Historical News
Week of August 18 - 24, 2019
Water Column Profiles
Water column profiles were measured at six sites in the Seekonk and Providence Rivers on August 21, 2019. In the five days prior to sampling, 0.51 inches of precipitation was recorded. The recent rainfall lead to some stratification at sites influenced by freshwater input, such as Phillipsdale Landing.
Salinity in surface waters ranged from 17 psu at Phillipsdale Landing to 27 psu at Bullock Reach. Bottom salinity ranged from 26 psu at Phillipsdale Landing and India Point Park to 30 psu at Conimicut Point. Water column temperatures averaged 23.9°C this week, warmer than last week. Warmest waters were observed at Point St. Bridge, with surface temperatures of 27.6°C and bottom temperatures of 27.2°C. Bottom waters were coolest at Conimicut Point, with recorded temperatures of 20.8°C. Surface water temperatures were around 25.5°C at most sites.
Dissolved oxygen (DO) concentrations were low at several sites this week. Waters were hypoxic (i.e., <2.9 mg/L DO) below 1.25 m at Phillipsdale Landing, below 3.25 m at India Point Park, and throughout the water column at Point St. Bridge. The lowest bottom DO (<0.1 mg/L) was measured at Phillipsdale Landing. Surface DO ranged from 5 to 8 mg/L at most sites. Fluorescence was slightly lower than the previous week. Maximum fluorescence readings of >70 mg/m3 occurred at Phillipsdale Landing.
Salinity in surface waters ranged from 17 psu at Phillipsdale Landing to 27 psu at Bullock Reach. Bottom salinity ranged from 26 psu at Phillipsdale Landing and India Point Park to 30 psu at Conimicut Point. Water column temperatures averaged 23.9°C this week, warmer than last week. Warmest waters were observed at Point St. Bridge, with surface temperatures of 27.6°C and bottom temperatures of 27.2°C. Bottom waters were coolest at Conimicut Point, with recorded temperatures of 20.8°C. Surface water temperatures were around 25.5°C at most sites.
Dissolved oxygen (DO) concentrations were low at several sites this week. Waters were hypoxic (i.e., <2.9 mg/L DO) below 1.25 m at Phillipsdale Landing, below 3.25 m at India Point Park, and throughout the water column at Point St. Bridge. The lowest bottom DO (<0.1 mg/L) was measured at Phillipsdale Landing. Surface DO ranged from 5 to 8 mg/L at most sites. Fluorescence was slightly lower than the previous week. Maximum fluorescence readings of >70 mg/m3 occurred at Phillipsdale Landing.
Week of August 18 - 24, 2019
Fixed Site Network
Phillipsdale Landing
Water quality was fair to poor this week at Phillipsdale Landing; sondes were changed out for regular maintenance on August 20 at 13:30 EDT. An erroneous row of data (August 21 0700 EST) was excluded from the following data summary. In addition, approximately 8 hours of surface data were impacted by a buoyancy issue – on August 24 from 10:01 through 17:46 EST the surface sonde depth was 0.75-1.4 m, instead of the typical 0.6 m. These data have been excluded from the summary written below. Rainfall was moderate throughout the week, approximately 0.4 inches recorded on August 19, 0.2 inches on August 21, and 0.1 inches on August 23. Surface salinity averaged 15 ppt, ranging 7.8 – 21.7 ppt, generally decreasing over the course of the week. Bottom salinity averaged 22.8 ppt, ranging 13.7 – 28.7 ppt. Water temperatures were slightly warmer this week than last, with surface waters averaging 25.8°C and bottom waters averaging 24.8°C. Dissolved oxygen (DO) levels were fair at the start of the week, showing some decline as the week progressed. Surface water DO averaged 7.3 mg/L, with observations of hypoxia (DO <2.9 mg/L) occurring periodically; the longest period of continuous hypoxia at the surface was approximately four hours during the morning of August 20. Bottom DO averaged 2.1 mg/L and waters were hypoxic for much of the second half of the week. The longest continuous stretch of hypoxic conditions about 24 hours, from the evening on August 22 to the evening on August 23. Chlorophyll was slightly higher this week than last week, averaging 69.8 ug/L in surface waters; peaks in chlorophyll concentrations >300 ug/L occurred in the early morning on August 18 and in the afternoon on August 21, 22, and 23.
Note that tidal fluctuations and Blackstone River flow greatly influence water column DO, temperature, and salinity at this location.
