News – Narrabay

“Follow the Flush” with a Free Tour!

Narragansett Bay Commission Offers Free Clean Water Tours: Follow the Flush!

In celebration of Rhode Island Clean Water Week, the Narragansett Bay Commission (NBC) will offer free public tours of its award-winning Field’s Point Wastewater Treatment Facility in Providence on Saturday, April 12 from 10:00 AM to 1:00 PM.

The tours will include a look at the region’s most sophisticated water quality lab, “touch-a-truck” and “touch-a-boat” with the NBC’s maintenance and research vehicles, a clean water scavenger hunt, and other fun activities.

“This facility is simultaneously one of the oldest and most advanced clean water facilities in the nation,” said NBC Chairman Vincent Mesolella. “We’re so excited to give the public the opportunity to ‘follow the flush’ and view the process that has made Narragansett Bay cleaner than it has been in 150 years.”

In addition, the NBC will issue certificates of completion to all students who take the tour that may be redeemed for extra credit at school (but students are advised check with their teacher first).

“I am confident that anyone who experiences this tour will be amazed and appreciative by the clean water efforts in our community,” Mesolella added.

Members of the public can book a tour on the half hours between 10:00 AM and 1:00 PM by emailing nbcpr@narrabay.com. Spaces are limited. The tour will take approximately 90 minutes.

The NBC joins four other clean water agencies in Rhode Island offering free public tours during Rhode Island Clean Water Week. Information on other tours is available at ricwa.org

September 3, 2025

Surface chlorophyll data were collected on September 3, 2025, while the R/V Monitor was underway collecting nutrient samples in the Providence and Seekonk River estuary. The average chlorophyll concentrations were categorized as good in the Southern Providence River Channel, poor in the Seekonk River, and as fair in all other areas. The average chlorophyll concentrations were categorized as fair over all areas surveyed. Overall, chlorophyll ranged from 2.31 µg/L to 38.36 µg/L with an average of 11.11 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.

September 3, 2025

Water clarity was measured at eight locations in the Providence River and Seekonk River estuaries on September 3, 2025. In the five days prior to the survey, 0.00 inches of precipitation were recorded at TF Green. Secchi depth averaged 2.0 meters. The lowest clarity this week (1.2 meters) was measured at Phillipsdale Landing, while the greatest clarity (3.3 meters) was measured at Conimicut Point. There was a general north-to-south trend of increasing water clarity among the sites this week. Compared to previous measurements taken on August 27, 2025, water clarity remained relatively consistent at most sites. However, India Point Park showed a notable decrease of 1.3 meters.

August 27, 2025

Water clarity was measured at eight locations in the Providence River and Seekonk River estuaries on August 27, 2025. In the five days prior to the survey, 0.02 inches of precipitation were recorded at TF Green. Secchi depth averaged 2.4 meters. The lowest clarity this week (0.9 meters) was measured at Phillipsdale Landing, while the greatest clarity (3.3 meters) was measured at Conimicut Point and India Point Park. There was a general north-to-south trend of increasing water clarity among the sites this week. Compared to previous measurements taken on August 20, 2025, water clarity remained remained relatively consistent at most sites. However, India Point Park showed a notable increase of 1.1 meters.

August 27, 2025

Surface chlorophyll data were collected on August 27, 2025, while the R/V Monitor was underway collecting nutrient samples in the Providence and Seekonk River estuary. The average chlorophyll concentrations were categorized as good in the Northern Providence River Channel, poor in the Seekonk River, and as fair in all other areas. The average chlorophyll concentrations were categorized as poor over all areas surveyed. Overall, chlorophyll ranged from 1.43 µg/L to 610.7 µg/L with an average of 30.00 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.

August 27, 2025

On August 27th, 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. There was no precipitation at TF Green over the five days prior to the August 27^th, 2025 sampling event. Overall, bacteria counts remained approximately the same as the previous sampling event.

Fecal coliform counts were higher in the Seekonk River, compared to the Providence River (geometric mean of 23 MPN/100 mL for the Seekonk River compared to 6 MPN/100mL for the Providence River) for sampling conducted on August 27th. The maximum count (93 MPN/100 mL) was measured at the Point Street Bridge sampling location.

