Water Column Profiles

Water column profiles were conducted at six locations in the Providence and Seekonk River Estuaries on April 5, 2023 using a Seabird Electronics profiler. There was no precipitation recorded at T.F. Green in the three days leading up to the survey. Evidence of strong density stratification was observed at Phillipsdale Landing, Edgewood Shoal, and Pawtuxet Cove; all other sites showed signs of moderate density stratification.

Surface salinities ranged from 4.3 psu at Pawtuxet Cove to 22.1 psu at Pomham Rocks; bottom salinities ranged from 23.9 psu at Pawtuxet Cove to 28.0 psu at Pomham Rocks. Surface temperatures ranged 9.0°C at India Point Park to 10.8°C at Pawtuxet Cove, while bottom temperatures ranged from 7.3°C at Pomham Rocks to 9.0°C at Pawtuxet Cove.

Dissolved oxygen (DO) conditions remained above the hypoxia threshold (2.9 mg/L) at all sites this week; the lowest DO observed was approximately 8.5 mg/L in the bottom waters at Pawtuxet Cove. Fluorescence was fairly low, with the highest value (5.05 mg/m3) observed near the middle of the water column (3.25 meters deep) at Pomham Rocks.

Water column profiles were conducted at seven locations in the Providence and Seekonk River Estuaries on March 22, 2023 using a Seabird Electronics profiler. There was no precipitation recorded at T.F. Green in the three days leading up to the survey. Evidence of strong density stratification was observed at sites near the middle of the bay (Pomham Rocks, Edgewood Yacht Club, and Pawtuxet Cove), with sites to the north and south of these showing signs of weak to moderate density stratification.

Surface salinities ranged from 3.2 psu at Pawtuxet Cove to 24.3 psu at Bullock Reach Buoy; bottom salinities ranged from 22.8 psu at Phillipsdale Landing to 28.8 psu at Conimicut Point. Surface temperatures ranged from 6.3°C at India Point Park to 7.2°C at Pawtuxet Cove, while bottom temperatures ranged from 5.8°C at Conimicut Point to 6.7°C at Pawtuxet Cove.

Dissolved oxygen (DO) conditions remained above the hypoxia threshold (2.9 mg/L) at all sites this week; the lowest DO observed was approximately 9.9 mg/L in the bottom waters at Edgewood Yacht Club. Fluorescence was higher than the previous survey, with the highest value (22.98 mg/m3) observed near the surface at India Point Park but many other areas remaining relatively low. ​

Water column profiles were conducted at seven locations in the Providence River Estuary on February 22, 2023 using a Seabird Electronics profiler. In the three days leading up to the survey, 0.17 inches of rainfall were recorded at T.F. Green. Evidence of moderate density stratification was observed at most sites this week, with Pawtuxet Cove showing signs of strong stratification and Bullock Reach and Edgewood Shoals showing signs of weak stratification.

Surface salinities ranged from 20 psu at Pawtuxet Cove to 26 psu at Bullock Reach Buoy and Edgewood Shoal. Bottom salinities ranged from 27 psu at Pawtuxet Cove to 30 psu at Conimicut Point. The coolest water temperatures ranged from 5.4°C at the surface of Conimicut Point to 5.7°C at bottom of India Point Park. The warmest surface water temperature (5.9°C) was observed at Pawtuxet Cove and Edgewood Shoal, while the warmest bottom temperature (6.0°C) was observed at Pawtuxet Cove and Conimicut Point. 

Dissolved oxygen (DO) conditions remained above the hypoxia threshold (2.9 mg/L) at all sites this week; the lowest DO observed was approximately 9.4 mg/L in the bottom waters at India Point Park. Overall, fluorescence was generally low, with the highest value (9.23 mg/m³) observed near the middle of the water column (4.0 meters deep) at Edgewood Yacht Club. Please note numerical fluorescence data were not posted from 2020 to 2021 due to a QC issue. This issue has been resolved and fluorescence data from 2020 and 2021 will be backfilled.