Historical News
Week of April 29 - May 5, 2024
Fixed Site Network
Phillipsdale Landing
Sondes were swapped this week on the morning of April 30th. Overall, water quality at Phillipsdale Landing was good this week. Weather conditions included sporadic rain events, with 0.38 inches of precipitation recorded at T.F. Green. The Blackstone River flow declined this week, remaining below the 19-year daily median for the week. Salinity at the surface averaged 5.9 ppt and ranged from 1.4 ppt to 19.5 ppt. At the bottom, salinity averaged 15.4 ppt and ranged from 3.0 ppt to 25.1 ppt. Temperatures this week averaged 14.4°C at the surface and 12.4°C at the bottom. Surface temperatures ranged from 11.8°C to 16.1°C, while bottom temperatures ranged from 9.7°C to 15.7°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 10.0 mg/L and ranged from 8.5-12.7 mg/L. Bottom water DO concentration averaged 8.9 mg/L and ranged from 7.6 mg/L to 11.5 mg/L. Chlorophyll remained low, averaging 3.5 ug/L at the surface and 4.2 ug/L at the bottom. Maximum surface chlorophyll readings reached 8.7 ug/L, recorded on the night of May 4th. 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 remains out of the water for the winter. EM will coordinate with RIDEM to redeploy the buoy in late spring.
May 22, 2024
Bacteria Sampling
On May 22nd, 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 0.27 inches as recorded at TF Green. Overall, bacteria counts were higher in both the Seekonk and Providence Rivers than during the previous sampling event on April 24th.
Fecal coliform counts were higher in the Seekonk River sites than in the Providence River sites (geometric means of 135 MPN/100 mL and 52 MPN/100 mL, respectively). The maximum count (430 MPN/100 mL) was measured at Collier Point Park.
Enterococci results had an overall geometric mean of 15 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at Conimicut Point to 85 MPN/100 mL at Phillipsdale Landing.
The next scheduled sampling date is June 5.
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.
May 14, 2024
Phytoplankton Sampling
Phytoplankton samples were collected on May 14, 2024 at Bullock Reach and analyzed in the laboratory shortly after collection. It was a beautiful day on Narragansett Bay with partly cloudy conditions and a slight breeze. Sonde data revealed the surface water temperature was 14.67°C, salinity was 21.36 psu, and chlorophyll a was 8.77 ug/L. Secchi disk water clarity was 3.4 m. The qualitative tow net sample had a long filtration time, and the filtrate was dark brown and cloudy.
The analysis of the quantitative whole water sample revealed a total of 8,741,000 cells per Liter. The most predominant phytoplankton genus was Skeletonema spp. at 4,912,000 cells/L. Other representative genera include Thalassiosira spp., Leptocylindrus spp., and Chaetoceros spp. This week's featured image (200x phase contrast) shows the diversity of the phytoplankton sample, containing many different genera. Phytoplankton are primary producers and contain chlorophyll to capture sunlight to produce energy.
Week of April 22 - 28, 2024
Fixed Site Network
Phillipsdale Landing
Overall, water quality at Phillipsdale Landing was good this week. Weather conditions were dry, with only 0.05 inches on April 30th, recorded at T.F. Green. The Blackstone River flow declined this week, remaining below the 19-year daily median for the majority of the week. Surface salinity averaged 4.1 ppt and ranged from 1.2 ppt to 9.1 ppt. At the bottom, salinity averaged 13.5 ppt and ranged from 2.3 ppt to 27.1 ppt. Temperatures remained stabilized this week, averaging 12.7°C at the surface and ranging 10.0°C – 14.5°C. At the bottom, temperatures averaged 11.3°C and ranged 8.0°C – 14.4°C.
Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO average 10.5 mg/L and ranged from 9.5 mg/L to 11.7 mg/L.. Bottom DO concentrations averaged 9.3 mg/L and ranged from 8.1 mg/L to 11.3 mg/L. Chlorophyll readings remained comparable from last week, averaging 2.6 ug/L at the surface and 2.9 ug/L at the bottom. Maximum chlorophyll at the surface reached 14.3 ug/L on the afternoon of April 24th. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location. Also, please note that isolated portions of suspect chlorophyll data from April 28th were excluded from the summary.
Bullock Reach
The Bullock Reach Buoy remains out of the water for the winter. EM will coordinate with RIDEM to redeploy the buoy in late spring.
Week of April 15 - 21, 2024
Fixed Site Network
Phillipsdale Landing
Sondes were swap this week on the morning of April 16th. Overall, water quality at Phillipsdale Landing was good this week. Weather conditions were mostly dry, with only 0.4 inches of precipitation recorded at T.F. Green. The Blackstone River flow declined this week, remaining above the 19-year daily median for the week. Salinity at the surface averaged 1.8 ppt and ranged from 0.4 ppt to 4.4 ppt. At the bottom, salinity averaged 9.2 ppt and ranged from 0.4 ppt to 26.3 ppt. Temperatures continued to increase this week, averaging 12.9°C at the surface and 11.6 °C at the bottom. Surface temperatures ranged from 10.7°C to 15.5°C, while bottom temperatures ranged from 8.1°C to 15.3°C.
Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO remained similar to the previous week, averaging 10.5 mg/L and ranging 9.7-11.8 mg/L. Bottom water DO concentration averaged 9.7 mg/L and ranged from 7.7 mg/L to 11.6 mg/L. Chlorophyll concentrations remained low, averaging 2.7 ug/L at the surface and 2.6 ug/L at the bottom. Maximum surface chlorophyll readings reached 11.9 ug/L, recorded in the morning of April 20th. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location. Also, please note that isolated portion of suspect chlorophyll data from April 15th was excluded from the summary.
Bullock Reach
The Bullock Reach Buoy remains out of the water for the winter. EM will coordinate with RIDEM to redeploy the buoy in late spring.
