Nutrients Sampling

Nutrient samples were collected from seven bay stations on January 10th; seven local river stations and one bay station were sampled on January 11th. Sampling was split over two days due to boating safety concerns on the routine scheduled day due to weather. All of the bay stations were sampled at the surface and bottom. In the five days prior to sampling, 0.18 inches of precipitation were recorded at T.F. Green.

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 @ Roger Williams Ave. (TN = 1,910 ppb, TDN = 1,930 ppb, DIN = 1,550 ppb, average of duplicates). The lowest TN, TDN, and DIN were observed at Moshassuck River @ Higginson Ave. (TN = 704 ppb, TDN = 756 ppb, DIN = 547 ppb).

Among the bay stations sampled, the highest surface nitrogen concentrations were observed at Pawtuxet Cove (TN = 1,320 ppb, TDN = 1,230 ppb, DIN = 1,030 ppb); the lowest surface nitrogen concentrations were observed at Bullock Reach (TN = 523 ppb, TDN = 439 ppb, DIN = 285 ppb). Chlorophyll a concentrations at the surface bay stations were relatively low, averaging 0.920 μg/L across all sites with a maximum of 1.663 μg/L at Bullock Reach Buoy. 

Data from additional sampling dates (typically every two weeks) are pending analysis and writeup.

Nutrient samples were collected from seven local river stations and one bay station on December 28th; additional bay sampling was cancelled due to freezing temperatures. The lone bay station (Phillipsdale Landing) was sampled at the surface and bottom. Leading up to sampling, there were 1.17 inches total precipitation recorded at T.F. Green on the 23rd and no precipitation on the 24th – 27th.

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 = 1,580 ppb, TDN = 1,710 ppb, DIN = 1,350 ppb). The lowest TN was observed at Woonasquatucket River @ Valley St. (TN = 651 ppb); the lowest TDN and DIN were observed Woonasquatucket River @ Manton Ave. Bridge (TDN = 680 ppb, DIN = 463 ppb).

At the one bay station sampled, Phillipsdale Landing, surface TN was 1,130 ppb, surface TDN was 1,160 ppb, and surface DIN was 899 ppb.

Data from additional sampling dates (typically every two weeks) are pending analysis and writeup.