Historical News
Nutrients Sampling
Nutrient samples were collected from the surface waters at eight bay stations on September 23rd; samples were also collected from bottom waters at one of these stations. Nutrient samples were also collected at fourteen local and border river stations. In the three days prior to sampling there was no recorded rainfall.
Among the river stations samples, the highest total nitrogen (TN), total dissolved nitrogen (TDN), and dissolved inorganic nitrogen (DIN) were all observed at Ten Mile River at Central Avenue. At this site, concentrations for TN, TDN, and DIN were 2,340 ppb, 2,460 ppb, and 1,821 ppb, respectively. The lowest TN (516 ppb) and TDN (252 ppb) results were observed at Pawtuxet River at Broad Street, while the lowest TDN (13 ppb) result was observed at Palmer River at Route 6.
Among the bay stations sampled, the highest TN (924 ppb) in surface waters was observed at Phillipsdale Landing, with the greatest surface TDN (455 ppb), and DIN (228 ppb) observed at Pawtuxet River at Broad Street. The lowest surface TN (422 ppb) result was observed at Edgewood Yacht Club, while the lowest surface TDN (187 ppb) and DIN (13 ppb) results were observed at Conimicut Point and Phillipsdale Landing, respectively. Chlorophyll a concentrations averaged 11.7 ug/L, with a maximum result of 50.2 ug/L occurring at Phillipsdale Landing.
Results from nutrients sampling on October 7th and 21st are pending analysis. The next scheduled date of sampling is November 4th, 2020.
Nutrients Sampling
Nutrient samples were collected at six bay stations and seven local and border river stations on Sept 10, 2020; all bay stations were sampled at the surface and bottom waters. Approximately 0.03 inches of rainfall was recorded on the sampling day with no recorded rainfall in the three days prior.
Among the river stations sampled, the highest total nitrogen (TN), total dissolved nitrogen (TDN), and dissolved inorganic nitrogen (DIN) were all observed at Pawtuxet River at Broad Street. At this site, concentrations for TN, TDN, and DIN were 1,680 ppb, 1,740 ppb, and 1,496 ppb, respectively. The lowest TN result was observed at Moshassuck River at Higginson Avenue, with 671 ppb. The lowest TDN (721 ppb) and DIN (381 ppb) results were observed at Ten Mile River at Roger Williams Avenue site.
Among the bay stations sampled, the greatest TN (705 ppb) in surface waters was observed at Edgewood Shoal (duplicate sample), with the greatest surface TDN (346 ppb), and DIN (127 ppb) observed at Phillipsdale Landing. The lowest surface TN (491 ppb) occurred at Bullock Reach Buoy, while the lowest TDN (187 ppb) and DIN (13 ppb) occurred at Conimicut Point and Edgewood Shoal, respectively. Chlorophyll a concentrations averaged 23.2 ug/L, with a maximum result of 33.9 ug/L occurring at India Point Park.
Results from nutrients sampling on September 23, October 7 and 21 are pending analysis. The next scheduled date of sampling is November 4, 2020.
Water Column Profiles
Water column profiles were measured at eight locations in the Providence and Seekonk Rivers on October 28, 2020. There was 0.20 inches of total rainfall recorded on the day of sampling, with no rainfall recorded in the three days prior. Water column profiles across all sites exhibited relatively well-mixed conditions.
Surface salinities were highest at Pomham Rocks (30 psu), and lowest at Phillipsdale Landing (26 psu). The highest bottom salinity (31 psu) was observed four locations: Bullock Reach Buoy, Conimicut Point, Point Street Bridge, and Pomham Rocks. Bottom salinity was lowest at Pawtuxet Cove and Phillipsdale Landing (29 psu). The warmest waters overall were observed at Point Street Bridge, from 18.9°C at the surface to 16.7°C at the bottom. The coolest surface waters (15.0°C) were observed at Conimicut Point, while the coolest bottom waters (16.3°C) were observed at three locations: Bullock Reach Buoy, Conimicut Point, and Pawtuxet Cove.
This week, hypoxic conditions (e.g., dissolved oxygen [DO] concentrations <2.9 mg/L) were not observed at any of the sites. Surface and bottom DO ranged from 5 to 8 mg/L across all sites. Please note that due to a quality control issue, numerical fluorescence data are not posted at this time.
Water Column Profiles
Water column profiles were measured at eight locations in the Providence and Seekonk Rivers on October 21, 2020. In the three days prior to sampling, 0.26 inches of total rainfall was recorded. Most sites exhibited well-mixed conditions, though moderate salinity stratification was evident at Phillipsdale Landing and Pawtuxet Cove.
Surface salinities were highest at Pomham Rocks (27 psu), and lowest at Pawtuxet Cove (9 psu). The highest bottom salinity (31 psu) was observed at Conimicut Point, while the lowest (26 psu) was observed at Edgewood Yacht Club. Surface water temperatures were warmest at Edgewood Shoal and India Point Park (17.4°C), with the coolest surface temperatures observed at Phillipsdale Landing (16.3°C). Phillipsdale Landing exhibited the warmest bottom waters (16.8°C), while the coolest bottom waters were observed at Bullock Reach Buoy and Pomham Rocks (16.3°C).
This week, hypoxic conditions (e.g., dissolved oxygen [DO] concentrations <2.9 mg/L) were not observed at any of the sites. Surface and bottom DO ranged from 4 to 9 mg/L across all sites. Please note that due to a quality control issue, numerical fluorescence data are not posted at this time.
Water Column Profiles
Water column profiles were measured at eight locations in the Providence and Seekonk Rivers on October 15, 2020. In the three days prior to sampling 1.11 inches of total rainfall was recorded. Most sites exhibited a well-mixed water column, though moderate salinity stratification was evident at Phillipsdale Landing.
Surface salinities were highest at Bullock Reach and Conimicut Point (30 psu), and lowest at Pawtuxet Cove (15 psu). The highest bottom salinity (31 psu) was observed at Pomham Rocks and Conimicut Point, while the lowest (28 psu) was observed at Phillipsdale Landing. The warmest waters overall were observed at Point Street Bridge, from 20.2°C at the surface to 20.1°C at the bottom. The coolest surface waters (16.3°C) were observed at Conimicut Point, while the coolest bottom waters (16.6°C) were observed at Bullock Reach.
This week, hypoxic conditions (e.g., dissolved oxygen [DO] concentrations <2.9 mg/L) were not observed at any of the sites. Surface and bottom DO ranged from 4 to 9 mg/L across all sites. Please note that due to a quality control issue, numerical fluorescence data are not posted at this time.
