Maine was in the grips of a worsening drought in the fall of 2016 when a 4-inch rainstorm delivered temporary but much-needed relief to parched streams, wells and reservoirs in the Portland area.

The storm also delivered an unhealthy punch to Casco Bay, however.

Nearly 69 million gallons of stormwater mixed with raw sewage, debris and polluted runoff flowed into Back Cove, Portland Harbor and local waterways on Oct. 21 and 22 as the storm exceeded the capacity of Portland’s treatment plants. That’s enough stormwater and untreated sewage to fill more than 100 Olympic-sized swimming pools, which, if lined up end to end, would stretch for nearly three miles.

All told, Portland reported that 318.4 million gallons of combined sewage and stormwater overflowed into surrounding waters in 2016, avoiding sewer backups into homes, businesses and streets but contributing to Casco Bay pollution. Yet as recently as 30 years ago the city was discharging 1.8 billion gallons of sewage-tainted water that gushed into Portland’s scenic and economically vital waterways – an 80 percent reduction that illustrates both the strides the city has made but also the slow progress of fixing an underground infrastructure built generations before environmental regulations were created.

“This is a legacy problem. It started 100 to 150 years ago when they built the combined sewers,” said Mike Riley, coordinator of the Maine Department of Environmental Protection’s combined sewer overflow, or CSO, program. “It took decades to get into this problem and it is going to take decades to get out.”

Compounding those challenges, Portland and coastal cities across the U.S. are trying to fix century-old problems while facing uncertainties over future sea level rise and other impacts from climate change.

“I think Portland has made a considerable amount of progress and has made a considerable amount of investment to address the issue of combined sewer overflows and the treatment of waste,” said Sean Mahoney, vice president and Maine director of the Conservation Law Foundation, which sued the cities of Portland and South Portland in 1989 to force federal and state regulators to crack down on the storm-related sewage overflows.

“The health of Casco Bay was in a very different state back then than it is today, although there are certainly still issues today, as witnessed by the recent closure of clam flats because of a late algae bloom,” Mahoney said.

MASSIVE INFRASTRUCTURE UPGRADES

Portland is more than halfway through what is now a roughly 40-year, nearly $250 million plan to dramatically reduce the amount of raw sewage flowing into local waterways. In addition to violating the federal Clean Water Act and state environmental regulations, those storm-related discharges carry such hidden dangers as E. coli and salmonella that threaten the health of local residents who come in contact with the water, the vitality of Casco Bay’s commercial fishing industry and Portland’s status as a tourism destination.

Fixing the problem isn’t easy, however, and many city residents are feeling the sting during their commutes and in their wallets as the city undertakes massive infrastructure projects to reduce sewage/stormwater discharges into Back Cove.

PORTLAND, ME -DECEMBER 11: Portland is half-way through a $170 million plan to drastically reduce the amount of raw sewage that discharges into Back Cove and Portland Harbor. Included in the project is a disruptive construction of State Street, a major thoroughfare in the city. Roger Elie, from Biddeford, directs traffic detoured around the State Street construction work. (Photo by John Ewing/Staff Photographer)

Major downtown corridors – State Street, Forest Avenue and Woodford Street, to name a few – were torn up last year to install new separate sewer and stormwater pipelines, creating traffic hassles for months on end. A heavily trafficked stretch of State Street, for instance, was closed from August to mid-December as crews separated sewer and stormwater lines while also installing new water and gas mains. Busy Woodford Street was also torn up for much of 2017, and periodic closures of State Street Extension, Preble Street Extension and Park Avenue resulted in traffic delays and detours.

Over the next year and a half, Portland plans to install “storage conduits” under the ballfields in Back Cove Park and along the western side of Back Cove that can hold 6 million to 7 million gallons. The idea behind the massive storage tanks is to capture the first inch of storm runoff – which contains the most contaminants, debris and other pollutants – and later treat this “first flush” when the East End Wastewater Treatment Facility has the capacity.

