The sampling results for May 12, 2026 are available.
The results for nitrate downstream of the Brockton wastewater treatment plant (WWTP) were higher than the Mount Hope Bay water quality target of TN 0.45 mg/l however by Church St sampling station down river in Raynham the river met this criterion. The results for total phosphorus were all below the EPA Gold Book freshwater stream criterion of 0.100 mg/l. The bacteria levels exceeded the EPA water quality criterion of 35 colony forming units (CFU) for enterococci more frequently than last month, 12 of our 20 sampling locations exceeded the criteria in May but by smaller amounts than we saw last summer.
It is noteworthy that at the beginning of May flow was 400 cubic feet per second (CFS) as measured at the Taunton River USGS Bridgewater gauge. The day we sampled river flow was 278 cfs. By May 24th river flow was only 145 cfs which is fairly close to the lowest flow on record 138 cfs for this day of the year. The beneficial rain on 5/25 increased river flow to 223 cfs. Development in the watershed coupled with poor or no stormwater management of the runoff from impervious surfaces has caused the river to be very flashy. Unless we have prolonged moderate rainfall the expectation is that river flow will continue to decline.
It will be important for us to see if drought flows return to the watershed’s rivers and streams this summer as they have over the last several decades and if we monitor the same adverse water quality impact of low flows coupled with stormwater pollution from intense short duration storm events. These summer storm events, a product of global warming, deliver pollution but do not quench the thirst of the watershed’s rivers and groundwater table.
Because of the outsized adverse impact of stormwater pollution on our water quality TRWA supports the Watershed Protection Standard (WPS) in partnership with the Southeast New England Program (SNEP) Network, the watershed’s Regional Planning Agencies and our Environmental Organization partners. To address the twin challenges of development and climate change municipalities need support in adopting the latest science and techniques which allow new development to: maintain pre-development groundwater recharge volume, maintain pre-development nutrient (nitrogen and phosphorus) export loads from the site, and maintain a resilient landscape as determined by response to extreme storms and manage runoff to pre-development volume.