A woman recently described her walk through Alewife Brook Reservation: “The path was covered with black water. We had to walk through it and push the stroller along. We all got diarrhea and worse. There was blood. It was an open sewer,” said the woman. The Alewife Brook flows around the backside of Cambridge and Somerville, nearly two miles from the Alewife MBTA Station to the Mystic River. It starts with a culvert beneath a bridge where waters barely seen the light of day beneath urban hardscapes converge from Fresh Pond and Jerry’s Pond. The brook is cement-lined to speed water to the Mystic River and onto the ocean without delay.
Approximately 80 people attended a recent meeting with state and city stormwater managers, with 30 testifying about their negative experiences on the 3.5-mile out-and-back trail in the urban forest. They called for an end to the Massachusetts Water Resources Authority's (MWRA) unjust treatment of Alewife Brook. It has been more than 25 years since the Deer Island Treatment Plant began treating the region’s sewage, transforming Boston Harbor from a harbor of shame to a harbor of pride, with beaches open for swimming on most days.
The MWRA manages combined sewer pollution discharges in 10 areas. Alewife Brook is far and away the worst, with no treatments and the highest amount of untreated discharge. In 2021, 51 million gallons of untreated sewage were released into the Alewife. When not inundated, the brook has a flow volume of 2.13 cubic feet per second (March 2024). At this volume, stormwater contaminated with E. coli, microbial pathogens (i.e., bacteria, viruses, and parasites), and toxins (i.e., metals and synthetic organic chemicals) may have spread upstream to Fresh Pond, where Cambridge draws and treats drinking water.
The year 2023 was the worst year ever for Alewife Brook as it repeatedly overflowed its banks, flooding the Greenway of Alewife Brook Reservation State Park with Combined Sewer Overflow (CSO) and human and industrial waste discharges. After heavy rains, residents from nearby neighborhoods walked, jogged, bicycled, and pushed baby strollers through untreated sewage. This poses a serious health risk for the 5,000 plus residents living in the brook’s 100-year floodplain. The densest and lowest-cost housing, including Rindge Towers, is in a location that is only 12 feet above sea level. This represents an environmental justice issue, where people with the least means are compelled to live.
The MWRA knows how to engineer solutions, including stormwater drains separate from the sewage pipes leading to every building and an enormous nearly two-mile storage tunnel built beneath the brook. However, ratepayers will not suffer higher bills to benefit a community of low-income individuals with no beaches along the Alewife. Instead, we are compelled to investigate what should have been addressed when constructing the Deer Island Treatment Plant: identifying the causes of record amounts of stormwater.
Why are we experiencing deluges, erosion, sedimentation, and nutrient outflow, leading to harmful algal blooms, when Boston’s annual average for rainfall plus snowfall has remained nearly steady at 44 inches from 1991 to 2020? Not surprisingly, the answer is climate change and the increase in greenhouse gases that trap heat. Contrary to popular belief, science indicates that reducing fossil fuel emissions, although important, will have little impact on mitigating stormwater damage or cooling the planet. A recent scientific report unpacked why 2023 was so much warmer than expected. They found that about 10% of global warming was due to rising carbon dioxide and about 80% due to a record-low planetary albedo caused by reduced cumulus cloud cover in the northern mid-latitudes, including the USA, Canada, and tropics including the Amazon and Congo.
Climate change primarily results from crossing a tipping point where urbanization has replaced vegetation and soil with hard, impervious surfaces. The detrimental cascading effects are multiplying. Plants require deep, healthy soil to photosynthesize and grow, even during dry periods. Trees release significant amounts of bacteria and fungi into the air, providing organic material for water vapor to nucleate around, forming clouds. (Water nucleating around dust particles transforms into smog, with particles that repel due to an electrostatic charge, preventing rainfall.) Water vapor constitutes most greenhouse gases, absorbing and holding heat energy. Cumulus clouds, however, reflect more heat than they absorb, cooling the planet. (High cirrus clouds primarily absorb heat). Global cumulus cloud cover once exceeded 50%. Today, the report shows that the cumulus cloud cover is slightly lower (1-2%) and is in decline.
Not only are there fewer cooling clouds, but also more heat islands absorbing solar energy. Plants once regulated their temperatures and microclimate by intentionally releasing water vapor to cool through evaporation and warm with morning dew.
Cambridge's rainfall has averaged 48 inches, with some years receiving slightly more and others receiving slightly less. Rainstorms have become stronger, portioning out more water at once. The plants' and soils' carbon sponge has been diminished—stormwater barrels over hard surfaces, eroding properties and dumping sediments. The water is warmed and dumps heat into the ocean, resulting in rising sea levels.
Belmont Woods, located on the uplands behind Alewife Station, was home to young trees and dozens of old trees that provided cavities for wildlife. The woods were cut down, and the soil was scraped away to make way for 238 luxury apartments and 60 condominium units at the high end of affordability. Rainwater no longer infiltrates the ground to cool the Mystic River during hot summers. Replaced by large stormwater overflow culverts that dump into the Alewife. The developers got rich while residents along the Alewife were left standing in you-know-what, and we battled the consequences of climate change.
The solution for when there are developments is to offset and replace the vegetation and soil removed to maintain natural cooling and retain the carbon sponge function within our constructed developments. Water is valuable, so don’t flush it when in abundance, slow water down, and let plants use it to draw more carbon and grow healthy ecosystems. Developers must be responsible for holding water. Let water return to soil and aquifers, with more rain gardens, permeable pavers, and by incorporating cisterns or French drains beneath constructions. We address climate change with nature-based solutions and more carbon sponges along the banks of our waterways.
H. F. Goessling, T. Rackow, T. Jung, Recent global temperature surge intensified by record-low planetary albedo. Science 387 (6729), 68–73 (2024), https://doi.org/10.1126/science.adq7280
Steady on,
Rob
