Historical News

Week of December 12 – 18, 2021

Water Column Clarity

​Water clarity was measured at seven locations in the Providence River estuary on December 15, 2021. Less than 0.1 inches of precipitation occurred in the three days prior to sampling. Overall, secchi depth increased by 0.8 meters compared to the previous week. Secchi depth averaged 3.1 meters. The lowest clarity (2.4 meters) was measured at Edgewood Shoal, while the greatest clarity (3.6 meters) was measured at Bullock Reach Buoy. Generally, water clarity increased along a gradient from north to south.

Week of December 12 - 18, 2021

Fixed Site Network

Phillipsdale Landing

Sondes were swapped for routine maintenance on the morning of December​ 14. Water quality at Phillipsdale Landing was good this week. Minor rainfall was recorded over the course of the week, with daily rain totals less than 0.1 inches on December 12, 15, and 16, and 0.14 inches on December 18, as recorded at TF Green. Blackstone River flows generally increased this week, though remain low compared to historical median levels. Salinity at the surface decreased, averaging 5.2 ppt and ranging 2.0–14.0 ppt. Bottom salinity also declined, averaging 19.2 ppt and ranging 2.6–31.4 ppt.  Water temperatures cooled slightly, averaging 6.7°C at the surface and 8.0°C at the bottom. Surface temperatures ranged from 4.5°C to 8.5°C while bottom temperatures ranged from 5.6°C to 9.0°C.

Dissolved oxygen (DO) continues to remain well above the hypoxia threshold of 2.9 mg/L; it is unusual to see hypoxic conditions at this time of year. Surface DO averaged 11.4 mg/L with a minimum of 9.6 mg/L. Bottom DO averaged 9.1 mg/L with a minimum of 7.4 mg/L. Chlorophyll concentrations remained low this week, averaging 1.4 ug/L on the surface and 1.2 ug/L on the bottom, with a surface maximum of 2.1 ug/L. Please note that tidal fluctuations and Blackstone River flow greatly influence water column salinity, temperature, and DO at this location.

Bullock Reach

The Bullock Reach sondes were removed for the 2021 monitoring season on November 18.

Week of December 5 - 11, 2021

Fixed Site Network

Phillipsdale Landing

Water quality at Phillipsdale Landing was good this week. After a dry week prior, this week included 0.37 inches of rainfall on December 6, 0.2 inches of snow over December 8-9, and 0.17 inches of rain on December 11, as recorded at TF Green. Despite the precipitation, Blackstone River flows remained relatively low and steady all week. Salinity at the surface increased slightly from the previous week, averaging 13.0 ppt and ranging 2.1–26.7 ppt. Bottom salinity declined slightly, averaging 22.0 ppt and ranging 2.2–32.5 ppt.  Water temperatures warmed slightly at the surface, averaging 7.1°C, and cooled slightly at the bottom, averaging 8.4°C. Surface temperatures ranged from 4.9°C to 9.2°C while bottom temperatures ranged from 6.9°C to 9.6°C.

Dissolved oxygen (DO) continues to remain well above the hypoxia threshold of 2.9 mg/L; it is unusual to see hypoxic conditions at this time of year. Surface DO averaged 10.2 mg/L with a minimum of 8.2 mg/L. Bottom DO averaged 8.1 mg/L with a minimum of 7.2 mg/L. Chlorophyll concentrations remained low this week, averaging 1.7 ug/L on the surface and 1.5 ug/L on the bottom, with a surface maximum of 4.5 ug/L. Please note that tidal fluctuations and Blackstone River flow greatly influence water column salinity, temperature, and DO at this location.

Bullock Reach

The Bullock Reach sondes were removed for the 2021 monitoring season on November 18.

Week of December 5 – 11, 2021

Water Column Clarity

​Water clarity was measured at six locations in the Providence and Seekonk River estuaries on December 8, 2021. Two days prior to sampling, 0.37 inches of precipitation was recorded at T.F. Green. Overall, secchi depth averaged 2.3 meters. The lowest clarity (1.2 meters) was measured at Point St. Bridge, while the greatest clarity (2.8 meters) was measured at Conimicut Point. Generally, water clarity increased along a gradient from north to south.

Week of November 28 - December 4, 2021

Fixed Site Network

Phillipsdale Landing

Sondes were swapped for routine maintenance on the morning of November 30. Water quality at Phillipsdale Landing was good this week. The weather was dry, with no rainfall recorded at TF Green, and Blackstone River flows declined all week. Blackstone River flows had been elevated above 16-year historical median flow rates since July, but this week finally dipped below these historical rates. Salinities throughout the water column increased over the course of the week, averaging 9.2 ppt at the surface and 23.8 ppt at the bottom. Surface salinity ranged 2.1-27.7 ppt and was generally more variable later in the week. Bottom salinity ranged 6.2-34.9 ppt, fluctuating with the tides. Water temperatures cooled slightly, averaging 6.6°C on the surface and 9.7°C on the bottom. Surface temperatures ranged from 3.6°C to 9.7°C while bottom temperatures ranged from 5.6°C to 12.7°C.

Dissolved oxygen (DO) continued to remain well above the hypoxia threshold of 2.9 mg/L; it is unusual to see hypoxic conditions at this time of year. Surface DO averaged 10.7 mg/L with a minimum of 7.9 mg/L. Bottom DO averaged 7.6 mg/L with a minimum of 6.0 mg/L. Chlorophyll concentrations remain low, averaging 1.4 ug/L on the surface and 1.4 ug/L on the bottom, with a surface maximum of 3.3 ug/L. Please note that tidal fluctuations and Blackstone River flow greatly influence water column salinity, temperature, and DO at this location.

Bullock Reach

The Bullock Reach sondes were removed for the 2021 monitoring season on November 18.

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