Nutrient samples were collected from seven river stations and seven bay stations on July 12th. All bay stations were sampled at the surface and bottom. In the five days prior to sampling, there were 1.91 inches of rainfall recorded at T.F. Green, all from a rain event on July 10th.
Among the river stations sampled, the highest total nitrogen (TN), total dissolved nitrogen (TDN), and dissolved inorganic nitrogen (DIN) concentrations were observed at Pawtuxet River @ Broad St. (TN = 1,140 ppb, TDN = 1,080 ppb, DIN = 796 ppb). The lowest TN and TDN were observed at Woonasquatucket River @ Manton Ave. Bridge (TN = 664 ppb, TDN = 633 ppb, average of duplicates), while the lowest DIN was at Blackstone River @ Stateline (357 ppb).
Among the bay stations sampled, the highest surface TN, TDN, and DIN concentrations were observed at Pawtuxet Cove (TN = 1,100 ppb, TDN = 882 ppb, DIN = 640 ppb, average of duplicates). The lowest surface TN and DIN were observed at Conimicut Point (TN = 577 ppb, DIN < 13.0 ppb), while the lowest surface TDN was at Bullock Reach Buoy (181 ppb). Chlorophyll a concentrations at the surface bay stations were relatively low at most sites and moderately elevated at Edgewood Yacht Club and Pawtuxet Cove; concentrations averaged 5.46 μg/L overall with a maximum of 15.7 μg/L in one of the duplicate samples at Edgewood Yacht Club.
The next scheduled sampling date is July 26, 2023.