Historical News
Week of April 4 - 10, 2021
Water Column Profiles
Water column profiles were measured at six locations in the Providence and Seekonk rivers on April 7, 2021. The five days prior to the survey were dry, with no recorded rainfall measured at TF Green. The water column at most sites was well-mixed, though some stratification was observed at Pawtuxet Cove and Edgewood Yacht Club.
Surface salinities among the sites ranged from 6.6 psu at Pawtuxet Cove to 27.3 psu at Bullock Reach Buoy. Bottom salinities ranged from 27.6 psu at Pawtuxet Cove to 30.8 psu at Conimicut Point. Surface water temperatures ranged from 8.1°C at India Point Park to 11.4°C at Pawtuxet Cove. Bottom water temperatures ranged from 6.3°C at Conimicut Point to 8.8°C at Pawtuxet Cove.
Dissolved oxygen (DO) ranged from a minimum of 10.1 mg/L in the bottom waters at Conimicut Point to 12.8 mg/L in the bottom waters at Pawtuxet Cove. Hypoxic conditions (e.g., DO concentrations <2.9 mg/L) were not observed at any of the sites. Generally, fluorescence readings were low among all sites with no strong evidence of phytoplankton blooms. Please note that due to a quality control issue, numerical fluorescence data are not posted at this time.
Week of April 25 - May 1, 2021
Fixed Site Network
Phillipsdale Landing
Water quality at Phillipsdale was good this week. A total of 0.79 inches of rainfall was recorded at TF Green, the majority (0.57 inches) occurring on April 25. Blackstone River flows remained relatively low, and salinity exhibited an increase compared to the prior week. Salinity at the surface averaged 12.7 ppt and ranged from 3.9 ppt to 23.1 ppt. Bottom salinity averaged 21.1 ppt and ranged from 8.8 ppt to 27.5 ppt. Surface temperatures averaged 12.3°C and ranged from 9.9°C to 14.5°C, exhibiting warmer conditions than the week prior. Bottom water temperature averaged 11.0°C and ranged from 9.5°C to 14.3°C.
Dissolved oxygen (DO) remained well above the hypoxia threshold (2.9 mg/L) this week. Surface DO averaged 9.6 mg/L, with a minimum of 8.0 mg/L, and bottom DO averaged 8.3 mg/L, with a minimum of 6.6 mg/L. Chlorophyll concentrations generally remain low, averaging 7.1 ug/L at the surface and 23.1 ug/L at the bottom. Maximum surface chlorophyll concentrations reached 195.5 ug/L, measured on April 29, and chlorophyll readings generally suggested increased phytoplankton activity toward the end of the week. Please note that tidal fluctuations and Blackstone River flow greatly influence water column salinity, temperature, and dissolved oxygen at this location; chlorophyll readings could also be impacted by suspended matter/particulates and macroalgae.
Bullock Reach
Bullock Reach sondes will be deployed the first week of June.
Week of April 18 - 24, 2021
Fixed Site Network
Phillipsdale Landing
Water quality at Phillipsdale was good this week. Very little rainfall was recorded, just 0.07 inches on April 21, measured at TF Green; Blackstone River flows declined over the course of the week. Salinity was lower than last week, likely continued impacts of those heavier rains and river flows during last week. Salinity at the Phillipsdale surface averaged 3.7 ppt and ranged from 1.0 ppt to 15.3 ppt. Bottom salinity averaged 15.3 ppt and ranged from 1.0 ppt to 28.8 ppt. Water temperatures remained similar to the week prior. Surface temperatures averaged 11.6°C and ranged from 8.6°C to 14.3°C. Bottom water temperature averaged 10.3°C and ranged from 8.1°C to 13.9°C.
