Using ROMS to Model the Distribution of Hypoxic Water in Narragansett Bay, RI USA Deanna Bergondo and Chris Kincaid University of Rhode Island Narragansett, RI USA University of Rhode Island

Narragansett Bay Three drowned river valleys: West Passage, East Passage and Sekonnet River Five major rivers: Tauton, Blackstone, Pawtuxet, Woonasquatucket, and Moshassuck Mean salinity of 29-31ppt Tends to be moderately stratified in summer, though some areas can be highly stratified and at some times there can be strong mixing

Narragansett Bay x x x x x x x

Bullock Reach - July 2001 High surface DO values Decrease in bottom DO values Bottom DO below 3 mg/L on 7/18 Increased variability in Bottom DO beginning 7/21

Bullock Reach - August 2002 High surface DO values Decrease in bottom DO values Bottom DO below 3 mg/L on 7/31 Bottom DO recovers 8/6

Moderate to High Q Low Tidal Range Low to Moderate Wind from the North Low to Moderate Q High Tidal Range Moderate Wind High Tidal Range Strong Wind Wind Hypoxia in Narragansett Bay

Narragansett Bay

Pollution, rain created a toxic bathtub in Greenwich Bay Remedies will be neither easy nor cheap, environmentalists say. Sunday, August 24, 2003 BY NEIL SHEA and DANIEL BARBARISI Journal Staff Writers Photo by Tom Ardito Narragansett Bay Estaury Program Greenwich Bay Fish Kill

Photo by Tom Ardito Narragansett Bay Estaury Program

Hypoxia in Narragansett Bay 2003

Bergondo, Kester, Stoffel, and Woods, Marine Chemistry, In Press

Model Domain Grid: 0.5 km x: 118 y: 70 z: 10

Flow Through Providence River Transect Depth (m) Distance across channel (km) Depth (m) Wind from North

Flow Through Providence River Transect Distance across channel (km) Wind from South Depth (m) West East

Tracking Hypoxic Water 6 m/s from SW6 m/s from NE

Providence River Tracking Hypoxic Water

ADCP Data Under what conditions is water flushed from the Providence River into the Upper Bay and Greenwich Bay?

Future Work Create higher resolution grid for the Upper Bay and Providence River Incorporate data assimilation to the model Apply the Fasham based biological model to Narragansett Bay - compare with the results of the Kremer and Nixon ecological model and field data Use model to simulate nitrogen-reduction experiments taking place in the Bay

North Prudence Transect

ADCP Data from Providence River

Tracking Hypoxic Water