Assessment of Narragansett Bay Assessment of Narragansett Bay Waters using data from the Fixed-Site Waters using data from the Fixed-Site

Water Quality Monitoring Network Water Quality Monitoring Network

By By

Heather StoffelHeather StoffelUniversity of Rhode Island- Graduate School of OceanographyUniversity of Rhode Island- Graduate School of Oceanography

Rhode Island Department of Environmental Management -Office of Water Rhode Island Department of Environmental Management -Office of Water ResourcesResources

Narragansett, Rhode Island, USANarragansett, Rhode Island, USA

October 15, 2007October 15, 2007

Narragansett Bay Fixed-Site Water Quality Monitoring NetworkNarragansett Bay Fixed-Site Water Quality Monitoring Network

•Agencies: RIDEM-OWR, URI/GSO,NBC, NBNERR, NBNEP, & RWU

•13 Site Locations: West Passage (NP,MV,QP, GSO) East Passage (PP,PC,TW)Providence River (BR, CP)Seekonk River (PD)West Greenwich Bay (GB)Mt. Hope Bay (RWU, MH)

•Monitoring Season: buoy stations (May-Oct) & land-based stations (year round)

•Funding: NOAA Bay Window Program, EPA Clean Water Act (sections 319 & 106), NBC, & NOAA National Estuary Program

Data CollectionData Collection

TemperatureTemperatureSalinitySalinityDissolved OxygenDissolved OxygenpHpHChlorophyllChlorophyllTurbidityTurbidity

YSI 6600 EDS

Dissolved Oxygen Criteria for Saltwater Dissolved Oxygen Criteria for Saltwater of Rhode Islandof Rhode Island

• The criteria was derived from the The criteria was derived from the USEPA criteria for DOUSEPA criteria for DO

• Limits are based a subset of the Limits are based a subset of the death rates of 12 fish, 9 crustaceans, death rates of 12 fish, 9 crustaceans, & 1 bivalve species during critical & 1 bivalve species during critical development stagesdevelopment stages

Dissolved Oxygen Criteria For Surface Waters & Waters without a Pycnocline

Waters with a DO concentration above an instantaneous value of 4.8 mg/l shall be considered protective of Aquatic Life Uses.

Greenwich Bay Marina Station: Surface DO in 2003

Dissolved Oxygen Criteria For Waters Dissolved Oxygen Criteria For Waters with a Pycnocline (Bottom Waters)with a Pycnocline (Bottom Waters)

Waters with a DO concentration above an instantaneous value of 4.8 mg/l shall be considered protective of Aquatic Life Uses. When instantaneous DO values fall below 4.8 mg/l, the waters shall not be:

1. Less than 2.9 mg/l for more than 24 consecutive hours during the recruitment season; nor

2. Less than 1.4 mg/l for more than 1 hour more than twice during the recruitment season; nor

3. Shall they exceed the cumulative DO exposure presented in Table 3.A.

Allowable Number of Days without Exceeding a Allowable Number of Days without Exceeding a 5% Reduction in Seasonal Larval Recruitment5% Reduction in Seasonal Larval Recruitment

RIDOCS Software Assessment RIDOCS Software Assessment ToolTool

• Software tool developed by EPA and Software tool developed by EPA and applied to Rhode Islandapplied to Rhode Island

• Runs the time-series data against the Runs the time-series data against the criteria & identifies cumulative criteria & identifies cumulative exceedence.exceedence.

• DO levels should not exceed a 67% DO levels should not exceed a 67% mortality rate for more than one day.mortality rate for more than one day.

• Violations of the criteria are not to occur Violations of the criteria are not to occur more than once every 3 years.more than once every 3 years.

