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Department of Environmental Protection - Letter - Proposed Extension to Alewife/Upper Mystic CSO Variance

CSO = Combined Sewer Overflow
Format of original document altered for the Web. All text is included.

ONE WINTER STREET, BOSTON, MA 02108 617-292-5500




This information is available in alternate format by calling our ADA Coordinator at (617) 574-6872. DEP on the World Wide Web:
Printed on Recycled Paper

May 8, 2002

Frederick Laskey, Executive Director
Massachusetts Water Resources Authority
100 First Avenue
Charlestown Navy Yard
Boston, MA 02129
Final Determination


Lisa Peterson, Commissioner
Cambridge Department of Public Works
147 Hampshire Street
Cambridge, MA 02139


Thom Donahue, Director
Somerville Department of Public Works
Franey Road
Somerville, MA 02145

Dear Messrs. Laskey and Donahue and Ms. Peterson:

On December 14, 2001, MWRA submitted to DEP a request to extend the CSO Variance in the Alewife/Upper Mystic watershed. DEP has reviewed the request, the supporting information, and has separately solicited public comments on the proposed extension to the CSO Variance. Based on this process, DEP has made a Final Determination to grant the extension request. The attached Final Determination for Extension to Variance for CSO Discharges to Alewife Brook/Upper Mystic River Basin formally extends the CSO Variance to September 5, 2003.

Background Discussion

In 1987, through a Stipulation entered in the Boston Harbor Case, MWRA accepted responsibility for developing a control plan to address CSO discharges from all CSOs hydraulically connected to the MWRA sewer system, including outfalls owned by the member communities. Under a Court-ordered schedule, MWRA developed a CSO Conceptual Control Plan in 1994, recommending more than 25 site-specific CSO projects located in Boston, Cambridge, Somerville and Chelsea. The CSO Conceptual Control Plan was later refined; and, on July 31, 1997, the MWRA filed a Final CSO Facilities Plan/Environmental Impact Report with MEPA. MEPA issued a certificate for the project on October 30, 1997.

In 1996, design and construction milestones for the 25 projects in the Final CSO Plan were added to the Federal Court Schedule, requiring implementation of the projects. MWRA is directly responsible for implementation of many of the projects and has negotiated agreements with each of the four CSO communities for implementation of certain projects affecting the community systems. The Facilities Plan evaluated and selected abatement alternatives for each CSO and was conducted in accordance with both EPA's National CSO Control Policy and DEP's August 11, 1997 CSO Guidance for Abatement of Pollution from CSOs.

For those CSOs which MWRA did not believe could be eliminated, the plan included information to support a Use Attainability Analysis (UAA), which is an evaluation conducted by the state which supports removal of a National Goal Use based on technical and financial criteria associated with attaining that use. DEP submitted its Final Administrative Determinations, including a UAA, to EPA for approval on December 31, 1997. On February 27, 1998, EPA approved the state's changes to water quality standards which included removal of CSO-impacted designations for the Neponset River, North Dorchester Bay, South Dorchester Bay, and Constitution Beach; a SBCSO designation for Boston Inner Harbor; a BCSO designation for the Muddy River; and a tentative determination for the issuance of Variances for the Lower Charles River and the Alewife Brook/Upper Mystic River Basins.

A Variance for CSO discharges to the Alewife Brook/Upper Mystic River Basin was issued by DEP on March 5, 1999. The Variance is a short-term modification of the Water Quality Standards allowing CSO discharges from the outfalls along the Alewife Brook/Upper Mystic River permitted to the Massachusetts Water Resource Authority (MWRA) and the Cities of Cambridge and Somerville, subject to specific conditions, while providing time for DEP to obtain the information necessary to determine the appropriate water quality standard and level of CSO control for the Basin. The Variance required the implementation of the CSO control actions included in the MWRA Final CSO Facilities Plan/Environmental Impact Report and other actions necessary to credibly assess pollutant loads in the Basin and minimize the impact of CSO discharges.

The March 5, 1999 Alewife Brook/Upper Mystic River Basin Variance included the following specific conditions of the MWRA and the Cities of Cambridge and Somerville:

The January 1, 2002 Reassessment Report was intended to provide the basis for a final determination on the level of CSO controls to be required.

In the course of implementing the 1997 CSO control program for the Alewife Brook, the City of Cambridge and MWRA determined during the design phase that the nature of the combined sewer system in Cambridge was significantly different from that documented in the 1997 FEIR. Not only were there significantly more cross-connections, but a previously unknown CSO outfall was also discovered. The MWRA subsequently determined that the CSO activations and volumes in this basin greatly exceeded that estimated in the 1997 FEIR, and that the 1997 recommended plan no longer represented an effective approach to mitigate CSO discharges.

