Historical News
Nutrients Sampling
On January 3, 2018, five river stations were sampled for nutrients. Due to inclement weather, not all stations were able to be sampled. The weather during the three days prior to sampling was very cold, with little to no precipitation in the three days prior to sampling.
Among the five river stations sampled, the highest total dissolved nitrogen (TDN), total nitrogen (TN), and dissolved inorganic nitrogen (DIN) were observed on Pawtuxet River with measurements of 1815 ppb, 1840, and 1542 ppb, respectively. The lowest nitrogen values were measured at the Moshassuck River at Higginson Ave with values of 827 ppb for TDN, 888 ppb for TN, and 644 ppb for DIN.
Results from nutrient sampling completed on January 17, January 31, and February 14 are pending analysis from the NBC Laboratory. The next anticipated nutrients sampling data is February 28, 2018.
Surface Mapping
Data was collected on February 21, 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 in areas surveyed with evidence of a slight north-south gradient. From north to south, average chlorophyll concentrations were as follows: Seekonk River (1.45 µg/l), Upper Providence River (0.95 µg/l), Edgewood Shoals area (0.93 µg/l), Pawtuxet River area (0.92 µg/l), and the Lower Providence River (0.92 µg/l). Overall, chlorophyll ranged between non-detectable and 6.8 µg/l with an overall average of 1.09 µg/l. The chlorophyll data from this date is presented in the map below:
Water Column Clarity
Water clarity was measured at five locations in the Providence and Seekonk Rivers on February 21, 2018. A total of 0.86 inches of precipitation occurred during the five days prior to sampling. Overall, clarity increased from the previous week. The overall Secchi depth averaged 2.8 meters, a 0.7 m increase from the previous sampling. The largest increases (1.1 m) occurred at the two southernmost sites, Conimicut Point and Bullock Reach. Secchi depth ranged from 2.0 m at Phillipsdale Landing in the Seekonk River to 3.5 m at Conimicut Point, in the Providence River. Water clarity was higher at the southernmost stations, closer to Narragansett Bay.
Water Column Clarity
Water clarity was measured at six stations in the Providence River estuary on February 14, 2018. The five days prior to sampling were rainy, with a precipitation total of 1.49 inches. Secchi depth ranged from 1.5 m at India Point Park to 2.6 m at Pomham Rocks, with no evidence of a north to south gradient in water clarity. Overall, the average Secchi depth was 2.1 meters, a decrease of 0.5 m in comparison to the previous sampling on December 20, 2017. The largest decrease of 1.3 m was observed at Edgewood Yacht Club.
R/V Monitor's Blog
On Wednesday, February 14th, the crew of the R/V Monitor was out on the upper Bay collecting nutrients and plankton 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. Jeff captained the boat while monitoring professionals Dave, Mike, and Heather collected the samples and data. Sara replaced Heather in the afternoon. The weather was cloudy and cool in the morning, warming up nicely in the afternoon with some sunshine and a light breeze. The water was relatively calm all day. Below is a picture taken of a cargo ship leaving port this day.
