May 14, 2025

​Water clarity was measured at seven locations in the Providence River and Seekonk River estuaries on May 14, 2025. In the five days prior to the survey, 1.73 inches of precipitation were recorded at TF Green. Secchi depth averaged 2.0 meters. The lowest clarity this week (1.7 meters) was measured at Phillipsdale Landing, Edgewood Yacht Club, and Bullock’s Reach, while the greatest clarity (2.5 meters) was measured at Conimicut Point. There was no clear north-to-south gradient in water clarity among the sites this week. Overall, water clarity decreased from the previous measurements (data collected May 7, 2025).

September 16 – 22, 2024

Phillipsdale Landing

Sondes were swapped this week on the morning of September 17th.  Overall, water quality at Phillipsdale Landing was good to fair this week. Weather conditions included sporadic rain events, with 0.78 inches of precipitation recorded at T.F. Green. The Blackstone River flow remained below the 20-year daily median. Surface salinity averaged 24.3 ppt and ranged from 20.4 ppt to 28.3 ppt. At the bottom, salinity averaged 26.3 ppt and ranged from 22.9 ppt to 29.6 ppt. Temperatures continued to decline this week, averaging 21.3°C at the surface and ranging 18.5°C – 24.0°C. At the bottom, temperatures averaged 21.4°C and ranged 19.2°C – 23.5°C.

Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO average 5.97 mg/L and ranged from 3.93 mg/L to 10.82 mg/L. Bottom DO concentrations averaged 5.0 mg/L and ranged from 3.3 mg/L to 8.5 mg/L. Chlorophyll readings decreased from last week, averaging 16.01 µg/L at the surface and 12.8 µg/L at the bottom. Maximum chlorophyll at the surface reached 57.03 µg/L on the evening of September 17th. 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 to fair at Bullock Reach this week. Salinity averaged 28.7 ppt, 29.2 ppt, and 30.5 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 27.5 – 29.7 ppt, mid salinity ranged 27.9 – 30.1 ppt, and bottom salinity ranged 29.0 – 31.4 ppt. Surface temperature averaged 21.0°C and ranged from 19.2°C to 23.1°C. Mid temperatures averaged 20.8°C and ranged from 19.1°C to 22.1°C. Bottom temperatures averaged 20.4°C and ranged from 19.1°C to 21.6°C.

DO at Bullock Reach remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week Surface DO averaged 6.7 mg/L and ranged 5.5 – 10.2 mg/L. In the mid waters, DO averaged 6.1 mg/L and ranged 4.6 – 8.7 mg/L. At the bottom, DO averaged 5.6 mg/L and ranged 3.8 – 6.7 mg/L.  Chlorophyll readings ranged from low to elevated, with evidence of moderate phytoplankton blooms occurring throughout the week. Readings averaged 5.5 µg/L at the surface, 6.2 µg/L at mid-depth, and 6.7 µg/L at the bottom.  The maximum surface chlorophyll was 17.5 µg/L on the afternoon of September 16th.

March 26, 2025

On March 26th, 2025, 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, 1.06 inches of precipitation was recorded at TF Green. Overall, bacteria counts were higher in both the Seekonk and Providence Rivers than during the previous sampling event.

Fecal coliform counts were higher in the Providence River, compared to the previous sampling on March 12th  (geometric mean of 38 MPN/100 mL compared to 10 MPN/100 mL on 3/12). The maximum count (430 MPN/100 mL) was measured at the Point St. Bridge sampling location.

Enterococci results had an overall geometric mean of 15 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at Conimicut Point (geometric mean of two samples) to 20 MPN/100 mL at most other sites.

The next scheduled sampling date is April 9th.

​The table below lists the Rhode Island bacteria standards for primary contact and shellfishing established by the Rhode Island Department of Environmental Management (RIDEM). RIDEM defines primary contact as any recreational activities in which there is prolonged and intimate contact with water, involving considerable risk of ingesting water (e.g., swimming, diving, water skiing and surfing). Please note that the RIDEM bacteria standards are provided here for informational purposes only and are not intended to indicate official state compliance with primary contact or shellfishing standards.

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

 ​​​Fec​al Co​li​fo​r​mEnterococci
Primary
Con​​​t​a​c​t1​​​​​		Geom​e​tric ​m​e​a​n​ ≤50​ MPN/1​​00​ mL​
<10% ​o​f​​ samples >4​00 MPN/100 ​mL		Geom​etric mean ≤35 colo​nies​/100 mL​
All sa​mples ≤104 colonies/100 ​​mL2
ShellfishingGeometr​ic mean ≤14 MPN/100​ mL
<10% of samples >49 MPN/100 mL3​		NO ENTEROCOCCI CR​ITERIA​

1Fecal coliform primary contact criteria app​lied 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.​​​​​​​​​​

March 12, 2025

On March 12th, 2025, 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, no precipitation was recorded at TF Green. Overall, bacteria counts were higher in both the Seekonk and Providence Rivers than during the previous sampling event.

