Water Column Clarity
Water clarity was measured at six locations in the Providence River on December 4, 2019. Approximately 1.4 inches of rainfall occurred over the three days prior to the survey. The average Secchi depth increased clarity since the last survey on November 4, from 2.4 m to 3.2 m. India Point Park is the only site that exhibited decreased clarity since the previous survey, down 0.2 m. Four sites exhibited increase clarity, the greatest of which was seen at both Conimicut Point and Ponham Rocks (up 0.93 m). The remaining site (Edgewood Shoals) had not been surveyed recently. Water clarity ranged from 2.5 m at India Point Park to 3.6 m at Conimicut Point. Overall, water clarity in Upper Narragansett Bay increased from north to south.
Fixed Site Network
Water quality was good this week at Phillipsdale Landing. The sondes were changed out for routine maintenance on the morning of November 26. Approximately 1.6 inches of precipitation was recorded over the week, with most of the rain occurring on November 24. Surface salinity decreased at Phillipsdale in response to the precipitation and increase in freshwater flow from the Blackstone River. Surface salinity averaged 11.1 ppt and ranged from 2.2 ppt to 24.1 ppt while bottom salinity averaged 21.2 ppt and ranged from 6.4 ppt to 29.3 ppt. Compared to the rest of the November, the water temperatures at both depths continued to cool. Surface temperatures for the week averaged 6.8°C and bottom temperatures averaged 8.1°C. Dissolved oxygen (DO) concentrations continue to be good for the week, remaining above the hypoxia threshold (2.9 mg/L) at both depths. Surface DO averaged 10.9 mg/L with a minimum of 8.3 mg/L and bottom DO averaged 9.2 mg/L with a minimum of 7.8 mg/L. Surface chlorophyll-a remained low all week, averaging 2.1 ug/L with a maximum of 5.4 ug/L. Note that tidal fluctuations and Blackstone River flow greatly influence water column DO, temperature, and salinity at this location.
Due to remote data transfer issues, there are no current Bullock Reach data available since October 19. The data are being internally logged by the sondes, and will be updated to the blog as they become available.
Please note, the Bullock Reach sondes were removed for the 2019 season on November 19.
R/V Monitor's Blog
On Wednesday, December 4th, the crew of the R/V Monitor was out on the upper Bay collecting nutrients 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. Sara captained the boat while monitoring professionals Mike and Fern collected the samples and data. It was a very cloudy day with no wind. A heavy fog in the early morning resulted in a delay getting underway. The photo featured this day shows Field's Point in the foreground with the City of Providence in the background.