Phillipsdale Landing
The surface sonde deployed on February 7th failed to log data internally, and so there is a data gap until DCP communications were restored this week on February 15th. Unfortunately, restoration of this connection resulted in lost depth data for both sondes through the end of the deployment on February 23rd. Data in this week’s summary should be interpreted with caution due to the gap in surface data and lack of depth data to confirm sonde positioning at both depths.
Weather conditions this week were mostly dry, with just 0.25 inches of rainfall on February 17th and trace rainfall on the 13th and 16th. Blackstone River flows continued to decline all week and fell below the 18-year median flow rates for this time of year. Surface salinity from the latter half of the week averaged 7.4 ppt and ranged from 2.0 ppt to 20.3 ppt. At the bottom, salinity averaged 20.6 ppt and ranged from 5.2 ppt to 29.8 ppt. Temperatures at the surface (latter half of the week) averaged 6.4°C, ranging 4.4°C – 8.1°C. At the bottom, temperatures averaged 5.4°C and ranged 4.6°C – 7.0°C.
Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold of 2.9 mg/L throughout the week. Surface DO (latter half of the week) averaged 11.3 mg/L and ranged 10.1 – 12.4 mg/L. Bottom DO concentrations averaged 9.9 mg/L and ranged from 8.8 mg/L to 12.3 mg/L. Chlorophyll readings generally remained low, averaging 0.8 ug/L at the surface (latter half of the week) and 2.9 ug/L at the bottom. Maximum chlorophyll at the surface reached just 6.8 ug/L in the data available this week. At the bottom, chlorophyll hit an isolated maximum of 25.1 ug/L on February 17th, though this does not appear to be related to phytoplankton activity as there were no concurrent changes to pH or DO. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.
Bullock Reach
Bullock Reach sondes will be deployed later this spring for the 2023 monitoring season.