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From Sean Riley

The Governor has asked me to respond to your letter regarding revisions to water quality standards for the Muddy River, specifically the Commonwealth and EPA processing of the Massachusetts Water Resources Authority (MWRA) Long-tern Combined Sewer Control Plan. Initially, let me say that both the Governor and I are aware of the unique and important resources in the Charles River Basin in general, and the Muddy River in particular. The Commonwealth has no plans to "lower" the water quality standards (WQS) in either the Charles or Muddy Rivers

The current WQS for the Muddy River is Class B (CSO impacted) due to the current extensive impacts to the river from CSO's to Stony Brook. The MWRA CSO Control Plan for Stony Brook and the Muddy River is sewer separation which is the most aggressive and expensive CSO control option available. Unfortunately, due to the specific characteristics of the stormwater systems in this area, current information indicates that it is not technically feasible to completely eliminate all CSO discharges in the Stony Brook Area which impact the Muddy River. There will continue to be the potential for minor CSO overflows to the Muddy River during extreme wet weather. The Commonwealth cannot designate a water body as full B unless all CSO discharges are completely eliminated, a situation which does not appear to be technically feasible at this time. Therefore the highest WQS that can be applied to the Muddy River is B(CSO). However, because the MWRA permit is reissued every five years and water quality standards are reviewed every three years, there will be ongoing opportunity (sic) to ensure that should a solution become feasible, it will be implemented as soon as possible.

The use of the B(CSO) standard provides the regulatory flexibility to acknowledge potential short-term excursions from the criteria, resulting from extreme and infrequent storm event conditions without downgrading WQS. This designation is similar to the Class B and SB standards, which are also based on statistical compliance and similarly acknowledge excursions resulting from extreme, infrequent low-flow conditions.

DEP will be incorporation an interim schedule into the Boston Water and Sewer Commission's (BWSC) CSO/Stormwater NPDES Permit (currently undergoing final review at EPA) to require that BWSC periodically report to EPA and DEP on the status of the separation work in the Stony Brook Area and complementary hydraulic analyses of the overall sewer/stormwater systems to assess the potential for further limiting and/or completely eliminating CSO overflows to the Charles and Muddy Rivers. If complete elimination of CSO discharges becomes possible, DEP will modify the permit to remove the SCO discharge and will reclassify the Muddy River to class B. It is important to understand that the B(CSO) classification will only allow for CSO activations and discharges during extreme storm events, as defined in the MWRA CSO Control Plan, and does not affect the need for full compliance with Class B standards by other discharges to the Muddy River. Without this option extreme storm events would result in raw sewage flooding homes and businesses.

In addition, DEP will review the BWSC NPDES/MA stormwater permit for consistency with its Stormwater Policy and will incorporate any additional stormwater performance standards necessary to ensure that water quality in the Muddy River improves. Staff from the Department of Environmental Protection (DEP) have met on a number of occasions with representatives from the Muddy River Action Group and related organizations; most recently on January 26th to discuss this issue.

I hope that this correspondence clarifies this issue. If you have any further question (sic), please contact Mark Smith at (617) 727-9800 ext 211.


Trudy Coxe
cc: Judith Barber, DEP/NERO, 10 Commerce Way, Woburn, MA 01901