Phillipsdale Landing
Sondes were retrieved for the end of the season on the morning of November 4th. Overall, the water quality at Phillipsdale Landing was good this week. There was no rain recorded at T.F. Green. The Blackstone River flow reached a minimum on November 5th, and then increased for the remainder of the week. Surface salinity averaged 15.1 ppt and ranged from 6.1 ppt–25.1 ppt. At the bottom, salinity averaged 24.3 ppt and ranged from 14.1 ppt–28.9 ppt. Temperatures decreased this week, averaging 12.4°C at the surface and 13.9°C at the bottom. Surface temperatures ranged from 10.1°C–14.1°C, while bottom temperatures ranged from 12.4°C–14.6°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 8.1 mg/L and ranged from 6.3 mg/L–9.9 mg/L. Bottom DO concentrations averaged 6.4 mg/L and ranged from 5.7 mg/L–7.6 mg/L. Chlorophyll readings remained relatively constant compared to last week, averaging 0.4 µg/L at the surface and 2.5 µg/L at the bottom. Maximum chlorophyll at the surface reached 1.6 µg/L on the morning of November 3rd. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.
Bullock’s Reach
Sondes were retrieved for the end of the season on the morning of November 7th. Overall, water quality was good at Bullock’s Reach this week. Salinity averaged 24.5 ppt, 24.0 ppt, and 29.3 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 10.0–29.3 ppt, mid-depth salinity ranged 9.6–30.1 ppt, and bottom salinity ranged 27.2–30.5 ppt. Surface temperature averaged 12.3°C and ranged from 10.4°C to 13.3C. Mid-depth temperatures averaged 12.6°C and ranged from 11.7°C to 13.5°C. Bottom temperatures averaged 12.6°C and ranged from 11.6°C to 13.5°C.
Dissolved oxygen (DO) at Bullock’s Reach remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO averaged 8.4 mg/L and ranged 8.0–9.3 mg/L. In the mid-depth waters, DO averaged 8.5 mg/L and ranged 7.8–9.3 mg/L. At the bottom, DO averaged 8.2 mg/L and ranged 7.7–8.9 mg/L. Chlorophyll concentrations remained relatively constant compared to last week. Readings averaged 1.6 µg/L at the surface, 2.4 µg/L at mid-depth, and 4.7 µg/L at the bottom. The maximum surface chlorophyll was 3.1 µg/L on the morning of November 3rd.