Fecal coliform counts were higher in the Providence River, compared to the previous sampling on February 26th (geometric mean of 10 MPN/100 mL compared to 7 MPN/100 mL on 2/26). The maximum count (230 MPN/100 mL) was measured at the Point St. Bridge sampling location.

Enterococci results had an overall geometric mean of 12 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at most sites to 411 MPN/100 mL at Point St. Bridge.

The next scheduled sampling date is March 26.

​The table below lists the Rhode Island bacteria standards for primary contact and shellfishing established by the Rhode Island Department of Environmental Management (RIDEM). RIDEM defines primary contact as any recreational activities in which there is prolonged and intimate contact with water, involving considerable risk of ingesting water (e.g., swimming, diving, water skiing and surfing). Please note that the RIDEM bacteria standards are provided here for informational purposes only and are not intended to indicate official state compliance with primary contact or shellfishing standards.

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

 ​​​Fec​al Co​li​fo​r​mEnterococci
Primary
Con​​​t​a​c​t1​​​​​		Geom​e​tric ​m​e​a​n​ ≤50​ MPN/1​​00​ mL​
<10% ​o​f​​ samples >4​00 MPN/100 ​mL		Geom​etric mean ≤35 colo​nies​/100 mL​
All sa​mples ≤104 colonies/100 ​​mL2
ShellfishingGeometr​ic mean ≤14 MPN/100​ mL
<10% of samples >49 MPN/100 mL3​		NO ENTEROCOCCI CR​ITERIA​

1Fecal coliform primary contact criteria app​lied 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.​​​​​​​​​​

February 26, 2025

On February 26th, 2025, 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, no precipitation was recorded at TF Green. Overall, bacteria counts were lower in both the Seekonk and Providence Rivers than during the previous sampling event.

Fecal coliform counts were lower in the Providence River, compared to the previous sampling on December 18th (geometric mean of 7 MPN/100 mL compared to 91 MPN/100 mL on 12/18). The maximum count (430 MPN/100 mL) was measured at the Point St. Bridge sampling location.

Enterococci results had an overall geometric mean of 15 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at most sites to 146 MPN/100 mL at the Point St. Bridge sampling location.

The next scheduled sampling date is March 12.

​The table below lists the Rhode Island bacteria standards for primary contact and shellfishing established by the Rhode Island Department of Environmental Management (RIDEM). RIDEM defines primary contact as any recreational activities in which there is prolonged and intimate contact with water, involving considerable risk of ingesting water (e.g., swimming, diving, water skiing and surfing). Please note that the RIDEM bacteria standards are provided here for informational purposes only and are not intended to indicate official state compliance with primary contact or shellfishing standards.

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

 ​​​Fec​al Co​li​fo​r​mEnterococci
Primary
Con​​​t​a​c​t1​​​​​		Geom​e​tric ​m​e​a​n​ ≤50​ MPN/1​​00​ mL​
<10% ​o​f​​ samples >4​00 MPN/100 ​mL		Geom​etric mean ≤35 colo​nies​/100 mL​
All sa​mples ≤104 colonies/100 ​​mL2
ShellfishingGeometr​ic mean ≤14 MPN/100​ mL
<10% of samples >49 MPN/100 mL3​		NO ENTEROCOCCI CR​ITERIA​

1Fecal coliform primary contact criteria app​lied 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.​​​​​​​​​​

May 7, 2025

​Water clarity was measured at seven locations in the Providence River and Seekonk River estuaries on May 7, 2025. In the five days prior to the survey, 2.10 inches of precipitation were recorded at TF Green. Secchi depth averaged 2.8 meters. The lowest clarity this week (1.5 meters) was measured at Phillipsdale Landing, while the greatest clarity (4.3 meters) was measured at Conimicut Point. There was a general north-to-south trend of increasing water clarity among the sites this week.

May 14, 2025

Phytoplankton samples were collected on May 14, 2025 at Bullock’s Reach and analyzed in the laboratory shortly after collection.

The water temperature was 16.64 degrees Celsius, and the salinity was 13.43 psu. The qualitative tow net sample had a quick filtration time and the filtrate was mostly clear in appearance.

