On July 26, 1.69 million gallons of partially-treated wastewater overflowed from Portland’s East End Sewage Treatment Facility into Casco Bay. This story made the news and captured our attention. That same day, 9.85 million gallons of combined sewer overflows (CSOs), containing raw sewage and toxic chemicals, also entered the Bay. Not a single news outlet reported that fact.
So while swimmers—especially those preparing for the Peaks to Portland Swim—worried about the impact of the partially-treated discharge from the East End plant (wastewater that had already had solids removed and been chlorinated to kill bacteria), we worried about the close to 10 million gallons of a far more toxic slurry that entered the Bay.
On that day, the combined sewer overflow at Mackworth Street discharged 824,000 gallons of untreated water and the CSO at Dartmouth Street discharged 833,000 gallons into Back Cove. The India Street CSO discharged 415,000 gallons and the Long Wharf CSO released 563,000 gallons of untreated water into Portland Harbor.
Photo credit: Dave Laliberte
What is a Combined Sewer Overflow?
Combined sewer systems are relics of the past that we are still using today. In Portland and many cities across the county, these systems were designed to collect—and combine— sewage and stormwater in the same pipes. Most of the time, the pipes transport all the collected wastewater to a sewage treatment plant, where it is treated and then discharged into a body of water. But when we experience heavy rains or snowmelt, the runoff entering the system exceeds the capacity of the pipes. When the pipes fill to certain levels, these antiquated systems are designed to dump a mix of stormwater, untreated waste, toxic materials, and debris directly into the ocean, or into nearby streams and rivers that flow into the Bay.
These periodic discharges are far more concerning to us than a one-time breach at the East End facility. For over 25 years, Friends of Casco Bay has been pushing the City to eliminate these combined sewer overflows. We are very supportive of Portland’s current work to separate combined pipes, build storage tanks, and eliminate CSOs. Over the next two years, as Casco Baykeeper, I will represent Friends of Casco Bay as a member of the stakeholder team that helps shepherd a process called integrated planning, which will enable the City to meet these objectives efficiently and in ways that best improve water quality.
The Environmental Protection Agency created the integrated planning approach to help municipalities such as Portland meet multiple Clean Water Act requirements by identifying efficiencies from separate wastewater and stormwater programs and sequencing investments so that the highest priority projects come first. This approach can also lead to more sustainable and comprehensive solutions, such as green infrastructure, that improve water quality and provide multiple benefits that enhance community vitality.
We will continue to participate, as we have for over 25 years, to help ensure that these combined efforts achieve more effective and timely improvements in water quality in Casco Bay.
What you can do to reduce stormwater and sewage pollution
- Support communities’ efforts to upgrade their wastewater and stormwater systems.
- Employ “green solutions” to reduce stormwater runoff from our own properties:
- install permeable pavement on driveways and patios, so water percolates into the soil below
- reduce the size of the lawn; plant shrubs and ground cover, which hold water better then turf
- use rain barrels to catch runoff from roofs
- Boaters should use shoreside bathroom facilities or pumpout services to keep raw sewage out of the Bay.
Our pumpout boat operates from Memorial Day to Halloween. Contact pumpout@cascobay.org.
