Week of August 13 - 19, 2023
Water Column Profiles
Water column profiles were conducted at five locations in the Providence and Seekonk River estuaries on August 16, 2023 using a Seabird Electronics profiler. In the five days leading up to the survey, 0.59 inches of precipitation were recorded at T.F. Green. Most sites were moderately to strongly stratified this week.
Dissolved oxygen (DO) conditions were below the hypoxia threshold (2.9 mg/L) throughout the water column (upper, middle and lower portions) at the Point Street Bridge, India Point Park, and Phillipsdale Landing sites, but only in the middle and lower portions of the water column at Bullock Reach Buoy and Conimicut Point. The highest fluorescence readings for the week were measured around 1.5 meters below the surface at Conimicut Point.
Week of August 6 - 12, 2023
Water Column Profiles
Water column profiles were conducted at seven locations in the Providence and Seekonk River estuaries on August 9, 2023 using a Seabird Electronics profiler. In the five days leading up to the survey, 0.48 inches of precipitation were recorded at T.F. Green. Most sites were moderately to strongly stratified this week, other than Edgewood Yacht Club, which was weakly stratified.
Dissolved oxygen (DO) conditions were below the hypoxia threshold (2.9 mg/L) in the lower portions of the water column at Pomham Rocks and India Point Park, and in the middle and bottom portions of the water column at Phillipsdale Landing. The highest fluorescence readings for the week were measured around 2 meters below the surface at India Point Park.
Week of July 30 - August 5, 2023
Water Column Profiles
Water column profiles were conducted at six locations in the Providence and Seekonk River estuaries on August 2, 2023 using a Seabird Electronics profiler. In the five days leading up to the survey, 0.66 inches of precipitation were recorded at T.F. Green. All sites were moderately to strongly stratified this week.
Dissolved oxygen (DO) conditions were below the hypoxia threshold (2.9 mg/L) in the middle and lower portions of the water column at every profiled site, and in the full column (upper, middle and bottom portions) at Point Street Bridge, India Point Park, and Phillipsdale Landing. The highest fluorescence readings for the week were measured around 2 meters below the surface at Conimicut Point.
September 25, 2024
Water Column Clarity
Water clarity was measured at eight locations in the Providence River and Seekonk River estuaries on September 25, 2024. A total of 0.78 inches of rain were recorded at TF Green in the five days prior to the survey. Secchi depth averaged 2.8 meters. The lowest clarity this week (2.1 meters) was measured at Phillipsdale Landing, while the greatest clarity (3.5 meters) was measured at Conimicut Point. There was a general north-to-south gradient of increasing water clarity among the sites this week. Overall, water clarity increased from the previous measurements (data collected September 11, 2024).
Week of June 24 – June 30, 2024
Fixed Site Network
Phillipsdale Landing
Sondes were swapped this week on the morning of June 25th. Overall, water quality at Phillipsdale Landing was fair this week. Weather conditions included sporadic rain events, with 2.17 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 9.1 ppt and ranged from 2.6 ppt to 20.3 ppt. At the bottom, salinity averaged 18.6 ppt and ranged from 5.4 ppt to 28.1 ppt. Temperatures continued to increase this week, averaging 25.1°C at the surface and ranging 22.0°C – 27.8°C. At the bottom, temperatures averaged 22.1°C and ranged 19.6°C – 24.7°C.
Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold (i.e., DO >2.9 mg/L) at the surface throughout the week. DO sporadically dropped below the threshold in the bottom waters. Surface DO average 7.44 mg/L and ranged from 3.99 mg/L to 11.35 mg/L. Bottom DO concentrations averaged 4.5 mg/L and ranged from 2.2 mg/L to 10.3 mg/L. Chlorophyll readings dropped slightly from last week, averaging 28.64 µg/L at the surface and 19.9 µg/L at the bottom. Maximum chlorophyll at the surface reached 81.2 µg/L on the morning of June 30th. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.
Bullock Reach
Overall, water quality was good at Bullock Reach this week. Salinity averaged 24.7 ppt, 28.2 ppt, and 27.3 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 20.9 – 27.2 ppt, mid salinity ranged 25.1 – 29.8 ppt, and bottom salinity ranged 23.1 – 30.3 ppt. Surface temperature averaged 22.5°C and ranged from 21.1°C to 25.1°C. Mid temperatures averaged 19.8°C and ranged from 17.8°C to 22.2°C. Bottom temperatures averaged 21.5°C and ranged from 18.5°C to 23.3°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 7.5 mg/L and ranged 5.3 – 10.9 mg/L. In the mid waters, DO averaged 4.8 mg/L and ranged 3.1 – 6.8 mg/L. At the bottom, DO averaged 6.2 mg/L and ranged 4.3– 8.8 mg/L. Chlorophyll readings ranged from low to elevated, with evidence of moderate phytoplankton blooms occurring throughout the month. Readings averaged 17.1 µg/L at the surface, 8.2 µg/L at mid-depth, and 18.3 µg/L at the bottom. The maximum surface chlorophyll was 51.1 µg/L on the afternoon of June 28th.