The analysis of the quantitative whole water sample revealed a total of 1,158,000 cells/L. The microflagellates were found at 307,000 cells/L. The most predominant phytoplankton genera were Dinoflagellate spp. at 523,000 cells/L, Skeletonema spp. at 290,000 cells/L, and Chaetoceros spp. at 20,000 cells/L.

200x phase contrast micrograph of Dictyocha spp.

Dictyocha is a genus of silicoflagellates, which are marine photosynthetic unicellular protists that take the form of either flagellates or axopodial amoebae. Many important species of phytoplankton belong to this genus, and some of them are responsible for algal blooms that are toxic to fish. Silicoflagellates are most commonly found in inshore waters, though they can also be found in temperate, polar, coastal and oceanic regions.

September 9 – 15, 2024

Phillipsdale Landing

Overall, water quality at Phillipsdale Landing was good to fair this week. Weather was dry, with no precipitation recorded at T.F. Green. The Blackstone River flow remained below the 20-year daily daily median. Surface salinity averaged 21.6 ppt and ranged from 16.5 ppt to 26.4 ppt. At the bottom, salinity averaged 26.7 ppt and ranged from 21.4 ppt to 29.4 ppt. Temperatures continued to decrease this week, averaging 22.2°C at the surface and ranging 19.1°C – 24.9°C. At the bottom, temperatures averaged 21.5°C and ranged 20.7°C – 23.4°C.

Dissolved oxygen (DO) at Phillipsdale Landing dropped below the hypoxia threshold (i.e., DO >2.9 mg/L) during the week. Surface DO average 10.43 mg/L and ranged from 4.13 mg/L to 18.24 mg/L. Bottom DO concentrations averaged 4.5 mg/L and ranged from 2.5 mg/L to 10.8 mg/L. The longest periods of hypoxic conditions spanned an hour and a half, occurring at the bottom depth on the morning and then again in the afternoon of September 11th. During these periods, bottom DO averaged around 2.62 mg/L and 2.79 mg/L, respectively. Chlorophyll readings increased from last week, averaging 51.20 µg/L at the surface and 32.3 µg/L at the bottom. Maximum chlorophyll at the surface reached 95.4 µg/L on the evening of September 13th. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location. 

Bullock Reach

Sondes were swapped this week on the morning of September 10th. Overall, water quality was good at Bullock Reach this week. Salinity averaged 28.4 ppt, 29.2 ppt, and 30.8 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 27.0 – 29.1 ppt, mid salinity ranged 27.7 – 30.4 ppt, and bottom salinity ranged 30.0 – 31.5 ppt. Surface temperature averaged 21.3°C and ranged from 20.2°C to 23.4°C. Mid temperatures averaged 20.9°C and ranged from 20.1°C to 22.6°C. Bottom temperatures averaged 20.2°C and ranged from 19.3°C to 21.1°C. DO at Bullock Reach remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week.   Surface DO averaged 8.3 mg/L and ranged 6.1 – 11.3 mg/L. In the mid waters, DO averaged 6.6 mg/L and ranged 4.7 – 9.7 mg/L. At the bottom, DO averaged 4.5 mg/L and ranged 3.4 – 6.6 mg/L.  Chlorophyll readings ranged from low to elevated, with evidence of moderate phytoplankton blooms occurring throughout the week. Readings averaged 12.0 µg/L at the surface, 12.7 µg/L at mid-depth, and 6.9 µg/L at the bottom.  The maximum surface chlorophyll was 30.7 µg/L on the afternoon of September 9th.

September 2 – 8, 2024

Phillipsdale Landing

Sondes were swapped this week on the morning of September 5th.  Overall, water quality at Phillipsdale Landing was good to fair this week. Weather conditions were dry, with only a trace amount of precipitation recorded at T.F. Green. The Blackstone River flow remained below the 20-year daily median. Surface salinity averaged 21.7 ppt and ranged from 14.8 ppt to 25.6 ppt. At the bottom, salinity averaged 25.7 ppt and ranged from 20.4 ppt to 28.4 ppt. Temperatures continued to decrease this week, averaging 22.7°C at the surface and ranging 20.6°C – 24.6°C. At the bottom, temperatures averaged 22.4°C and ranged 21.6°C – 24.3°C.

