BOURNE – According to data collected by the Buzzards Bay Coalition, the majority of locations around the Bay showed slight declines in water quality during the summer of 2019.
The coalition’s volunteers collected water quality data at more than 200 monitoring stations on 30 major harbors, coves and rivers across Buzzards Bay.
They measured temperature, salinity, water clarity, dissolved oxygen, and general weather conditions.
This data, combined with laboratory analysis of nitrogen and chlorophyll levels by the Marine Biological Laboratory in Woods Hole, produce the Bay Health Index.
About 37 percent of the Bay is considered “healthy,” while another 47 percent of waterways are in “fair” condition.
In the “fair” condition areas, algal blooms cause cloudy water and eelgrass beds are sparse, while dissolved oxygen levels periodically drop.
The number of waterways in “poor” health, impacted by pollution and murky waters, ticked up slightly to 16 percent.
“This year’s data include measurements that were taken shortly after a major rainfall last July that washed elevated levels of nitrogen pollution into the Bay,” said Dr. Rachael Jakuba, the Coalition’s science director, in a statement.
Storm water runoff and overloaded or failed wastewater treatment systems can lead to severe nitrogen and phosphorus pollution in the Bay, causing disruptions in natural processes that remove nitrogen from the environment.
Sewage overflows in New Bedford discharge excess untreated sewage directly to nearby streams, rivers or other water bodies, as well.
However, New Bedford Harbor continues to show gains in water quality that reflect the city’s efforts to remove overflows from wastewater systems, which gives hope for Buzzards Bay.
“While the high nitrogen levels in many places following the July rainstorm showed the often negative impacts of development on water quality, the 2019 data also show the potential for smart development to have a beneficial impact on water quality,” Jakuba said in a statement.
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