July 8, 2026

Nutrient samples were collected from thirteen river stations and eight bay stations on July 8th.  All bay stations were sampled at the surface; Edgewood Shoal was sampled at the surface and bottom. In the five days prior to sampling, 2.89 inches of precipitation were recorded at T.F. Green. 

Among the river stations sampled, the highest total nitrogen (TN), total dissolved nitrogen (TDN) and dissolved inorganic nitrogen (DIN) were observed at Blackstone River @ Fairmount St (TN = 1,850 ppb, TDN = 1,915 ppb, DIN = 1,610.5, averages of duplicates). The lowest TN was observed at Moshassuck River @ Higginson Ave (426 ppb). The lowest TDN and DIN were observed at Palmer River @ Rt. 6 (TDN = 372 ppb, DIN =  70.6).

Among the bay stations sampled, the highest surface TN was observed at Phillipsdale Landing (1,330 ppb). The highest surface TDN and DIN were observed at Pawtuxet Cove (TDN = 846 ppb, DIN = 717, averages of duplicates). The lowest surface TN and DIN were observed at Edgewood Shoal (TN = 555 ppb, DIN = 126.8 ppb). The lowest surface TDN was observed at Edgewood Yacht Club (180 ppb).

The next scheduled sampling date is July 22nd, 2026.​

August 19, 2026

Surface chlorophyll data were collected on August 19, 2026, while the R/V Data Stream was underway collecting bacteria samples in the Providence and Seekonk River Estuaries. The chlorophyll concentrations were categorized as fair overall with most areas sampled having average chlorophyll concentrations between 5 µg/L and 20 µg/L, with the exception of the Seekonk River, which had average chlorophyll concentrations above 20 µg/L (categorized as poor), and the Northern Providence River Channel, which had average chlorophyll concentrations below 5 µg/L (categorized as good). Overall, chlorophyll ranged from 1.93 µg/L to 557.34 µg/L with an average of 17.05 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.

August 19, 2026

Water column profiles were conducted using a Seabird Electronics profiler at sixlocations in the Providence River and one location in the Seekonk River on August 19, 2026. In the five days leading up to this, there were 0.31 inches of rain recorded at T.F. Green International Airport (Warwick, RI). Moderate water column stratification was observed at Phillipsdale Landing. The water column was weakly stratified at Conimicut Point, Bullock Reach, Edgewood Yacht Club, Pomham Rocks, and India Point Park. The water column at Pawtuxet Cove was well mixed.

Dissolved oxygen conditions below the hypoxia threshold (2.9 mg/L) were observed throughout the water column at India Point Park. The lower part of the water column at Bullock Reach, Pawtuxet Cove, Edgewood Yacht Club, Pomham Rocks and Phillipsdale Landing had dissolved oxygen conditions below the hypoxia threshold (2.9 mg/L). The highest fluorescence reading was observed two meters below the surface at Edgewood Yacht Club.

August 5, 2026

Water column profiles were conducted using a Seabird Electronics profiler at seven locations in the Providence River and one location in the Seekonk River on August 5, 2026. In the five days leading up to this, there were 2.57 inches of rain recorded at T.F. Green International Airport (Warwick, RI). The water column was strongly stratified at Conimicut Point, Edgewood Yacht Club, Edgewood Shoal, India Point Park and Phillipsdale Landing; moderate water column stratification was observed at Bullock Reach, Pawtuxet Cove and Pomham Rocks.

Dissolved oxygen conditions below the hypoxia threshold (2.9 mg/L) were observed in the lower part of the water column at Bullock Reach, Edgewood Yacht Club, Edgewood Shoal, Pomham Rocks, India Point Park and Phillipsdale Landing. The highest fluorescence reading was observed one meter below the surface at Edgewood Yacht Club.

August 19, 2026

Water clarity was measured at seven locations in the Providence River and Seekonk River estuaries on August 19, 2026. In the five days prior to the survey, 0.13 inches of precipitation were recorded at TF Green. Secchi depth averaged 2.4 meters. The lowest clarity this week (0.7 meters) was measured at Phillipsdale Landing, while the greatest clarity (3.7 meters) was observed at Conimicut Point. There was no clear north-to-south gradient in water clarity among the sites this week. Overall, water clarity increased from the previous measurements (data collected August 5, 2026).

July 30, 2026

Surface chlorophyll data were collected on July 30, 2026, while the R/V Data Stream was underway collecting bacteria samples in the Providence and Seekonk River Estuaries. The chlorophyll concentrations were categorized as fair overall with most areas sampled having average chlorophyll concentrations between 5 µg/L and 20 µg/L, with the exception of the Seekonk River, which had average chlorophyll concentrations above 20 µg/L (categorized as poor). Overall, chlorophyll ranged from 3.63 µg/L to 128.48 µg/L with an average of 15.46 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.