Dissolved oxygen (DO) at Phillipsdale Landing dropped below the hypoxia threshold (i.e., DO >2.9 mg/L) briefly during the week. Surface DO average 8.2 mg/L and ranged from 3.73 mg/L to 15.08 mg/L. Bottom DO concentrations averaged 4.9 mg/L and ranged from 2.4 mg/L to 10.5 mg/L. The longest period of hypoxic conditions (1 hour, 30 minutes) occurred at the bottom depth on the morning of September 4th. During this period, bottom DO averaged around 2.53 mg/L. Chlorophyll readings decreased from last week, averaging 34.9 µg/L at the surface and 21.7 µg/L at the bottom. Maximum chlorophyll at the surface reached 79.24 µg/L on the morning of September 2nd. 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 to fair at Bullock Reach this week. Salinity averaged 27.6 ppt, 28.9 ppt, and 30.4 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 25.9 – 28.6 ppt, mid salinity ranged 26.8 – 30.2 ppt, and bottom salinity ranged 28.4 – 31.2 ppt. Surface temperature averaged 21.9°C and ranged from 20.6°C to 23.5°C. Mid temperatures averaged 21.7°C and ranged from 20.6°C to 23.3°C. Bottom temperatures averaged 20.9°C and ranged from 19.7°C to 22.7°C.

DO at Bullock Reach remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO averaged 7.5 mg/L and ranged 5.6 – 10.5 mg/L. In the mid waters, DO averaged 6.3 mg/L and ranged 4.3 – 8.8 mg/L. At the bottom, DO averaged 4.5 mg/L and ranged 2.9 – 8.0 mg/L.  Chlorophyll readings ranged from low to elevated, with evidence of moderate phytoplankton blooms occurring throughout the week. Readings averaged 15.4 µg/L at the surface, 12.0 µg/L at mid-depth, and 2.9 µg/L at the bottom.  The maximum surface chlorophyll was 40.7 µg/L on the afternoon of September 3rd.

August 26 – September 1, 2024

Phillipsdale Landing

Overall, water quality at Phillipsdale Landing was good to fair this week. Weather was rainy, with 1.38 inches of precipitation recorded at T.F. Green. The Blackstone River flow fluctuated through the week in response to rain, but remained below the 20-year daily median for most of the week. Surface salinity averaged 20.2 ppt and ranged from 12.9 ppt to 24.4 ppt. At the bottom, salinity averaged 24.5 ppt and ranged from 18.9 ppt to 28.2 ppt. Temperatures continued to increase this week, averaging 24.0°C at the surface and ranging 21.0°C – 26.6°C. At the bottom, temperatures averaged 23.4°C and ranged 22.2°C – 25.0°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, while DO at the bottom waters dropped below the hypoxic threshold throughout the week. Surface DO average 7.70 mg/L and ranged from 2.96 mg/L to 16.08 mg/L. Bottom DO concentrations averaged 3.7 mg/L and ranged from 1.4 mg/L to 8.0 mg/L. The longest period of hypoxic conditions (9 hours) occurred at the bottom depth during the evening of August 29th. During this period, bottom DO averaged around 2.00 mg/L. Chlorophyll readings increased from last week, averaging 49.5 µg/L at the surface and 18.8 µg/L at the bottom. Maximum chlorophyll at the surface reached 108.3 µg/L on the afternoon of August 29th. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location. 

Bullock Reach

Sondes were swapped this week on the morning of August 27th. Overall, water quality was good at Bullock Reach this week. Salinity averaged 26.6 ppt, 28.3 ppt, and 30.1 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 24.8 – 28.1 ppt, mid salinity ranged 26.3 – 30.0 ppt, and bottom salinity ranged 28.3 – 31.2 ppt. Surface temperature averaged 23.4°C and ranged from 21.7°C to 24.5°C. Mid temperatures averaged 22.8°C and ranged from 21.5°C to 24.2°C. Bottom temperatures averaged 21.5°C and ranged from 20.1°C to 23.0°C.

DO at Bullock Reach remained above the hypoxia threshold (i.e., DO >2.9 mg/L) at the surface and mid depths throughout the week.  Bottom DO sporadically dropped below the hypoxia threshold this week. Surface DO averaged 7.8 mg/L and ranged 5.5 – 9.5 mg/L. In the mid waters, DO averaged 5.7 mg/L and ranged 3.2 – 8.6 mg/L. At the bottom, DO averaged 3.9 mg/L and ranged 2.7 – 6.1 mg/L.  The longest period of hypoxic conditions (1 hour and 30 minutes) occurred at the bottom depth during August 31st.  During this period, bottom DO averaged around 2.83 mg/L. Chlorophyll readings ranged from low to elevated, with evidence of moderate phytoplankton blooms occurring throughout the week. Readings averaged 16.2 µg/L at the surface, 11.6 µg/L at mid-depth, and 3.3 µg/L at the bottom.  The maximum surface chlorophyll was 30.4 µg/L on the morning of September 1st.

Scroll to Top