Evan Thompson – Page 10

Week of October 22 – 28, 2023

On October 25^th, 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 1.14 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 October 11th. Fecal coliform counts were higher in the Seekonk River sites than in the Providence River sites (geometric means of 187 MPN/100 mL and 55 MPN/100 mL, respectively). The maximum count (930 MPN/100 mL) was measured at India Point Park.

Enterococci results had an overall geometric mean of 55 MPN/100 mL and ranged from 10 MPN/100 mL in one of the duplicate samples at Conimicut Point to 160 MPN/100 mL at South FP East.

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

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

Week of November 26 – December 2, 2023

Water clarity was measured at seven locations in the Providence River and Seekonk River estuaries on November 30th, 2023. Rainfall totaling 0.69 inches was recorded at TF Green in the five days prior to the survey. Secchi depth averaged 4.5 meters, compared to 4.7 meters on the previous survey (November 15th). The lowest clarity this week (3.0 meters) was measured at Phillipsdale Landing, while the greatest clarity (5.5 meters) was measured at Bullock Reach. There was a general north-to-south gradient of increasing water clarity among the sites this week.

Week of November 12 – 18, 2023

Water clarity was measured at seven locations in the Providence River and Seekonk River estuaries on November 15th, 2023. Trace amounts of rainfall was recorded at TF Green in the five days prior to the survey. Secchi depth averaged 4.7 meters, compared to 3.0 meters on the previous survey (November 1st). The lowest clarity this week (3.4 meters) was measured at India Point, while the greatest clarity (5.8 meters) was measured at Conimicut Point. There was a general north-to-south gradient of increasing water clarity among the sites this week.

Week of October 22 – 28, 2023

Water clarity was measured at eight locations in the Providence River and Seekonk River estuaries on October 25th, 2023. Rainfall totaling 1.14 inches was recorded at TF Green in the five days prior to the survey. Secchi depth averaged 3.6 meters, compared to 3.5 meters on the previous survey (October 18th). The lowest clarity this week (1.7 meters) was measured at Phillipsdale Landing, while the greatest clarity (6.1 meters) was measured at Bullock Reach. There was a general north-to-south gradient of increasing water clarity among the sites this week.

Week of October 15 – 21, 2023

Water clarity was measured at eight locations in the Providence River and Seekonk River estuaries on October 18th, 2023. There was trace amounts of precipitation recorded at TF Green in the five days prior to the survey. Secchi depth averaged 3.5 meters, compared to 2.9 meters on the previous survey (October 11th). The lowest clarity this week (2.4 meters) was measured at Phillipsdale Landing and India Point, while the greatest clarity (4.8 meters) was measured at Conimicut Point and Bullock Reach. There was a general north-to-south gradient of increasing water clarity among the sites this week.

Week of October 8 – 14, 2023

Water clarity was measured at seven locations in the Providence River and Seekonk River estuaries on October 11th, 2023. Rainfall totaling 0.36 inches was recorded at TF Green in the five days prior to the survey. Secchi depth averaged 2.9 meters, compared to 2.2 meters on the previous survey (October 4th). The lowest clarity this week (2.2 meters) was measured at Phillipsdale, while the greatest clarity (3.4 meters) was measured at Edgewood Yacht Club and Bullock Reach. There was a general north-to-south gradient of increasing water clarity among the sites this week.

Week of October 1 – 7, 2023

Water clarity was measured at seven locations in the Providence River and Seekonk River estuaries on October 4th, 2023. Rainfall totaling 1.27 inches was recorded at TF Green in the five days prior to the survey. Secchi depth averaged 2.2 meters, compared to 2.6 meters on the previous survey (September 27th). The lowest clarity this week (1.4 meters) was measured at India Point, while the greatest clarity (2.7 meters) was measured at Edgewood Yacht Club. There was no clear north-to-south gradient in water clarity among the sites this week.

Week of September 24 – 30, 2023

Water clarity was measured at six locations in the Providence River and Seekonk River estuaries on September 27th, 2023. Rainfall totaling 2.77 inches was recorded at TF Green in the five days prior to the survey. Secchi depth averaged 2.6 meters, compared to 2.5 meters on the previous survey (September 20th). The lowest clarity this week (2.2 meters) was measured at Phillipsdale Landing, Point Street Bridge, and India Point while the greatest clarity (3.0 meters) was measured at Edgewood Yacht Club. There was a general north-to-south gradient of increasing water clarity among the sites this week.

Week of September 17 – 23, 2023

Water clarity was measured at eight locations in the Providence River and Seekonk River estuaries on September 20th, 2023. Rainfall totaling 1.55 inches was recorded at TF Green in the five days prior to the survey. Secchi depth averaged 2.5 meters, compared to 1.4 meters on the previous survey (September 14). The lowest clarity this week (1.3 meters) was measured at India Point, while the greatest clarity (3.4 meters) was measured at Bullock Reach. There was a general north-to-south gradient of increasing water clarity among the sites this week.

Week of September 10 – 16, 2023

Water clarity was measured at seven locations in the Providence River and Seekonk River estuaries on September 14th, 2023. Rainfall totaling 1.23 inches was recorded at TF Green in the five days prior to the survey. Secchi depth averaged 1.4 meters, compared to 2.2 meters on the previous survey (September 16th). The lowest clarity this week (0.9 meters) was measured at Phillipsdale Landing, while the greatest clarity (1.6 meters) was measured at Point Street Bridge, Bullock Reach and Conimicut Point. There was no clear north-to-south gradient in water clarity among the sites this week.