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

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.

August 15, 2025

On August 15th, 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, 0.00 inches of precipitation was recorded at TF Green. Overall bacteria counts were lower than during the previous sampling event.

Fecal coliform counts were higher in the Seekonk River, compared to the Providence River (geometric mean of 25 MPN/100 mL for the Seekonk River compared to 7 MPN/100mL for the Providence River) for sampling conducted on August 13th. The maximum count (93 MPN/100 mL) was measured at the Division St. Dock, Bishop Point, and Collier Point Park sampling locations.

Fecal coliform counts remained approximately the same in the Providence River, compared to the previous sampling on July 30th (geometric mean of 7 MPN/100 mL compared to 9 MPN/100 mL on 7/30). Fecal coliform counts were lower in the Seekonk River, compared to the previous sampling on July 30th (geometric mean of 25 MPN/100 mL compared to 55 MPN/100 mL on 7/30).

Enterococci results had an overall geometric mean of 11 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at most sites to 20 MPN/100 mL at Point Street Bridge.

The next scheduled sampling date is August 27th.

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.

July 23, 2025

Nutrient samples were collected from seven river stations and seven bay stations on July 23^rd. All bay stations were sampled at the surface and bottom. In the five days prior to sampling, trace amounts of precipitation were recorded at T.F. Green.

Among the river stations sampled, the highest total nitrogen (TN), total dissolved nitrogen (TDN), and dissolved inorganic nitrogen (DIN) were observed at Pawtuxet River @ Broad St. (TN = 1,430 ppb, TDN = 1,390 ppb, DIN = 1,222.9 ppb). The lowest TN, TDN, and DIN were observed at Blackstone River @ Bikepath Bridge (TN = 789 ppb, TDN = 794 ppb, DIN = 509.5 ppb).

Among the bay stations sampled, the highest surface TN, TDN, and DIN were observed at Pawtuxet Cover (TN = 1,200 ppb, TDN = 838 ppb, DIN = 628.6 ppb). The lowest surface TN and TDN were observed at Edgewood Yacht Club (TN = 493 ppb, TDN = 195 ppb). The lowest surface DIN was observed at four of the seven bay stations (13 ppb, reflecting minimum detection limits for DIN).

The next scheduled sampling date is August 6^th, 2025.

July 8, 2025

Nutrient samples were collected from thirteen river stations and eight bay stations on July 8^th. All bay stations were sampled at the surface; Edgewood Shoals was sampled at the surface and bottom. In the five days prior to sampling, there were 0.55 inches of precipitation recorded at T.F. Green.

Among the river stations sampled, the highest total nitrogen (TN), total dissolved nitrogen (TDN), and dissolved inorganic nitrogen (DIN) were observed at Pawtuxet River @ Broad St. (TN = 1,360 ppb, TDN = 1,350 ppb, DIN = 1,044.4 ppb). The lowest TN was observed at Runnings River @ River Rd. (617 ppb). The lowest TDN and DIN were observed at Palmer River @ Rt. 6 (TDN = 374 ppb, DIN = 21.3 ppb).

Among the bay stations sampled, the highest surface TN and TDN were observed at Phillipsdale Landing (TN = 1,200 ppb, TDN = 509 ppb). The highest DIN was observed at Pawtuxet Cove (189 ppb). The lowest surface TN and TDN were observed at Conimicut Point (TN = 538 ppb, TDN = 164 ppb). The lowest surface DIN was observed at Conimicut Point and India Point Park (13 ppb, reflecting minimum detection limits for DIN).

The next scheduled sampling date is July 23^rd, 2025.

June 30 – July 6, 2025

Phillipsdale Landing

Sondes were swapped this week on July 1^st. Overall, water quality at Phillipsdale Landing was poor to good this week. Weather conditions were moderately rainy this week, with a total of 0.55 inches recorded at T.F. Green, and the majority of rainfall occurring on the 3^rd. Blackstone River flow reached its peak on July 3^rd, where the flow was similar to the 20-year daily median flow, but was otherwise below the 20-year daily median value for the rest of the week. Salinity at the surface averaged 15.5 ppt and ranged from 6.5 ppt to 23.3 ppt. At the bottom, salinity averaged 23.8 ppt and ranged from 16.1 ppt to 28.5 ppt. Temperatures this week averaged 24.6 °C at the surface and 22.3 °C at the bottom. Surface temperatures ranged from 21.8 °C to 28.5 °C, while bottom temperatures ranged from 20.2 °C to 24.9 °C.

Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold (i.e., DO >2.9 mg/L) at the surface, but below the hypoxia threshold at the bottom for most of the week. Hypoxic conditions were observed at the surface briefly during the morning on July 1^st. Hypoxic conditions were observed at the bottom for multiple extended periods from July 2^nd to July 6^th, including one 21-hour period from the evening of July 2^nd to the evening of July 3^rd. Surface DO averaged 9.4 mg/L and ranged from 2.8 to 20.8 mg/L. Bottom water DO concentration averaged 2.8 mg/L and ranged from 0.8 mg/L to 8.8 mg/L. Chlorophyll ranged from low to elevated levels throughout the week, averaging 38.6 ug/L at the surface and 34.7 ug/L at the bottom, with evidence of substantial phytoplankton blooms occurring throughout the week. Maximum surface chlorophyll readings reached 113.1 ug/L on the afternoon of July 5^th. 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 ranged from fair to good at Bullock Reach this week. Salinity averaged 27.0 ppt, 29.0 ppt, and 30.8 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged from 24.9 to 28.7 ppt, mid salinity ranged from 26.2 to 30.8 ppt, and bottom salinity ranged from 29.3 to 31.9 ppt. Surface temperature averaged 23.4 °C and ranged from 21.4 °C to 25.3 °C. Mid temperatures averaged 22.3 °C and ranged from 20.0 °C to 24.5 °C. Bottom temperatures averaged 20.2 °C and ranged from 19.0 °C to 23.3 °C.

DO at Bullock Reach remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO averaged 7.4 mg/L and ranged from 5.2 to 10.2 mg/L. In the mid waters, DO averaged 5.9 mg/L and ranged from 3.9 to 8.6 mg/L. At the bottom, DO averaged 4.6 mg/L and ranged 3.0 to 7.1 mg/L. Chlorophyll readings ranged from low to moderate, with evidence of moderate phytoplankton blooms occurring throughout the week. Readings averaged 10.1 µg/L at the surface, 13.1 µg/L at mid-depth, and 9.2 µg/L at the bottom. The maximum surface chlorophyll was 32.8 µg/L on the afternoon of July 4^th.

Trolls In the Narragansett Bay: Adventures in Bacteria sampling

Most people picture Narragansett Bay as calm, sparkling, and post card-perfect. But if you’ve ever been out there in a small boat with a cooler full of sample bottles and a mission to track down bacteria data, you should know the truth: the bay has trolls.

Every other week, we’re out on the bay collecting water samples to test for bacteria. Why? Because the health of Narragansett Bay isn’t just about how pretty it looks, its about what’s living in it, and sometimes, what’s floating in it that shouldn’t be. Bacteria levels can mean the difference between a thriving shellfish industry and a “DO Not Harvest” sign. Our data helps protect public health, the environment, and the economy.

Why would trolls be out in the bay, you ask? A few theories staff have in mind. Perhaps trolls follow the plankton blooms. Scientist track all sorts of information, why not troll movement. Trolls may have a curiosity about science and wants to see what we are doing. Water sampling is fascinating! Finally we think the trolls like a good swim in the Narragansett Bay. So, next time your out on the bay and something catches your eye, don’t be too quick to dismiss it. It just might be …a troll!

June 23 – June 29, 2025

Phillipsdale Landing

Overall, water quality at Phillipsdale Landing was poor to good this week. Weather conditions were relatively dry this week, with a total of 0.07 inches recorded at T.F. Green, and the majority of rainfall occurring on the 26^th. Blackstone River flow decreased slightly over the course of the week, and remained below the 20-year daily median flow. Salinity at the surface averaged 20.6 ppt and ranged from 14.3 ppt to 25.3 ppt. At the bottom, salinity averaged 23.4 ppt and ranged from 4.6 ppt to 27.2 ppt. Temperatures this week averaged 22.3 °C at the surface and 21.4 °C at the bottom. Surface temperatures ranged from 19.8 °C to 26.4 °C, while bottom temperatures ranged from 19.4 °C to 24.6 °C.

Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold (i.e., DO >2.9 mg/L) for most of the week. Hypoxic conditions were observed at the surface briefly during early morning on June 27^th and June 29^th. Hypoxic conditions were observed at the bottom for multiple hours in the early morning of June 27^th, briefly in the evening of June 28^th, and for multiple hours in the evening of June 29^th. Surface DO averaged 7.3 mg/L and ranged from 2.8 to 15.1 mg/L. Bottom water DO concentration averaged 5.3 mg/L and ranged from 2.3 mg/L to 12.3 mg/L. Chlorophyll ranged from low to elevated levels throughout the week, averaging 22.2 ug/L at the surface and 16.1 ug/L at the bottom, with evidence of moderate phytoplankton blooms occurring throughout the week. Maximum surface chlorophyll readings reached 92.1 ug/L on the early morning of June 27^st. 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 June 24^th. Overall, water quality ranged from fair to good at Bullock Reach this week. Salinity averaged 26.1 ppt, 28.4 ppt, and 30.4 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged from 22.2 to 29.1 ppt, mid salinity ranged from 24.9 to 30.6 ppt, and bottom salinity ranged from 28.4 to 31.4 ppt. Surface temperature averaged 22.6 °C and ranged from 20.2 °C to 26.5 °C. Mid temperatures averaged 21.1 °C and ranged from 19.2 °C to 24.6 °C. Bottom temperatures averaged 19.1 °C and ranged from 17.4 °C to 20.6 °C.

DO at Bullock Reach remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO averaged 7.6 mg/L and ranged from 5.1 to 11.3 mg/L. In the mid waters, DO averaged 6.0 mg/L and ranged from 3.9 to 9.7 mg/L. At the bottom, DO averaged 4.9 mg/L and ranged 3.9 to 6.3 mg/L. Chlorophyll readings ranged from low to moderate, with evidence of moderate phytoplankton blooms occurring throughout the week. Readings averaged 10.1 µg/L at the surface, 12.5 µg/L at mid-depth, and 9.8 µg/L at the bottom. The maximum surface chlorophyll was 42.7 µg/L on the afternoon of June 28^th.

July 8, 2025

Phytoplankton samples were collected on July 8, 2025 at Bullock’s Reach and analyzed in the laboratory shortly after collection.

It was sunny, hot, and humid on this day. The water temperature was 25.24 °C, the salinity was 27.85 psu, and the chlorophyll a was 5.55 ug/L.

The qualitative tow net sample had a quick filtration time. The filtrate contained seaweed and particulates and had a reddish brown coloration.

The analysis of the quantitative whole water sample revealed a total of 875,000 cells/L. The microflagellates were found at 268,000 cells/L. The most predominant phytoplankton genera were Prorocentrum spp. at 284,000 cells/L , and Thalassiosira spp. at 198,000 cells/L.

200x phase contrast micrograph of Monogonontan Rotifer

Rotifers of the subclass Monogononta are common metazoans found in freshwater, brackish and marine environments. Although they are small, ranging in size from 50–500 µm, they are extremely important in the transfer of energy from algae, microbes, and detritus to higher trophic levels in community food webs.

June 16 – June 22, 2025

Phillipsdale Landing

Sondes were swapped this week on June 17^th. Overall, water quality at Phillipsdale Landing was fair to good this week. Weather conditions were slightly drier than the previous week, with a total of 0.21 inches recorded at T.F. Green, and the majority of rainfall occurring on the 17^th. Blackstone River flow remained near the 20-year daily median until the end of the week, when flows declined below the 20-year daily median values. Salinity at the surface averaged 13.1 ppt and ranged from 3.1 ppt to 21.7 ppt. At the bottom, salinity averaged 21.5 ppt and ranged from 3.1 ppt to 27.9 ppt. Temperatures this week averaged 21.1 °C at the surface and 19.0 °C at the bottom. Surface temperatures ranged from 17.7 °C to 25.6 °C, while bottom temperatures ranged from 16.0 °C to 22.4 °C.

Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO averaged 9.0 mg/L and ranged from 4.4 to 17.1 mg/L. Bottom water DO concentration averaged 5.6 mg/L and ranged from 3.9 mg/L to 10.4 mg/L. Chlorophyll ranged from low to moderate levels throughout the week, averaging 21.4 ug/L at the surface and 17.1 ug/L at the bottom. Maximum surface chlorophyll readings reached 92.1 ug/L on the morning of June 21^st. 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 ranged from fair to good at Bullock Reach this week. Salinity averaged 24.7 ppt, 26.8 ppt, and 29.9 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged from 21.5 to 26.6 ppt, mid salinity ranged from 23.6 to 28.7 ppt, and bottom salinity ranged from 27.9 to 31.0 ppt. Surface temperature averaged 20.6 °C and ranged from 18.3 °C to 23.4 °C. Mid temperatures averaged 19.5 °C and ranged from 16.5 °C to 22.7 °C. Bottom temperatures averaged 16.7 °C and ranged from 15.1 °C to 20.1 °C.

DO at Bullock Reach remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO averaged 9.5 mg/L and ranged from 7.0 to 12.8 mg/L. In the mid waters, DO averaged 7.5 mg/L and ranged from 4.9 to 9.7 mg/L. At the bottom, DO averaged 4.7 mg/L and ranged 3.6 to 6.7mg/L. Chlorophyll readings ranged from low to elevated, with evidence of moderate phytoplankton blooms occurring throughout the week. Readings averaged 18.2 µg/L at the surface, 18.2 µg/L at mid-depth, and 6.5 µg/L at the bottom. The maximum surface chlorophyll was 63.8 µg/L on the evening of June 20^th.

June 9 – June 15, 2025

Phillipsdale Landing

Overall, water quality at Phillipsdale Landing was fair to good this week. Weather conditions were slightly drier than the previous week, with a total of 0.31 inches recorded at T.F. Green, and the majority of rainfall occurring on the 10^th. The Blackstone River flow decreased throughout the week, exceeding the 20-year daily median until the 15^th. Salinity at the surface averaged 8.4 ppt and ranged from 2.8 ppt to 21.8 ppt. At the bottom, salinity averaged 20.1 ppt and ranged from 4.2 ppt to 27.9 ppt. Temperatures this week averaged 20.1 °C at the surface and 17.6 °C at the bottom. Surface temperatures ranged from 17.5 °C to 23.4 °C, while bottom temperatures ranged from 15.0 °C to 22.6 °C.

Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO averaged 8.0 mg/L and ranged from 4.9 to 10.6 mg/L. Bottom water DO concentration averaged 5.1mg/L and ranged from 3.3 mg/L to 8.9 mg/L. Chlorophyll ranged from low to moderate levels throughout the week, averaging 8.1 ug/L at the surface and 10.1 ug/L at the bottom. Maximum surface chlorophyll readings reached 24.9 ug/L on the evening of June 13^th. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.

Bullock Reach

The Bullock Reach Buoy sondes were deployed for the season on June 10^th, 2025. Overall, water quality ranged from fair to good at Bullock Reach this week. Salinity averaged 22.7 ppt, 26.8 ppt, and 30.5 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged from 15.4 to 26.4 ppt, mid salinity ranged from 21.7 to 29.8 ppt, and bottom salinity ranged from 29.0 to 31.5 ppt. Surface temperature averaged 19.0 °C and ranged from 17.0 °C to 20.9 °C. Mid temperatures averaged 17.7 °C and ranged from 15.5 °C to 20.3 °C. Bottom temperatures averaged 14.9 °C and ranged from 13.8 °C to 16.7 °C.

DO at Bullock Reach remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO averaged 10.5 mg/L and ranged from 6.1 to 14.2 mg/L. In the mid waters, DO averaged 7.6 mg/L and ranged from 4.6 to 12.0 mg/L. At the bottom, DO averaged 4.9 mg/L and ranged 4.3 to 6.1mg/L. Chlorophyll readings ranged from low to elevated, with evidence of substantial phytoplankton blooms occurring throughout the week. Readings averaged 32.9 µg/L at the surface, 31.3 µg/L at mid-depth, and 6.0 µg/L at the bottom. The maximum surface chlorophyll was 78.7 µg/L on the evening of June 14^th.