Historical News
Week of August 2 – August 8, 2020
Surface Mapping
Data were collected on August 5, 2020 while the R/V Monitor was underway collecting bacteria samples in the Providence and Seekonk River estuaries. The chlorophyll concentrations were variable ranging from good to poor. From north to south, average chlorophyll concentrations were as follows: Seekonk River (18.90 µg/L), Upper Providence River (13.25 µg/L), Edgewood Shoals area (13.83 µg/L), Pawtuxet River area (11.65 µg/L ), and Lower Providence River area (7.76 µg/L ). Overall, chlorophyll ranged between non-detectable and 36.80 µg/L with an overall average of 13.31 µg/L. The chlorophyll data from this date are presented in the map below:
Week of July 26 - August 1, 2020
Fixed Site Network
Phillipsdale Landing
Water quality was poor to fair this week at Phillipsdale Landing; the surface sonde was periodically hung-up on old pilings on July 27 (~5 hours) and July 29 (~3 hours), and data from these periods have been excluded from the summary below. Despite 0.45 inches of rainfall on July 28, conditions at Phillipsdale Landing remained steady all week; salinity actually exhibited a slight increasing trend over the course of the week. Surface salinity averaged 20.7 ppt (range 14.6 – 25.9 ppt), while bottom salinity averaged 24.8 ppt (range 16.2 – 27.6 ppt). Water temperatures warmed since last week; surface temperatures ranged from 24.5°C to 30.2°C and averaged 27.0°C, while bottom temperatures ranged from 24.7°C to 27.7°C and averaged 26.1°C. Dissolved oxygen (DO) concentrations were hypoxic (<2.9 mg/L) in both surface and bottom waters for a portion of the week. Surface water DO averaged 7.3 mg/L with a minimum of 2.0 mg/L; surface hypoxia occurred primarily during early-morning low tides, for up to one hour at a time. Bottom DO improved slightly compared to last week, averaging 3.2 mg/L with a minimum of 0.8 mg/L; bottom waters were hypoxic for 48% of the week. Surface chlorophyll increased this week compared to last, averaging 52.2 ug/L with evidence of phytoplankton bloom activity peaking on July 26. Note that tidal fluctuations and Blackstone River flow greatly influence water column salinity, temperature, and DO at this location.
Bullock Reach
Sondes were changed out for maintenance on the morning of July 28. The newly deployed bottom sonde exhibited signs of excessive drift; the salinity data from this sensor have been excluded from the following summary, and the sensor is slated for replacement as soon as possible. Water quality at Bullock Reach was fair this week. Surface salinity increased slightly from the previous week, averaging 28.0 ppt and ranging 23.8 – 29.0 ppt. Salinity at the mid and bottom sondes averaged 29.1 ppt and 30.3 ppt, respectively. Water temperatures also increased slightly, averaging 26.5°C at the surface, 25.7°C at the mid depth, and 23.6°C at the bottom. Surface waters remained above the hypoxia threshold this week, with a DO minimum of 5.0 mg/L. Hypoxia was observed in mid waters, averaging 5.6 mg/L but reaching a minimum of 2.3 mg/L; mid-water hypoxia was limited to two half-hour periods mid-day on July 30. Bottom water DO averaged 3.4 mg/L with a minimum of 2.1 mg/L; bottom hypoxia occurred periodically, for up to approximately two hours at a time. Please note, calculation of DO in mg/L utilizes information from the salinity probe; as a result of the drift in the salinity probe, bottom DO readings may have been impacted during this reporting period. Chlorophyll was similar this week to last, averaging 11.8 ug/L at the surface and reaching a maximum of 66.1 ug/L; evidence of highest phytoplankton activity occurred on July 30. Mid-depth chlorophyll averaged 10.9 ug/L, while bottom chlorophyll averaged 7.5 ug/L.
Week of July 19 - 25, 2020
Fixed Site Network
Phillipsdale Landing
Sondes were swapped out for maintenance on the morning of July 21. The surface sonde was periodically hung-up on old pilings from July 22 through 25, coming out of water for several hours at a time; data from these periods have been excluded from the summary below.
