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Save the Alewife Brook

environmental health is community health

Document Category: CSOs


TitleSummaryCategoriesLinkhf:doc_categories
Second Stipulation from Harbor Court Case

Court Document from 03/15/2006. Includes chart of allowable discharges at each CSO outfall in Alewife …

CSOs, EPA, Legal, MWRA
csos epa legal mwra
MassDEP’s 11-17-2025 letter to MWRA Board

Based on the information presented at the October 29 meeting, MassDEP is concerned that Recommended …

Cambridge, CSOs, MassDEP, MWRA, Somerville
cambridge csos dep mwra somerville
Harbor Court Case Second Stipulation, from 2006

This is the Boston the Harbor Court Case’s 2006 “Second Stipulation,” which not only updates …

CSOs, EPA, Historical, Legal, MassDEP, MWRA
csos epa historical legal dep mwra
Letter to MWRA Board of Directors, November 2025

Save the Alewife Brook’s November 2025 comments on the updated sewage elimination plan. Includes a …

CSOs, MWRA
csos mwra
Better Know a CSO

A Tour of the Alewife Brook Combined Sewer Outfalls From our CSOs 101 Course …

Arlington, Belmont, Cambridge, Climate Change, CSOs, EPA, Flooding
arlington belmont cambridge climate-change csos epa flooding
kayaking Broadway Bridge 09-07-2024

On Alewife Brook, behind Dilboy Park, under the Broadway Bridge, kayaking through a mass of …

Arlington, Cambridge, CSOs, Somerville
arlington cambridge csos somerville
Alewife Sewage Pollution Flooding

During heavy rainstorms, the Alewife Brook floods into the parks, yards, and houses of area residents in Environmental Justice Communities. The flood water contains hazardous sewage that is dumped into the Brook from the active Combined Sewer Overflows (CSOs) owned by Cambridge, Somerville, and the Massachusetts Water Resources Authority (MWRA).

Climate change, with its wetter rainy seasons, more intense storms, and sea level rise, is expected to increase the severity and frequency of these events. MWRA’s sewer infrastructure is failing to meet capacity during many rains, causing hazardous sewage pollution discharges.

In 2023, Alewife Brook flooded repeatedly, overtopping its banks and inundating the Greenway of Alewife Brook Reservation State Park with untreated Combined Sewer Overflow discharges of human and industrial waste. Area residents from Somerville, Cambridge, and Arlington unknowingly bicycled, jogged, and pushed baby strollers through untreated sewage flood water in their state park.

The Alewife Greenway Path is a heavily used transportation and recreation corridor that runs through multiple Environmental Justice neighborhoods. The Alewife Greenway Path is on DCR land and it links Medford, Somerville, and Arlington pedestrians and cyclists to the Alewife Red Line T stop.

Arlington, Cambridge, Climate Change, CSOs, EPA, Flooding, MassDEP, MDC and DCR, MWRA, Somerville
arlington cambridge climate-change csos epa flooding dep mdc-and-dcr mwra somerville
EPA Combined vs Separated Sewer System

In a combined sewer system, both wastewater and stormwater flow through the same pipes. In dry weather, all wastewater flows to a wastewater treatment plant where it is treated before being discharged to a waterbody. But during wet weather, stormwater also enters the system. The combined flow of wastewater and stormwater can overwhelm the system. Permitted outfalls are located throughout the system to act as relief points during wet weather. These outfalls discharge untreated or partially treated stormwater and wastewater into nearby waterbodies. These discharges are called CSOs.

CSOs are a major water pollution and public health concern for approximately 700 communities in the United States. CSOs can contain bacteria, debris, and other hazardous substances that can be harmful to people, pets, and wildlife. CSOs can also cause beach closures, shellfish bed closures, algae growth, reduced oxygen levels in waterways, and aesthetic impacts from floating debris or oil slicks. The Clean Water Act requires communities with CSOs to put controls in place to address these concerns.

CSOs, EPA
csos epa
MassDEP 2024 Draft Water Quality Variance to Allow for CSO discharges to Alewife Brook

This is MassDEP’s 2024 draft of the Water Quality Variance for Alewife Brook, which would …

Arlington, Belmont, Cambridge, CSOs, EPA, MassDEP, MWRA, Somerville
arlington belmont cambridge csos epa dep mwra somerville
2024 Comments on DEPWater Quality Variance – Charles River Watershed Association

“… we are deeply concerned that the proposed variance is failing to protect a valuable natural resource and is not delivering continued, meaningful progress. As drafted, the Tentative Variance is inadequate as it allows for continued pollution without requiring substantive corrective actions during the variance period… We do not support the Tentative Variance as written… the ultimate goal should be nothing less than complete or functional elimination of the CSO discharges… The current financial analysis is inadequate for determining the economic feasibility of CSO elimination… Combined Sewer Overflow is an Environmental Justice issue. Environmental Justice (EJ) is a stated priority for the federal government and the Healey-Driscoll administration.”

