Week of November 19 – 25, 2023
Bacteria Sampling
On November 21, 2023, 15 stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers; 3 of these stations were also sampled for enterococci bacteria. There was a smaller set of locations sampled than normal due to cold weather conditions and time constraints. In the five days prior to sampling, precipitation totaled 0.15 inches as recorded at TF Green.
Overall, bacteria levels were lower in both the Seekonk and Providence Rivers this week than during the previous sampling event on October 25th. Fecal coliform levels similar in the Seekonk River and Providence River sites (geometric means of 22 MPN/100 mL and 23 MPN/100 mL, respectively). The maximum concentration (230 MPN/100 mL) was measured at Point St Bridge.
Enterococci results had an overall geometric mean of 19 MPN/100 mL and ranged from <10 MPN/100 mL at Phillipsdale Landing and South FP East to 134 MPN/100 mL at Point St. 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
<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 22 - 28, 2023
Bacteria Sampling
On October 25th, 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
Month of October, 2023
Fixed Site Network
Phillipsdale Landing
The Phillipsdale Landing sondes have been deployed for the season since May 9th, 2023 utilizing a new setup allowing staff access to the equipment from the boat instead of standing on the dock. During the month of October, sondes were changed out for routine maintenance on October 10th and 24th.
Surface DO remained above the hypoxia threshold all month. The bottom waters were hypoxic periodically throughout the month, with the longest sustained hypoxic periods (8 hours) occurring in the early morning of October 14th. DO averaged 8.4 mg/L at the surface with a minimum of 4.9 mg/L, while bottom waters averaged 5.5 mg/L with a minimum of 2.3 mg/L.
Chlorophyll readings were relatively low all month with a couple of moderately elevated readings in the bottom waters. The surface and bottom readings averaged 1.1 µg/L and 1.5 µg/L, respectively.
Bullock ReachThe Bullock Reach buoy was deployed June 1st for the 2023 season. During the month of October, sondes were changed out for routine maintenance on October 3rd, 17th, and 31st.
DO remained above the hypoxia threshold all month at the surface, middle, and bottom and averaged 7.7 mg/L, 6.7 mg/L, and 5.8 mg/L, respectively.
Chlorophyll readings ranged from low to elevated, with evidence of moderate phytoplankton blooms occurring throughout the month and some highly elevated (>200 ug/L) chlorophyll levels at the middle sonde throughout the day on October 16th. Readings averaged 6.5 µg/L at the surface, 18.3 µg/L at mid-depth, and 3.1 µg/L at the bottom.
Please note that data from the Bullock Reach Surface sonde were not available between 11:15am on October 21st and 9:15 am on October 24th due to an equipment issue.
Week of October 29 - November 4, 2023
R/V Monitor's Blog
The R/V Monitor has been retired since the last blog update for the week of February 19-25, 2023. However, the Narragansett Bay Commission is excited to announce its new monitoring vessel, Data Stream. The Data Stream is a brand new 2023 Parker 23290 SL: Sport cabin boat. The Data Stream is equipped with state-of-the-art electronics, including the latest Garmin GPS with Radar overlay capability, a remote-control spotlight, and salt and freshwater wash down. Data Stream’s Yamaha engine is a 300hp electronic shift engine which is an upgrade from the 250 HP Mercury on the Monitor.
The Data Stream picked up where the Monitor left off monitoring water quality in the upper Narragansett Bay. Throughout the Spring and Summer, the crew of the Data Stream was out on the upper Bay collecting bacteria, nutrients and plankton samples, taking Secchi Disk water clarity measurements, conducting water column profiles using the Seabird instrument, and conducting real-time surface mapping of water quality parameters, including dissolved oxygen, chlorophyll, water temperature, salinity, and pH. In addition, the fixed site monitoring stations were deployed and continuously maintained. The featured photo shows the new monitoring vessel, Data Stream.
Week of October 22 - October 28, 2023
Surface Mapping
Surface chlorophyll data were collected on October 25, 2023 while the R/V Monitor was underway collecting nutrient samples in the Providence and Seekonk River estuaries. The average chlorophyll concentrations were categorized Good in the areas surveyed. Overall, chlorophyll ranged from 0.91 µg/L to 4.06 µg/L with an average of 1.73 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation. 
