Snapshot of the Bay

Historical News

Week of April 29 - May 5, 2018

Fixed Site Network

Phillipsdale
This week at Phillipsdale, data revealed good water quality. Over the course of the week there were only trace amounts of rainfall and flow from the Blackstone River decreased as compared to the prior week. Surface salinities were still quite low and remained below 6.0 psu for most of the week. Overall, surface salinity averaged 2.5 psu with a minimum of 0.9 psu, and a maximum of 6.4 psu. Bottom salinity fluctuated with the tides over the course of the week with an average of 11.4 psu and a range of 1.2 psu – 26.1 psu. Surface and bottom temperatures increased considerably by approximately 3-4^oC as compared to last week with surface temperatures averaging 15.5^oC with a range of 11.7^oC – 19.4^oC and bottom temperatures averaging 13.0^oC and ranged between 8.4^oC – 19.2oC. Surface chlorophyll was relatively low though did increase over the week with a weekly average of 1.3 ug/L, with a daily average peak of about 4.5 ug/L. Dissolved oxygen (DO) for the week was very good at both the surface and the bottom though slightly decreased from previous weeks; surface DO had an average of 10.1 mg/L and a range of 8.6 mg/L – 11.5 mg/L. Dissolved oxygen in the bottom waters had a weekly average of 9.0 mg/l and ranged from a minimum of 7.0 mg/L to a maximum of 11.2 mg/L. Note that tidal fluctuations and Blackstone River flow greatly influence bottom DO, temperature and salinity at this location.

Bullocks Reach
The sondes at Bullocks Reach were removed for the season in November 2017. Staff is currently testing and preparing new equipment for deployment. It is anticipated that the station will be operational again for the season in May/June 2018.

Week of May 13 – May 19, 2018

Bacteria Sampling

Twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers on May 16, 2018. A total of 0.71 inches of rain occurred during the five days prior to sampling.

Fecal coliform geometric mean increased from the previous week to 254 MPN/100 mL. The fecal coliform geomean was higher in the Seekonk River (1079 MPN/100 mL) compared to the Providence River (129 MPN/100 mL). The maximum fecal coliform concentration (9300 MPN/100mL) was measured at Collier Point Park in the Providence River and at Phillipsdale Landing in the Seekonk River. Fecal coliform concentration results for both rivers were above state guidelines for shellfishing and primary contact.

The Enterococci geometric mean for the Seekonk and Providence Rivers also increased from the previous week to 51 MPN/100 mL. Enterococci concentrations ranged from below detection at two stations to 663 MPN/100 mL at Point Street Bridge. These results are above the state criteria for primary contact.

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.

Week of May 6 - 12, 2018

Water Column Profiles

Water column profiles were measured at eight sites in the Providence and Seekonk Rivers on May 9, 2018. Rainfall over the five days prior to the survey was light, with 0.15 inches recorded on May 6. Stratification was observed at most sites, with warmer and fresher water at the surface and cooler, saline waters at depth. Surface temperatures ranged from 15°C at India Point Park, to 18°C at Phillipsdale Landing, Pawtuxet Cove, and Edgewood Yacht Club. Temperatures at depth ranged from 8°C at Bullock Reach, Conimicut Point, and India Point Park, to 13°C at Pomham Rocks, Pawtuxet Cove, and Edgewood Yacht Club. Surface salinity ranged from 2 PSU at Phillipsdale Landing and Pawtuxet Cove, to 20 PSU at Conimicut Point. Salinity at depth ranged from 24 PSU at Pawtuxet Cove and Pomham Rocks, to 30 PSU at Bullock Reach and Conimicut Point.

Oxygen levels were high this week and hypoxic conditions were not observed. DO concentrations ranged from 5.8 mg/L to 15.5 mg/L. Lastly, the maximum fluorescence, 26 mg/m³, was observed at a depth of 2 meters at Edgewood Yacht Club and Pomham Rocks.

Week of May 13 - 19. 2018

Surface Mapping

Data was collected on May 16, 2018 while the R/V Monitor was underway collecting bacteria samples and performing vertical profiles in the Providence and Seekonk River estuaries. The chlorophyll concentrations were good to fair in areas surveyed with evidence of a slight north-south gradient. From north to south, average chlorophyll concentrations were as follows: Seekonk River (3.58 µg/l), Upper Providence River (5.08 µg/l), Edgewood Shoals area (7.79 µg/l), Pawtuxet River area (5.19 µg/l), and the Lower Providence River (6.41 µg/l). Overall, chlorophyll ranged between non-detectable and 12.20 µg/l with an overall average of 5.28 µg/l. The chlorophyll data from this date is presented in the map below:

Dataflow 2018-05-16_small.jpg

Week of May 13 - 19, 2018

R/V Monitor's Blog

On Wednesday, May 16th, the crew of the R/V Monitor was out on the upper Bay collecting bacteria samples, taking Secchi Disk and Par sensor water clarity measurements, conducting water column profiles using the Seabird instrument, 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. It was a partly cloudy day with a breeze out of the west, and a couple of brief showers occurred in the morning. The water was fairly calm this day, but mucky as a result of the rain the prior evening. The photo shown below was taken at the Conimicut Point Lighthouse, where a fisherman was enjoying the day.

5-16-18 Conimicut Light.jpg