Historical News
Month of September, 2023
Fixed Site Network
Phillipsdale Landing
The Phillipsdale Landing sondes have been deployed for the season since May 9th, 2023 utilizing a new setup allowing staff access to the equipment from the boat instead of standing on the dock. During the month of September, sondes were changed out for routine maintenance on September 14th and 27th.
Surface DO remained above the hypoxia threshold all month. The bottom waters were hypoxic periodically throughout the month, with the longest sustained hypoxic periods (10 hours) occurring in the early morning of September 10th and again on the afternoon of the 10th and the morning of the 11th. DO averaged 8.2 mg/L at the surface with a minimum of 3.2 mg/L, while bottom waters averaged 4.4 mg/L with a minimum of 0.0 mg/L.
Chlorophyll readings were frequently elevated during the first half of the month, suggestive of phytoplankton blooms, but went back down in the second half of the month. The surface and bottom readings averaged 12.0 µg/L and 6.1 µg/L, respectively.
Bullock Reach
The Bullock Reach buoy was deployed June 1st for the 2023 season. During the month of September, sondes were changed out for routine maintenance on September 7th and 21st.
Surface DO remained above the hypoxia threshold all month. There were a few brief periods of hypoxic conditions in the middle waters, with the longest duration at 1.5 hours on September 24th. The bottom waters were hypoxic periodically throughout the month, with the longest sustained period of hypoxic conditions at 26 hours between the 13th and 14th. Surface, middle, and bottom DO averaged 7.3 mg/L, 5.4 mg/L, and 4.0 mg/L, respectively.
Chlorophyll readings ranged from low to elevated, with evidence of moderate phytoplankton blooms occurring throughout the month. Readings averaged 11.7 µg/L at the surface, 9.6 µg/L at mid-depth, and 3.5 µg/L at the bottom.
Month of August, 2023
Fixed Site Network
Phillipsdale Landing
The Phillipsdale Landing sondes have been deployed for the season since May 9th, 2023 utilizing a new setup allowing staff access to the equipment from the boat instead of standing on the dock. During the month of August, sondes were changed out for routine maintenance on August 1st, 16th, and 29th.
Surface DO remained mostly above the hypoxia threshold, dropping briefly below the threshold for approximately an hour and a half on August 2nd and again on August 3rd. The bottom waters were hypoxic periodically throughout the month, with the longest sustained hypoxic periods (11 hours) occurring overnight between August 16th and 17th, and again overnight August 17th to 18th. DO averaged 6.4 mg/L at the surface with a minimum of 1.6 mg/L, while bottom waters averaged 3.0 mg/L with a minimum of 0.6 mg/L.
Chlorophyll readings were generally low with intermittent periods of elevated readings through the month, suggestive of minor phytoplankton blooms. The surface and bottom readings averaged 4.3 µg/L and 4.1 µg/L, respectively. The maximum surface reading of 43.6 µg/L occurred on August 8th and the maximum bottom reading of 30.0 µg/L occurred on August 24th.
Bullock Reach
The Bullock Reach buoy was deployed June 1st for the 2023 season. During the month of August, sondes were changed out for routine maintenance on August 8th and 22nd.
Surface DO remained above the hypoxia threshold all month. There were a few brief periods of hypoxic conditions in the middle waters, with the longest duration at 2 hours on August 18th. The bottom waters had hypoxic conditions on and off all month, with the longest sustained period of hypoxic conditions at 2.5 days between the 16th and 19th. Surface, middle, and bottom DO averaged 7.3 mg/L, 5.1 mg/L, and 3.5 mg/L, respectively.
Chlorophyll readings ranged from low to elevated, with evidence of moderate phytoplankton blooms occurring throughout the month. Readings averaged 13.8 µg/L at the surface, 11.1 µg/L at mid-depth, and 3.3 µg/L at the bottom. The maximum surface reading of 70.0 µg/L occurred on August 21st. Please note that data gaps occurred between the 1st and 2nd and between the 28th and 29th on the middle sonde due to equipment failure.
Month of July, 2023
Fixed Site Network
Phillipsdale Landing
The Phillipsdale Landing sondes have been deployed since May 9th, 2023 utilizing a new setup allowing staff access to the equipment from the boat instead of standing on the dock. Sondes were changed out for routine maintenance on July 6th and July 18th. July was a wet month, with 8.37 inches of precipitation recorded at T.F. Green. The largest storm occurred on July 16th (3.35 inches). Blackstone River flows were elevated due to the frequent precipitation throughout the month of July. Salinity at Phillipsdale averaged 4.3 ppt at the surface (range 0.2 – 18.8 ppt) and 42.0 ppt at the bottom (range -0.6 – 108.9 ppt). Temperatures increased from June, averaging 25.4°C at the surface and 24.0°C at the bottom. Surface temperatures ranged 22.6 – 30.0°C, while bottom temperatures ranged 21.0 – 26.7°C.
