News – Page 3 – Narrabay

August 12, 2026

On August 12^th, 2026 nineteen stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers; five of these stations were also sampled for enterococci bacteria. There was no precipitation at TF Green over the five days prior to the August 12th, 2026 sampling event. Overall, bacteria counts were lower than during the previous sampling event.

Fecal coliform counts were higher in the Seekonk River, compared to the Providence River (geometric mean of 50 MPN/100 mL for the Seekonk River compared to 10 MPN/100mL for the Providence River) for sampling conducted on August 12th. The maximum count (930 MPN/100 mL) was measured at the Point St Bridge sampling location.

Enterococci results had an overall geometric mean of 24 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at most sites to 256 MPN/100 mL at Point St Bridge.

The next scheduled sampling date is August 26^th.

Summary of Rhode Island Bacteria Standards for Saltwater Primary Contact and Shellfishing

	Fecal Coliform	Enterococci
Primary Contact¹	Geometric mean ≤50 MPN/100 mL <10% of samples >400 MPN/100 mL	Geometric mean ≤35 colonies/100 mL All samples ≤104 colonies/100 mL²
Shellfishing	Geometric mean ≤14 MPN/100 mL <10% of samples >49 MPN/100 mL³	NO ENTEROCOCCI CRITERIA

¹Fecal coliform primary contact criteria applied only when adequate enterococci data are not available; ²Single sample maximum criterion for determining beach swimming advisories at designated beaches as evaluated by the Rhode Island Department of Health; ³For a three-tube decimal dilution.

Table adapted from Rhode Island Water Quality Regulations (250-RICR-150-05-1); see regulations for complete details.

July 8, 2026

Phytoplankton samples were collected on July 8, 2026 at Bullock Reach and analyzed in the laboratory shortly after collection.

The water temperature was 21.7 °C, the salinity was 27.4 PSU, and the chlorophyll a was 1.09 ug/L.

The qualitative tow net sample had a long filtration time. It had a dark brown coloration and contained jellyfish.

The analysis of the quantitative whole water sample revealed a total of 625,000 cells/L. The microflagellates were found at 367,000 cells/L. The most predominant phytoplankton genera were Thalassiosira spp. at 93,000 cells/L, Chaetoceros spp. at 60,000 cells/L, and Skeletonema spp. at 13,000 cells/L.

200x phase contrast image of Coscinodiscus spp.

Coscinodiscus is a widespread genus of solitary, disc-shaped diatoms. It is often regarded as one of the largest marine planktonic diatom genera with 400 – 500 described taxa. One singular freshwater species has also been identified.

June 24, 2026

Phytoplankton samples were collected on June 24, 2026 at Bullock Reach and analyzed in the laboratory shortly after collection.

It was sunny and clear on this day. The water temperature was 21.3 °C, the salinity was 27.2 PSU, and the chlorophyll a was 0.84 ug/L.

The qualitative tow net sample had a short filtration time and was cloudy and medium brown in coloration.

The analysis of the quantitative whole water sample revealed a total of 1,316,000 cells/L. The microflagellates were found at 1,106,000 cells/L. The most predominant phytoplankton genera were Cerataulina spp. at 110,000 cells/L, Skeletonema spp. at 27,000 cells/L, and Heterocapsa spp. at 23,000 cells/L.

200x phase contrast image of Chaetoceros lorenzianus

Chaetoceros lorenzianus is a species of centric diatom with a large diameter of 7 – 85 μm. Individual cells are usually joined in straight, stiff chains, connected by the touching of cell corners and fused adjacent spines. They have a wide distribution throughout the world and are commonly found throughout spring and summer in warm, shallow, marine waters.

July 30, 2026

On July 30^th, 2026, twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers; five of these stations were also sampled for enterococci bacteria. In the five days prior to sampling, 0.72 inches of precipitation were recorded at TF Green.

Fecal coliform counts were higher in the Seekonk River, compared to the previous sampling on July 30^th (geometric mean of 1,615 MPN/100 mL compared to 204 MPN/100 mL on 7/15). Fecal coliform counts were also higher in the Providence River, compared to the previous sampling (geometric mean of 8 MPN/100 mL on July 15^th compared to 63 on July 30^th).

Enterococci results had an overall geometric mean of 111 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at Conimicut Point to 1,842 MPN/100 mL at Point St Bridge.

The next scheduled sampling date is August 12^th.

Summary of Rhode Island Bacteria Standards for Saltwater Primary Contact and Shellfishing

	Fecal Coliform	Enterococci
Primary Contact¹	Geometric mean ≤50 MPN/100 mL <10% of samples >400 MPN/100 mL	Geometric mean ≤35 colonies/100 mL All samples ≤104 colonies/100 mL²
Shellfishing	Geometric mean ≤14 MPN/100 mL <10% of samples >49 MPN/100 mL³	NO ENTEROCOCCI CRITERIA

Table adapted from Rhode Island Water Quality Regulations (250-RICR-150-05-1); see regulations for complete details.

July 22-23, 2026

Nutrient samples were collected from seven river stations and seven bay stations on July 22^nd and 23^rd. All bay stations were sampled at the surface and bottom. In the five days prior to sampling, 2.28 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 Pawtuxet River @ Broad St. (TN = 1,390 ppb, TDN = 1,355 ppb, DIN = 1,127 ppb, averages of duplicates). The lowest TN TDN, and DIN were observed at Moshassuck River @ Footbridge at Mill St. (TN = 703 ppb, TDN = 645 ppb, DIN = 396.7 ppb).

Among the bay stations sampled, the highest surface TN was observed at Phillipsdale Landing (1,760 ppb). The highest surface TDN and DIN were observed at Pawtuxet Cove (TDN = 543 ppb, DIN = 627.5). The lowest surface TN was observed at Conimicut Point (523 ppb). The lowest surface TDN was observed at Bullock Reach Buoy (120 ppb), and the lowest surface DIN was observed at Edgewood Yacht Club (13 ppb, representing minimum detection limits).

The next scheduled sampling date is August 5^th, 2026.

July 8, 2026

Nutrient samples were collected from thirteen river stations and eight bay stations on July 8^th. 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 22^nd, 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).