS072 and BOS073 for all but the two largest storms in a typical year.  In Charlestown, the Facilities Plan/ EIR recommended constructing a 380-foot long, 12’x12’ box conduit adjacent to the Tobin Bridge and Chelsea St. to store most of the CSO flows that discharge at outfall BOS019.  For both conduits, the stored flows would be pumped back to the Deer Island transport system after each storm passes and system capacity becomes available.  At each location, an above-ground building would be constructed to house the dewatering equipment, as well as the activated carbon odor control systems which would treat the air that is displaced when the conduit fills with combined sewage.  During larger storms that cause overflows that exceed the storage volume of each conduit, system relief would continue to be provided through the existing outfalls. For this reason, underflow baffles were recommended to be installed within the existing and proposed regulators as part of these projects to provide floatables control.

MWRA commenced the design contract for both the Fort Point Channel storage conduit and the BOS019 storage conduit in July 2002, in compliance with Schedule Six.  An updating of baseline flow conditions and other project assumptions and a full reassessment of the cost and performance of the storage conduits were conducted as first efforts in the preliminary design phase.  The goals of the reassessment were to reevaluate the recommended plan with any new information changing assumed conditions and to conduct a value engineering study to determine if there were any less costly project alternatives that could meet CSO control and water quality goals .  The reassessment was motivated by new information on improved system performance, a potential for changes in system flows due to planned development projects, higher soft-ground tunneling costs and risks, and other construction risks, including the presence of subsurface contamination.

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In June 2003, MWRA completed the Fort Point Channel reassessment report and filed with MEPA a Notice of Project Change (the “NPC”) recommending that the storage/consolidation conduit project be replaced with a plan for sewer separation and system optimization.  The NPC concluded that sewer separation in the BOS073 tributary area, along with optimization at the BOS072 CSO regulator, would meet or exceed the CSO control goals were established in the 1997 plan for these outfalls (2 overflows per year with a total annual discharge volume of 1.4 million gallons), at greatly reduced cost.  The NPC also demonstrated that while the previous recommended plan would have long-term impacts in the neighborhood from a permanent CSO pumping and odor control facility, the revised plan would not require an aboveground facility and would have only temporary construction impacts from pipeline work.

On August 14, 2003, following an extended public comment period during which MWRA conducted two public meetings, the Secretary of Environmental Affairs issued a certificate accepting the NPC. Numerous public comment letters had been received, including letters from EPA and DEP supporting the project change but noting that higher levels of CSO control might be deemed appropriate in future water quality standards reviews with proposed changes to recreational uses in the Fort Point Channel.

The Secretary’s certificate noted that the NPC had adequately explained the environmental impacts of the proposed changes and demonstrated that the impacts did not warrant the preparation of a Supplemental Environmental Impact Report.  The Certificate termed MWRA’s commitment to participate in the Water Quality Task Force to be formed as part of the Boston Redevelopment Authority’s 2002 Watersheet Activation Plan for the Fort Point Channel as necessary to mitigate project impacts.  The Certificate also required MWRA to “look towards feasible methods of increasing the rate of inflow removal in this project as the final design progresses.”  Specifically, the NPC conservatively assumed that 70 percent of the stormwater inflow sources to the sewer system could be eliminated.  The Certificate noted that up to 90 percent removal had been achieved on other sewer separation projects and should be examined for the Fort Point Channel.

On September 17, 2003, MWRA obtained approval from its Board of Directors to seek revisions to Schedule Six to change the scope of the project to appropriately reflect the new recommended plan.  At the same time, MWRA and the Boston Water and Sewer Commission (BWSC) met to begin discussions regarding mutual cooperation in managing the final design and construction of the sewer separation and system optimization project.  At this time, MWRA and BWSC propose that these phases of work be managed by BWSC and funded by MWRA, similar to other sewer separation projects in MWRA’s long-term CSO control plan.  Preliminary design of the recommended plan by MWRA began in September 2003.

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On October 22, 2003, MWRA met with EPA and DEP to discuss amending Schedule Six to remove the Fort Point Channel Storage Conduit project and replace it with Sewer Separation and System Optimization for outfalls BOS072-073 (see Figure 14).  As a result of this meeting, MWRA agreed to perform additional hydraulic modeling to examine ways that a level of CSO control higher than two overflows in a typical year may be achieved at these outfalls.  The additional analyses that showed that elimination of CSOs in a typical rainfall year may be achieved by optimizing the NPC recommendation with reconstruction of both the BOS072 and BOS073 regulators and achieving an 80% level of stormwater removal in the BOS073 tributary area, compared to the 70% removal assumed in the NPC.

