Phillipsdale Landing
Overall, water quality at Phillipsdale Landing was fair this week. Weather conditions included sporadic rain events, with 2.22 inches of precipitation recorded at T.F. Green. The Blackstone River flow fluctuate through the week in response to rain, while still remaining above the 19-year daily median. Surface salinity averaged 9.4 ppt and ranged from 2.5 ppt to 19.8 ppt. At the bottom, salinity averaged 18.9 ppt and ranged from 5.9 ppt to 26.0 ppt. Temperatures continued to increase this week, averaging 23.9°C at the surface and ranging 20.6°C – 28.3°C. At the bottom, temperatures averaged 21.4°C and ranged 18.3°C – 25.5°C.
Dissolved oxygen (DO) at Phillipsdale Landing has remained high at the surface, with only a few dropped readings below the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO was lower than the previous week, averaging 8.3 mg/L and ranging 2.65 mg/L to 14.1 mg/L. Bottom DO concentrations dropped below the hypoxia level (i.e., DO <2.9 mg/L) briefly this week, averaging 4.2 mg/L and ranged from 2.0 mg/L to 10.0 mg/L. Chlorophyll readings have risen from last week, averaging 35.54 µg/L at the surface and 27.7 µg/L at the bottom. Maximum chlorophyll at the surface reached 98.2 µg/L on the night of June 21st. 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 morning of June 18th. Overall, water quality was good at Bullock Reach this week. Salinity averaged 23.9 ppt, 28.0 ppt, and 24.0 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 19.3 – 27.0 ppt, mid salinity ranged 25.1 – 30.0 ppt, and bottom salinity ranged 0.0 – 29.9 ppt. Surface temperature averaged 23.3°C and ranged from 19.8°C to 26.1°C. Mid temperatures averaged 18.8°C and ranged from 16.4°C to 21.9°C. Bottom temperatures averaged 21.5°C and ranged from 15.7°C to 25.0°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 8.1 mg/L and ranged 5.7 – 11.6 mg/L. In the mid waters, DO averaged 5.0 mg/L and ranged 3.4 – 9.0 mg/L. At the bottom, DO averaged 6.6 mg/L and ranged 2.9– 9.4 mg/L. Chlorophyll readings ranged from low to elevated, with evidence of moderate phytoplankton blooms occurring throughout the month. Readings averaged 15.8 µg/L at the surface, 8.4 µg/L at mid-depth, and 11.2 µg/L at the bottom. The maximum surface chlorophyll was 47.9 µg/L on the morning of June 23rd.