TRWA’s most recent sampling summary spreadsheets showing the results for April through June are available from the monitoring tab on the website or this link.
Nitrate
Lower stream flows and warmer water appears to be contributing to increased nitrate results downstream of the Brockton wastewater treatment plant (WWTP) in the Matfield River and downstream in the Taunton River as far as Cherry St. in Bridgewater. We are measuring elevated nitrate at the two most downstream sampling sites on the Three Mile River, Town River below the Bridgewater WWTP and in the Taunton at Church St. in Raynham.
Total Phosphorus
Total Phosphorus (TP) measured was higher than last month with two locations (upper and lower Taunton River) above the 0.100 mg/l in-stream target used by EPA in permit limit development. Elevated TP in the 0.07 to 0.095 mg/l range were measured downstream of the Brockton, Bridgewater and Taunton WWTPs. TP levels of 0.077 and .087 mg/l were measured in Raynham at Church St. and the Forge River possibly from stormwater runoff from paved parking lots and roadways in the area. This is an indication of a potential need for better stormwater management.
Bacteria
Bacteria levels (enterococci) were frequently above state standards in June.
In Taunton River’s 562 square mile watershed because of significant wetlands including the largest in Massachusetts, the Hockomock Swamp and the Assawompset Pond Complex, the largest natural pond system in the state the start of our low water period typically lags other watersheds by about one month (July through September). As stream flow decreases further this summer and temperatures rise we will be looking to see how this affects water quality. We will also be looking to see how recent work on upgrades at the Brockton and Bridgewater WWTPs affect water quality. Middleborough and the Mansfield/Foxboro/Norton Regional WWTPs completed upgrades in 2019. Both TRWA and our partners at Save The Bay in RI have been encouraging EPA Region 1 in Boston to reissue the last two WWTP permits requiring nitrogen removal upgrades Somerset and Fall River this year so that all seven major WWTPs in the watershed will have adequate wastewater treatment someday.
We are also reviewing Combined Sewer Overflows from Fall River which has 19 outfalls. Information is available from the recent MassDEP annual CSO summary report and MassDEP CSO webpage and the City’s CSO website. Thank you to our monitoring program volunteers who are making the case for better wastewater treatment and stormwater management!