On January 15, 2004, MWRA filed a motion with the Court seeking to incorporate the project change for outfalls BOS072 and BOS073 into Schedule Six, with no change to construction milestone dates. The Court accepted the motion on February 27, 2004.  In the motion, MWRA stated it would strive to eliminate CSO discharges at these outfalls in a typical year by maximizing inflow removal with its sewer separation work and by optimizing the overflow weir configurations. These considerations are part of the preliminary design work MWRA has now substantially completed.

A final preliminary design report is due in April 2004.

BOS019 Storage Conduit

MWRA completed a reassessment of the BOS019 storage conduit project in June 2003.  The reassessment verified that a storage conduit to reduce overflows at BOS019 is cost-effective to meet the CSO control goals of 2 overflows per year and a total annual discharge volume of 0.4 million gallons.  With this conclusion, MWRA commenced preliminary design work.

In February 2004, MWRA completed 50% design plans for the BOS019 conduit.  The design work included a reexamination of system hydraulic conditions using flow meter data it collected in the fall of 2003.  With the new data, MWRA has concluded that a storage volume of 670,000 gallons is necessary to meet the 1997 CSO control goals, a significant increase in size, as well as cost, over the 410,000-gallon storage conduit recommended in the 1997 Facilities Plan/EIR.  Work towards 75% design is ongoing, with the recommended storage conduit comprising twin 10-foot wide by 17-foot high barrels, 280 feet long. The project schedule calls for completing design and advertising the construction contract in late 2004, to commence construction by March 2005.

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CHELSEA RELIEF SEWERS

Chelsea Trunk Sewer Replacement

This project was recommended to minimize CSO discharges to the Inner Harbor at outfalls CHE002, CHE003 and CHE004.  The existing Chelsea Trunk Sewer, which varied in diameter from 8 to 15 inches, was replaced with 2,300 feet of 30-inch diameter pipe using open cut and jacked casing methods. Information obtained during design about the physical conditions of the CHE002, CHE003 and CHE004 outfalls led to a decision by MWRA to add replacement or rehabilitation of sections of the CHE002 and CHE003 outfalls to the construction contract.  MWRA managed the construction, but the City of Chelsea retains ownership and responsibility for operation and maintenance.  This project was completed in 2000, on schedule.

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Chelsea Branch Sewer Relief

The Facilities Plan/EIR recommended relieving MWRA’s Chelsea Branch Sewer to minimize CSO discharges to Chelsea Creek at outfall CHE008 and reduce surcharging in the upstream transport system. The construction contract also included repairs to the existing CSO outfall at CHE008.  MWRA installed 4,200 feet of 42-inch pipe and 3,500 feet of 66-inch pipe along Cabot Street and Eastern Avenue, to replace or relieve MWRA’s Chelsea Branch Sewer and Revere Extension Sewer, which lie parallel along Eastern Avenue.  The new pipes were constructed primarily using microtunneling methods. This project was completed in 2001, on schedule.

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CHE008 Floatables Control and Outfall Repairs

Outfall repairs at CHE008 included relining approximately 540 feet of the existing 42-inch outfall pipe, replacing 35 feet of the pipe at its downstream end, replacing the headwall and laying new riprap shore protection.  An underflow baffle was installed at the sole regulator structure associated with this outfall, to provide floatables control.  This project was completed in 2001, on schedule.

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UNION PARK DETENTION/TREATMENT FACILITY

The Union Park Detention/Treatment Facility will improve water quality in the Fort Point Channel by providing treatment of CSO flows that are discharged through BWSC’s Union Park Pumping Station. The existing pumping station, constructed in 1976, provides flood control for the South End neighborhood of Boston.  The Facilities Plan/EIR calls for the detention/treatment facility to be constructed adjacent to the existing pumping station, on property now owned by BWSC at the intersections of Albany, Malden and Union Park Streets in the South End.  Flows will pass through the new treatment facility before entering the pumping station wet well.  The facility will treat 88% of the CSO flow that is discharged to the Fort Point Channel in a typical year.

The recommended plan calls for adding finer screens, chlorination with sodium hypochlorite, dechlorination with sodium bisulfite and underground storage tanks with a capacity of 2.2 million gallons. The storage tanks are designed to reduce the average annual number of pumping station CSO discharges to the Fort Point Channel (from 25 to 17 per year) and to detain flows that exceed the storage capacity in larger storms, to allow a level of solids removal.  Sewer system improvements planned by BWSC in the South End neighborhood will further reduce overflows to the pump station and Fort Point Channel.  While a large portion of the new facility will be below ground, the plan includes a significant addition to the aboveground structure of the pumping station, to house treatment system components and accommodate operations.