Water quality was poor to fair this week at Phillipsdale Landing. The weather was mostly dry and salinities increased as the week progressed. Surface salinity averaged 15.9 ppt (range 1.4 – 24.6 ppt), while bottom salinity averaged 22.8 ppt (range 15.6 – 27.0 ppt). Water temperatures warmed since last week; surface temperatures ranged from 24.3°C to 29.3°C and averaged 26.3°C, while bottom temperatures ranged from 23.7°C to 26.9°C and averaged 25.5°C. Dissolved oxygen (DO) concentrations were hypoxic (<2.9 mg/L) in both surface and bottom waters for a substantial portion of the week. Surface waters averaged 6.7 mg/L with a minimum of 0.7 mg/L; surface hypoxia occurred primarily during early-morning low tides. Bottom DO averaged 2.8 mg/L with a minimum of 0.1 mg/L; bottom waters were hypoxic for 60% of the week. Surface chlorophyll was similar this week compared to last, averaging 38.9 ug/L with evidence of phytoplankton bloom activity throughout the week. Note that tidal fluctuations and Blackstone River flow greatly influence water column salinity, temperature, and DO at this location.
Bullock Reach
Water quality at Bullock Reach was fair this week. Surface salinity averaged 27.0 ppt, ranging 24.0 - 28.6 ppt. Salinity values at the mid and bottom sondes averaged 28.3 ppt and 29.8 ppt, respectively. Water temperatures continue to warm, averaging 26.1°C at the surface, 25.2°C at the mid depth, and 23.2°C at the bottom. Surface and mid waters remained above the hypoxia threshold this week, with DO minima of 5.2 mg/L and 3.3 mg/L, respectively; hypoxia was observed in bottom waters, averaging 3.8 mg/L with a minimum of 2.7 mg/L. Bottom hypoxia occurred primarily on July 23, for short durations up to 45 minutes at a time. Chlorophyll was similar this week to last, averaging 14.4 ug/L at the surface and reaching a maximum of 27.7 ug/L; mid-depth chlorophyll averaged 10.0 ug/L and bottom chlorophyll averaged 6.9 ug/L.
Week of July 12 - 18, 2020
Fixed Site Network
Phillipsdale Landing
Water quality was poor this week at Phillipsdale Landing. There was rainfall recorded at TF Green on two days this week (0.82 inches July 14; 0.14 inches July 17); salinity at Phillipsdale declined toward the end of the week in response to this rainfall. Surface salinity averaged 12.2 ppt (range 1.2 – 19.6 ppt), while bottom salinity averaged 23.1 ppt (range 14.2 – 28.7 ppt). Water temperatures warmed since last week; surface temperatures ranged from 21.7°C to 28.9°C and averaged 25.4°C, while bottom temperatures ranged from 21.9°C to 26.2°C and averaged 24.1°C. Dissolved oxygen (DO) concentrations were hypoxic (<2.9 mg/L) in both surface and bottom waters for a substantial portion of the week. Surface waters averaged 6.8 mg/L with a minimum of 0.2 mg/L; surface hypoxia occurred primarily during early-morning low tides, for durations up to three hours. Bottom DO was extremely hypoxic or anoxic, averaging 0.7 mg/L with a minimum of 0.1 mg/L; bottom waters were hypoxic for 97% of the week. Surface chlorophyll was slightly lower this week than last, averaging 30.4 ug/L; evidence of phytoplankton bloom activity was strongest on July 12, with smaller peaks into the midweek. Note that tidal fluctuations and Blackstone River flow greatly influence water column salinity, temperature, and DO at this location.
Bullock Reach
Sondes were swapped out for maintenance on the morning of July 14. The bottom sonde retrieved that day had exhibited excessive drift in specific conductivity and salinity data beginning the previous week; bottom salinity data from this sonde have been excluded from the following summary.
