Tara Franey – Narrabay

September 10, 2025

Surface chlorophyll data were collected on September 10, 2025, while the R/V Monitor was underway collecting nutrient samples in the Providence and Seekonk River estuary. The average chlorophyll concentrations were categorized as good in the Northern Providence River Channel and the Seekonk River, and as fair in all other areas. The average chlorophyll concentrations were categorized as fair over all areas surveyed. Overall, chlorophyll ranged from 2.34 µg/L to 36.38 µg/L with an average of 6.79 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.

September 3, 2025

Surface chlorophyll data were collected on September 3, 2025, while the R/V Monitor was underway collecting nutrient samples in the Providence and Seekonk River estuary. The average chlorophyll concentrations were categorized as good in the Southern Providence River Channel, poor in the Seekonk River, and as fair in all other areas. The average chlorophyll concentrations were categorized as fair over all areas surveyed. Overall, chlorophyll ranged from 2.31 µg/L to 38.36 µg/L with an average of 11.11 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.

August 27, 2025

Surface chlorophyll data were collected on August 27, 2025, while the R/V Monitor was underway collecting nutrient samples in the Providence and Seekonk River estuary. The average chlorophyll concentrations were categorized as good in the Northern Providence River Channel, poor in the Seekonk River, and as fair in all other areas. The average chlorophyll concentrations were categorized as poor over all areas surveyed. Overall, chlorophyll ranged from 1.43 µg/L to 610.7 µg/L with an average of 30.00 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.

August 13, 2025

Surface chlorophyll data were collected on August 13, 2025, while the R/V Monitor was underway collecting nutrient samples in the Providence and Seekonk River estuary. The average chlorophyll concentrations were categorized as poor in the Seekonk River, and as fair in all other areas. The average chlorophyll concentrations were categorized as poor over all areas surveyed. Overall, chlorophyll ranged from 2.01 µg/L to 610.0 µg/L with an average of 21.56 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.

August 6, 2025

Nutrient samples were collected from thirteen river on August 6^th. In the five days prior to sampling, 0.46 inches of precipitation were recorded at T.F. Green.

Among the river stations sampled, the highest total nitrogen (TN) was observed at Pawtuxet River @ Broad St. (1,450 ppb). The highest total dissolved nitrogen (TDN) and dissolved inorganic nitrogen (DIN) were observed at Ten Mile River @ Central Ave. (TDN = 1,315 ppb, DIN = 1,058.8 ppb, averages of duplicates). The lowest TN was observed at Runnins River @ River Rd. (386 ppb), and the lowest TDN was observed at Taunton River @ Berkley Bridge (303 ppb). The lowest DIN was observed at Palmer River @ Rt. 6 (13 ppb, reflecting minimum detection limits for DIN).

The next scheduled sampling date is August 20^th, 2025.

July 23, 2025

Nutrient samples were collected from seven river stations and seven bay stations on July 23^rd. All bay stations were sampled at the surface and bottom. In the five days prior to sampling, trace amounts 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) were observed at Pawtuxet River @ Broad St. (TN = 1,430 ppb, TDN = 1,390 ppb, DIN = 1,222.9 ppb). The lowest TN, TDN, and DIN were observed at Blackstone River @ Bikepath Bridge (TN = 789 ppb, TDN = 794 ppb, DIN = 509.5 ppb).

Among the bay stations sampled, the highest surface TN, TDN, and DIN were observed at Pawtuxet Cover (TN = 1,200 ppb, TDN = 838 ppb, DIN = 628.6 ppb). The lowest surface TN and TDN were observed at Edgewood Yacht Club (TN = 493 ppb, TDN = 195 ppb). The lowest surface DIN was observed at four of the seven bay stations (13 ppb, reflecting minimum detection limits for DIN).

The next scheduled sampling date is August 6^th, 2025.

July 8, 2025

Nutrient samples were collected from thirteen river stations and eight bay stations on July 8^th. All bay stations were sampled at the surface; Edgewood Shoals was sampled at the surface and bottom. In the five days prior to sampling, there were 0.55 inches of precipitation 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 Pawtuxet River @ Broad St. (TN = 1,360 ppb, TDN = 1,350 ppb, DIN = 1,044.4 ppb). The lowest TN was observed at Runnings River @ River Rd. (617 ppb). The lowest TDN and DIN were observed at Palmer River @ Rt. 6 (TDN = 374 ppb, DIN = 21.3 ppb).

