November 28, 2023 - City of Somerville

U.S. Environmental Protection Agency · from the EPA · 4 pages · 267 KB
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C ITY O F S OMERVILLE, M ASSACHUSETTS 
KATJANA BALLANTYNE
M AYOR 
D EPARTMENT of I NFRASTRUCTURE & A SSET M ANAGEMENT 
E NGINEERING D IVISION 
R ICHARD E. R AICHE , PE, PMP B RIAN P OSTLEWAITE , PE
D IRECTOR OF I NFRASTRUCTURE & A SSET M ANAGEMENT D IRECTOR OF E NGINEERING 
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Department of Public Works Building, First Floor • 1 Franey Road • Somerville, Massachusetts 02145 
November 28, 2023 
Michele Barden 
U.S. Environmental Protection Agency – Region 1 
5 P0st office Square, Suite 100 (09-1) 
Boston, MA 02109 
AND 
Claire Golden 
MassDEP, Surface water Discharge Program 
150Presidential Way, Woburn, MA 01801 
RE: Comments on the Draft NPDES Permit No. MA0103284 Authorization to Discharge under the
National Pollutant Discharge Elimination System 
Dear Ms. Barden and Ms. Golden, 
The City of Somerville (City) appreciates the opportunity to comment on the U.S. Environmental 
Protection Agency’s (EPA) draft National Pollutant Discharge Elimination System (NPDES) permit (Draft
Permit) number MA0103284 for the MWRA Deer Island Treatment Plant (DITP) and explanatory Fact
Sheet. The City is providing the following comments in accordance with 40 C.F.R. §124.13. 
Comments on inclusion of Co-permittees in the Draft Permit 
The City is requesting that EPA update the CSO-responsible Co-permittee and Co-permittee contact
information for the City of Somerville on page 2 of the Draft Permit and in Appendix B page 5, to the
following:

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Department of Public Works Building, First Floor • 1 Franey Road • Somerville, Massachusetts 02145 
City of Somerville 
Department of Water and Sewer 
17 Franey Road 
Somerville, MA 02144 
Comments on Part I.A. Effluent limitations and monitoring requirements for outfall T01 
The inclusion of CSO-responsible Co-permittees and Co-permittees creates unacceptable liability and
risks to these communities. Furthermore, it is unreasonable to hold them to the standard of number
Part I.A.2. The City is requesting EPA to consider and clarify the liability, obligations, and cost impacts
the requirements under Part I.A.2 will have for all the CSO-responsible Co-permittees and Co-
permittees. Any additional costs that MWRA will incur will become costs to the Co-permittees. 
Comments on Part I.B. Combined Sewer overflows (CSOs) 
Part I.B.2.a. “ The discharge shall not cause a violation of the water quality standards of the
receiving water. ” 
The City is requesting EPA to update this language to allow performance-based CSO discharges rather
than prescriptive-based, as we are in the process of an Updated CSO Control Plan for the CSO discharges
into the Alewife Brook and the Mystic River, as required in the variance included as Attachment K. We
believe that having this in the final permit suppresses and supersedes the work we are currently doing
for the Update CSO Control Plan, which is what will define what the CSO-responsible Co-permittees will
implement and achieve in the long term. 
Part I.B.2.e. “The authorized typical year discharge activations and volumes for the Alewife
Book and Upper Mystic River CSO outfalls are limited as shown in Attachment I. Discharge frequencies
and volumes are expected to vary from year to year as a function of rainfall. CSO outfalls discharging
to the Alewife Brook/Upper Mystic River Basin have been granted a variance under the Massachusetts
Water WQS through August 31, 2024. A copy of this determination letter for the variance extension is
included as Attachment K. The conditions of this variance are incorporated into and are enforceable 
element of this Permit.” 
The City is requesting EPA to update this section to reflect the following: 
(1) the existing variance, as included in Appendix K of the Draft Permit, is in the process of being
reissued; 
(2) the authorized typical year discharge activations and volumes as shown in Attachment I are based on
the 1992 typical year. The City, along with the City of Cambridge and the Massachusetts water
Resources Authority (MWRA), has developed a 2050 typical year as part of the Updated CSO Control
Plans. This 2050 typical year includes future climate projections, has been reviewed by EPA, and will
likely be used as the performance tool for the Updated CSO Control Plans. We expect the Updated CSO
Control Plan to be reviewed and approved within the 5-year permit timeframe and we expect the 2050
typical year to be adopted. It is unreasonable to potentially have two different typical year authorized
CSO discharges and cumbersome to comply and report on these two different requirements.