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In March 2003, MWRA commenced the construction contract for the treatment facility, in compliance with Schedule Six.  However, the subcontract for electrical work, which had been rebid by MWRA, was the subject of a bid protest and an Attorney General’s decision which held up execution of the subcontract until June, causing some delay in the construction schedule.  In the meantime, the site was cleared for construction, including the removal of a playground operated by the Boston Parks and Recreation Department (“Boston Parks”).  Removal of the playground was stipulated in an agreement between MWRA and Boston Parks in March 2003, under which Boston Parks assumed responsibility for designing, constructing and operating a replacement playground and a park over the completed detention tanks. MWRA agreed to provide funds for playground and park design and construction.

The design and construction of this project has faced difficulties that are typical of projects in older urban areas.  To protect the old residential and industrial buildings that surround the site, the contractor conducted pre-construction building surveys and has complied with limitations on vibrations from the heavier work.  The project design also incorporated construction measures to prevent groundwater effects during and after construction, and several groundwater wells were installed by the contractor to monitor groundwater conditions.

Construction of the treatment facility is being conducted under a Release Abatement Measure plan (RAM) in accordance with state and federal rules regulating the handling of contaminated materials, due to historical contamination releases on the property, which has been used for flood-control pumping purposes for nearly a century.  Early in construction, newly discovered contamination on the property was identified, increasing the amount of work the contractor had to perform to comply with the RAM.  In addition, the construction contract required the contractor to remove an abandoned 1914 pump station foundation. The old pump station was razed in the mid-1970’s, and it was then reported that all equipment had been removed and the foundation had been filled with soil.  However, the current contractor found the abandoned foundation only partially filled and found a considerable quantity of oily waste liquid and oil-saturated equipment and debris.

The discovery of this additional contamination caused a temporary suspension of the construction work while the contractor performed additional site remediation. This additional work, together with the effects of the late electrical subcontract, has resulted in a three-month delay. MWRA plans to execute a change order later this spring extending the substantial completion date from September 29, 2005, to January 9, 2006.

After overcoming the initial setbacks, the contractor was able to make substantial progress, attaining 21% completion by the end of the year.  The contractor completed work on a new concrete influent channel and commenced work on the influent chamber structure.  The contractor also completed demolition of the abandoned 1914 pump station foundation, constructed a temporary bypass pipe for the 48-inch influent sewer that carried overflows to the pump station’s “Annex” building, and completed demolition of the Annex. In addition, the contractor commenced the first phase of structural modifications to other parts of the existing pump station building.

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The additional contamination was not the only surprise discovery on the site.  The contractor encountered several building foundations, concrete stairwells, a cistern, large pieces of architectural stone, granite blocks and similar demolition debris during excavation.  These materials were found in a previously damaged state, with the exception of a keystone, or decorative architectural element, of the bust of a “soldier” (see photo), which was found in a near perfect condition.  The City of Boston Archaeologist is working to identify this soldier by contacting historical groups and researching the gallantry medals formed on his uniform.

The contractor made additional construction progress in the first quarter of 2004, but less than expected, due to severe cold weather in January.  By the end of March, construction of the influent chamber was well underway.  The contractor completed installation of sheeting for the earth support system associated with the detention tanks and was working on the first level of bracing and first level of excavation for the tanks. Installation of the second phase of bracing and second level of excavation was underway in the area where the new treatment building will be constructed.  The contractor also continued demolition work to be able to reconfigure the pumping station layout with the new treatment facility.  Demolition work to gain access to the pump station wet well in order to add pumps proposed by BWSC and construct the new pump room was also underway. The contractor and MWRA staff continued to respond to public inquiries during construction, including holding periodic public meetings.

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UPGRADES TO EXISTING CSO FACILITIES

MWRA has upgraded five of its six CSO facilities (Commercial Point, Cottage Farm, Fox Point, Prison Point and Somerville Marginal) to improve treatment performance and meet new residual chlorine discharge limits.  The sixth facility, at Constitution Beach in East Boston, was decommissioned by MWRA in 2000, following completion of sewer separation work in that area (see later discussion, under “Constitution Beach Sewer Separation”).  The work generally included replacement and upgrading of the existing chlorine disinfection systems and construction of dechlorination systems, as well as other process control and safety improvements.

