(Image: Algae on Scarborough Pond at Franklin Park on July 5, 2019)
Sewage and runoff
This year may be the largest algae bloom in the history of the Charles River. 2018 was the rainiest winter in New England history. It created huge runoff of fertilizer and animal waste into the Charles, making the water murky green. The river’s EPA rating fell from an “A” to a “B”, which translates into a 50% decrease in days that are qualified for swimming. The Charles River Conservancy’s City Swim was cancelled ed because of “turbidity,” i.e. floating crap. 11,000 storm drains deposit untreated street sewage directly into the Charles.11,000 storm drains deposit untreated street sewage directly into the Charles. Click To Tweet
Pollution or algae?
However, this year’s historic rainfall has cooled the Charles dramatically. The perfect algae recipe is heat, sunlight, and crap in the water, and, as of a month ago, the Charles was only 55 degrees. But the rain also filled the river with waste. I can’t see the shallow river bottom off my dock. The rains have stopped, and the temperature is now 79. The big question is: will the turbidity block enough sunlight that the algae don’t get stimulated?
Right now, the stew is simmering. There have already been lakes closed because of dangerous algae in every state in New England. Indian Lake in Worcester was closed July 1 for algaecide treatment. The Charles is well on its way to algae formation. Here is the likely sequence of events.
When the summer drought begins, the locks on the Charles River Dam must be closed to maintain the water level. Otherwise the Back Bay, built on moist soil and timbers, collapses. With the locks closed, the paltry flow of the river drops to ZERO. The Charles River is now the Charles Pond. With no current, the green floatsam sinks to the bottom. The main Basin, From the BU Bridge to the Longfellow, is nearly 2000 feet across, but only 20 feet deep. It acts like a sauté pan. Temperatures begin to rise.
The EPA water quality measurements become meaningless. The EPA standard is to test water from the surface down to three feet. The surface of the Charles flows at 400 cubic feet/minute (CFM). In comparison, the Merrimack flows at 16,000 CFM. Think of the Charles as water slowly flowing on top of an immovable collection of sludge, hydrocarbons, heavy metals, car batteries, human and animal waste. In some places the sludge is twelve feet thick. The police may know the exact spot a body entered the Charles’ water, but the sludge is so thick they can’t find it with sonar, lights, or nets. They have wait ‘till the body rises from decomposition.If you smell the algae walking by, you are absorbing airborne toxins. Click To Tweet
The sun and warmth trigger the algae to produce oxygen; the algae float to the surface, creating green shoals at the eastern end of the Basin near Community Boating. The algae produce neurotoxins, hepatotoxins, and dermatoxins. Drinking the water will kill your dog. If you smell the algae walking by, you are absorbing airborne toxins. At night, the algae can exhaust all the oxygen in the river. In 2015, fish as far upstream as Newton died. BMAA, an algae toxin, is associated with 25 times greater risk of Amyotrophic Lateral Sclerosis (Lou Gehrig’s Disease), especially among those who eat fish from the fouled ponds.
Harmful Algae Blooms can look like foam, scum, or mats on the surface of water (or it may not be visible on the water surface.) It may look like paint floating on the water in colors as varied as blue, green, brown, yellow, orange, or red, and frequently smell like rotting plants.
My advice is simple – stay away!