Historical News

Week of July 5 – July 11, 2020

Surface Mapping

​Data were collected on July 8, 2020 while the R/V Monitor was underway collecting bacteria samples in the Providence and Seekonk River estuaries. The chlorophyll concentrations were variable and mostly fair to moderate with poor concentrations in the Seekonk River.  From north to south, average chlorophyll concentrations were as follows: Seekonk River (47.64 µg/L), Upper Providence River (8.18 µg/L), Edgewood Shoals area (14.23 µg/L), Pawtuxet River area (10.35 µg/L ), and Lower Providence River area (14.16 µg/L ). Overall, chlorophyll ranged between 0.90 and 498.90 µg/L with an overall average of 22.85 µg/L.  The chlorophyll data from this date are presented in the map below:

Dataflow 2020-07-08 small.jpg

Week of July 5 - 11, 2020

R/V Monitor's Blog

​On Wednesday, July 8th, the crew of the R/V Monitor was out on the upper Bay collecting bacteria samples, taking Secchi Disk water clarity measurements, 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.  Jeff captained the boat while monitoring professionals Gerard and Steve collected the samples and data.  In addition, the crew deployed NBC's temporary buoy in Pawtuxet Cove on this day. This buoy will remain at this location throughout the remainder of this monitoring season. The day began foggy but became sunny by late morning.  The wind was blowing from the southwest.  On Thursday, July 9th, the crew of R/V Monitor went to Pawtuxet Cove and deployed the sonde on the temporary buoy.  Sara captained the boat, while monitoring professionals Jeff and Steve depoyed the sonde.  It was a cloudy and windy day on the Bay this day.  The featured photo was taken of the temporary buoy installed at Pawtuxet Cove.

7-9-20 Pawtuxet Buoy.jpg 

Week of June 21 – 27, 2020

Fixed Site Network

Phillipsdale Landing

Water quality was good to fair this week at Phillipsdale Landing. This week, 1.22 inches of precipitation was recorded; over 1 inch of rainfall occurred between June 26 and 27. Sondes were changed out for routine maintenance during the early afternoon of June 23 between 12 and 12:30 PM.

Surface salinity averaged 17.1 ppt and ranged from 9.4 ppt to 22.0 ppt. Bottom salinity averaged 21.6 ppt and ranged from 14.9 ppt to 25.7 ppt. Decreases in salinity occurred in both surface and bottom waters on June 26 following the rainfall. Surface and bottom temperatures continued to increase this week, averaging 25.0°C and 24.0°C, respectively. Surface temperatures ranged from 22.8°C to 27.2°C, while bottom temperatures ranged from 21.8°C to 26.2°C.

Dissolved oxygen (DO) concentrations remained above the hypoxia threshold (2.9 mg/L) at the surface, however, intermittent hypoxia was observed in bottom waters. Surface DO averaged 9.1 mg/L, with a minimum of 4.7 mg/L, while bottom DO averaged 5.2 mg/L, with a minimum of <2.0 mg/L. The longest period of hypoxia in bottom waters was 1.25 hours on June 26. Surface chlorophyll averaged 46.9 ug/L; readings greater than 100 ug/L were observed during the latter half of the week. Note that tidal fluctuations and Blackstone River flow greatly influence water column salinity, temperature, and dissolved oxygen at this location.

Bullock Reach

Water quality was good this week at Bullock Reach. Please note, bottom salinity data are not available due to extensive drift observed on the conductivity probe of the bottom sonde. Salinity at the mid depth averaged 29.2 ppt for the week and ranged from 27.1 ppt to 30.3 ppt. Surface salinity averaged 27.1 ppt and ranged from 24.7 ppt to 28.9 ppt. Temperatures at all three depths increased this week, averaging 24.2°C, 23.4°C, and 20.7°C at the surface, middle, and bottom of the water column, respectively. Surface temperatures ranged from 22.6°C to 25.8°C, mid temperatures ranged from 19.5°C to 24.7°C, and bottom temperatures ranged from 17.4°C to 23.5°C.

Dissolved oxygen (DO) concentrations remained above the hypoxia threshold (2.9 mg/L) at all three depths. Surface DO averaged 7.6 mg/L, with a minimum of 5.7 mg/L. Mid DO averaged 6.5 mg/L, with a minimum of 4.2 mg/L, and bottom DO averaged 4.7 mg/L, with a minimum of 3.3 mg/L. 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. Surface chlorophyll averaged 11.8 ug/L, with a maximum concentration of 37.0 ug/L.

Week of June 14 – 20, 2020

Fixed Site Network

Phillipsdale Landing

Water quality was good to fair this week at Phillipsdale Landing. This was a dry week, with no precipitation recorded at TF Green Airport. Average salinity was higher in both surface and bottom waters than the previous week. Surface salinity ranged from 8.7 ppt to 23.4 ppt and averaged 16.6 ppt. Bottom salinity ranged from 12.8 ppt to 29.5 ppt and averaged 24.7 ppt. Surface and bottom temperatures continued to increase this week, averaging 21.8°C and 19.5°C, respectively. Temperatures in surface waters ranged from 17.9°C to 25.7°C, while bottom water temperatures ranged from 16.5°C to 23.9°C.