By mid-2002, MWRA completed acceptance testing at all five upgraded facilities.  MWRA operations staff continued to optimize treatment processes and finalize standard operating procedures, during the periods of “startup and system optimization” referenced in footnote 35 of Schedule Six.  By early 2003, the startup and optimization periods had come to an end, and all five facilities are now subject to the discharge limits in MWRA’s NPDES permit.

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5.2   Community Managed Projects

SOUTH DORCHESTER BAY SEWER SEPARATION

This project is intended to eliminate CSO discharges to South Dorchester Bay by separating combined sewer systems in Dorchester.  The separation work primarily involves the construction of new storm drains and appurtenant structures, relocation of storm runoff connections from the existing combined sewer to the new storm drains, and rehabilitation of the existing combined sewers for use as sanitary sewers.  The plan calls for approximately 140,000 linear feet of new storm drains.  BWSC is implementing the project with MWRA funds.

Figure 15 and Table 5 show the project’s design and construction progress.  Schedule Six requires a construction progress rate of 10% per year from the commencement of construction in April 1999 (i.e. 50% complete by April 2004).  As of March 2004, construction is about 54% complete, measured by linear feet of installed storm drain.  In 2003, BWSC installed approximately 16,800 linear feet of new storm drain, 12% of the total length to be installed by this project.  BWSC plans to install a similar amount of storm drain in 2004.  This project comprises nine major sewer separation construction contracts.  In 2003, BWSC completed Contracts 2 and 6, bringing the total number of completed contracts to five.  Only two of the nine separation contracts - Contracts 4 and 8, together representing 30% of the total program - are not yet in construction, and these contracts are scheduled to commence in 2004.

BWSC completed the first street paving contract and awarded the second paving contract in 2003. The sediment cleaning contract (Contract 10), which is intended to restore the full hydraulic capacity of the Commercial Point and Fox Point outfall pipes to be able to convey the new separated stormwater flows, commenced in November 2002 and was completed on schedule in 2003. The initial downspout disconnection contract for Dorchester, which also includes downspout disconnection work in other CSO project areas, such as Jamaica Plain (Stony Brook project), Neponset and East Boston (Constitution Beach), commenced in August 2003. BWSC’s plans include two additional downspout disconnection contracts in Dorchester.  The disconnection of downspouts from the combined sewer systems is necessary to remove enough stormwater from the sewers to meet CSO project goals. 

BWSC plans a total of 16 construction contracts to complete the South Dorchester Bay sewer separation project.  Once these contracts are complete and the CSO regulators are then closed, MWRA plans to decommission its Commercial Point and Fox Point CSO treatment facilities.

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STONY BROOK SEWER SEPARATION

This project is intended to minimize CSO discharges to the Stony Brook Conduit and the Back Bay Fens, both of which drain to the Charles River, by separating combined sewers in parts of Roxbury and Jamaica Plain. The separation work involves approximately 73,300 linear feet of new storm drain installation.  BWSC is implementing the project with MWRA funds.

Figure 16 and Table 6 show the project’s design and construction progress.  Schedule Six requires a construction progress rate of 15% per year from the commencement of construction in July 2000 (i.e. 60% complete by July 2004).  As of March 2004, construction is approximately 53% complete, measured as

linear feet of installed storm drain. In 2003, BWSC installed approximately 17,000 linear feet of storm drain, 23% of the total length of storm drain to be installed by this project.  BWSC plans to install a similar amount of storm drain in 2004.  Contract 1, which was awarded in April 2001, is 99% complete. Contract 2, which commenced in March 2003 is approximately 37% complete.  With the commencement of Contract 3 in January 2004, cons

truction activity will soon reach a peak, and actual progress is expected to surpass the Court mandated progress rate by the end of the year.  In 2003, BWSC also awarded the initial paving and downspout disconnection contracts.  BWSC plans a total of seven construction contracts (sewer separation, paving and downspout disconnection) to complete the Stony Brook sewer separation project.

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NEPONSET RIVER SEWER SEPARATION

This project involved sewer separation in the Neponset section of Dorchester, to eliminate CSO discharges to the Neponset River at outfalls BOS093 and BOS095.  The separation work included construction of approximately 10,000 feet of new storm drain.  BWSC performed the work with MWRA funds.

BWSC completed storm drain construction and closed the last remaining CSO outfall to the Neponset River in June 2000.  It continues to perform downspout disconnection and other work to remove additional stormwater inflow from the sewer system, in order to minimize the risk of surcharging and flooding. In December 2002, BWSC commenced an additional contract to remove inflow sources from sewer systems in the Neponset area, in addition to the South Dorchester Bay contract mentioned above, which commenced in August 2003 and included some inflow removal in the Neponset area.  This contract will further reduce the amount of stormwater flow into the sewer system by removing non-residential, private drainage connections, such as connections from private parking lots.

