Historical News

Week of November 3 - 9, 2019

R/V Monitor's Blog

​The R/V Monitor was out on the upper Bay twice this week.  First, on Tuesday, November 5th, the crew was out servicing the Bullock's Reach and temporary buoys.  Jeff captained the boat while monitoring professionals Bekki and Mike serviced the buoys.  It was a sunny day with no wind and calm waters.  On Wednesday, November 6th , the crew was collecting nutrients samples, taking Secchi Disk and Par sensor water clarity measurements, conducting water column profiles using the Seabird instruments, 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.  Jeff captained the boat while monitoring professionals Fern and Mike collected the samples and data.  It was another sunny day with a slight breeze out of the west-northwest.  There were some small waves out on the Bay this day, and a few elusive seals were spotted. The featured photo shows NBC's Seabird instruments being readied for deployment this day.

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Week of November 3 – November 9, 2019

Surface Mapping

​Data were collected on November 6, 2019 while the R/V Monitor was underway collecting nutrient samples in the Seekonk and Providence River estuaries. The chlorophyll concentrations were good. From north to south, average chlorophyll concentrations were as follows: Seekonk River (2.98 µg/L), Upper Providence River (2.40 µg/L), Edgewood Shoals area (2.35 µg/L), Pawtuxet River area (2.88 µg/L), and Lower Providence River area (3.18 µg/L). Overall, chlorophyll ranged between 0.80 and 5.20 µg/L with an overall average of 2.79 µg/L.  The chlorophyll data from this date are presented in the map below:​​Dataflow 2019-11-06 small.jpg

Week of October 20 - 26, 2019

Water Column Clarity

Water clarity was measured at six locations in the Providence and Seekonk Rivers on October 24, 2019. Approximately 0.53 inches of rainfall occurred the day prior to the survey. The average Secchi depth increased since the last survey on September 25, from 1.5 m to 3.3 m. All sites exhibited increased clarity since the previous survey, with the greatest increase (2.8 m) observed at Conimicut Point. Water clarity ranged from 2.3 m at Pawtuxet Cove to 4.7 m at Conimicut Point.  Overall, water clarity in Upper Narragansett Bay increased from north to south.

Week of October 13 - 19, 2019

Fixed Site Network

Phillipsdale Landing
Water quality was good to fair this week at Phillipsdale Landing. The sondes were changed for routine maintenance on the morning of October 16. Approximately 1.8 inches of precipitation occurred over the course of the week, nearly all on October 16 and 17. This rain and subsequent increases in freshwater river flow contributed to declines in salinities mid-week​​​​. Surface salinity averaged 16.5 ppt, and ranged from 2 ppt to 28 ppt. Some of this week’s bottom salinity data were deemed suspect by NBC scientists. These data appeared anomalously low, believed to be due to bottom debris and snails that were observed in the cage around the sensors when the sonde was retrieved on October 16. The remaining data (October 16 late morning – October 19) averaged 20.5 ppt for bottom salinity, ranging 3 – 31 ppt. Water temperatures cooled slightly this week, averaging 15.4°C at the surface and 16.0°C at the bottom overall. Hypoxic conditions (dissolved oxygen [DO] <2.9 mg/L) were observed in the bottom waters briefly on October 16 (30 min maximum duration), where DO concentrations hit a minimum of 1.4 mg/L. Surface DO remained above the hypoxia threshold all week, averaging 7.8 mg/L with a minimum of 5.8 mg/L. Surface chlorophyll-a was low for most of the week, with an overall average of 5.1 ug/L and a maximum of 19.4 ug/L. Note that tidal fluctuations and Blackstone River flow greatly influence water column DO, temperature, and salinity at this location.

Bullock Reach
Bullock Reach data for late October are in review by NBC Scientists – at this time the only data available are partial for this week, ending mid-day on October 19. Additional data will be posted and discussed as they are reviewed. 

Good water quality was observed this week at Bullock Reach. Water temperatures continue to cool, averaging 15.7°C at the surface and mid depths and 15.4°C at the bottom. Surface salinity averaged 28.3 ppt, ranging from 24 ppt to 30 ppt. Salinity values at the mid and bottom sondes averaged 29.9 ppt and 31.9 ppt, respectively. Salinity at all depths decreased over the course of the week; this was most pronounced for the surface waters, most impacted by the mid-week rainfall. There were no recorded measurements of hypoxia (DO <2.9 mg/L) at any depths. For the week overall, surface DO averaged 8.0 mg/L with a minimum of 7.3 mg/L, mid averaged 7.7 mg/L with a minimum of 7.3 mg/L, and bottom averaged 7.5 mg/L with a minimum of 6.8 mg/L. Chlorophyll at all depths remained low this week, averaging 3.4 ug/L at the surface, 2.7 ug/L at the mid, and 3.5 ug/L at the bottom.

Week of October 27 - November 2, 2019

Bacteria Sampling

​Eleven stations were sampled for fecal coliform bacteria and three stations were sampled for enterococci in the Providence River on October 30, 2019. Bacteria samples were not collected in the Seekonk River due to the presence of thick fog. Three days prior to sampling, 1.4 inches of rainfall occurred.

The geometric mean of the eleven stations sampled for fecal coliform in the Providence River was 76 MPN/100 mL; the highest result occurred at Bullock Reach Buoy, with a reading of 230 MPN/100 mL. Providence River fecal coliform results exceeded standards for primary contact and shellfishing.

Enterococci results ranged from 10 MPN/100 mL at Conimicut Point to 108 MPN/100 mL at Gaspee Point, with an overall geometric mean of 31 MPN/100 mL. The Providence River enterococci geometric mean was less than the primary contact geometric mean criterion of 35 MPN/100 mL, however, the single sample maximum criterion of 104 MPN was exceeded.

Please note: the results of NBC's fecal coliform and enterococci monitoring are for informational/research purposes only and are not intended to suggest official state compliance with bathing or shellfishing standards.

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