Phillipsdale Landing
Sondes were swapped this week on the morning of October 29th. Overall, water quality at Phillipsdale Landing was good to fair this week. Weather conditions were dry this week, with 0.03 inches of precipitation recorded at T.F. Green. The Blackstone River flow remained relatively stable through the week, remaining below the 22-year daily median. Surface salinity averaged 21.4 ppt and ranged from 11.2 ppt to 27.2 ppt. At the bottom, salinity averaged 25.8 ppt and ranged from 19.5 ppt to 29.6 ppt. Temperatures remained stabilized this week, averaging 15.1°C at the surface and ranging 12.0°C – 16.7°C. At the bottom, temperatures averaged 15.4°C and ranged 14.5°C – 16.2°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 8.5 mg/L and ranged from 5.6 mg/L to 12.8 mg/L. Bottom DO concentrations averaged 6.8 mg/L and ranged from 4.4 mg/L to 10.9 mg/L. Chlorophyll readings remained stabilized from last week, averaging 14.0 µg/L at the surface and 8.1 µg/L at the bottom. Maximum chlorophyll at the surface reached 105.0 µg/L at midday on November 11th. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.
Bullock Reach
Overall, the water quality was good at Bullock Reach this week. Salinity averaged 28.8 ppt, 29.8 ppt, and 31.2 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 27.3 – 30.0 ppt, mid salinity ranged 28.1 – 31.1 ppt, and bottom salinity ranged 29.5 – 32.6 ppt. Surface temperature averaged 14.3°C and ranged from 13.0°C to 15.4°C. Mid temperatures averaged 14.4°C and ranged from 13.5°C to 15.3°C. Bottom temperatures averaged 14.5°C and ranged from 13.8°C to 15.6°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 8.4 mg/L and ranged 7.6 – 9.7 mg/L. In the mid waters, DO averaged 8.3 mg/L and ranged 7.5 – 8.9 mg/L. At the bottom, DO averaged 7.9 mg/L and ranged 7.0 – 8.5 mg/L. Chlorophyll readings ranged from low to moderate, with evidence of sporadic phytoplankton blooms occurring throughout the week. Readings averaged 3.2 µg/L at the surface, 3.8 µg/L at mid-depth, and 1.2 µg/L at the bottom. The maximum surface chlorophyll was 11.3 µg/L on the afternoon of October 29th.