Phillipsdale Landing
Sondes were swapped this week on the morning of May 31st. Overall, water quality at Phillipsdale Landing was good this week. Weather conditions included sporadic rain events, with 0.84 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 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 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 an isolated portion of suspect chlorophyll data from May 27th and an isolated portion of suspect depth from May 31st were excluded from the summary.
Bullock Reach
Overall, water quality was good at Bullock Reach this week. Salinity averaged 19.3 ppt, 25.9 ppt, and 29.5 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 14.9 – 23.9 ppt, mid salinity ranged 19.6 – 29.6 ppt, and bottom salinity ranged 26.9 – 30.5 ppt. Surface temperature averaged 19.1°C and ranged from 16.5°C to 21.7°C. Mid temperatures averaged 16.9°C and ranged from 14.3°C to 19.1°C. Bottom temperatures averaged 14.1°C and ranged from 13.0°C to 20.0°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 8.4 mg/L and ranged 5.5 – 11.8 mg/L. In the mid waters, DO averaged 7.4 mg/L and ranged 5.8 – 12.0 mg/L. At the bottom, DO averaged 6.1 mg/L and ranged 5.0– 9.2 mg/L. Chlorophyll readings ranged from low to elevated, with evidence of moderate phytoplankton blooms occurring throughout the month. Readings averaged 19.1 µg/L at the surface, 6.0 µg/L at mid-depth, and 3.5 µg/L at the bottom. The maximum surface chlorophyll was 77.6 µg/L on the morning of May 31st.
Please note that data gaps occurred in the surface, middle and bottom on May 29th, 30th and 31st and is due to equipment failure.