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Department of Public Works Building, First Floor • 1 Franey Road • Somerville, Massachusetts 02145 
Part I.B.2.f. “The Permit’s discharges must meet federal and state WQS subject to and 
consistent with any water quality standards variances or variance extensions issued by MassDEP and
approved by EPA." 
The City reserves the right to further comment on this section as the updated variance language for the
Alewife Brook and the Mystic River has yet to be made available to the public. The City is requesting EPA
to include language that makes it clear that these sections of the permit will be reopened for comment
upon approval of the Updated CSO Control Plans. 
Part I.B.3. Nine Minimum Controls Implementation Levels 
The City has submitted a Draft Updated Nine Minimum Control Plan Report to EPA and DEP on June 30,
2022. The City expects to receive comments from EPA and DEP, if any, in time to finalize the report for
the deadline prescribed in the Draft Permit. 
Part I.B.3. j. (5) “…with white lettering against a green background…” 
The City has an existing sign at CSO outfall at SOM001A that is with black lettering against a white
background and is inclusive of all the information required in the Draft Permit. The City is requesting EPA
to allow the existing sign and update the permit to allow other color combinations, if existing. 
Part I.B.3.e. and f. 
The City is requesting EPA to update these two sections to reflect and allow flexibility for the typical year
CSO discharges as we continue to work closely with the City of Cambridge, MWRA, EPA, and DEP on the
three Updated CSO Control Plans. 
Please consider rewriting the following “…using the updated MWRA model (or equivalent)…” to “…using 
the most up-to-date available model to the Co-permittee community…”. 
Please define and provide official guidance on the “ precipitation in the typical year under future planned
conditions. ” 
Comments on Part I.E.2. Operation and Maintenance Sewer System 
Part I.E.2.e. Sewer System O&M Plan 
Developing the Sewer System O&M Plan and its components requires outside expertise for which the
City will have to budget and hire . Moreover, the City’s experience with similar planning efforts, including 
the Updated CSP Control Plan, highlights the complexity of these issues and the considerable technical
expertise required to develop actionable and effective plans. Considering the lengthy procurement
process in Massachusetts, the time needed to gather data, and the time needed to complete the
evaluations, analysis, and writing if these report components, the City is requesting that EPA to extend
the deadlines for developing and submitting the Sewer System O&M Plan components as follows: 
(1) Sewer System Major Storm and Flood Events Plan 
a. Component 1: Asset Vulnerability Evaluation – The City is requesting this be due at least
2 years from the effective date of the Permit.

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Department of Public Works Building, First Floor • 1 Franey Road • Somerville, Massachusetts 02145 
b. Component 2: Systemic Vulnerability Evaluation - The City is requesting this be due at
least 4 years from the effective date of the Permit. 
c. Component 3: Alternative Analysis - The City is requesting this be due at least 6 years
from the effective date of the Permit. 
(2) Sewer System O&M Plan – the City is requesting this be due at least 6 years from the effective
date of the Permit or have the Sewer System Major Storm and Flood Events Plan removed as
one of the components. 
Additionally, the steps EPA is requiring in the completion of the Sewer System Major Storm and Flood
Events Plan are prescriptive and may not be aligned with the extensive climate planning and
implementation work the City of Somerville has been doing in the past decade and with what the City is
planning to do in the future. Furthermore, these steps do not align with other State required and
recommended resiliency plans, for example Hazard Mitigation Plans, Climate Change Vulnerability
Assessments, or Updated CSO Control Plans. The City is urging EPA to rewrite the steps to: 
(1) allow flexibility in how communities can incorporate resiliency into the sewer system
operational and maintenance work, 
(2) allow Co-permittees to take credit and use prior resiliency work to satisfy the requirements of
this section of the Permit, 
(3) remove the need to update the Plan every five years. 
Comments of the Fact Sheet: Appendix I – Summary of CSO Activations and Volumes 
Please correct the amount for CSO discharge volume f or Somerville’s permitted CSO SOM001A : 2021
total reported CSO volume is 17.98 million gallons, not 97.98 million gallons. 
Thank you for your consideration of these comments. 
Sincerely, 
LucicaHiller 
Lucica S. Hiller 
Stormwater Program Manager 
IAM Department, Engineering Division 
City of Somerville 
1 Franey Road, Somerville MA 02145