Among the bay stations sampled, the highest surface TN and TDN were observed at Phillipsdale Landing (TN = 1,200 ppb, TDN = 509 ppb). The highest DIN was observed at Pawtuxet Cove (189 ppb). The lowest surface TN and TDN were observed at Conimicut Point (TN = 538 ppb, TDN = 164 ppb). The lowest surface DIN was observed at Conimicut Point and India Point Park (13 ppb, reflecting minimum detection limits for DIN).

The next scheduled sampling date is July 23^rd, 2025.

June 30 – July 6, 2025

Phillipsdale Landing

Sondes were swapped this week on July 1^st. Overall, water quality at Phillipsdale Landing was poor to good this week. Weather conditions were moderately rainy this week, with a total of 0.55 inches recorded at T.F. Green, and the majority of rainfall occurring on the 3^rd. Blackstone River flow reached its peak on July 3^rd, where the flow was similar to the 20-year daily median flow, but was otherwise below the 20-year daily median value for the rest of the week. Salinity at the surface averaged 15.5 ppt and ranged from 6.5 ppt to 23.3 ppt. At the bottom, salinity averaged 23.8 ppt and ranged from 16.1 ppt to 28.5 ppt. Temperatures this week averaged 24.6 °C at the surface and 22.3 °C at the bottom. Surface temperatures ranged from 21.8 °C to 28.5 °C, while bottom temperatures ranged from 20.2 °C to 24.9 °C.

Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold (i.e., DO >2.9 mg/L) at the surface, but below the hypoxia threshold at the bottom for most of the week. Hypoxic conditions were observed at the surface briefly during the morning on July 1^st. Hypoxic conditions were observed at the bottom for multiple extended periods from July 2^nd to July 6^th, including one 21-hour period from the evening of July 2^nd to the evening of July 3^rd. Surface DO averaged 9.4 mg/L and ranged from 2.8 to 20.8 mg/L. Bottom water DO concentration averaged 2.8 mg/L and ranged from 0.8 mg/L to 8.8 mg/L. Chlorophyll ranged from low to elevated levels throughout the week, averaging 38.6 ug/L at the surface and 34.7 ug/L at the bottom, with evidence of substantial phytoplankton blooms occurring throughout the week. Maximum surface chlorophyll readings reached 113.1 ug/L on the afternoon of July 5^th. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.

Bullock Reach

Overall, water quality ranged from fair to good at Bullock Reach this week. Salinity averaged 27.0 ppt, 29.0 ppt, and 30.8 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged from 24.9 to 28.7 ppt, mid salinity ranged from 26.2 to 30.8 ppt, and bottom salinity ranged from 29.3 to 31.9 ppt. Surface temperature averaged 23.4 °C and ranged from 21.4 °C to 25.3 °C. Mid temperatures averaged 22.3 °C and ranged from 20.0 °C to 24.5 °C. Bottom temperatures averaged 20.2 °C and ranged from 19.0 °C to 23.3 °C.

DO at Bullock Reach remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO averaged 7.4 mg/L and ranged from 5.2 to 10.2 mg/L. In the mid waters, DO averaged 5.9 mg/L and ranged from 3.9 to 8.6 mg/L. At the bottom, DO averaged 4.6 mg/L and ranged 3.0 to 7.1 mg/L. Chlorophyll readings ranged from low to moderate, with evidence of moderate phytoplankton blooms occurring throughout the week. Readings averaged 10.1 µg/L at the surface, 13.1 µg/L at mid-depth, and 9.2 µg/L at the bottom. The maximum surface chlorophyll was 32.8 µg/L on the afternoon of July 4^th.

June 23 – June 29, 2025

Phillipsdale Landing

Overall, water quality at Phillipsdale Landing was poor to good this week. Weather conditions were relatively dry this week, with a total of 0.07 inches recorded at T.F. Green, and the majority of rainfall occurring on the 26^th. Blackstone River flow decreased slightly over the course of the week, and remained below the 20-year daily median flow. Salinity at the surface averaged 20.6 ppt and ranged from 14.3 ppt to 25.3 ppt. At the bottom, salinity averaged 23.4 ppt and ranged from 4.6 ppt to 27.2 ppt. Temperatures this week averaged 22.3 °C at the surface and 21.4 °C at the bottom. Surface temperatures ranged from 19.8 °C to 26.4 °C, while bottom temperatures ranged from 19.4 °C to 24.6 °C.

Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold (i.e., DO >2.9 mg/L) for most of the week. Hypoxic conditions were observed at the surface briefly during early morning on June 27^th and June 29^th. Hypoxic conditions were observed at the bottom for multiple hours in the early morning of June 27^th, briefly in the evening of June 28^th, and for multiple hours in the evening of June 29^th. Surface DO averaged 7.3 mg/L and ranged from 2.8 to 15.1 mg/L. Bottom water DO concentration averaged 5.3 mg/L and ranged from 2.3 mg/L to 12.3 mg/L. Chlorophyll ranged from low to elevated levels throughout the week, averaging 22.2 ug/L at the surface and 16.1 ug/L at the bottom, with evidence of moderate phytoplankton blooms occurring throughout the week. Maximum surface chlorophyll readings reached 92.1 ug/L on the early morning of June 27^st. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.

Bullock Reach

Sondes were swapped this week on June 24^th. Overall, water quality ranged from fair to good at Bullock Reach this week. Salinity averaged 26.1 ppt, 28.4 ppt, and 30.4 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged from 22.2 to 29.1 ppt, mid salinity ranged from 24.9 to 30.6 ppt, and bottom salinity ranged from 28.4 to 31.4 ppt. Surface temperature averaged 22.6 °C and ranged from 20.2 °C to 26.5 °C. Mid temperatures averaged 21.1 °C and ranged from 19.2 °C to 24.6 °C. Bottom temperatures averaged 19.1 °C and ranged from 17.4 °C to 20.6 °C.

DO at Bullock Reach remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO averaged 7.6 mg/L and ranged from 5.1 to 11.3 mg/L. In the mid waters, DO averaged 6.0 mg/L and ranged from 3.9 to 9.7 mg/L. At the bottom, DO averaged 4.9 mg/L and ranged 3.9 to 6.3 mg/L. Chlorophyll readings ranged from low to moderate, with evidence of moderate phytoplankton blooms occurring throughout the week. Readings averaged 10.1 µg/L at the surface, 12.5 µg/L at mid-depth, and 9.8 µg/L at the bottom. The maximum surface chlorophyll was 42.7 µg/L on the afternoon of June 28^th.

June 16 – June 22, 2025

Phillipsdale Landing

Sondes were swapped this week on June 17^th. Overall, water quality at Phillipsdale Landing was fair to good this week. Weather conditions were slightly drier than the previous week, with a total of 0.21 inches recorded at T.F. Green, and the majority of rainfall occurring on the 17^th. Blackstone River flow remained near the 20-year daily median until the end of the week, when flows declined below the 20-year daily median values. Salinity at the surface averaged 13.1 ppt and ranged from 3.1 ppt to 21.7 ppt. At the bottom, salinity averaged 21.5 ppt and ranged from 3.1 ppt to 27.9 ppt. Temperatures this week averaged 21.1 °C at the surface and 19.0 °C at the bottom. Surface temperatures ranged from 17.7 °C to 25.6 °C, while bottom temperatures ranged from 16.0 °C to 22.4 °C.

Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO averaged 9.0 mg/L and ranged from 4.4 to 17.1 mg/L. Bottom water DO concentration averaged 5.6 mg/L and ranged from 3.9 mg/L to 10.4 mg/L. Chlorophyll ranged from low to moderate levels throughout the week, averaging 21.4 ug/L at the surface and 17.1 ug/L at the bottom. Maximum surface chlorophyll readings reached 92.1 ug/L on the morning of June 21^st. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.

Bullock Reach

Overall, water quality ranged from fair to good at Bullock Reach this week. Salinity averaged 24.7 ppt, 26.8 ppt, and 29.9 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged from 21.5 to 26.6 ppt, mid salinity ranged from 23.6 to 28.7 ppt, and bottom salinity ranged from 27.9 to 31.0 ppt. Surface temperature averaged 20.6 °C and ranged from 18.3 °C to 23.4 °C. Mid temperatures averaged 19.5 °C and ranged from 16.5 °C to 22.7 °C. Bottom temperatures averaged 16.7 °C and ranged from 15.1 °C to 20.1 °C.

DO at Bullock Reach remained above the hypoxia threshold (i.e., DO >2.9 mg/L) throughout the week. Surface DO averaged 9.5 mg/L and ranged from 7.0 to 12.8 mg/L. In the mid waters, DO averaged 7.5 mg/L and ranged from 4.9 to 9.7 mg/L. At the bottom, DO averaged 4.7 mg/L and ranged 3.6 to 6.7mg/L. Chlorophyll readings ranged from low to elevated, with evidence of moderate phytoplankton blooms occurring throughout the week. Readings averaged 18.2 µg/L at the surface, 18.2 µg/L at mid-depth, and 6.5 µg/L at the bottom. The maximum surface chlorophyll was 63.8 µg/L on the evening of June 20^th.