RIDOC Results:RIDOC Results:Cumulative Criteria ExceedenceCumulative Criteria Exceedence

Station Name 2001 2002 2003 2004 2005 2006 2007 Mean St. Dev. Upper Bay: Bullock Reach 49.1 29.6 28.6 6.0 12.4 39.9 27.6 16.22 Conimicut Pt 18.2 12.8 23.4 18.1 5.3 North Prudence 19.4 14.8 39.1 1.7 12.3 16.8 17.4 12.3 West Passage: Greenwich Bay 57.5 59.7 51.9 60.2 57.5 3.8 Mt. View 0.3 13.5 39.6 6.8 15.1 17.2 Quonset Pt 0.0 15.1 0.0 5.03 8.7 GSO Dock 0.0 0.0 0.0 0.0 0.0 East Passage: Popposquash Pt 2.6 2.3 24.5 9.8 12.7 Mt. Hope Bay 0.0 9.2 0.0 T-Wharf 0.0 0.0 1.9 0.6 1.1 -Blanks indicate no data available for analysis -Non-Bold indicates data missing during critical period

Bullock Reach Bottom Oxygen Levels: 2001-2006Bullock Reach Bottom Oxygen Levels: 2001-2006

DO mg/L

DO Criteria (4.8 mg/L)

min daily limit (2.9 mg/L)

North Prudence Bottom Oxygen Levels: 2001-2006North Prudence Bottom Oxygen Levels: 2001-2006

Mount View Bottom Oxygen Levels: 2004-2006Mount View Bottom Oxygen Levels: 2004-2006

DO mg/L

DO Criteria (4.8 mg/L)

min daily limit (2.9 mg/L)

Popposquash Pt. Bottom Oxygen Levels: 2004-Popposquash Pt. Bottom Oxygen Levels: 2004-20062006

2004

2005

2006

Insomniac Surveys Support Time Series Data: Insomniac Surveys Support Time Series Data:

Mt. View & Popposquash PointMt. View & Popposquash Point

Mt. View Buoy July 2006

Popposquash Point July 2006

Hypoxic Event SummaryHypoxic Event Summary

20012001 7/1-7/23 (10)7/1-7/23 (10)

8/13-9/1 (19)8/13-9/1 (19)1.18 mg/L1.18 mg/L

0.68 mg/L0.68 mg/LNP/BRNP/BR S 20-25S 20-25

B 19-24B 19-24

20022002 6/28-7/10 (7)6/28-7/10 (7)

7/29-8/8 (11)7/29-8/8 (11)1.4 mg/L1.4 mg/L

1.7 mg/L1.7 mg/LNP/BRNP/BR S 22-26S 22-26

B 19-24B 19-24

20032003 6/20-8/31 (72)6/20-8/31 (72)

(8/14-8/25)(8/14-8/25)0 mg/L0 mg/L BR,CT,NP, BR,CT,NP,

GBGBS 19-28S 19-28

B 15-26B 15-26

20042004 7/19-7/25 (6)7/19-7/25 (6)

8/14-8/20 (6)8/14-8/20 (6)1.92 mg/L1.92 mg/L

1.06 mg/L1.06 mg/LGBGB S 22-24S 22-24

B 20-24B 20-24

20052005 6/30-7/5 (6)6/30-7/5 (6)

7/30-8/18 (20)7/30-8/18 (20)3.5 mg/L3.5 mg/L

2.0 mg/L2.0 mg/LNP,MV,GB,CNP,MV,GB,CT,T,

BRBR

S 22-26S 22-26

B 21-26B 21-26

20062006 6/29-8/10 (43)6/29-8/10 (43)

(7/30-8/10)(7/30-8/10)0 mg/L0 mg/L

0 mg/L0 mg/LBR,CT,NP,BR,CT,NP,

MV,GB,QP,PMV,GB,QP,PPP

S 22-25S 22-25

B 19-24B 19-24

YEARYEAR DURATION DURATION (days)(days)

DO MIN.DO MIN. SITESITE TEMP RTEMP R

Translating the RIDOCS Results into Impairment Listings for Oxygen in

Narragansett Bay

RIDEM’s Recommendations for RIDEM’s Recommendations for Regarding Impairments due to Hypoxia Regarding Impairments due to Hypoxia

in Narragansett Bayin Narragansett Bay

• Previously listed waters remain listedPreviously listed waters remain listed– Providence River, Upper Bay, & Greenwich BayProvidence River, Upper Bay, & Greenwich Bay

• Portion of the West & East Passage is identified by Portion of the West & East Passage is identified by RIDOCS as impairedRIDOCS as impaired– Mt. ViewMt. View– Popposquash Pt.Popposquash Pt.

• West Passage may have more possible West Passage may have more possible impairmentsimpairments– Not enough data at this time to support based on criteriaNot enough data at this time to support based on criteria– Area of concern: Mt. View to Quonset PointArea of concern: Mt. View to Quonset Point