CONSTITUTION BEACH SEWER SEPARATION

This project involved sewer separation in a section of East Boston, to eliminate CSO discharges at the Constitution Beach CSO facility (outfall BOS002/MWR207).  The separation work included construction of approximately 14,000 feet of new storm drain.  BWSC performed the work with MWRA funds.

BWSC completed storm drain construction and closed the last remaining CSO regulator in September 2000, and MWRA decommissioned the Constitution Beach CSO Facility soon after.  Following a vote in March 2003 by the MWRA Board of Directors that the property and facility were surplus for operations, MWRA transferred the site to the control of the Division of Capital Asset Management.

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DORCHESTER BROOK CONDUIT IN-LINE STORAGE

The 1994 CSO Conceptual Plan recommended this project to minimize CSO discharges from the Dorchester Brook Conduit to Fort Point Channel.  MWRA’s final plan for CSO control (1997) deleted this recommendation, based on updated hydraulic modeling results showing that the CSO discharges to Dorchester Brook Conduit were less than earlier estimated and that further reductions would occur by bringing the full planned pumping capacity at Deer Island on-line. 

In 2000 and 2001, MWRA performed hydraulic analyses which confirmed the lower discharges and determined that discharges could be further reduced with a set of relatively low cost system optimization measures, including raising a weir at one CSO regulator, cleaning the dry weather connection at another regulator, and installing a new tide gate.

MWRA filed a motion in July 2001 seeking to delete the design and construction milestones for the Dorchester Brook Conduit In-Line Storage project from Schedule Six.  The motion was allowed by the Court on August 8, 2001, contingent upon MWRA’s commitment to implement the optimization measures.  BWSC completed the implementation of the optimization measures, with MWRA funding assistance, in August 2003.

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CAMBRIDGE/ALEWIFE BROOK SEWER SEPARATION

This project is intended to minimize CSO flows to Alewife Brook, primarily by separating combined sewer systems in parts of Cambridge.  The separation work is being done by the City of Cambridge with MWRA funds.

In April 2001, MWRA and the City of Cambridge submitted a Notice of Project Change recommending an expanded and more costly sewer separation plan to control CSO discharges to Alewife Brook (the “Alewife NPC”) than had been recommended in the 1997 plan.  Many public comments were received, and the Secretary of Environmental Affairs issued a certificate on the Alewife NPC on June 15, 2001.  The Secretary’s Certificate required the MWRA and Cambridge to prepare a document responding to all public comments, including comments related to the feasibility of obtaining necessary federal and state permits and other approvals to build the project.

In May 2003, MWRA and the City of Cambridge submitted a response to MEPA addressing all public comments on the Alewife NPC.  This document was two years in the making and involved extensive interactions with regulatory agencies, community officials in Arlington, Belmont and Cambridge, the Department of Conservation and Recreation (DCR), formerly the MDC,  and the public. The Response to Comments document also presented a final project plan that incorporated adjustments made to respond to the various concerns that had been raised. 

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In particular, significant adjustments were made to Cambridge’s proposed stormwater system and wetland basin to ensure that the stormwater flows generated by the sewer separation work will have no adverse effect on Alewife Brook flood elevations and that the wetland basin will contribute to the ecological and recreational goals in DCR’s master plan for the Alewife Reservation. Submission of the Response to Comments document effectively completed the MEPA review process for this project, allowing MWRA and Cambridge to move the project into design and construction.

Cambridge began construction of the original (1997) plan for sewer separation in July 1998, in compliance with Schedule Six, and has completed all four of the construction contracts awarded to date. The construction work already completed has significantly reduced CSO discharges to Alewife Brook. Hydraulic model simulations show that CSO discharges have been reduced from 63 times per year on average with 50 million gallons annual volume to 25 times per year on average with 33 million gallons annual volume.

Remaining design and construction has resumed with the initial emphasis on final design of CAM400 common manholeseparation and Contract 12, the new stormwater outfall and stormwater wetland which will handle the increased stormwater flows from the CAM004 tributary area after future separation contracts are completed.  Construction in the CAM400 area is expected to begin this summer.

On a related subject, DEP extended the Alewife Brook/Upper Mystic River variance by twelve months, from September 2003 to September 2004.  The additional time will allow DEP to complete their review and public process before making a final water quality determination.