City engineers originally planned to install the ballfields storage conduit under Marginal Way but reconsidered when the price tag jumped from $24 million to $32 million and after assessing the massive disruption.

“We wanted to look at alternatives that were going to reduce the business impacts, the traffic impacts and the cost while still meeting the DEP requirements,” said Bradley Roland, the top engineer with the Portland Department of Public Works. “We would have basically been shutting down sections of Marginal Way for months on end.”

To date, Portland has spent more than $112 million on overflow-related projects and expected to spend another $147 million on the 15-year plan adopted in 2014. Those costs are reflected in sewer and, more recently, stormwater fees that have risen more than 30 percent for the average household since 2014. Nearly 30 percent of the revenues collected by the Portland Water District from sewer bills – which average $64.19 a month for a household – are spent on capital and infrastructure work, including separating those legacy combined sewer-stormwater pipes hidden beneath much of old Portland.

CAPE ELIZABETH TO CALAIS

Portland is by no means unique in facing a costly and unsightly sewage overflow problem.

Nationwide, more than 800 communities have infrastructure with combined stormwater and sewer pipes that result in discharges, according to the U.S. Environmental Protection Agency. New York Harbor alone receives an estimated 27 billion gallons of untreated stormwater and sewage annually from New York City and neighboring communities. The communities in Greater Boston, meanwhile, have reduced combined sewer overflow discharges by 98 percent since the late-1980s through a $900 million infrastructure improvement plan.

In Maine, 473.6 million gallons of untreated stormwater and sewage were discharged into state waterways in 2016 by 25 communities spanning the geographic and demographic gamut from Cape Elizabeth to Calais. But Portland’s 318.4 gallons accounted for 67 percent of that total as the combination of stormwater and untreated sewage was passively diverted out of more than 31 overflow sites discharging directly into surrounding waterways.

The national problem is most acute in older cities in the Northeast and Midwest. City engineers at the time designed cutting-edge infrastructure projects around the idea that Mother Nature can periodically help flush sewers with stormwater, often into rivers or oceans that will carry the waste away. In a testament to the craftsmanship of the time, many of the brick-lined sewers laid down by workers 100 or even 150 years ago are still used today in many cities, including Portland.

Unfortunately, human waste doesn’t always float. And the disease-causing bacteria found in that waste readily contaminates surrounding waters.

‘FAIR TO SAY WE ARE BEHIND’

In 1988, the Conservation Law Foundation and the Island Institute published a report titled “Troubled Waters” that focused public attention on the issue and preceded the lawsuits against Portland and South Portland. The 78-page report, which inspired the creation of Friends of Casco Bay, said “signs of environmental degradation” in the waters, sediments and marine life of Casco Bay should serve as a warning sign to the public and policymakers. While chemical pollution from industries, farms and households was part of the problem, discharges of untreated sewage and stormwater were among the largest suspected contributors.

The lawsuits filed by the Conservation Law Foundation one year later eventually led to a settlement agreement between Portland, the U.S. Environmental Protection Agency and the DEP that laid out the city’s long-term plan to address the issue.

Roland, the city’s chief public works engineer, said Portland is making steady if slower-than-anticipated progress.

“If you go back to the original 30-year plan the city had, I think it is fair to say we are behind. But over the last three to four years, we have made attempts to catch up,” said Roland.

The alternate plan for a 3 million-gallon storage conduit under Back Cove Park ballfields (which will be replaced) has been endorsed by the DEP, which never favored installing a storage system under Marginal Way. As a result, the department is allowing Portland to miss its original deadline for the Marginal Way project as long as the city still meets its obligations for the tanks on the western side of Back Cove.

“With Back Cove-West, if they don’t meet those deadlines, we will have a problem and there will be enforcement there,” said Riley, the DEP’s CSO program director. “We want to see both of those tanks go in as soon as possible.”

Portland is more than halfway along on a 40-year, nearly $250 million project to drastically reduce the amount of raw sewage that discharges into Back Cove, above, and Portland Harbor whenever storms overwhelm the capacity at the city’s treatment plants.