The surface dissolved oxygen (DO) concentrations remained mostly above the hypoxia threshold (2.9 mg/L), only briefly dropping below the threshold for a half hour the morning of July 10th. The bottom waters were hypoxic periodically throughout the month. The longest sustained period of hypoxic conditions (~1.5 days) occurring from the morning of July 9th until the night of July 10th. DO averaged 7.3 mg/L at the surface with a minimum of 2.2 mg/L, while bottom waters averaged 3.3 mg/L with a minimum of -0.1 mg/L.
Chlorophyll readings were generally low with periods of moderately elevated chlorophyll intermittently through the month, suggestive of moderate phytoplankton blooms. The surface and bottom readings averaged 8.3µg/L and 8.6 µg/L, respectively. The maximum surface reading of 112.8 µg/L occurred on July 9th and the maximum bottom reading of 130.9 µg/L occurred on July 22nd. Please note that data from the bottom sonde between July 23rd and the 29th was excluded due to mud compromising the results. Also, gaps occurred in the bottom on July 4th to the 6th potentially due to equipment failure.
Bullock Reach
The Bullock Reach buoy was deployed June 1st for the 2023 season. Sondes were changed out for routine maintenance on July 11th and 25th. Overall, water quality was fair at Bullock Reach Buoy throughout the month of July 2023. Surface, middle, and bottom DO averaged 7.5 mg/L, 4.8 mg/L, and 2.6 mg/L, respectively. Hypoxic conditions were not observed at the surface. However, hypoxic conditions occurred sporadically in middle waters beginning July 19th. Bottom waters periodically fell below the hypoxia threshold (2.9 mg/L) throughout the month and the longest duration of hypoxic conditions occurred for 5.5 days between the 22nd and the 28th.
Surface salinity at Bullock Reach ranged 9.5 – 27.2 ppt and averaged 21.1 ppt. Mid-depth salinity ranged 16.4 – 30.0 ppt and averaged 25.7 ppt. Bottom salinity ranged 23.5 – 31.3 ppt and averaged 30.1 ppt. Water column temperatures averaged 25.7°C, 25.1°C, and 22.1°C at the surface, middle, and bottom, respectively. Temperatures ranged 23.2°C – 28.6°C at the surface, 21.6°C – 27.4°C at mid-depth, and 19.4°C – 25.7°C at the bottom.
Chlorophyll readings were moderately elevated, averaging 25.7 µg/L at the surface, 15.0 µg/L at mid-depth, and 2.8 µg/L at the bottom. Periods of elevated chlorophyll occurred around July 6th – 10th. The maximum surface reading of 81.2 µg/L occurred on July 22nd. Please note that minor data gaps occurred between the 8th to the 25th on the surface and bottom due to potential equipment failure and fouling.
Please note that the data exclusions mentioned in the above text for Phillipsdale Landing and Bullock Reach does not affect the raw data, and any exclusions occurred during a QC process, prior to the average, maximum, and minimum calculations discussed.
Month of June, 2023
Fixed Site Network
Phillipsdale Landing
The Phillipsdale Landing sondes have been deployed since May 9th, 2023 utilizing a new setup allowing staff access to the equipment from the boat instead of standing on the dock. Sondes were changed out for routine maintenance on June 6th and June 20th.
June was relatively wet, with 3.1 inches of precipitation recorded at T.F. Green. The largest storm occurred on June 17th (1.3 inches). Blackstone River flows were elevated for June 18th (i.e., above the 18-year median statistic of USGS data) in response to the precipitation. Salinity at Phillipsdale averaged 14.0 ppt at the surface (range 1.7 – 26.1 ppt) and 24.4 ppt at the bottom (range 8.3 – 29.5 ppt). Temperatures increased from May, averaging 20.4°C at the surface and 18.0°C at the bottom. Surface temperatures ranged 14.9 – 26.7°C, while bottom temperatures ranged 14.9 – 24.5°C.
The surface dissolved oxygen (DO) concentrations remained above the hypoxia threshold (2.9 mg/L) while the bottom waters were hypoxic periodically throughout the month. The longest sustained period of hypoxic conditions (~13 hours) occurred during the late morning of June 22nd into the early morning of June 23rd. DO averaged 8.3 mg/L at the surface with a minimum of 3.6 mg/L, while bottom waters averaged 3.6 mg/L with a minimum of 0.01 mg/L.
