Walker Point
Sondes were swapped this week on October 27th. The Walker Point Buoy and sondes were removed for the season on the morning of October 29th. Overall, water quality at Walker Point was good this week. Weather conditions were dry this week, no precipitation recorded at T.F. Green. Blackstone River flow remained relatively consistent throughout the week, well below the 22-year daily median flow. Salinity at Walker Point surface averaged 21.9 ppt and ranged from 15.5 ppt to 27.7 ppt. At the bottom, salinity averaged 26.5 ppt and ranged from 17.5 ppt to 28.8 ppt. Temperatures this week averaged 14.6 °C at the surface and 15.4 °C at the bottom. Surface temperatures ranged from 12.2 °C to 15.4 °C, while bottom temperatures ranged from 14.4 °C to 15.7 °C.
Dissolved oxygen (DO) at Walker Point remained above the hypoxia threshold (2.9 mg/L) at the surface and bottom for the entire week. Surface DO averaged 7.3 mg/L and ranged from 6.6 to 8.2 mg/L. Bottom water DO concentration averaged 6.6 mg/L and ranged from 5.9 mg/L to 7.1 mg/L. Chlorophyll ranged from low to mildly elevated levels throughout the week, averaging 0.7 ug/L at the surface and 1.5 ug/L at the bottom, with little evidence of any phytoplankton blooms occurring throughout the week. Maximum chlorophyll readings reached 31.0 ug/L in bottom waters on the early morning of October 26th. 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 October 27th. Salinity averaged 27.8 ppt, 29.4 ppt, and 30.5 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged from 25.1 to 29.8 ppt, mid salinity ranged from 27.5 to 30.9 ppt, and bottom salinity ranged from 29.2 to 31.5 ppt. Surface temperature averaged 14.2 °C and ranged from 12.3 °C to 15.4 °C. Mid temperatures averaged 14.3 °C and ranged from 13.4 °C to 15.2 °C. Bottom temperatures averaged 14.3 °C and ranged from 13.8 °C to 14.8 °C.
DO at Bullock Reach did not experience hypoxic conditions (i.e., DO < 2.9 mg/L) during the week. Surface DO averaged 8.6 mg/L and ranged from 7.9 to 9.8 mg/L. In the mid waters, DO averaged 8.2 mg/L and ranged from 7.6 to 8.7 mg/L. At the bottom, DO averaged 7.9 mg/L and ranged from 7.4 to 8.6 mg/L. Chlorophyll readings remained low to moderately elevated this week, with evidence of moderate phytoplankton blooms occurring during the week. Readings averaged 1.2 µg/L at the surface, 3.3 µg/L at mid-depth, and 4.0 µg/L at the bottom. The maximum chlorophyll was observed in bottom waters at 24.4 µg/L on the evening of October 28th.