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5.3   Region-wide Floatables Control and Outfall Closing Projects

The Facilities Plan/EIR calls for the control of floatable materials in all remaining CSO discharges in accordance with the National CSO Policy.  Floatables controls will be installed at many of the CSO outfalls as part of the larger CSO control projects described above.  For instance, the Chelsea Trunk Sewer Relief project included the installation of underflow baffles for floatables control at outfalls CHE002, CHE003 and CHE004.  The Region-wide Floatables Control and Outfall Closing Projects described in the following sections involve floatables controls and regulator or outfall closings that are independent of the larger projects.

MWRA, BWSC, Cambridge and Somerville are responsible for implementing these controls in their respective systems.  MWRA met the March 1999 milestone for commencement of construction with work at outfalls MWR018-022.  Schedule Six required the completion of all related construction work by May 2001.

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MWRA FLOATABLES CONTROL AT OUTFALLS MWR018–020 AND OUTFALL CLOSINGS AT MWR021-022

CSO outfalls MWR018, 019, 020, 021 and 022 conveyed overflows from MWRA's Boston Marginal Conduit (“BMC”) to the Lower Charles River Basin in very large storms.  The project called for closing outfalls 021 and 022 and providing floatables control at the remaining locations.  The plan for floatables control involved the installation of underflow baffles at eleven CSO regulator structures upstream of outfalls 018-020.

MWRA completed the installation of underflow baffles in four of the eleven BWSC regulators (MC-12, MC-15, MC-19 and MC-25) in late 1999.  In March 2000, MWRA closed outfalls MWR021 and MWR022 to CSO discharges.

During preliminary design of floatables control at the seven remaining CSO regulators, which were located in the Old Stony Brook Conduit System, it was determined that the installation of underflow baffles at these regulators would be difficult and potentially prohibitive due to extensive construction requirements, construction impacts and cost.  Outfalls MWR018, 019 and 020 only rarely activated. The main problem at each location was the lack of physical space to permit the installation of the baffle and weir in the existing structures while maintaining the capacity of the regulator structure to relieve the system and control upstream flooding during very large storms.  In most cases, the existing regulator structures would have to be replaced with much larger structures, requiring major and difficult construction in busy streets and intersections and within railroad rights of way at certain locations.

MWRA conducted modeling evaluations in 2000 to update and confirm the predictions of annual CSO activation frequencies and volumes at outfalls MWR018, 019 and 020 and reassess floatables control options. In April 2001, MWRA submitted a report entitled Re-assessing Long Term Floatables Control for Outfalls MWR018, 019, and 020 to EPA and DEP, with final recommendations for reducing CSO discharges at these outfalls. Earlier in the year, MWRA raised weirs at each of the three outfalls and completed installation of a permanent level monitoring system in the upstream end of the BMC, to allow MWRA to identify hydraulic grade line changes and overflow conditions for each storm.  MWRA has used the data to evaluate the performance of the Prison Point CSO Facility and the BMC during significant storms, although few storms occurred through the latter half of 2001. In addition, the standard operating procedures at Prison Point were changed.  MWRA operations staff now allow flows to enter the facility earlier, when a large storm is predicted, in an attempt to control the level of backwater in the BMC and reduce untreated overflows into the Charles River Basin.

MWRA’s April 2001 report also concluded that removing sediments in the BMC could further reduce CSO discharges at these outfalls. In January 2002, MWRA maintenance staff completed work to clean the BMC, optimizing the conveyance capacity of this conduit and further lowering CSO discharges. MWRA has monitors sediment deposition in the BMC, in part to identify routine cleaning needs.

In June 2002, MWRA wrote to EPA and DEP seeking their approvals to delete the remaining underflow baffle installations from the long-term CSO control plan. On October 29, 2002, DEP issued its approval, subject to MWRA maintaining the BMC free of sediments, continuing to operate the Prison Point CSO facility as recommended, and preparing a report on the data from the depth sensor in the BMC and the results of MWRA’s evaluations to optimize weir heights at MWR018, 019 and 020. MWRA submitted its first evaluation report tracking overflows at MWR018, 019 and 020 to EPA and DEP by letter dated May 20, 2003. The report confirmed that overflows at these outfalls rarely occur, as predicted.

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CSO CONTROL AT OUTFALL MWR010

In April and May 2001, MWRA submitted reports to EPA and DEP on studies conducted to reassess CSO discharges at outfall MWR010. The scope of the reassessment included updating the hydraulic model of the combined sewer systems affecting this outfall, evaluating the feasibility of closing the outfall to CSO discharges, and recommending measures to minimize discharges if the outfall could not be closed.  

