Phillipsdale Landing
Sondes were swapped the morning of October 21st. Overall, the water quality at Phillipsdale Landing was good this week. There was light rain with 0.73 inches of rain recorded at T.F. Green. The Blackstone River flow was at its highest between October 21st and October 23rd. Surface salinity averaged 8.8 ppt and ranged from 2.5 ppt–24.6 ppt. At the bottom, salinity averaged 20.9 ppt and ranged from 4.4 ppt–29.1 ppt. Temperatures decreased this week, averaging 14.9°C at the surface and 16.2°C at the bottom. Surface temperatures ranged from 12.3°C–17.1°C, while bottom temperatures ranged from 14.3°C–17.3°C.
Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold (i.e., DO>2.9mg/L) in both the surface and bottom waters. Surface DO averaged 8.5 mg/L and ranged from 6.1 mg/L–10.1 mg/L. Bottom DO concentrations averaged 6.2 mg/L and ranged from 4.5 mg/L–9.3 mg/L. Chlorophyll readings decreased from last week, averaging 0.9 µg/L at the surface and 1.8 µg/L at the bottom. Maximum chlorophyll at the surface reached 4.5 µg/L on the morning of October 20th. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.
Bullock’s Reach
Overall, water quality was good at Bullock’s Reach this week. Salinity averaged 27.6 ppt, 29.8 ppt, and 30.9 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 22.1–30.7 ppt, mid-depth salinity ranged 27.5–31.1 ppt, and bottom salinity ranged 29.9–31.8 ppt. Surface temperature averaged 15.8°C and ranged from 14.1°C to 16.7°C. Mid-depth temperatures averaged 15.8°C and ranged from 15.2°C to 16.5°C. Bottom temperatures averaged 15.7°C and ranged from 15.3°C to 16.3°C.
Dissolved oxygen (DO) at Bullock Reach’s remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO averaged 7.8 mg/L and ranged 7.2–8.5 mg/L. In the mid-depth waters, DO averaged 7.7 mg/L and ranged 6.9–9.2 mg/L. At the bottom, DO averaged 7.3 mg/L and ranged 6.6–7.8 mg/L. Chlorophyll concentrations increased at all depths compared to last week. Readings averaged 4.1 µg/L at the surface, 4.5 µg/L at mid-depth, and 24.1 µg/L at the bottom. The maximum surface chlorophyll was 11.4 µg/L on the afternoon of October 24th.