Phillipsdale Landing
Sondes were swapped this week on the morning of June 11th. Overall, water quality at Phillipsdale Landing was good this week. Weather conditions were dry, with only 0.06 inches on June 14th, recorded at T.F. Green. The Blackstone River flow declined this week, dropping below the 19-year daily median mid-week. Surface salinity averaged 8.5 ppt and ranged from 3.2 ppt to 18.6 ppt. At the bottom, salinity averaged 20.3 ppt and ranged from 5.3 ppt to 26.7 ppt. Temperatures continued to increase this week, averaging 21.8°C at the surface and ranging 19.1°C – 24.5°C. At the bottom, temperatures averaged 19.0°C and ranged 16.2°C – 23.6°C.
Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO average 10.7 mg/L and ranged from 5.36 mg/L to 20.3 mg/L. Bottom DO concentrations averaged 6.1 mg/L and ranged from 3.8 mg/L to 13.7 mg/L. Chlorophyll readings have risen from last week, averaging 26.64 µg/L at the surface and 19.6 µg/L at the bottom. Maximum chlorophyll at the surface reached 132.6 µg/L on the morning of June 16th. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.
Bullock Reach
Overall, water quality was good at Bullock Reach this week. Salinity averaged 23.5 ppt, 26.3 ppt, and 28.5 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 19.8 – 25.4 ppt, mid salinity ranged 22.2 – 28.5 ppt, and bottom salinity ranged 18.0 – 30.2 ppt. Surface temperature averaged 20.4°C and ranged from 18.3°C to 22.5°C. Mid temperatures averaged 19.2°C and ranged from 16.5°C to 21.8°C. Bottom temperatures averaged 16.5°C and ranged from 14.8°C to 20.3°C.
DO at Bullock Reach remained above the hypoxia threshold (i.e., DO >2.9 mg/L) at all depths throughout the week. Surface DO averaged 9.2 mg/L and ranged 5.1 – 13.8 mg/L. In the mid waters, DO averaged 7.1 mg/L and ranged 4.9 – 8.9 mg/L. At the bottom, DO averaged 5.1 mg/L and ranged 3.6 – 6.6 mg/L. Chlorophyll readings ranged from low to elevated, with evidence of moderate phytoplankton blooms occurring throughout the month. Readings averaged 10.4 µg/L at the surface, 8.5 µg/L at mid-depth, and 3.3 µg/L at the bottom. The maximum surface chlorophyll was 41.5 µg/L on the morning of June 11th.