Nutrients Sampling

​Nutrient samples were collected from six bay stations and 15 local and border river stations on April 5th, 2023. Most bay stations were sampled at the surface only; one station, Edgewood Shoal, was sampled at the surface and bottom. In the five days prior to sampling, there was 0.5 inches of rainfall recorded at T.F. Green.

Among the river stations sampled, the highest total nitrogen (TN), total dissolved nitrogen (TDN), and dissolved inorganic nitrogen (DIN) were observed at Ten Mile River at Central Ave. The TN, TDN, DIN were 2,300 ppb, 2,000 ppb, and 1,727 ppb, respectively. The lowest TN was observed at Moshassuck River at Higginson Ave as 500 ppb. The lowest TDN and DIN were observed in the duplicates at Palmer River at Route 6. The lowest TDN and DIN were averaging 404.5 ppb and 92.4 ppb, respectively.

Among the bay stations sampled, the highest surface nitrogen concentrations were observed at Pawtuxet Cove. The TN, TDN, and DIN were 1,200 ppb, 990 ppb, and 847.3 ppb, respectively. The lowest surface TN (722 ppb) was observed in one of the duplicate samples collected at Edgewood Yacht Club; the duplicate was higher at 740 ppb. The lowest TDN and DIN were observed at Pomham Rocks as 361 ppb and 241.5 ppb, respectively. Chlorophyll a concentrations at the bay stations have increased (averaging 3.4 ug/L over all sites) since the March 22nd sampling event. The maximum result (6.13 ug/L) occurred at India Point Park. 

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

​Nutrient samples were collected from seven local river stations, and seven bay stations on March 22nd, 2023. All bay stations were sampled at surface and bottom. In the five days prior to sampling, 0.02 inches of rainfall was recorded at T.F. Green. 

Among the river stations sampled, the highest total nitrogen (TN), total dissolved nitrogen (TDN), and dissolved inorganic nitrogen (DIN) were observed at Blackstone River at Slater Mill. The TN, TDN, and DIN were 1,080 ppb, 1,160 ppb, and 885 ppb, respectively. The lowest TN (698 ppb) was observed at Woonasquatucket River at Manton Ave Bridge. The lowest TDN and DIN were observed at one of duplicate samples collected at the Moshassuck River at Footbridge at Mill Street; 697 ppb and 554 ppb, respectively. 

Among the bay stations sampled, the highest TN (1,050 ppb) and TDN (978 ppb) was observed at Phillipsdale Landing. The highest DIN were observed at Pawtuxet Cove as 697.7 ppb. The lowest surface TN (485 ppb), TDN (328 ppb) and DIN (193 ppb) were observed at Conimicut Point. Chlorophyll a concentrations at the bay stations have decreased (averaging 2.66 ug/L over all sites) since the February 22nd sampling event. The maximum result of 4.78 ug/L occurred at India Point Park.

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

Nutrient samples were collected from one bay station and seven local river stations on March 8th, 2023. Bay station Phillipsdale Landing was sampled at the surface and the bottom. In the five days prior to sampling, 0.85 inches of rainfall was recorded at T.F. Green.

Among the river stations sampled, the highest total nitrogen (TN), total dissolved nitrogen (TDN), and dissolved inorganic nitrogen (DIN) were observed in one of the duplicate samples collected at Ten Mile River at Roger Williams Ave. The TN, TDN, and DIN were averaging 1,910 ppb, 1,905 ppb, and 1,647 ppb, respectively. The lowest TN, TDN, and DIN were observed at Moshassuck River at Higginson Ave. The TN, TDN, and DIN were 590 ppb, 609 ppb, and 452 ppb, respectively.

Phillipsdale Landing was the only bay station sampled, and recorded a TN of 958 ppb, TDN of 831 ppb, and a DIN concentration of 644 ppb.  Chlorophyll a concentration has decreased at the Phillipsdale Landing (0.71 ug/L) since it was last sampled on February 22nd. 

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

Nutrient samples were collected from fifteen local and border river stations, and eight bay stations on February 22nd, 2023. The Edgewood Shoal bay station was sampled at surface and bottom while all other bay stations were only sampled at the surface. In the five days prior to sampling, 0.42 inches of rainfall was recorded at T.F. Green. 

Among the river stations sampled, the highest total nitrogen (TN), total dissolved nitrogen (TDN), and dissolved inorganic nitrogen (DIN) were observed at Ten Mile River at Central Ave. The TN, TDN, and DIN were 2,680 ppb, 2,670 ppb, and 2,410 ppb respectively. The lowest total nitrogen (TN), total dissolved nitrogen (TDN), and dissolved inorganic nitrogen (DIN) were observed at Palmer River at Route 6. The TN, TDN, and DIN were 606 ppb, 387 ppb, and 171.9 ppb, respectively. 

Among the bay stations sampled, the highest surface TN, TDN, and DIN concentrations was observed at Phillipsdale Landing as 1,740 ppb, 1,610 ppb, and 1,326 ppb, respectively. The lowest surface TN (551 ppb), TDN (289 ppb) and DIN (166 ppb) were observed at Bullock Reach Buoy. Chlorophyll a concentrations at the bay stations have increased (averaging 5.54 ug/L) since all these sites had previously been sampled in January. The maximum result (10.65 ug/L) occurred at Bullock Reach Buoy.

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

Nutrient samples were collected from one bay station and seven local river stations on February 8th, 2023. Bay station Phillipsdale Landing was sampled at the surface and the bottom. In the five days prior to sampling, 0.05 inches of rainfall was recorded at T.F. Green.

Among the river stations sampled, the highest total nitrogen (TN), total dissolved nitrogen (TDN), and dissolved inorganic nitrogen (DIN) were observed at Ten Mile River at Roger Williams Ave. The TN, TDN, and DIN were 2,310 ppb, 2,370 ppb, and 2,023.9 ppb respectively. The lowest TN, TDN, and DIN were observed in the duplicates at Moshassuck River at Higginson Ave. The TN, TDN, and DIN were averaging 877 ppb, 878 ppb, and 740.6 ppb, respectively.

The Phillipsdale Landing station had TN, TDN, and DIN concentrations of 1,500 ppb, 1,350 ppb, and 1,142 ppb, respectively. Chlorophyll a concentration has decreased at Phillipsdale Landing (0.566 ug/L) since it was last sampled in January. The maximum result (10.65 ug/L) occurred at Bullock Reach Buoy.

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

Nutrient samples were collected from 15 local river stations on January 25th. Bay sampling was cancelled due to a small craft advisory. In the five days prior to sampling, 1.48 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 @ Central Ave. (TN = 1,930 ppb, TDN = 1,980 ppb, DIN = 1,640 ppb). The lowest TN was observed at Palmer River @ Rt. 6 (TN = 624 ppb). The lowest TDN was measured in one of the duplicate samples from Coles River @ Milford Rd. (649 ppb), while the other duplicate was slightly higher at 657 ppb; TDN was similarly low at Palmer River @ Rt. 6 (652 ppb). The lowest DIN was observed at Coles River @ Milford Rd. (DIN = 221 ppb, average of duplicates).

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

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.