SIGNS OF ENVIRONMENTAL IMBALANCE

The number of combined sewer overflow discharge locations in Portland and South Portland has fallen from 60 to 36 over the past 20 years, reflecting the steady progress in both communities but particularly South Portland. The city of Portland and the Portland Water District have also spent tens of millions of dollars upgrading the capacity and efficiency of the East End Wastewater Treatment Facility.

The East End plant visible from Tukey’s Bridge on Interstate 295 just north of downtown can apply the full treatment regimen (solid separation and dewatering, plus disinfection of solids and water) to 36 million gallons per day. During days of heavy flows, however, the treatment plant can also disinfect an additional 43 million gallons that cannot go through the full, multistage process but at least gets treated with chlorine.

Plant upgrades and “primary treatment” of up to 43 million additional gallons per day enabled the city and the Portland Water District to intercept and treat 178 million gallons of stormwater mixed with sewage in 2016 that would otherwise have flowed into Back Cove without any treatment.

“When you look at CSOs, the primary concern is with bacteria. And we are removing the bacteria,” said Scott Firman, director of wastewater at the water district.

The Conservation Law Foundation’s Mahoney said untreated sewage and stormwater discharges “continue to be a real problem for the health of the bay,” but he said the city has done a “good job” of identifying top priorities in the next phase of work.

“The one risk is the political will to continue to address the problem,” Mahoney said. “It’s not easy but fortunately it is also the law. And when the political will is not there, the law is.”

Back Cove seems clean today, but it is still Portland’s primary catch basin.

The popular Back Cove Trail circumnavigating the estuary is dotted with more than a half-dozen green-and-white signs marking discharge locations. While few people likely stop to read them, the signs advise of “Wet Weather Sewage Discharge” and provide the bureaucratic license or permit information for that particular discharge spot.

More noticeable to many people, parts of Back Cove have taken on a greenish tinge during the past two summers. The thick mats of algae carpeting the cove and other mudflats in Portland Harbor are an alarming development, threatening to smother shellfish and deplete oxygen levels in the water.

They also signal an environmental imbalance.

Ivy Frignoca, a former Conservation Law Foundation attorney who took over as baykeeper for Friends of Casco Bay in 2016, said it is still unclear what is causing the algae blooms, but they are “likely a combination of everything,” including lawn fertilizer runoff and sewer overflows.

She credited Portland for agreeing to include the Fore River in the next phase of improvements and for adjusting its plans for the Marginal Way stormwater storage system.

“I think that kind of delay is sensible,” Frignoca said. “I am supportive of it … when their delays are thoughtful and for a reason rather than because they just didn’t want to do the work.”

ANOTHER FACTOR: CHANGING CLIMATE

Ultimately, the best indicator of Portland’s progress is the health of the bay. And over the past several decades, the number of “no swimming” days at East End Beach caused by bacterial pollution have fallen dramatically while local shellfish flats have reopened to harvesting and Portland Harbor’s commercial fishermen are enjoying healthier waters and catches.

Still, Portland’s 30-plus-year plan would only reduce the city’s historic overflow discharges by 88 percent. That means the city could face additional required upgrades if and when state or federal regulators decide that even a single gallon of sewage-contaminated stormwater is too much.

Climate change, meanwhile, presents other challenges.

In order to qualify for a loan through a state-run program, municipalities must design projects capable of withstanding a 100-year storm plus 3 feet of sea level rise. Portland’s Back Cove and Marginal Way areas already flood during severe storms or astronomically high tides, forcing the city to install gates to prevent a backflow of water into discharge pipes.

Frignoca listed overflow discharges, so-called “non-point” nitrogen pollution from other sources and climate change as the likely top factors in recent changes – such as algae blooms – seen in Casco Bay.

“A lot of these questions, we don’t have answers to,” Frignoca said. “But we know for sure that the bay is changing and changing quickly.”

Kevin Miller can be contacted at 791-6312 or at:

kmiller@mainetoday.com

Twitter: KevinMillerPPH