Dissolved oxygen (DO) remained well above the hypoxia threshold (2.9 mg/L) this week. Surface DO averaged 10.5 mg/L, with a minimum of 9.4 mg/L, and bottom DO averaged 8.7 mg/L, with a minimum of 6.8 mg/L. Chlorophyll concentrations generally remain low, averaging 2.9 ug/L at the surface and 18.3 ug/L at the bottom. Maximum surface chlorophyll concentrations reached 15.2 ug/L, measured on April 21; elevated bottom chlorophyll readings are not believed to be due to phytoplankton activity, based on a lack of concurrent response in DO or pH. Please note that tidal fluctuations and Blackstone River flow greatly influence water column salinity, temperature, and dissolved oxygen at this location; chlorophyll readings could also be impacted by suspended matter/particulates and macroalgae.
Bullock Reach
Bullock Reach sondes will be deployed the first week of June.
Week of April 11 - 17, 2021
Fixed Site Network
Phillipsdale Landing
Sondes were changed out for routine maintenance this week mid-morning on April 13. Water quality at Phillipsdale was good this week. Rainfall totaled 1.72 inches as measured at TF Green, with the majority (1.66 inches) falling on April 15-16; Blackstone River flows increased during and following the rain. Salinity at the Phillipsdale surface averaged 13.2 ppt and ranged from 3.7 ppt to 25.8 ppt. Bottom salinity averaged 23.0 ppt and ranged from 6.0 ppt to 29.4 ppt. Water temperatures warmed slightly this week compared to the week prior. Surface temperatures averaged 11.3°C and ranged from 8.9°C to 14.6°C. Bottom water temperature averaged 10.0°C and ranged from 8.1°C to 13.7°C.
Dissolved oxygen (DO) remained well above the hypoxia threshold (2.9 mg/L) this week. Surface DO averaged 10.3 mg/L, with a minimum of 9.2 mg/L, and bottom DO averaged 9.2 mg/L, with a minimum of 7.5 mg/L. Chlorophyll concentrations generally remain low, averaging 4.8 ug/L at the surface and 22.2 ug/L at the bottom. Maximum surface chlorophyll concentrations reached 49.5 ug/L, measured on April 13; spikes in surface chlorophyll coincided with low tides. Please note that tidal fluctuations and Blackstone River flow greatly influence water column salinity, temperature, and dissolved oxygen at this location; chlorophyll readings could also be impacted by suspended matter/particulates and macroalgae.
Bullock Reach
Bullock Reach sondes will be deployed the first week of June.
Week of April 4 - 10, 2021
Fixed Site Network
Phillipsdale Landing
Water quality at Phillipsdale was good this week. Rainfall was low, just 0.1 inches recorded at TF Green on the last day of the week, and Blackstone River flows were below average for this time of year. Salinity at the Phillipsdale surface averaged 9.9 ppt and ranged from 4.2 ppt to 20.4 ppt. Bottom salinity averaged 23.3 ppt and ranged from 8.4 ppt to 30.4 ppt. Surface temperatures warmed slightly compared to last week, averaging 11.2°C and ranging from 7.6°C to 16.2°C. Bottom water temperature was similar to the prior week, averaging 9.1°C and ranging from 7.2°C to 13.2°C.
Dissolved oxygen (DO) was high at both depths, typical for this time of year, and well above the hypoxia threshold (2.9 mg/L). Surface DO averaged 11.3 mg/L, with a minimum of 9.9 mg/L, and bottom DO averaged 9.9 mg/L, with a minimum of 7.6 mg/L. Chlorophyll concentrations generally remain low, averaging 5.9 ug/L at the surface and 32.5 ug/L at the bottom. Maximum surface chlorophyll concentrations reached 145.2 ug/L, measured on April 4; spikes in surface chlorophyll coincided with low tides. Although bottom chlorophyll was elevated, the data trends did not track as expected with tide, therefore the readings are somewhat suspect. Please note that tidal fluctuations and Blackstone River flow greatly influence water column salinity, temperature, and dissolved oxygen at this location; chlorophyll readings could also be impacted by suspended matter/particulates and macroalgae.
Bullock Reach
Bullock Reach sondes are expected to be deployed in May 2021.