Bullock Reach
This week at Bullock Reach water quality was good to fair, with density stratification apparent all week. Average water temperatures were 25.3°C at the surface, 24.3°C at the mid sonde, and 21.8°C at the bottom. Surface salinity ranged from 23.3 to 28.4 ppt, averaging 26.0 ppt. Salinity values at the mid sonde and bottom sondes averaged 28.2 and 30.6 ppt, respectively. DO showed some improvement compared to the previous week. There were no recorded measurements of hypoxia (DO <2.9 mg/L) at the surface or mid sondes; DO at the bottom sonde dipped below the hypoxia threshold occasionally, up to 1.5 hours at a time (August 23 morning). For the week overall, surface DO averaged 7.5 mg/L with a minimum of 5.4 mg/L, the mid depth had an average of 5.7 mg/L with a minimum of 2.9 mg/L, and the bottom had an average of 3.6 mg/L with a minimum of 2.5 mg/L. Water column chlorophyll was variable throughout the week and was generally highest at the surface. Surface chlorophyll averaged 13.4 ug/L, chlorophyll at the mid sonde averaged 6.5 ug/L, and chlorophyll at the bottom sonde averaged 6.9 ug/L.
Week of August 11 - 17, 2019
Water Column Profiles
Water column profiles were measured at eight sites in the Seekonk and Providence Rivers on August 15, 2019. Two days prior to sampling, 0.13 inches of precipitation was recorded. At some sites, stratification was evident (e.g., Conimicut Point, Bullock Reach, Phillipsdale Landing), while other sites were well-mixed (e.g., Pomham Rocks).
Lowest water column salinity this week was observed at Phillipsdale Landing, with a surface salinity of 21 psu and bottom salinity of 27 psu. Water column salinity was highest at Conimicut Point, ranging from 26 psu at the surface to 31 psu in bottom waters.
Water column temperatures averaged 22.7°C this week. Waters were coolest at Conimicut Point, ranging from bottom temperatures of 20°C to surface temperatures of 23°C. Surface water temperatures were warmest at Phillipsdale Landing, at 24°C. Bottom temperatures were around 23°C at most sites.
Dissolved oxygen (DO) concentrations were low at several sites this week. Waters were hypoxic (i.e., <2.9 mg/L DO) below 1.5 m at Phillipsdale Landing, below 3 m at Edgewood Yacht Club, and below 4.25 m at Edgewood Shoals. The lowest bottom DO (1.14 mg/L) was measured at Edgewood Yacht Club. DO at the surface was in the 6 - 8 mg/L range at most sites. Fluorescence was higher than the previous week, with maximum readings of >70 mg/m3 at Phillipsdale Landing.
Lowest water column salinity this week was observed at Phillipsdale Landing, with a surface salinity of 21 psu and bottom salinity of 27 psu. Water column salinity was highest at Conimicut Point, ranging from 26 psu at the surface to 31 psu in bottom waters.
Water column temperatures averaged 22.7°C this week. Waters were coolest at Conimicut Point, ranging from bottom temperatures of 20°C to surface temperatures of 23°C. Surface water temperatures were warmest at Phillipsdale Landing, at 24°C. Bottom temperatures were around 23°C at most sites.
Dissolved oxygen (DO) concentrations were low at several sites this week. Waters were hypoxic (i.e., <2.9 mg/L DO) below 1.5 m at Phillipsdale Landing, below 3 m at Edgewood Yacht Club, and below 4.25 m at Edgewood Shoals. The lowest bottom DO (1.14 mg/L) was measured at Edgewood Yacht Club. DO at the surface was in the 6 - 8 mg/L range at most sites. Fluorescence was higher than the previous week, with maximum readings of >70 mg/m3 at Phillipsdale Landing.
Week of August 11 - 17, 2019
Fixed Site Network
Phillipsdale Landing
Water quality was poor to fair this week at Phillipsdale Landing. Rainfall was light throughout the week, just 0.13 inches recorded on August 13, and 0.1 inches on August 17; salinity at the surface and bottom increased over the course of the week. Surface salinity averaged around 15 ppt, ranging 5.6 – 23 ppt; bottom salinity averaged 24 ppt, ranging 11.5 – 28.5 ppt. Water temperatures were slightly cooler this week than last, with surface waters averaging 24.4°C and bottom waters averaging 23.8°C. Dissolved oxygen (DO) levels were poor at the start of the week, showing some improvement as the week progressed. Surface water DO averaged 8.6 mg/L, with observations of hypoxia (DO <2.9 mg/L) occurring periodically; the longest period of continuous hypoxia at the surface was just over two hours during the night of August 13-14. Bottom DO averaged 2.6 mg/L and waters were hypoxic for much of the first half of the week. The longest continuous stretch of hypoxic conditions was 22 hours, from mid-day August 12 to mid-day August 13. Chlorophyll was slightly higher this week than last, averaging 51.6 ug/L in surface waters; peaks in chlorophyll concentrations >300 ug/L occurred overnight on August 12-13 and August 13-14.
