Fixed Site Network
Overall, water quality at Phillipsdale Landing was fair this week. A total of 1.81 inches of rainfall was recorded at T.F. Green on June 08 and 09, which led to increased flows from the Blackstone River in the middle of the week. Following the influx of freshwater in the middle of the week, salinity decreased at Phillipsdale Landing as the week progressed. Surface salinity averaged 11.9 ppt and ranged from 4.0 ppt to 21.0 ppt, while bottom salinity averaged 22.5 ppt and ranged from 8.3 ppt to 28.2 ppt. Temperatures continue to warm, averaging 21.7°C at the surface and 19.8°C on the bottom. Surface temperatures ranged from 19.0°C to 24.7°C, while bottom temperatures ranged from 17.6°C to 22.4°C.
Dissolved oxygen (DO) concentrations decreased through the week but remained mostly above the hypoxia threshold (2.9 mg/L). Surface DO averaged 8.2 mg/L with a minimum of 3.3 mg/L, while bottom DO averaged 4.2 mg/L, with a minimum of 1.6 mg/L. Chlorophyll readings decreased from the previous week, averaging 15.8 µg/L on the surface and 12.7 µg/L on the bottom. Maximum surface chlorophyll readings reached 80.5 µg/L. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.
Sondes were swapped for routine maintenance at mid-day on June 08. Please note that there is an extra hour's worth of data included in the summary below caused by updating the timestamps of the sondes to local eastern standard time. Also note that portions of chlorophyll data from the mid-depth sonde from June 08 – 11 are not included in the summary below due to an issue with the chlorophyll sensor. Overall, water quality at Bullock Reach was good this week. Surface salinity ranged from 24.3 ppt to 28.8 ppt and averaged 26.9 ppt. Salinity at mid-depth ranged from 26.4 ppt to 30.2 ppt and averaged 28.8 ppt. Bottom salinity ranged from 29.1 ppt to 32.3 ppt and averaged 30.8 ppt. Water column temperatures averaged 20.5°C, 19.6°C, and 18.0°C at the surface, mid, and bottom, respectively. Surface temperatures ranged from 18.4°C to 22.5°C, mid temperatures ranged from 17.9°C to 21.2°C, and bottom temperatures ranged from 15.9°C to 19.8°C.
This week, DO averaged 8.2 mg/L at the surface, 6.8 mg/L at mid-depth, and 5.3 mg/L at the bottom. Waters at all depths remained above the hypoxia threshold, with minimum bottom DO measuring 4.1 mg/L. Chlorophyll concentrations were low, averaging 8.0 µg/L at the surface, 6.0 µg/L at mid-depth, and 3.0 µg/L at the bottom. The maximum chlorophyll this week was 36.2 µg/L measured in surface waters on June 11.
Summary of Rhode Island Bacteria Standards for Saltwater Primary Contact and Shellfishing
| ||Fecal Coliform||Enterococci|
Geometric mean ≤50 MPN/100 mL
Geometric mean ≤35 colonies/100 mL
Geometric mean ≤14 MPN/100 mL
|NO ENTEROCOCCI CRITERIA|
Water Column Clarity
Water clarity was measured at six locations in the Providence River estuary on June 15, 2022. Conditions leading up to the survey were wet, with 1.34 inches of precipitation recorded in the three days prior. Secchi depth averaged 1.4 meters, compared to 1.8 meters on the previous survey (June 7). The lowest clarity this week (0.9 meters) was measured at Pawtuxet Cove, while the greatest clarity (2.0 meters) was measured at Bullock Reach. There was no clear north-to-south gradient in water clarity among the sites this week.
R/V Monitor's Blog
On Wednesday, June 15th, the crew of the R/V Monitor was out on the upper Bay collecting 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, all in an effort to document water quality improvements associated with NBC construction projects. Sara captained the boat while monitoring professionals Fern, Justin and Tyler collected the samples and data. It was a warm and sunny day with a breeze from the northwest. There was a slight chop on the water this day. The featured photo is of the Providence-Newport ferry with the I-195 Iway bridge in the background.
Data were collected on June 15, 2022, while the R/V Monitor was underway collecting nutrient samples in the Providence River estuary. The average chlorophyll concentrations were good to fair in the areas surveyed. From north to south, average chlorophyll concentrations were as follows: Upper Providence River (6.63 µg/L), Edgewood Shoals area (7.67 µg/L), Pawtuxet River area (5.81 µg/L), and Lower Providence River (4.11 µg/L). Overall, chlorophyll ranged between 1.90 and 17.02 µg/L with an overall average of 5.62 µg/L. The chlorophyll data from this date are presented in the map below: