Historical News

Week of November 6 – November 12, 2022

Surface Mapping

​Data were collected on November 9, 2022, while the R/V Monitor was underway collecting bacteria samples and swapping sondes in the Providence River estuary. The average chlorophyll concentrations were good in the areas surveyed. From north to south, average chlorophyll concentrations were as follows: Upper Providence River (0.58 µg/L), Edgewood Shoals area (0.80 µg/L), Pawtuxet River area (0.84 µg/L), and Lower Providence River (1.12 µg/L). Overall, chlorophyll ranged between 0.21 and 2.74 µg/L with an overall average of 0.95 µg/L. The chlorophyll data from this date are presented in the map below:​

Dataflow 2022-11-09_small.jpg

Week of October 30 - November 5, 2022

Water Column Clarity

Water clarity was measured at six locations in the Providence River estuary on November 2, 2022. Rainfall totaling 0.05 inches was recorded at TF Green in the five days prior to the survey. Secchi depth averaged 2.5 meters, compared to 3.0 meters on the previous survey (October 27). The lowest clarity this week (1.5 meters) was measured at Pawtuxet Cove, while the greatest clarity (3.9 meters) was measured at Bullock Reach. There was no clear north-to-south gradient in water clarity among the sites this week. ​

Week of October 23 - 29, 2022

Water Column Clarity

​Water clarity was measured at seven locations in the Providence River and Seekonk River estuaries on October 27, 2022.  Rainfall totaling 1.99 inches was recorded at TF Green in the five days prior to the survey. Secchi depth averaged 3.0 meters, unchanged from the previous survey on October 19. The lowest clarity this week (1.6 meters) was measured at Phillipsdale Landing, while the greatest clarity (3.6 meters) was measured at four sites (India Point Park, Bullock Reach, Conimicut Point, and Point St. Bridge). There was a general north-to-south gradient of increasing water clarity among the sites this week. ​

Week of October 30 – November 5, 2022

Surface Mapping

​Data were collected on November 2, 2022, while the R/V Monitor was underway collecting nutrient samples in the Providence River estuary. The average chlorophyll concentrations were good in the areas surveyed. From north to south, average chlorophyll concentrations were as follows: Upper Providence River (0.88 µg/L), Edgewood Shoals area (1.60 µg/L), Pawtuxet River area (0.77 µg/L), and Lower Providence River (1.28 µg/L). Overall, chlorophyll ranged between 0.41 and 4.30 µg/L with an overall average of 1.08 µg/L. The chlorophyll data from this date are presented in the map below:​

Dataflow 2022-11-02_small.jpg


Week of October 16 - 22

Fixed Site Network

​Phillipsdale Landing

Sondes were swapped for routine maintenance on the morning of October 18th. Overall, water quality at Phillipsdale Landing was fair to good this week. Weather conditions were mostly dry, with 0.35 inches of rainfall recorded at T.F. Green. The Blackstone River flow increased mid-week in response to rain, leading to minor drops in salinity at Phillipsdale mid-week. Salinity at the surface averaged 4.2 ppt and ranged from 1.5 ppt to 13.1 ppt. At the bottom, salinity averaged 20.3 ppt and ranged from 2.5 ppt to 28.2 ppt. Temperatures this week averaged 15.1°C at the surface and 16.4°C at the bottom. Surface temperatures ranged from 11.6°C to 18.4°C, while bottom temperatures ranged from 13.0°C to 17.4°C.

Dissolved oxygen (DO) at Phillipsdale Landing has remained high at the surface, staying above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO was higher than the previous week, averaging 8.5 mg/L and ranging 6.2 mg/L to 9.8 mg/L. Bottom DO concentrations dropped below the hypoxia level (i.e., DO <2.9 mg/L) briefly this week. The longest periods of hypoxic conditions in the bottom waters (~ 2 hours) occurred on the mornings of October 18th and October 19th.  Bottom water DO concentration averaged 4.6 mg/L and ranged from 2.5 mg/L to 9.0 mg/L. Chlorophyll concentrations decreased from the previous week, averaging 2.4 ug/L at the surface and 3.1 ug/L at the bottom. Maximum surface chlorophyll readings reached 25.6 ug/L, recorded close to noon on October 16th. 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 was good at Bullock Reach this week. Salinity averaged 25.8 ppt, 29.2 ppt, and 30.8 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged from 21.9 to 28.9 ppt, mid salinity ranged from 26.6 to 30.7 ppt, and bottom salinity ranged from 29.4 to 31.6 ppt. Temperatures have remained relatively stable compared to the previous week. Surface temperature averaged 16.6°C and ranged from 14.0°C to 18.1°C. Mid temperatures averaged 16.7°C and ranged from 15.4°C to 17.4°C. Bottom temperatures averaged 16.9°C and ranged from 16.5°C to 17.1°C.

DO concentrations at Bullock Reach remained above the hypoxia threshold all week. Surface DO averaged 8.1 mg/L and ranged from 7.0 to 9.6 mg/L. In the mid waters, DO averaged 7.3 mg/L and ranged from 6.3 to 8.5 mg/L. At the bottom, DO averaged 6.1 mg/L and ranged from 5.0 to 7.2 mg/L. The bottom DO declined over the course of the week while there was an increase seen in the mid and surface DO. Chlorophyll concentrations were low all week. Overall, chlorophyll averaged 6.0 ug/L, 5.2 ug/L, and 3.0 ug/L at the surface, mid, and bottom waters, respectively. The maximum surface chlorophyll reading was 17.1 ug/L on October 21st. 

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