Cambridge, Climate Change, CSOs, MassDEP
cambridge climate-change csos dep
MWRA Joint Press Release April 2023

Dated April 14th, 2023 Joint Press Release APRIL 2023 Alewife Brook/Upper Mystic Combined Sewer Overflow …

Arlington, Belmont, Cambridge, CSOs, MWRA, Somerville
arlington belmont cambridge csos mwra somerville
H.886 Fact Sheet: An Act Relative to Combined Sewer Overflows

Please Support H.886: An Act Relative to Combined Sewer Overflows Filed by Representatives Adrian Madaro …

Climate Change, CSOs, MWRA
climate-change csos mwra
HD3316: An Act relative to combined sewer overflows.

An Act relative to combined sewer overflows. Be it enacted by the Senate and House …

CSOs, MWRA
csos mwra
MWRA CSO MAP

This is the Massachusetts Water Resources Authority map from 2016, which we believe has not …

Arlington, Belmont, Cambridge, CSOs, MWRA, Somerville
arlington belmont cambridge csos mwra somerville
Alewife Brook 2004 Through 2021 Calendar Year and Typical Year Hydraulic Model Results vs LTCP

The “Alewife Brook 2004 Through 2021 Calendar Year and Typical Year Hydraulic Model Results vs …

CSOs, MWRA
csos mwra
Typical Year Rainfall Analysis for Cambridge-Somerville-MWRA Combined Sewer Overflow (CSO) Control Plans

Development of Future Typical Year of Rainfall Technical Information in Support of the December 15th …

Cambridge, Climate Change, CSOs, MWRA, Somerville
cambridge climate-change csos mwra somerville
Alewife CSO Permittees Request Extension

The 2019 Alewife Brook CSO Variances (permits to pollute through sewage pollution discharges) expire on …

Cambridge, Climate Change, CSOs, MassDEP, MWRA, Somerville
cambridge climate-change csos dep mwra somerville
EPA response to Draft Scope, sent to MWRA

This is the EPA’s May 11, 2022, guidance for MWRA, regarding their new CSO control …

CSOs, EPA, Flooding, Green Infrastructure, MDC and DCR, MWRA, Stormwater
csos epa flooding green-infrastructure mdc-and-dcr mwra stormwater
EPA response to Draft Scope, sent to Cambridge

This is the EPA’s guidance for Cambridge, regarding their new CSO control plan “draft …

Cambridge, Climate Change, CSOs, EPA, Flooding, Green Infrastructure, MDC and DCR, Stormwater
cambridge climate-change csos epa flooding green-infrastructure mdc-and-dcr stormwater
EPA response to Draft Scope, sent to Somerville

This is the EPA’s response to Somerville’s new CSO control plan “draft …

Climate Change, CSOs, EPA, Green Infrastructure, MDC and DCR, Somerville, Stormwater
climate-change csos epa green-infrastructure mdc-and-dcr somerville stormwater
MWRA 2018 Wastewater Master Plan

…

CSOs, MWRA, Stormwater
csos mwra stormwater
City of Cambridge CSO Control Plan Scope

…

Cambridge, CSOs
cambridge csos
Somerville Updated CSO Control Plan Scope of Work and Schedule 04/01/2022

…

CSOs, Somerville
csos somerville
MWRA Updated CSO Control Plan – Draft Scope of Work and Schedule 04/01/2022

…

CSOs, MWRA
csos mwra
1978 MAPC Boston Area Waste Treatment Management Plan

…

Arlington, Cambridge, CSOs, Flooding, Historical, Somerville, Stormwater
arlington cambridge csos flooding historical somerville stormwater
MWRA 1997 CSO Facilities Plan and EIR Table of Contents

…

CSOs, MWRA
csos mwra
MWRA 1997 Combined Sewer Overflow Facilities Plan and Environmental Impact Report VOL. 3

…

CSOs, MWRA
csos mwra
MWRA 1997 Combined Sewer Overflow Facilities Plan and Environmental Impact Report VOL. 5

…

CSOs, MWRA
csos mwra
MWRA 1997 Combined Sewer Overflow Facilities Plan and Environmental Impact Report VOL. 4

…

CSOs, MWRA
csos mwra
MWRA 1997 Combined Sewer Overflow Facilities Plan and Environmental Impact Report VOL. 2

…

CSOs, MWRA
csos mwra
MWRA 1997 Combined Sewer Overflow Facilities Plan and Environmental Impact Report VOL. 1

…

CSOs, MWRA
csos mwra
MWRA 2001 CSO Control Plan Notice of Project Change

…

CSOs, MWRA
csos mwra
March 2022 Letter to Regulators from StAB & Watershed Associations

March 11, 2022   Via email   Regional Administrator David Cash Environmental Protection Agency, Region …

Climate Change, CSOs, EPA, Flooding, Green Infrastructure, MassDEP, MWRA
climate-change csos epa flooding green-infrastructure dep mwra
SOM001A Tannery Brook 1873 Atlas Detail

This is a cool image of the Tannery Brook, taken from the 1873 …

Cambridge, CSOs, Somerville
cambridge csos somerville
Somerville Stormwater Map

Dated June 15, 2020. Awesome map of Somerville stormwater, combined system, and sanitary system. Includes: …

CSOs, Somerville, Stormwater
csos somerville stormwater
Cambridge Catchment and Combined Sewer Map

This is a very cool and easy-to-read map of Cambridge’s stormwater catchments. It is well …

Cambridge, CSOs, MWRA, Stormwater
cambridge csos mwra stormwater
MWRA Final CSO Performance Assessment Hearing Notification

Massachusetts Water Resources Authority PRESS RELEASE Date: January 6, 2022 Contact: Ria Convery (617) 788-1105, ria.convery@mwra.com …

Arlington, Cambridge, CSOs, EPA, Legal, MassDEP, MWRA, Somerville
arlington cambridge csos epa legal dep mwra somerville
The Boston Harbor Cleanup by Paul F. Levy & Michael S. Connor, published in 1992

New England Journal of Public Policy Volume 8 | Issue 2 Article 7 9-23-1992 The …

CSOs, EPA, Historical, MassDEP, MDC and DCR, MWRA
csos epa historical dep mdc-and-dcr mwra
MWRA 2021 Final CSO Performance Assessment

MWRA CSO Report is Unfair to Alewife’s Environmental Justice Populations On December 30, 2021, the …

Arlington, Cambridge, CSOs, MWRA, Somerville, Stormwater
arlington cambridge csos mwra somerville stormwater
Somerville Stormwater Management Map, June 2020

Stormwater Management Map. Includes: Storm Discharge Points, CSO Outfalls, Stormwater Manholes, Sanitary and Combined Manholes, …

CSOs, Somerville, Stormwater
csos somerville stormwater
MWRA BIANNUAL COMPLIANCE AND PROGRESS REPORT AS OF JUNE 25, 2021

CIVIL ACTION No. 85-0489-RGS UNITED STATES DISTRICT COURT for the DISTRICT OF MASSACHUSETTS UNITED STATES …

Cambridge, CSOs, EPA, Legal, MassDEP, MDC and DCR, MWRA, Somerville, Stormwater
cambridge csos epa legal dep mdc-and-dcr mwra somerville stormwater
United States v. Metropolitan District Commission July 2021

Civil Action 83-1614-RGS United States District Court, District of Massachusetts United States v. Metropolitan District …

Arlington, Cambridge, CSOs, EPA, Legal, MWRA, Somerville
arlington cambridge csos epa legal mwra somerville
Court Case 2016 Document, including Compliance Order 239, USA v. MDC & CLF v. MDC

Doug Foy, Esq., director of the Conservation Law Foundation, who brought the groundbreaking Boston Harbor Clean-up lawsuit, probably quoting an ubran sociologist, said, “A great city had three characteristics: It had world-renown cultural and educational institutions. It had enduring distinctive residential neighborhoods, and it had a body of water that it embraced.”

Cambridge, Climate Change, CSOs, EPA, Green Infrastructure, Legal, MassDEP, MDC and DCR, MWRA, Somerville
cambridge climate-change csos epa green-infrastructure legal dep mdc-and-dcr mwra somerville
Somerville’s 2017 Infrastructure Presentation

New projects described here include combined sewer separation, flood control are encouraging. Interesting data about …

Climate Change, CSOs, Flooding, Green Infrastructure, Historical, Somerville
climate-change csos flooding green-infrastructure historical somerville
CRWA MyRWA 2021 Letter re US v MDC

2021 Letter from the Charles River Watershed Association and the Mystic River Watershed Association to …

CSOs, EPA, Green Infrastructure, Legal, MDC and DCR, MWRA
csos epa green-infrastructure legal mdc-and-dcr mwra
Cambridge’s 2017 Alewife Sewer Separation Project Overview

Wondering what’s involved in combined sewer separation and CSO elimination work? This is Cambridge’s $90 …

Cambridge, CSOs, Green Infrastructure
cambridge csos green-infrastructure
Alewife Reservation Stormwater Wetland MCWRA 2017 Symposium

This is a powerpoint presentation by Carter Stantec for the 2017 Massachusetts Coalition for Water …

Cambridge, CSOs, Green Infrastructure
cambridge csos green-infrastructure
Cambridge’s 2019 Alewife District Plan

This is Cambridge’s 2019 Alewife Planning and Development document. It includes information about flooding, water …

Cambridge, Climate Change, CSOs, Flooding, Green Infrastructure
cambridge climate-change csos flooding green-infrastructure

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  • Submit a Public Comment on the CSO Plan
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