Note that tidal fluctuations and Blackstone River flow greatly influence water column DO, temperature, and salinity at this location.
Bullock Reach
This week at Bullock Reach, water quality was good to fair; the sondes were changed-out for maintenance on August 14 at 09:30 EDT. Average water temperatures were 24.0°C at the surface, 23.3°C at the mid sonde, and 21.8°C at the bottom, all displaying a slight decrease compared to last week. Surface salinity ranged from 21.9 ppt to 28.4 ppt, averaging 26.4 ppt. Salinity values at the mid sonde and bottom sondes averaged 28.5 and 30.1 ppt, respectively. Density stratification was most apparent in the latter half of the week, when temperature differences between the surface and bottom reached 4 – 6°C and salinity differences of 3 – 7 ppt were observed. DO showed some improvement compared to the previous week. There were no recorded measurements of hypoxia (DO <2.9 mg/L) at the surface or bottom sondes; DO at the middle sonde dipped just below the hypoxia threshold for a single reading during the morning of August 16. For the week overall, surface DO averaged 7.8 mg/L with a minimum of 5.4 mg/L, the mid depth had an average of 5.9 mg/L with a minimum of 2.8 mg/L, and the bottom had an average of 4.2 mg/L with a minimum of 2.9 mg/L. Water column chlorophyll was variable throughout the week and hit the highest concentrations in bottom waters. Surface chlorophyll averaged 12.2 ug/L, chlorophyll at the mid sonde averaged 9.2 ug/L, and chlorophyll at the bottom sonde averaged 8.1 ug/L.
Week of July 28 - August 3, 2019
Nutrients Sampling
Seven bay stations and seven local and state border river stations were sampled for nutrients on July 31, 2019. Surface and bottom waters were sampled at all bay stations. Conditions were dry for the five days prior to sampling, with no recorded precipitation.
Among the river stations sampled, highest total nitrogen (TN), total dissolved nitrogen (TDN), and dissolved inorganic nitrogen (DIN) values occurred at the Pawtuxet River at Broad St. site, at 1290 ppb, 1340 ppb, and 1048 ppb, respectively. Lowest TN and TDN values were recorded at Ten Mile River at Roger Williams Ave, with concentrations of 497 ppb and 472 ppb. The Blackstone River at Slater Mill had the lowest recorded DIN concentrations, at 44 ppb.
At the bay surface stations, greatest TN, TDN, and DIN was observed at Pawtuxet Cove (average of duplicate samples: 1065 ppb, 746 ppb, 619 ppb, respectively). Lowest TN values were observed at Phillipsdale Landing, at 453 ppb. Four bay stations had TDN values below detection (<100 ppb) – Conimicut Point, Edgewood Yacht Club, Pomham Rocks, and Bullock Reach Buoy; low DIN values (<20 ppb) were also observed at these sites. Chlorophyll a concentrations averaged 5.2 ug/L and ranged from 1.8 ug/L at Bullock Reach Buoy to 12.3 ug/L at Edgewood Yacht Club.
Among the river stations sampled, highest total nitrogen (TN), total dissolved nitrogen (TDN), and dissolved inorganic nitrogen (DIN) values occurred at the Pawtuxet River at Broad St. site, at 1290 ppb, 1340 ppb, and 1048 ppb, respectively. Lowest TN and TDN values were recorded at Ten Mile River at Roger Williams Ave, with concentrations of 497 ppb and 472 ppb. The Blackstone River at Slater Mill had the lowest recorded DIN concentrations, at 44 ppb.
At the bay surface stations, greatest TN, TDN, and DIN was observed at Pawtuxet Cove (average of duplicate samples: 1065 ppb, 746 ppb, 619 ppb, respectively). Lowest TN values were observed at Phillipsdale Landing, at 453 ppb. Four bay stations had TDN values below detection (<100 ppb) – Conimicut Point, Edgewood Yacht Club, Pomham Rocks, and Bullock Reach Buoy; low DIN values (<20 ppb) were also observed at these sites. Chlorophyll a concentrations averaged 5.2 ug/L and ranged from 1.8 ug/L at Bullock Reach Buoy to 12.3 ug/L at Edgewood Yacht Club.