Results of the reassessment showed that the outfall did not discharge CSO in a typical rainfall year. Furthermore, CSO discharges could be reduced to the level of not occurring up to a 5-year storm by bringing back into service a blocked connection between the Town of Brookline and MWRA systems. The reports also concluded that MWR010 should not be permanently closed, since closure of the outfall was predicted to result in upstream flooding during extreme storms.

In January 2002, MWRA crews cleaned the blocked 18-inch Brookline connection, providing for system conditions that eliminate the potential for CSO discharge at MWR010 in up to a 5-year storm.  In June, MWRA wrote to EPA and DEP seeking their approvals to remove the closing of this outfall from the long-term CSO control plan.  On October 29, 2002, DEP issued its approval, subject to MWRA and Brookline maintaining the dry weather connection in an operable condition, evaluating further system optimization measures to minimize CSO discharges at MWR010 and at the hydraulically connected Cottage Farm CSO facility and implementing Best Management Practices in the tributary area to minimize wet weather pollutant loadings.  The results of initial system optimization evaluations were reported in the Cottage Farm CSO Facility Assessment Report in January 2004, which also described ongoing work by the Town of Brookline to separate sewers, which will enhance CSO control at MWR010 and at Cottage Farm. MWRA tracks the performance of the reactivated Brookline connection by reviewing upstream velocity and depth data collected by a permanent flow meter.  Velocity and depth at this location are directly affected by any capacity problems in the connection, which could indicate the need for cleaning.

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BWSC FLOATABLES CONTROL

Floatables control included in this project involved the installation of underflow baffles in ten existing CSO regulator structures associated with outfalls along Boston Inner Harbor and Fort Point Channel. BWSC designed and constructed the project, and MWRA funded costs.  BWSC completed the last of the ten installations in 2002.

CAMBRIDGE FLOATABLES CONTROL

This work involves providing floatables control at nine outfalls located along Alewife Brook and the Charles River in Cambridge.  Since Cambridge will be responsible for the operation and maintenance of its floatables control devices, MWRA has agreed to allow Cambridge to install devices of its choice, provided they meet or exceed the level of floatables control that would be achieved by MWRA’s recommended plan. At five locations along Alewife Brook, the floatables controls are being designed and installed in conjunction with the Cambridge/Alewife Brook sewer separation project.  Controls at four locations along the Charles River, are being separately designed and installed by Cambridge.  At these locations, Cambridge discovered structural problems with the existing outfalls, which have increased the scope of its work and delayed installation of floatables control.

Design work on floatables control is approximately 80% complete, and Cambridge expects to complete construction at all locations by June 2005.  Cambridge recently completed construction of floatables control at one of the Alewife Brook outfalls, CAM401A, as part of a Cambridge storm drainage contract titled “Bellis Circle Improvements.”

SOMERVILLE FLOATABLES CONTROLS

The final CSO plan called for the control of floatable materials in the CSO discharges at outfall SOM001A (Tannery Brook outfall) by installing an in-line net.  This work, like much of the work under Cambridge Floatables Control, is associated with the Cambridge/Alewife Brook sewer separation project.  The revised Alewife project in part calls for enlarging the local system connection to the MWRA interceptor at SOM001A, in addition to providing floatables control.  MWRA and the City of Cambridge are now developing plans and schedules for design and construction of floatables control at this outfall, as a part of the proposal MWRA plans to make to the Court Parties in seeking revisions to Schedule Six milestones for completing the Alewife project.  In the meantime, the City of Somerville continues to maintain a boom as an interim floatables control measure at this outfall.

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Key CSO Program Activities in 2004

While there are no 2004 CSO project milestones in Schedule Six, MWRA expects to make significant progress towards completing several projects and gaining regulatory and public acceptance of new plans that will allow CSO control to move forward in key areas.  In addition, MWRA anticipates having discussions with the Court Parties to consider amending Schedule Six to incorporate new plans for CSO control in South Boston, East Boston and Alewife Brook.

North Dorchester Bay and Reserved Channel: MWRA will submit the SFP/EIR and new recommended plan for controlling CSO discharges to North Dorchester Bay and the Reserved Channel by the end of April.  MWRA expects to discuss implementation schedules with the Court Parties and begin to take steps to implement the plan, following the completion of regulatory review and with a level of assurance that the new plan is acceptable to the public.

East Boston: MWRA expects to complete the ongoing construction contract to reline the main trunk of the East Boston Branch Sewer by June.  Through discussions with EPA and DEP on the results of the recently completed project reassessment, MWRA plans to select a recommended plan to complete the project and attain CSO control goals.  MWRA would then bring a final plan and implementation schedule to its Board of Directors for authorization to seek regulatory approvals.  Depending on the plan selected, MEPA review may be required. MWRA hopes to resume design of the East Boston project in 2004, subject to regulatory acceptance.

