Week of January 15 - 21, 2023
Bacteria Sampling
On January 18, twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers. Five of these stations were also sampled for enterococci bacteria. Precipitation in the five days prior to sampling totaled 0.72 inches as recorded at TF Green.
The geometric mean of fecal coliform results for all sites was 25 MPN/100 mL compared to 21 MPN/100 mL on November 23, 2022. Overall, bacteria counts were higher in the Providence River and lower in the Seekonk River this week than during the previous sampling event on November 23. Fecal coliform counts were higher in the Seekonk River sites than in the Providence River sites (geometric means of 55 MPN/100 mL and 17 MPN/100 mL, respectively). The maximum counts (93 MPN/100 mL) were measured at Bishop Point, Phillipsdale Landing, and Narragansett Boating Center in the Seekonk River, and Point St. Bridge and India Point Park in the Providence River.
Enterococci results had an overall geometric mean of 16 MPN/100 mL. Enterococci results ranged from non-detect at Point St. Bridge to 31 MPN/100 mL at the Phillipsdale Landing site.
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
| 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
Week of October 30 - November 5, 2022
Water Column Profiles
Water column profiles were conducted at six locations in the Providence River estuary using a Seabird instrument on November 2nd, 2022. In the three days leading up to the sampling event, 0.05 inches of rainfall was recorded at T.F. Green. Evidence of moderate density stratification was observed at most sites this week, with India Point Park and Edgewood Yacht Club showing signs of being strongly stratified.
Surface salinities among all sites ranged from 25.6 psu at Pomham Rocks down to 11.0 psu at Edgewood Yacht Club. Bottom salinities ranged from 29.8 psu at Conimicut Point down to 24.6 psu at Edgewood Yacht Club. The warmest surface water temperature (15.9°C) was observed at Pawtuxet Cove, while the warmest bottom temperature (15.8°C) was observed India Point Park. The coolest water temperatures ranged from 14.2°C at the surface of India Point Park to 15.3°C at bottom of Bullock Reach Buoy and Conimicut Point West.
Dissolved oxygen (DO) conditions remained above the hypoxia threshold (2.9 mg/L) at all sites this week; the lowest DO observed was approximately 6.4 mg/L in the bottom waters at India Point Park. Overall, fluorescence was similar to the previous survey, with the highest values (3.05 mg/m3) observed near the surface (~1.75 m) at India Point Park. 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.
Week of October 23-29, 2022
Water Column Profiles
Water column profiles were conducted at seven locations in the Providence and Seekonk River estuaries using a Seabird instrument on October 27th, 2022. In the three days leading up to the sampling event, 1.92 inches of rainfall was recorded at T.F. Green. Evidence of density stratification was observed at most sites this week, with Phillipsdale Landing and Edgewood Yacht Club showing signs of being well-mixed.
Surface salinities among all sites ranged from 28.2 psu at Bullock Reach Buoy down to 20.6 psu at Point St. Bridge. Bottom salinities ranged from 30.5 psu at Conimicut Point down to 22.8 psu at Phillipsdale Landing. The warmest surface water temperature (20.9°C) was observed at Point St. Bridge, while the warmest bottom temperature (16.7°C) was observed at Edgewood Yacht Club. The coolest water temperatures ranged from 16.6°C at the surface of the Bullock Reach Buoy and Phillipsdale Landing to 16.1°C at bottom of Pomham Rocks.
Dissolved oxygen (DO) conditions remained above the hypoxia threshold (2.9 mg/L) at all sites this week; the lowest DO observed was 4.6 mg/L mid-depth at Phillipsdale Landing. Overall, fluorescence was similar to the previous survey, with the highest values (3.42 mg/m3) observed the sub-surface (<2.00 m) at Pomham Rocks. 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.
Week of October 16-22, 2022
Water Column Profiles
Water column profiles were conducted at seven locations in the Providence and Seekonk River estuaries using a Seabird instrument on October 19th, 2022. In the three days leading up to the sampling event, 0.35 inches of rainfall was recorded at T.F. Green. Evidence of moderate density stratification was observed at most sites this week, with Conimicut Point, India Point Park, and Phillipsdale Landing showing signs of being strongly stratified.
Surface salinities among all sites ranged from 26.6 psu at Bullock Reach Buoy down to 3.5 psu at Phillipsdale Landing. Bottom salinities ranged from 30.9 psu at Conimicut Point West down to 24.4 psu at Phillipsdale Landing. The warmest surface water temperature (17.1°C) was observed at Bullock Reach Buoy, while the warmest bottom temperature (17.1°C) was observed at Pawtuxet Cove. The coolest water temperatures ranged from 16.7°C at the bottom of India Point Park to 14.4°C at surface of Phillipsdale Landing.
Dissolved oxygen (DO) conditions remained above the hypoxia threshold (2.9 mg/L) at all sites this week; the lowest DO observed was approximately 3.3 mg/L in the bottom waters at Phillipsdale Landing. Overall, fluorescence was similar to the previous survey, with the highest values (3.099 mg/m3) observed at the surface (<1.75 m) at Conimicut Point West. 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.
Week of October 9-15, 2022
Water Column Profiles
Water column profiles were conducted at five locations in the Providence and Seekonk River estuaries using a Seabird instrument on Oct. 12th, 2022. In the three days leading up to the sampling event, 0.00 inches of rainfall was recorded at T.F. Green. Evidence of weak density stratification was observed at all sites this week.
Surface salinities among all sites ranged from 29.4 psu at Conimicut Point West down to 25.1 psu at Point St. Bridge and Phillipsdale Landing. Bottom salinities ranged from 31.0 psu at Conimicut Point down to 27.6 psu at Point St. Bridge and Phillipsdale Landing. The warmest surface and bottom water temperature (19.7°C) was observed at Point St. Bridge. The coolest water temperatures at the surface and bottom were both at Bullock Reach Buoy, with 15.9°C at the surface and 16.3°C at bottom.
Dissolved oxygen (DO) conditions remained above the hypoxia threshold (2.9 mg/L) at all sites this week; the lowest DO observed was approximately 6.75 mg/L in the bottom waters at India Point Park. Overall, fluorescence decreased from the previous survey with the highest values (2.73 mg/m3) observed at ~2.00 m at Bullock Reach Buoy. 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.
