August Nitrate, Total Phosphorus, and Enterococci Results

The August nitrate, total phosphorus, and enterococci results have been added to the website. The results for nitrate our most critical water quality parameter because of the impact of excess nitrogen on the ecology of the estuarine portion of the river and Mount Hope Bay look comparable to 2018 and better than 2017 and 2016 (two low river flow years). We see the highest levels in the upper watershed (locations MAT-01, TWH-01, and CHE-01) reflecting the fact that Brockton and Bridgewater have not completed required upgrades to remove nitrogen yet. Brockton and Bridgewater are scheduled to remove nitrogen in April and May of 2022 respectively.

A good news story is that compared to 2017, nitrate levels in the Nemasket River are low this year most likely reflecting the completion of the upgrade of the Middleboro wastewater treatment plant early last year. The Mansfield/Norton/Foxboro nitrogen removal upgrade is scheduled to go on line in early 2020. We are looking forward to lower nitrogen levels throughout the river when Taunton, Brockton, and Bridgewater are all removing nitrogen by 2022. We are hoping EPA and MassDEP will resume Clean Water Act permitting in the Taunton River watershed soon so the remaining two major permits Somerset and Fall River will be reissued with upgrade schedules.

The other results we are watching are the new enterococci bacteria testing results. Levels in August were lower than in May through July potentially as a results of lower stormwater contributions of bacteria (from contaminated rainwater runoff). In August half of our samples still exceeded the state criteria for enterococci bacteria but the magnitude of the violations was lower. As we accumulate more data on this parameter, we will get a better idea of seasonal fluctuations and potential sources.


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