Water quality at Phillipsdale was fair-to-poor this week. Moderate rainfall of 0.56 inches was recorded at TF Green on July 1st, and sporadic pop-up showers throughout the watershed also occurred. Blackstone River flows remained elevated over historical median levels. Salinity at the surface averaged 11.3 ppt and ranged from 2.2 ppt to 18.5 ppt, while bottom salinity averaged 19.1 ppt and ranged from 2.5 ppt to 28.6 ppt. Surface water temperatures warmed compared to the previous week, averaging 24.6°C and ranging from 19.9°C to 30.2°C. Bottom water temperatures also warmed, averaging 23.0°C and ranging from 19.5°C to 25.4°C.
Surface DO averaged 7.9 mg/L, with a minimum of 3.6 mg/L, while bottom DO averaged 4.0 mg/L, with a minimum of 1.0 mg/L. Intermittent hypoxic conditions (DO <2.9 mg/L) were observed in bottom waters during the latter half of the week, with a maximum duration of 8 hours, occurring overnight from July 1st to 2nd. Surface chlorophyll concentrations were elevated, averaging 39.0 ug/L with a maximum result of 125.1 ug/L on June 29th. Bottom chlorophyll averaged 30.8 ug/L with an isolated spike in the data most likely due to particulate or macroalgae interference. Please note that tidal fluctuations and Blackstone River flow greatly influence water column salinity, temperature, and dissolved oxygen at this location.