Nutrient samples were collected from 14 river stations and 8 bay stations on September 20th, 2023. Edgewood Shoal was sampled at the surface and bottom; all other bay stations were sampled at the surface only. In the five days prior to sampling, there were 1.55 inches of rainfall recorded at T.F. Green with the majority accumulated during a heavy rain event on September 18th.
Among the river stations sampled, the highest total nitrogen (TN), total dissolved nitrogen (TDN), and dissolved inorganic nitrogen (DIN) concentrations were observed at Ten Mile River at Roger Williams Ave. (TN = 1,305 ppb, TDN = 1,195 ppb, DIN = 771.5 ppb; all averaged with duplicates). The lowest TN and TDN were observed at Woonasquatucket River @ Valley St. (TN = 665 ppb, TDN = 635 ppb), while the lowest DIN was at Coles River @ Milford Rd. (DIN = 139.2 ppb).
Among the bay stations sampled, the highest surface TN, TDN, and DIN concentrations were observed at Pawtuxet Cove (TN = 1,120 ppb, TDN = 1,070 ppb, DIN = 638.3 ppb). The lowest surface TN was observed at Conimicut Point (TN = 799 ppb), while the lowest surface TDN and DIN were observed at Bullock Reach (TDN = 607 ppb, DIN = 300 ppb). Chlorophyll a concentrations at the surface bay stations averaged 2.8 μg/L overall with a maximum of 4.2 μg/L at Bullock Reach Buoy.