Chlorophyll readings were generally low with periods of moderately elevated chlorophyll intermittently through the month, suggestive of moderate phytoplankton blooms. The surface and bottom readings averaged 20.6 µg/L and 19.8 µg/L, respectively. The maximum surface reading of 86.6 µg/L occurred on June 27th and the maximum bottom reading of 118.2 µg/L occurred on June 7th. Also, please note that data from the bottom sonde between June 23rd and the 29th was excluded due to mud compromising the results. Minor data gaps also occurred periodically between June 11th to the 29th on the surface and bottom due to potential sediment interference (common at this site), fouling, and when the surface sonde was tangled and reporting at an incorrect depth.
Bullock Reach
The Bullock Reach buoy was deployed June 1st for the 2023 season. Sondes were changed out for routine maintenance on June 13th and 27th. Please note that minor data gaps occurred in the surface, middle and bottom on June 1st, 8th, 16th and 27th and is potentially due to equipment failure.
Overall, water quality was good at Bullock Reach Buoy throughout the month of June 2023. Surface, middle, and bottom DO averaged 8.8 mg/L, 7.3 mg/L, and 5.6 mg/L, respectively. Hypoxic conditions were not observed at Bullock Reach this month; the minimum DO observed was 3.1 mg/L measured in bottom waters.
Surface salinity at Bullock Reach ranged 20.6 – 29.1 ppt and averaged 25.9 ppt. Mid-depth salinity ranged 19.7 – 30.5 ppt and averaged 28.1 ppt. Bottom salinity ranged 17.6 – 31.2 ppt and averaged 29.8 ppt. Water column temperatures averaged 19.7°C, 19.0°C, and 17.4°C at the surface, middle, and bottom, respectively. Temperatures ranged 14.6°C – 25.1°C at the surface, 15.2°C – 23.9°C at mid-depth, and 13.6°C – 22.5°C at the bottom. Chlorophyll readings were generally low, averaging 12.2 µg/L at the surface, 11.4 µg/L at mid-depth, and 4.0 µg/L at the bottom. The maximum reading of 38.9 µg/L occurred on June 15th in the surface waters.
Please note that the data exclusions mentioned in the above text for Phillipsdale Landing and Bullock Reach does not affect the raw data, and any exclusions occurred during a QC process, prior to the average, maximum, and minimum calculations discussed.
Week of May 28 - June 3, 2023
Fixed Site Network
Phillipsdale Landing
Overall, water quality at Phillipsdale Landing was fair to good. Weather conditions were dry this week, with only a very light rain of 0.02 inches recorded at T.F. Green. Blackstone River flow continued its declined over the course of the week from the increase in flow last week on May 20th. Surface salinity averaged 9.2 ppt and ranged from 3.3 ppt to 21.8 ppt. At the bottom, salinity averaged 21.0 ppt and ranged from 4.4 ppt to 27.6 ppt. Temperatures increased this week, averaging 20.2°C at the surface and ranging 16.5°C – 23.6°C. At the bottom, temperatures averaged 17.6°C and ranged 15.1°C –21.0°C.
Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold of 2.9 mg/L at the surface. DO dropped below the hypoxia threshold at the bottom intermittently through May 28th to May 31st. Surface DO increased from the previous week, averaging 10.3 mg/L and ranging 6.0-17.5 mg/L. Bottom water DO concentration averaged 4.9 mg/L and ranged from 1.9 mg/L to 11.3 mg/L. Chlorophyll readings increased from last week, averaging 18.9 ug/L at the surface and 18.4 ug/L at the bottom. Maximum chlorophyll at the surface reached 58.2 ug/L in the afternoon of May 31st. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location. Also, please note that an isolated portion of suspect chlorophyll data from May 29th was excluded from the summary.
Bullock Reach
Bullock Reach sondes was deployed on June 1st for the season. Please note that due to the technical difficulties which occurred on June 1st during set up and the week ending on June 3rd, this post is based on a very limited Bullock Reach data set. Overall, water quality was good at Bullock Reach this week. Salinity averaged 24.1 ppt, 25.8 ppt, and 30.0 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 21.3-26.2 ppt, mid salinity ranged 22.0-29.0 ppt, and bottom salinity ranged 28.2-31.1 ppt. Surface temperature averaged 20.1°C and ranged from 16.9°C to 21.9°C. Mid temperatures averaged 19.2°C and ranged from 16.7°C to 21.3°C. Bottom temperatures averaged 15.1°C and ranged from 13.6°C to 17.1°C.
DO concentrations at Bullock Reach remained above the hypoxia threshold all week. Surface DO averaged 8.6 mg/L and ranged 7.2 – 10.4 mg/L. In the mid waters, DO averaged 7.7 mg/L and ranged 5.9 – 9.1 mg/L. At the bottom, DO averaged 5.3 mg/L and ranged 4.6– 6.5 mg/L. Chlorophyll concentrations were low, averaged 7.4 ug/L, 8.6 ug/L, and 2.3 ug/L at the surface, mid, and bottom waters, respectively. The maximum surface chlorophyll of 11.6 ug/L was during the morning of June 3rd.
