Historical News
April 24, 2024
Bacteria Sampling
On April 24th, 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, precipitation totaled 0.28 inches as recorded at TF Green. Overall, bacteria counts were lower in both the Seekonk and Providence Rivers this week than during the previous sampling event on March 27th, likely because of the drier weather leading up to sampling.
Fecal coliform counts were higher in the Seekonk River sites than in the Providence River sites (geometric means of 59 MPN/100 mL and 7 MPN/100 mL, respectively). The maximum count (430 MPN/100 mL) was measured at Point St Bridge.
Enterococci results had an overall geometric mean of 14 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at South FP East, Gaspee Point, and Conimicut Point to 41 MPN/100 mL at Phillipsdale Landing.
The next scheduled sampling date is May 8.
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
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 | Geometric mean ≤35 colonies/100 mL |
| Shellfishing | Geometric mean ≤14 MPN/100 mL | NO ENTEROCOCCI CRITERIA |
Table adapted from Rhode Island Water Quality Regulations (250-RICR-150-05-1); see regulations for complete details.
March 27, 2024
Bacteria Sampling
On March 27th, 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, precipitation totaled 3.12 inches as recorded at TF Green. Overall, bacteria counts were higher in both the Seekonk and Providence Rivers this week than during the previous sampling event on March 13th, likely because this event had less time in between the rainfall and sampling.
Fecal coliform counts were slightly lower in the Seekonk River sites than in the Providence River sites (geometric means of 51 MPN/100 mL and 66 MPN/100 mL, respectively). The maximum count (430 MPN/100 mL) was measured at both Collier Point Park and Off FP Outfall.
Enterococci results had an overall geometric mean of 26 MPN/100 mL. Enterococci counts ranged from 20 MPN/100 mL at South FP East to 41 MPN/100 mL at both Phillipsdale Landing and Gaspee Point.
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 | Geometric mean ≤35 colonies/100 mL |
| Shellfishing | Geometric mean ≤14 MPN/100 mL | NO ENTEROCOCCI CRITERIA |
Table adapted from Rhode Island Water Quality Regulations (250-RICR-150-05-1); see regulations for complete details.
March 13, 2024
Bacteria Sampling
On March 13th, twenty stations were sampled for fecal coliform bacteria in the Providence River and Seekonk River; five of these stations were also sampled for enterococci bacteria. In the five days prior to sampling, precipitation totaled 2.32 inches as recorded at TF Green.
Fecal coliform counts were slightly lower in the Seekonk River sites than in the Providence River sites (geometric means of 29 MPN/100 mL and 33 MPN/100 mL, respectively). The maximum count (430 MPN/100 mL) was measured at Point Street Bridge.
Enterococci results had an overall geometric mean of 12 MPN/100 mL. Enterococci counts ranged from non-detect at most sites to a max of 31 MPN/100 mL at Point Street Bridge.
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 | Geometric mean ≤35 colonies/100 mL |
| Shellfishing | Geometric mean ≤14 MPN/100 mL | NO ENTEROCOCCI CRITERIA |
Table adapted from Rhode Island Water Quality Regulations (250-RICR-150-05-1); see regulations for complete details.
March 6, 2024
Water Column Clarity
Water clarity was measured at eight locations in the Providence River and Seekonk River estuaries on March 6, 2024. Rainfall totaling 3.16 inches was recorded at TF Green in the five days prior to the survey. Secchi depth averaged 2.9 meters. The lowest clarity this week (2.3 meters) was measured at Phillipsdale Landing, while the greatest clarity (3.7 meters) was measured at Conimicut Point. There was no evidence of a north-to-south gradient of increasing water clarity among the sites this week.
March 20, 2024
Phytoplankton Sampling
Phytoplankton samples were collected on March 20, 2024 at Bullock Reach and analyzed in the laboratory shortly after collection. It was partly sunny, breeze and brisk on Narragansett Bay. The qualitative tow net sample had a long filtration time, and the filtrate was a dark brown color. Some sediment and jellyfish were found in the sample.
The analysis of the quantitative whole water sample revealed a total of 3,536,000 cells per Liter. The micro flagellates were found at 20,000 cells/L. The most predominant phytoplankton genus was Thalassiosira spp. at 1,888,000 cells/L. Other representative genera include Skeletonema spp. and Leptocylindrus spp. Thalassiosira spp. (today's featured micrograph, 200x phase contrast) is a type of phytoplankton belonging to the centric diatom group. This photosynthetic species grows primarily in marine waters. Some species within the genus are found in estuaries and aquatic systems that have been impacted by human activities. They can be identified by their coin-like shape.
