Historical News
Fixed Site Network
The Bullock's Reach sondes are currently out for the winter season and are expected to be deployed in May. The Phillipsdale sondes were deployed for the 2017 monitoring season on April 14th.
R/V Monitor's Blog
On Wednesday, April 12th, the crew of the R/V Monitor was out on the upper Bay collecting nutrients and plankton 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. Sara captained the boat while monitoring professionals Michael and Amanda collected the samples and data. Karen, NBC's data analyst, also joined the crew in the morning to review sample collection and handling protocols. It was a partly sunny morning with clouds rolling in by the afternoon, but the temperature was mild all day and there was no wind, making for calm waters and a fantastic day on the upper Bay. Staff observed the US Coast Guard cleaning markers at Pawtuxet Cove as shown in the photo below.
Surface Mapping
Data was collected on April 12, 2017 while the R/V Monitor was underway collecting nutrient samples and performing vertical profiles in the Providence and Seekonk River estuaries. The chlorophyll concentrations were variable but fair in areas surveyed. The lowest average chlorophyll concentrations were observed in the Seekonk River (8.19 µg/l) and Pawtuxet Cove area (6.83 µg/l). The highest average concentrations were seen in the Edgewood Shoals area (12.86 µg/l) and the Lower Providence River (12.81 µg/l). Overall, chlorophyll ranged between non-detectable and 121.8 µg/l with an overall average of 10.88 µg/l. The chlorophyll data from this date is presented in the map below:
Bacteria Sampling
Twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers on March 22, 2017. Five of these stations were additionally sampled for Enterococci bacteria. Sampling occurred after five days of no rain.
Fecal coliform concentrations were higher in the Seekonk River than in the Providence River, although the maximum fecal concentration was measured in the Providence River. The geometric mean of fecal coliform was 11 MPN/100 mL in the Seekonk and 6 MPN/100 mL in the Providence River. The maximum fecal coliform concentration measured was 93 MPN/100 mL at Point Street Bridge and Collier Point Park in the Providence River. Fecal coliform concentrations for both rivers were within state criteria for primary contact and shellfishing. The overall fecal coliform geometric mean for both rivers was 8 MPN/100 mL. The last time this measurement was this low was July 27, 2016.
The geometric mean of Enterococci concentrations was 12 MPN/100 mL, which is below the state primary contact criteria. The highest Enterococci concentration, 31 MPN/100 ML, was observed at Point Street Bridge.
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.
Nutrients Sampling
Seven river stations and seven bay stations were sampled for nutrients on Wednesday, March 1, 2017. Bay stations were sampled at the surface and at depth. A total of 0.15 inches of rain fell during the five days prior to sampling, including 0.03 inches of rain early in the morning on March 1st. Among the river locations, the highest nutrient concentrations were observed on the Pawtuxet River at Broad Street, where concentrations of 2,060 ppb total nitrogen (TN), 1,990 ppb total dissolved nitrogen (TDN), and 1,701 ppb dissolved inorganic nitrogen (DIN) were measured. The lowest river nutrient concentrations were observed on the Moshassuck River at Higginson Avenue, where concentrations of 742 ppb TN, 684 ppb TDN, and 493 ppb DIN were measured. These two locations also had the high and low nutrient values on the last date of sampling, February 15th.
In the bay, the highest surface nutrient concentrations were measured at the Pawtuxet Cove, which had a TN concentration of 1,750 ppb, a TDN concentration of 1,470 ppb, and a DIN concentration of 1,036 ppb. The lowest surface TN was measured at the Bullock Reach buoy, with a concentration of 573 ppb, while the lowest surface TDN and DIN concentrations were measured at the Conimicut Point station, with respective concentrations of 152 ppb and 40 ppb. Chlorophyll a concentrations ranged from a low of 3.7 ug/L at Phillipsdale Landing to a high of 30.7 ug/L at Conimicut Point. Overall chlorophyll a averaged 16.4 ug/L at the seven bay stations, a large increase compared to the average chlorophyll measured on February 1, 2017.
Results from nutrient sampling done on March 15th and 29th are pending analysis from the NBC Laboratory. The next anticipated sampling date for nutrients is April 12th.