August 5, 2026

Water clarity was measured at eight locations in the Providence River and Seekonk River estuaries on August 5, 2026. In the five days prior to the survey, 2.57 inches of precipitation were recorded at TF Green. Secchi depth averaged 1.8 meters. The lowest clarity this week (1.2 meters) was measured at Pawtuxet Cove, while the greatest clarity (2.1 meters) was observed at Bullock Reach. There was no clear north-to-south gradient in water clarity among the sites this week. Overall, water clarity increased from the previous measurements (data collected July 23, 2026).

June 10, 2026

Phytoplankton samples were collected on June 10, 2026 at Bullock’s Reach and analyzed in the laboratory shortly after collection.

On this day, the water temperature was 20.03 °C, the salinity was 27.2 PSU, and the chlorophyll a was 1.54 ug/L.

The qualitative tow net sample had a long filtration time and was cloudy and light golden brown in coloration.

The analysis of the quantitative whole water sample revealed a total of 5,570,000 cells/L. The microflagellates were found at 515,000 cells/L. The most predominant phytoplankton genera were Dactyliosolen spp. at 4,650,000 cells/L, Skeletonema spp. at 250,000 cells/L, and Chaetoceros spp. at 120,000 cells/L.

200x phase contrast image of Peridinium spp.

Peridinium spp. are cosmopolitan dinoflagellates mostly found in freshwater lakes, ponds and pools. Some inhabit brackish environments. This genus was originally described in the early 1830s, making it one of the first known groups of dinoflagellates. They are thought to be mixotrophic, which means they obtain energy through photosynthesis (autotrophy), and ingestion of small organisms (heterotrophy).

July 23, 2026

Surface chlorophyll data were collected on July 23, 2026, while the R/V Data Stream was underway collecting bacteria samples in the Providence and Seekonk River Estuaries. The chlorophyll concentrations were categorized as fair overall with most areas sampled having average chlorophyll concentrations between 5 µg/L and 20 µg/L, with the exception of the Seekonk River, which had average chlorophyll concentrations above 20 µg/L (categorized as poor). Overall, chlorophyll ranged from 4.51 µg/L to 77.03 µg/L with an average of 15.49 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.

July 20 – July 26, 2026

Walkers Point

Overall, the water quality at Walkers Point was good to fair this week. Weather conditions were dry this week, except for 1.88 inches of precipitation recorded at T.F. Green on July 25th.  Surface salinity averaged 15.9 ppt and ranged from 6.3 ppt to 27.4 ppt. At the bottom, salinity averaged 26.4 ppt and ranged from 21.8 ppt to 29.5 ppt. Temperatures averaged 24.2°C at the surface and 23.7°C at the bottom. Surface temperatures ranged from 22.3°C to 26.7°C, while bottom temperatures ranged from 22.8°C to 24.3°C.

Dissolved oxygen (DO) at Walkers Point remained above the hypoxia threshold (i.e., DO>2.9mg/L) at the surface but dropped below at the bottom depth. The longest periods of hypoxic conditions spanned 49 hours and 46 minutes, occurring at the bottom depth between the evening of July 23rd and July 25th. During this period, the DO averaged around 1.59 mg/L. Surface DO averaged 10.4 mg/L and ranged from 4.7 mg/L to 18.7 mg/L. Bottom DO concentrations averaged 2.6 mg/L and ranged from 0.2 mg/L to 6.0 mg/L. Chlorophyll readings averaged 22.0 µg/L at the surface and 12.4µg/L at the bottom. Maximum chlorophyll at the surface reached 92.6 µg/L on the morning of July 24th.

Bullock Reach

Sondes were swapped this week on the morning of July 23rd. Overall, water quality was good to fair at Bullock Reach this week. Salinity averaged 27.6 ppt, 29.4 ppt, and 30.3 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 24.8 – 29.6 ppt, middle salinity range 26.1 – 31.2 ppt, and bottom salinity ranged 14.5 – 31.7 ppt. Surface temperature averaged 23.9°C and ranged from 22.9°C to 25.5°C. Middle temperature averaged 23.5°C and ranged from 22.0°C to 25.1°C. Bottom temperatures averaged 22.9°C and ranged from 22.0°C to 23.7°C.

Dissolved oxygen (DO) at Bullock Reach remained above the hypoxia threshold (i.e., DO>2.9mg/L) at all the depths. Surface DO averaged 9.3 mg/L and ranged 5.7 – 15.0 mg/L. Middle DO averaged 6.8 mg/L and ranged 4.1 – 11.7 mg/L. At the bottom, DO averaged 5.24 mg/L and ranged 3.79 – 7.22 mg/L.  Chlorophyll readings ranged from low to elevated throughout the week. Readings averaged 13.2 µg/L at the surface, 16.5 µg/L at the middle, and 6.87 µg/L at the bottom.  The maximum surface chlorophyll was 29.6 µg/L on the night of July 23rd.

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