Fecal coliform counts remained approximately the same in the Providence River, compared to the previous sampling on August 15th (geometric mean of 6 MPN/100 mL compared to 7 MPN/100 mL on 8/15). Fecal coliform counts also remained approximately the same in the Seekonk River, compared to the previous sampling on August 15th (geometric mean of 23 MPN/100 mL compared to 25 MPN/100 mL on 8/15).

Enterococci results had an overall geometric mean of 13 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at most sites to 52 MPN/100 mL at Point Street Bridge.

The next scheduled sampling date is September 10th.

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.

August 13, 2025

Surface chlorophyll data were collected on August 13, 2025, while the R/V Monitor was underway collecting nutrient samples in the Providence and Seekonk River estuary. The average chlorophyll concentrations were categorized as poor in the Seekonk River, and as fair in all other areas. The average chlorophyll concentrations were categorized as poor over all areas surveyed. Overall, chlorophyll ranged from 2.01 µg/L to 610.0 µg/L with an average of 21.56 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.

August 20, 2025

Water clarity was measured at seven locations in the Providence River and Seekonk River estuaries on August 20, 2025. In the five days prior to the survey, 0.89 inches of precipitation were recorded at TF Green. Secchi depth averaged 2.2 meters. The lowest clarity this week (1.1 meters) was measured at Phillipsdale Landing, while the greatest clarity (3.1 meters) was measured at Conimicut Point. There was a general north-to-south trend of increasing water clarity among the sites this week. Overall, water clarity remained approximately the same from the previous measurements (data collected August 13, 2025).

August 13, 2025

Water clarity was measured at three locations in the Providence River and Seekonk River estuaries on August 13, 2025. Due to an equipment malfunction, only a limited number of sites were visited during this sampling day. In the five days prior to the survey, 0.00 inches of precipitation were recorded at TF Green. Secchi depth averaged 2.5 meters. The lowest clarity this week (2.1 meters) was measured at Edgewood Yacht Club, while the greatest clarity (3.1 meters) was measured at Conimicut Point. There was a general north-to-south trend of increasing water clarity among the sites this week. Compared to the measurements taken on July 23, 2025, water clarity at Bullock Reach and Edgewood Yacht Club remained unchanged on July 30, while Conimicut Point showed an increase in water clarity of 0.8 meters.

August 6, 2025

Nutrient samples were collected from thirteen river on August 6^th. In the five days prior to sampling, 0.46 inches of precipitation were recorded at T.F. Green.

Among the river stations sampled, the highest total nitrogen (TN) was observed at Pawtuxet River @ Broad St. (1,450 ppb). The highest total dissolved nitrogen (TDN) and dissolved inorganic nitrogen (DIN) were observed at Ten Mile River @ Central Ave. (TDN = 1,315 ppb, DIN = 1,058.8 ppb, averages of duplicates). The lowest TN was observed at Runnins River @ River Rd. (386 ppb), and the lowest TDN was observed at Taunton River @ Berkley Bridge (303 ppb). The lowest DIN was observed at Palmer River @ Rt. 6 (13 ppb, reflecting minimum detection limits for DIN).

The next scheduled sampling date is August 20^th, 2025.

July 23, 2025

Phytoplankton samples were collected on July 23, 2025 at Bullock’s Reach and analyzed in the laboratory shortly after collection.

The water temperature was 23.72 °C, the salinity was 28.61 psu, and the chlorophyll a was 7.18 ug/L.

The qualitative tow net sample had a medium filtration time. The filtrate was clear with a light brown greenish coloration. Many comb jellies were detected in this sample.

The analysis of the quantitative whole water sample revealed a total of 4,386,000 cells/L. The microflagellates were found at 40,000 cells/L. The most predominant phytoplankton genera were Cylindrotheca spp. at 2,055,000 cells/L, Skeletonema spp. at 860,000 cells/L, and Leptocylindrus spp. at 840,000 cells/L.

200x phase contrast image of dinoflagellate *Protoperidinium* spp.

Protoperidinium spp. is a marine phytoplankton belonging to a family of armored dinoflagellates that are characterized by horns and spikes. They are heterotrophic predators who feed on other smaller organisms for nutrients. With the help of chloroplasts, these tiny creatures can produce their own nutrients with photosynthesis.