Phillipsdale Landing
Overall, water quality at Phillipsdale Landing was good this week. Weather conditions were dry except for one May 23rd rain event with 1.17 inches of rain recorded at T.F. Green. The Blackstone River flow declined this week, remaining above the 19-year daily median for the week. Surface salinity averaged 4.0 ppt and ranged from 1.0 ppt to 10.9 ppt. At the bottom, salinity averaged 14.0 ppt and ranged from 1.4 ppt to 27.9 ppt. Temperatures continued to increase this week, averaging 21.0 °C at the surface and ranging 17.7°C – 24.0 °C. At the bottom, temperatures averaged 18.1°C and ranged from 13.9°C – 23.2°C.
Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO average 7.6 mg/L and ranged from 6.2 mg/L to 8.5 mg/L. Bottom DO concentrations averaged 5.9 mg/L and ranged from 4.2 mg/L to 8.1 mg/L. Chlorophyll readings remained comparable from last week, averaging 2.4 µg/L at the surface and 2.7 µg/L at the bottom. Maximum chlorophyll at the surface reached 6.4 µg/L on the afternoon of May 29th. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location. Also, please note that isolated portions of suspect chlorophyll data from May 27th and May 31st were excluded from the summary.
Bullock Reach
The Bullock Reach buoy was deployed May 22nd for the 2024 season. Overall, water quality was good at Bullock Reach this week. Salinity averaged 19.4 ppt, 25.6 ppt, and 29.0 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 11.7 – 25.4 ppt, mid salinity ranged 21.0 – 28.6 ppt, and bottom salinity ranged 27.4 – 30.0 ppt. Surface temperature averaged 18.2°C and ranged from 16.0°C to 20.0°C. Mid temperatures averaged 16.2°C and ranged from 14.0°C to 18.5°C. Bottom temperatures averaged 13.4°C and ranged from 12.0°C to 15.1°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 9.3 mg/L and ranged 7.5 – 11.3 mg/L. In the mid waters, DO averaged 8.3 mg/L and ranged 6.8 – 10.0 mg/L. At the bottom, DO averaged 6.9 mg/L and ranged 5.7– 8.4 mg/L. Chlorophyll readings ranged from low to elevated, with evidence of moderate phytoplankton blooms occurring throughout the month. Readings averaged 18.0 µg/L at the surface, 7.6 µg/L at mid-depth, and 8.4 µg/L at the bottom. The maximum surface chlorophyll was 50.9 µg/L on the afternoon of May 23rd.
Please note that data gaps occurred in the surface, middle and bottom on May 29th and 30th and is potentially due to equipment failure.