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

Using ROMS to Model the Distribution of Hypoxic Water in

Narragansett Bay, RI USA

Deanna Bergondo and Chris KincaidUniversity of Rhode Island

Narragansett, RI 02852 USAdbergondo@gso.uri.edu

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

xx

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 QLow Tidal Range Low to Moderate Wind from the North

Low to Moderate QHigh Tidal Range Moderate Wind

High Tidal Range Strong Wind

Wind

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

http://www.savebay.org/index_next.asp

Greenwich Bay Fish Kill

Greenwich Bay Fish Kill

Photo by Tom ArditoNarragansett Bay Estaury Program

-10

-5

0

5

10

8/1 8/6 8/11 8/16 8/21 8/26 8/31

N-S

Com

pone

nt (

m/s

)

Wind To North Wind To South

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-5

0

5

10

8/1 8/6 8/11 8/16 8/21 8/26 8/31

E-W

Com

pone

nt (

m/s

)

Wind To East Wind to West

0.0

0.5

1.0

1.5

2.0

2.5

3.0

8/1 8/6 8/11 8/16 8/21 8/26 8/31

Pre

cipi

tati

on (

cm)

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10

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er F

low

(m

3 /s)

Precipitation

Flow

Hypoxia in Narragansett Bay 2003

0.0

0.2

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0.8

1.0

1.2

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7/1 7/11 7/21 7/31 8/10 8/20 8/30 9/9 9/19 9/29

Tida

l Ran

ge (m

) .

Region of Stratification: Hypoxia

Region of De-Stratification

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

Dep

th (

m)

Distance across channel (km)

Dep

th (

m)

Wind from North

Flow Through Providence River Transect

Distance across channel (km)

Wind from South

Dep

th (

m)

Dep

th (

m)

West

West East

East

Tracking Hypoxic Water6 m/s from SW 6 m/s from NE

East Passage

West Passage

0%

20%

40%

60%

80%

100%

0 50 100 150River Flow (m3/s)

Par

ticle

s

No Wind

Providence River

0%

20%

40%

60%

80%

100%

0 50 100 150

River Flow (m3/s)P

artic

les

3 m/s from South

Providence River

0%

20%

40%

60%

80%

100%

0 50 100 150River Flow (m3/s)

Par

ticle

s

3 m/s from West

Providence River

Tracking Hypoxic Water

ADCP DataUnder 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