Walker Point

Overall, water quality at Walker Point was poor this week. Weather conditions were rainy this week, with a total of 2.52 inches recorded at T.F. Green, and the majority of rainfall occurring on the 3^rd.  Blackstone River flow reached its peak on August 4^th, where the flow greatly exceeded the 20-year daily median flow, and flow remained above the 20-year daily median value for the rest of the week.   Salinity at the surface averaged 11.3 ppt and ranged from 3.6 ppt to 22.5 ppt. At the bottom, salinity averaged 24.3 ppt and ranged from 18.4 ppt to 28.5 ppt. Temperatures this week averaged 26.0 °C at the surface and 24.4 °C at the bottom. Surface temperatures ranged from 23.7  °C to 29.8 °C, while bottom temperatures ranged from 23.7 °C to 25.4 °C.

Dissolved oxygen (DO) at Walker Point remained above the hypoxia threshold (i.e., DO >2.9 mg/L) at the surface, but below the hypoxia threshold at the bottom for most of the week. Hypoxic conditions were observed at the surface briefly during the morning on August 3^rd. Hypoxic conditions were observed at the bottom for almost the entire week. Surface DO averaged 9.5 mg/L and ranged from 2.8 to 19.3 mg/L. Bottom water DO concentration averaged 1.6 mg/L and ranged from 0.1 mg/L to 3.9 mg/L. Chlorophyll ranged from low to elevated levels throughout the week, averaging 18.0 ug/L at the surface and 3.5 ug/L at the bottom, with evidence of substantial phytoplankton blooms occurring throughout the week. Maximum surface chlorophyll readings reached 157.4 ug/L on the morning of August 9^th. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.

Bullock Reach

Sondes were swapped this week on August 4^th. Overall, water quality ranged from fair to good at Bullock Reach this week. Salinity averaged 23.8 ppt, 28.0 ppt, and 31.1 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged from 19.9 to 28.7 ppt, mid salinity ranged from 24.1 to 31.0 ppt, and bottom salinity ranged from 28.7 to 32.3 ppt. Surface temperature averaged 26.1 °C and ranged from 24.1 °C to 28.5 °C. Mid temperatures averaged 24.7 °C and ranged from 23.1 °C to 27.0 °C. Bottom temperatures averaged 23.2 °C and ranged from 22.3 °C to 24.7 °C.

DO at Bullock Reach experienced hypoxic conditions (i.e., DO < 2.9 mg/L) towards the end of  the week in both middle and bottom waters. Surface DO averaged 8.1 mg/L and ranged from 4.9 to 14.2 mg/L. In the mid waters, DO averaged 4.9 mg/L and ranged from 1.1 to 8.4 mg/L. At the bottom, DO averaged 3.6 mg/L and ranged 1.8 to 7.4 mg/L.  Chlorophyll readings ranged from low to moderate, with evidence of moderate phytoplankton blooms occurring throughout the week. Readings averaged 15.5 µg/L at the surface, 14.8 µg/L at mid-depth, and 4.9 µg/L at the bottom.  The maximum surface chlorophyll was 37.2 µg/L on the afternoon of August 5^th.

Walker Point

Sondes were swapped this week on July 28^th. Overall, water quality at Walker Point was poor this week. Weather conditions were rainy this week, with a total of 1.25 inches recorded at T.F. Green, and the majority of rainfall occurring on the 29^th.  Blackstone River flow reached its peak on July 30^th, where the flow greatly exceeded the 20-year daily median flow, and flow remained above the 20-year daily median value for the rest of the week.   Salinity at the surface averaged 17.7 ppt and ranged from 7.5 ppt to 27.4 ppt. At the bottom, salinity averaged 26.7 ppt and ranged from 21.6 ppt to 29.4 ppt. Temperatures this week averaged 24.2 °C at the surface and 26.2 °C at the bottom. Surface temperatures ranged from 22.4  °C to 26.2 °C, while bottom temperatures ranged from 22.6 °C to 24.6 °C.

Dissolved oxygen (DO) at Walker Point remained above the hypoxia threshold (i.e., DO >2.9 mg/L) at the surface, but below the hypoxia threshold at the bottom for a substantial portion of the week. Hypoxic conditions were observed at the bottom for most of July 27^th, 28^th, August 1^st, and August 2^nd. Hypoxic conditions occurred intermittently on other days of the week. Surface DO averaged 7.7 mg/L and ranged from 3.5 to 15.1 mg/L. Bottom water DO concentration averaged 2.5 mg/L and ranged from 0.5 mg/L to 6.1 mg/L. Chlorophyll ranged from low to elevated levels throughout the week, averaging 16.2 ug/L at the surface and 5.6 ug/L at the bottom, with evidence of moderate phytoplankton blooms occurring throughout the week. Maximum surface chlorophyll readings reached 66.4 ug/L on the afternoon of August 2^nd. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.

Bullock Reach

Sondes were swapped this week on August 4^th. Overall, water quality ranged from por to good at Bullock Reach this week. Salinity averaged 27.9 ppt, 29.5 ppt, and 31.0 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged from 24.9 to 29.6 ppt, mid salinity ranged from 29.5 to 31.5 ppt, and bottom salinity ranged from 27.3 to 32.5 ppt. Surface temperature averaged 23.9 °C and ranged from 22.8 °C to 25.4 °C. Mid temperatures averaged 23.5 °C and ranged from 21.5 °C to 24.8 °C. Bottom temperatures averaged 22.5 °C and ranged from 20.2 °C to 24.1 °C. DO at Bullock Reach experienced hypoxic conditions (i.e., DO < 2.9 mg/L) towards the beginning of  the week in bottom waters, but otherwise did not experience hypoxic conditions. Surface DO averaged 7.2 mg/L and ranged from 5.0 to 11.4 mg/L. In the mid waters, DO averaged 5.9 mg/L and ranged from 3.3 to 9.1 mg/L. At the bottom, DO averaged 4.3 mg/L and ranged 2.2 to 7.6 mg/L.  Chlorophyll readings ranged from low to moderate, with evidence of moderate phytoplankton blooms occurring throughout the week. Readings averaged 10.1 µg/L at the surface, 13.0 µg/L at mid-depth, and 4.5 µg/L at the bottom.  The maximum surface chlorophyll was 26.8 µg/L on the afternoon of August 2^nd.