Alewife Brook/Upper Mystic River: MWRA anticipates participating in the ongoing DEP public process surrounding a decision on water quality standards for the Alewife Brook and Upper Mystic River.  MWRA understands that DEP plans to respond to public comments on the Final Alewife Variance Report later this year and issue a decision that would either change the Class B standard to Class B(cso), allowing the minimal CSO discharges under MWRA and Cambridge’s revised CSO plan, or extend the CSO variance in the short-term, until a long-term decision can be made.

MWRA does not anticipate that either decision will affect the work currently underway by MWRA and Cambridge to complete the design and construction of the revised plan for Cambridge/Alewife Brook Sewer Separation.  MWRA and Cambridge are currently developing implementation plans and schedules for their respective project elements.  When completed, MWRA will approach the Court Parties with a proposal to revise the project related milestones in Schedule Six.  In 2004, Cambridge also plans to complete most of the design work associated with the stormwater outfall and stormwater wetland that will allow separation of the combined sewer systems tributary to outfall CAM004 and the closing of this outfall to CSO discharges.   Cambridge’s schedule calls for commencing the construction contract for the basin and the stormwater outfall in July 2005.  For its part, MWRA plans to begin procuring engineering services for the improvements recommended at outfall MWR003 and for relief of its Rindge Avenue siphon in 2004, with the objective of commencing design in 2005.

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Charles River Basin: MWRA’s Cottage Farm CSO Facility Assessment Report demonstrated that additional storage at Cottage Farm would not reduce the duration of water quality violations during wet weather, because the facility’s discharges are treated and the frequency and duration of remaining water violations are caused primarily by non-CSO pollution sources.  The report also recommended that DEP extend the Charles River variance beyond the current end date of October 1, 2004, to allow final decisions on water quality standards to be made only after the benefits of ongoing and planned efforts to control CSO and non-CSO pollution are fully realized. MWRA anticipates participating this spring in the MEPA and DEP review of the Cottage Farm report and in the subsequent DEP public process that will lead to a determination on water quality standards.  Related efforts likely will include public meetings on the water quality of the Charles River Basin and the Cottage Farm report, as well as review of a tentative decision when it is issued by DEP.

In the meantime, BWSC will reach a peak construction rate on the Stony Brook Sewer Separation project towards completion of the project by the September 2006 milestone.  MWRA will also pursue further investigations of system optimization measures recommended in the Cottage Farm report to reduce treated CSO discharges at Cottage Farm and will track efforts by Brookline and Cambridge to separate combined sewer systems and further reduce CSOs to the Basin.  MWRA’s long-term water quality monitoring program in the Basin will continue.

Fort Point Channel

MWRA expects construction work for the Union Park Detention/Treatment Facility to reach peak levels in 2004, with progress anticipated to jump from about 21% complete at the end of 2003 to more than 50% complete at the end of 2004. The work in 2004 will include the placement of most of the 13,000 cubic yards of concrete required for the underground tanks and facility.  MWRA is evaluating the effects on the project completion date due to schedule delays experienced during the first several months of construction and in the severe cold weather period in early 2004.  MWRA expects to execute an extension to its construction contract when a new schedule is determined.

With preliminary design of the BOS072-073 sewer separation and system optimization project nearing completion, MWRA and BWSC will soon finalize an agreement by which BWSC will assume management responsibilities for final design and construction of the project, with MWRA funding the final design and construction-related costs.  MWRA anticipates that BWSC will complete most of the final design work in 2004 to meet the March 2005 milestone for commencement of construction.

South Dorchester Bay

BWSC will continue its efforts to complete construction of the South Dorchester Bay sewer separation project by the November 2008 milestone in Schedule Six.  In 2004, BWSC plans to commence the last two sewer separation construction contracts.

Annual CSO Discharge Reporting

In compliance with its NPDES permit, MWRA recently completed hydraulic modeling work to estimate CSO discharges during storms that occurred in calendar year 2003.  MWRA is sharing the results with its CSO communities to verify the estimates and coordinate the submissions to EPA and DEP. MWRA uses the annual CSO discharge estimates to verify progress in controlling CSO discharges towards realizing the goals of the long-term CSO control plan and meeting related NPDES permit limits that are the basis for compliance with water quality standards.

Later in 2004, MWRA will conduct flow monitoring and hydraulic modeling to estimate CSO discharges for storms occurring this year.

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