Phillipsdale Landing
Overall, the water quality at Phillipsdale Landing was good to fair this week. Weather conditions included sporadic rain events, with 0.95 inches of precipitation recorded at T.F. Green. The Blackstone River flow fluctuated through the week in response to rain but remained below the 22-year daily median throughout the week. Surface salinity averaged 22.4 ppt and ranged from 16.1 ppt to 26.9 ppt. At the bottom, salinity averaged 26.7 ppt and ranged from 22.5 ppt to 29.2 ppt. Temperatures continued to decrease this week, averaging 18.2°C at the surface and ranging 14.9°C – 19.8°C. At the bottom, temperatures averaged 18.9°C and ranged 17.1°C – 19.8°C.
Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO averaged 10.17 mg/L and ranged from 5.84 mg/L to 21.63 mg/L. Bottom DO concentrations averaged 6.0 mg/L and ranged from 4.0 mg/L to 10.9 mg/L. Chlorophyll readings increased from last week, averaging 73.19 µg/L at the surface and 35.6 µg/L at the bottom. Maximum chlorophyll at the surface reached 467.4 µg/L on the morning of October 10th. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.
Bullock Reach
Sondes were swapped this week on the afternoon of October 8th. Overall, the water quality was good at Bullock Reach this week. Salinity averaged 29.0 ppt, 29.7 ppt, and 30.1 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 27.8 – 30.1 ppt, mid salinity ranged from 28.6°C to 30.9°C, and bottom salinity ranged 29.7 – 31.8 ppt. Surface temperature averaged 17.8°C and ranged from 16.4°C to 19.1°C. Mid temperatures averaged 17.9°C and ranged from 16.5°C to 19.3°C. Bottom temperatures averaged 18.1°C and ranged from 16.6°C to 19.2°C.
DO at Bullock Reach remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO averaged 7.9 mg/L and ranged 7.0 – 9.7 mg/L. In the mid waters, DO averaged 7.6 mg/L and ranged 6.4 – 9.9 mg/L. At the bottom, DO averaged 7.1 mg/L and ranged 6.2 – 8.3 mg/L. Chlorophyll readings were low to elevated, with evidence of moderate phytoplankton blooms occurring throughout the week. Readings averaged 7.9 µg/L at the surface, 8.5 µg/L at mid-depth, and 6.8 µg/L at the bottom. The maximum surface chlorophyll was 18.9 µg/L on the afternoon of October 9th.