In response to this, MWRA and Cambridge completed a re-evaluation of the original CSO control plan for Alewife Brook and on April 30, 2001 filed a Notice of Project Change (NPC) with MEPA. While the level of CSO control for the revised recommended plan is comparable to the original 1997 plan and remains essentially one of targeted sewer separation, certain elements of the original plan, including areas slated for separation, have been substantially modified, resulting in a change in expected impacts and mitigation measures. The estimate of annual CSO volume and activation frequency increased significantly and the estimated costs of the project increased over six-fold, from $12 million to approximately $74 million. Notably, sewer separation associated with the CAM004 outfall will require construction of a new stormwater outfall to convey flows to a new wetland detention basin proposed within the MDC Alewife Reservation. This component was not in the original recommended plan and introduces an additional aspect to the scope of work that is substantially different from the typical pipe installation work in streets associated with the sewer separation activities.

Implementation of the recommended plan included in the NPC will result in an 84 percent reduction in annual CSO volume discharged in a typical year, and improved stormwater quality resulting in a reduction in stormwater pollutant loads to Alewife Brook.

In its June 15, 2001 Certification on the NPC, the Secretary of the Executive Office of Environmental Affairs required that MWRA and Cambridge prepare and file with MEPA a comprehensive Response to Comments document to address those comments received on the NPC. MWRA and Cambridge have been working on this document. However, due to the need for additional water quality work and hydraulic modeling and analysis to fully address complex permitting aspects, the Response to Comments document will not be filed until September 2002.

On December 14, 2001, MWRA submitted to DEP a request to extend the CSO Variance in the Alewife Brook/Upper Mystic River Basin. The request cited the lack of sufficient stormwater data, the changed conditions which prevented implementation of the 1997 CSO Plan, and the need for additional time to develop the information necessary to support the Final CSO Reassessment Plan.

Variance Extension Process

DEP reviewed the Variance extension request and the supporting information and proceeded to solicit public comments on the proposal to extend the CSO Variance. The February 9, 2002 MEPA Environmental Monitor included a Public Notice which indicated DEP's Tentative Determination to issue an 18-month extension to the Variance, and provided for public comment period through February 22, 2002. During this public comment period, DEP also held a public meeting on February 11, 2002 at Arlington Town Hall to discuss the proposed CSO Variance and general CSO regulatory issues related to the MWRA CSO Plan. Written comments were received from; Arlington Office of the Board of Selectmen, Arlington Conservation Commission,
Mystic River Watershed Association, Somerville Conservation Commission, Coalition for Alewife, Mr. Roger Frymire, Mr. Aram Hollman, and Mr. Stephen Kaiser.

Attached to the Final Determination is a Response to Comments document prepared by DEP to respond to the comments received. The Response to Comments document was set-up to respond to basic categories of comments and not to each individual comment.

DEP has considered the MWRA request for extension, the supporting information, and the comments from the public in making this determination to extend the CSO Variance. The attached Final Determination to Extend the Variance includes a description of the Variance conditions, and highlights those conditions which have been revised based on information developed during both the CSO planning process and the public participation process.

The information being gathered over the course of the Variance is intended to provide the basis for a determination on the final level of CSO control and associated water quality standard for the Alewife Brook/Upper Mystic River. During the Variance period, the MWRA, and the Cities of Cambridge and Somerville are required to comply with all of the conditions established by this Variance Extension.

Future DEP Administrative/Regulatory Actions Regarding Variance

(1) DEP will hold a Public Forum during the MEPA comment period related to Condition C.(1) (estimated to be mid-July 2003) for MWRA to present to interested parties the results of reports and assessments.

(2) DEP will hold a Public Hearing once the Department issues a Tentative Decision on the Water Quality Determination for the entire Alewife Brook/Upper Mystic River Basin. This will allow another opportunity for all interested parties to provide input to EPA and DEP on the Proposed Level of CSO Control for the Basin. This Hearing will likely be held in early September 2003.

If you have any questions regarding this correspondence or the appended Final Determination, feel free to contact me at (617) 292-5698 or Kevin Brander at (978) 661-7770.

Very truly yours,

Steven G. Lipman, P.E.
Special Projects Coordinator

CC: Michael Hornbrook, David Kubiak, Stephanie Moura and Christopher John (MWRA)
Owen O'Riordan (Cambridge DPW)
Mike Wagner, Eric Hall and Brian Pitt (EPA)
Mark Smith (EOEA)
Dick Foster (MEPA)
Cynthia Giles, Glenn Haas, Eric Worrall, William Gaughan, Madelyn Morris and Kevin Brander (DEP)

Contact the Alewife Study Group, North Cambridge Massachusetts, by email at