Water quality at Bullock Reach was fair this week. Rainfall on July 14 resulted in increased Pawtuxet River flows near this site, and surface salinities reflected an influx of freshwater. Surface salinity averaged 25.7 ppt, ranging 21.9 - 28.1 ppt. Salinity values at the mid and bottom sondes averaged 28.3 ppt and 30.4 ppt, respectively. Water temperatures continue to warm, averaging 25.1°C at the surface, 24.3°C at the mid depth, and 22.5°C at the bottom. Surface waters remained above the hypoxia threshold this week, with a DO minimum of 7.1 mg/L; hypoxia was observed in both mid and bottom depths, with DO minima of 2.0 mg/L and 2.1 mg/L, respectively. Hypoxia at the mid-depth occurred primarily from July 15 to 16, for up to nine hours at a time; hypoxia at the bottom occurred primarily on June 16 and 17, for up to five hours at a time. Please note, calculation of DO in mg/L utilizes information from the salinity probe; as a result of the drift in the salinity probe, bottom DO readings may be overestimated during this reporting period. Chlorophyll declined slightly this week, averaging 12.7 ug/L at the surface and reaching a maximum of 28.9 ug/L; mid-depth chlorophyll averaged 22.0 ug/L and bottom chlorophyll averaged 5.3 ug/L.
Week of July 5 - 11, 2020
Fixed Site Network
Phillipsdale Landing
Phillipsdale sondes were changed out for maintenance on the morning of July 7. The newly deployed bottom sonde depth readings were erroneous for the first several hours of deployment; the sensor functionality was restored later that day.
Water quality was poor to fair this week at Phillipsdale Landing. There was very little rain over the course of the week, less than 0.1 inch, and salinity generally increased compared to the previous week. Surface salinity averaged 14.4 ppt (range 2.5 - 22.3 ppt), while bottom salinity averaged 21.4 ppt (range 11.7 – 26.2 ppt). Water temperatures warmed since last week; surface temperatures ranged from 22.1°C to 27.9°C and averaged 24.7°C, while bottom temperatures ranged from 21.4°C to 26.0°C and averaged 23.6°C. Dissolved oxygen (DO) concentrations dipped below the hypoxia threshold (2.9 mg/L) in both surface and bottom waters this week. Surface waters averaged 7.3 mg/L with a minimum of 1.3 mg/L; surface hypoxia occurred during early-morning low tides, for up to two hours at a time. Bottom DO averaged 2.6 mg/L with a minimum of 0.1 mg/L; bottom waters were hypoxic for 67% of the week. Lastly, surface chlorophyll averaged 47.4 ug/L this week, evidence of phytoplankton bloom activity peaking on the 7th, 8th, and 11th. Note that tidal fluctuations and Blackstone River flow greatly influence water column salinity, temperature, and DO at this location.
Bullock Reach
Note that the bottom sonde began to exhibit excessive drift in specific conductivity and salinity data beginning in the evening of July 9; bottom salinity data from this time through the rest of the week have been excluded from the following summary.
Water quality at Bullock Reach was fair this week. Water temperatures continue to warm, averaging 24.2°C at the surface, 23.4°C at the mid depth, and 21.8°C at the bottom. Surface salinity averaged 26.8 ppt, ranging 24.4 - 28.7 ppt, slightly higher than the previous week. Salinity values at the mid and bottom sondes averaged 28.3 ppt and 31.8 ppt, respectively. Surface and mid-depth waters remained above the hypoxia threshold this week, with DO minima of 5.0 mg/L and 3.2 mg/L, respectively. Bottom water DO averaged 4.1 mg/L, with a minimum reading of 2.8 mg/L; hypoxia lasted for approximately two hours on July 6th. Please note, calculation of DO in mg/L utilizes information from the salinity probe; as a result of the drift in the salinity probe, bottom DO readings may be overestimated during this reporting period. Chlorophyll was slightly elevated this week, averaging 15.8 ug/L at the surface and reaching a maximum of 38.6 ug/L; mid-depth chlorophyll averaged 17.5 ug/L and bottom chlorophyll averaged 5.6 ug/L.