Dissolved oxygen (DO) concentrations remained above the hypoxia threshold (2.9 mg/L) at the surface depth through the duration of the deployment. Surface DO averaged 12.2 mg/L, with a minimum of 5.8 mg/L. Bottom waters experienced brief periods of hypoxia (consecutive DO readings under 2.9 mg/L for 2 hours or less) on June 16. Over the full deployment period, bottom DO averaged 6.0 mg/L, with a minimum value of 2.5 mg/L. Surface chlorophyll was higher than the previous week, averaging 35.8 ug/L; a maximum reading of greater than 100 ug/L was observed. Note that tidal fluctuations and Blackstone River flow greatly influence water column salinity, temperature, and dissolved oxygen at this location.

Bullock Reach

Water quality was good this week at Bullock Reach. There were continued issues with the bottom sonde salinity probe and the surface sonde communications and data logging, however, data were restored upon deployment of a new set of sondes during the morning of June 16 between 10:00 AM and 10:30 AM.

On the surface, salinity averaged 27.7 ppt and ranged from 25.1 ppt to 28.8 ppt. Salinity increased with depth, averaging 29.6 ppt and ranging from 25.4 ppt to 31.7 ppt at the mid depth and averaging 30.4 ppt and ranging from 27.9 ppt to 31.8 ppt at the bottom depth. Temperatures at all three depths increased over the course of the week. Water temperatures averaged 20.9°C, 19.2°C, and 16.6°C at the surface, middle, and bottom of the water column, respectively. Surface temperatures ranged from 18.4°C to 24.1°C, mid temperatures ranged from 15.9°C to 22.7°C, and bottom temperatures ranged from 14.7°C to 21.3°C.

Dissolved oxygen (DO) concentrations remained above the hypoxia threshold (2.9 mg/L) throughout the water column. Surface DO averaged 9.2 mg/L, with a minimum of 6.7 mg/L and mid DO averaged 7.2 mg/L, with a minimum of 4.6 mg/L. Bottom DO averaged 5.7 mg/L, with a minimum of 4.2 mg/L. Surface chlorophyll averaged 9.1 ug/L, with a maximum concentration of 26 ug/L observed towards the beginning of the week.

Week of June 7 – 13, 2020

Fixed Site Network

Phillipsdale Landing

Water quality was good this week at Phillipsdale Landing. This week, 0.82 inches of precipitation was recorded; all rainfall occurred on June 11. Sondes were changed out for routine maintenance during the early afternoon on June 9. Average salinity was lower in both surface and bottom waters than the previous week. Surface salinity averaged 13.3 ppt, with a maximum of 21.5 ppt observed towards the beginning of the week and a minimum of 5.6 ppt observed following the June 11 rain event.

Bottom salinity averaged 22.2 ppt and ranged from 10.8 ppt to 27.9 ppt. Surface temperatures were greater than last week, averaging 20.8°C and ranging from 18.1°C to 24.3°C. Bottom waters were also warmer than the previous week, averaging 18.9°C and ranging from 16.3°C to 22.3°C.

Dissolved oxygen (DO) concentrations remained above the hypoxia threshold (2.9 mg/L) at both depths. Surface DO averaged 8.9 mg/L, with a minimum of 4.2 mg/L, while bottom DO averaged 6.1 mg/L, with a minimum of 3.4 mg/L. Surface chlorophyll was slightly lower than the previous week, averaging 20.5 ug/L; readings greater than 100 ug/L were observed during the first three days of the week, while readings remained under 40 ug/L during the latter half of the week. Note that tidal fluctuations and Blackstone River flow greatly influence water column salinity, temperature, and dissolved oxygen at this location.

Bullock Reach

Water quality was good this week at Bullock Reach. Surface water quality data are not available for this week due to communications and logging issues with the surface sonde, while bottom salinity data are not available due to extensive probe drift on the bottom sonde. Salinity at the mid depth averaged 28.7 ppt for the week and ranged from 24.9 ppt to 30.8 ppt. Temperatures in mid and bottom waters increased over the course of the week, averaging 18.3°C and 16.4°C, respectively. Mid temperatures ranged from 15.9°C to 21.0°C, while bottom temperatures ranged from 15.0°C to 19.0°C.
 
Dissolved oxygen (DO) concentrations remained above the hypoxia threshold (2.9 mg/L) at the mid and bottom depths. Mid DO averaged 7.9 mg/L, with a minimum of 5.8 mg/L, while bottom DO averaged 6.6 mg/L, with a minimum of 4.7 mg/L. Surface chlorophyll data are not available, however, chlorophyll averaged 10 ug/L and 6.0 ug/L at the mid and bottom, with a maximum chlorophyll concentration of approximately 21 ug/L at both depths.

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