Historical News
Water Column Profiles
Six water column profiles were collected throughout the Providence River estuary on Wednesday, March 29th. Moderately heavy rainfall of 0.7 inches was recorded at T.F. Green Airport over the two days prior to the survey, and the two sites nearest to river inputs exhibited relatively low surface salinities. At Pawtuxet Cove, the top 1-m surface salinity measured 14.0 psu, while bottom salinity measured 24.2 psu; at India Point Park, surface salinity measured 15.5 psu, versus bottom salinities around 29.0 psu. The rest of the sites surveyed exhibited a more well-mixed water column. Temperatures among all sites were consistent, ranging 3.9-5.1°C, slightly cooler than the previous survey on March 1st. Dissolved oxygen (DO) was high at all sites; the minimum, 9.8 mg/L, was observed in the bottom waters at India Point Park. The highest DO was measured in the relatively fresh surface waters at 1 m at Pawtuxet Cove, at 11.4 mg/L. Fluorescence was variable and slightly lower than the previous survey; the lowest fluorescence was 2.4 ug/L, measured near the surface at India Point Park, while the highest, 25.9 ug/L, was measured at the bottom (10.25 m) at Conimicut Point.
Water Column Profiles
Six water column profiles were collected throughout the Providence and Seekonk River estuaries on Wednesday, March 1st. Light rainfall of 0.13 inches was recorded in the Providence area four days prior to the survey, with additional trace rain falling over the next three days. Rainfall on the survey date may have impacted sites surveyed in the afternoon (Edgewood Yacht Club, Pomham Rocks, and India Point Park). Low salinities were observed at Phillipsdale Landing, the site closest to the major river input of the Blackstone. The top 1-m surface salinity at this site ranged 7.5–11.3 psu, while bottom salinities of ~17.3 psu were also relatively low. Minor density stratification was observed at India Point Park, Pomham Rocks, and Edgewood Yacht Club, where surface salinities ranged ~13.0-21.0 psu and bottom salinities ranged 27.0-29.0 psu; temperatures were ~7°C at the surface versus ~5°C at the bottom. These surface temperatures represented a slight warming since the previous survey on February 1st. Dissolved oxygen (DO) was high at all sites; the minimum, 9.2 mg/L, was observed mid-water column at India Point Park. The highest DO was measured at the surface of Bullock Reach, at 12.7 mg/L. Fluorescence was variable, though generally higher than the previous survey; the lowest fluorescence was 0.3 ug/L, measured near the surface at Pawtuxet Cove, while the highest, 47.9 ug/L, was measured at the bottom (14 m) at Bullock Reach.
Water Column Profiles
Seven water column profiles were collected throughout the Providence River estuary on Wednesday, February 1st. Approximately 0.17 of rain and 3.0 inches of snow was recorded in Providence area in the day before and morning of sampling; during the previous week over 2.0 inches of rain fell. A relatively fresh surface layer was observed at Phillipsdale Landing, the site closest to the major river input of the Blackstone River. The top 1-m surface salinity at this site was 6.8 – 7.1 psu, versus salinities of ~ 28.0 psu at the bottom. The water column at other sites was generally more well-mixed, with only minor density gradients observed at the deepest sites; for example Conimicut Point and Bullock Reach exhibited surface waters around 2.7 - 3.0°C and 24.6 – 26.1 psu while the bottom waters below 7.0 m were slightly warmer and saltier at 4.3 – 4.5°C and 30.0 psu. Overall temperatures were consistent this week, ranging 3.0 – 4.9°C among all sites. Dissolved oxygen (DO) was high at all sites; the minimum, 8.7 mg/L, was observed in bottom waters at Pomham Rocks. The highest DO was measured at the surface of Phillipsdale at 11.5 mg/L, most likely due to the cool, freshwater input at this site. Fluorescence was variable, though lower than the previous water column survey with the lowest fluorescence of 1.0 ug/L at the near surface of Phillipsdale to the highest fluorescence results measured at 2.5 m at Bullock Reach, with a maximum of 15.3 mg/m3; phytoplankton activity leading to this elevated fluorescence are also the likely cause of these waters having the second highest DO this week, at 11.5 mg/L.
Water Column Clarity
Water clarity was measured using a Secchi disk at seven locations in the Providence and Seekonk River estuaries on April 12, 2017. The five days leading up to the survey date were dry, with no recordable precipitation measured at TF Green. Secchi depth averaged 1.6 meters over all seven sites, unchanged from the previous survey date, April 5. Secchi depth ranged from a minimum of 1.2 m at Edgewood Yacht Club to a maximum of 1.97 m at Pawtuxet Cove. Two sites exhibited an increase in clarity since the last survey; the largest increase was observed at Pawtuxet Cove, increasing by 0.5 m. Two sites exhibited a decrease since the last survey; the largest decrease was observed at Edgewood Yacht Club, decreasing by 0.5 m. Other sites had not been surveyed recently or remained unchanged from the most recent survey. A north-south water clarity gradient was not apparent this week.
Water Column Clarity
Water clarity was measured using a Secchi disk at seven locations in the Providence and Seekonk River estuaries on April 5, 2017. Heavy rain fell the day prior to sampling, with 1.5 inches recorded at TF Green Airport, and an additional 1.9 inches fell five days prior. Secchi depth averaged 1.6 m over all seven sites, a decrease of 0.5 m since the previous sampling on March 29th. Secchi depth ranged from a minimum of 1.3 meters at Phillipsdale Landing to a maximum of 2.1 m at Edgewood Yacht Club. Each individual site exhibited a decrease in clarity since the last survey; the largest decrease was observed at Phillipsdale Landing and Pomham Rocks, each decreasing by 0.8 m. A north-south water clarity gradient was not apparent this week.
