Sensitivity study of St Andrew Bay

rapid response system for Naval applications

LCDR Patrice Pauly, French NavyThesis Advisor: Pr. Peter C. Chu, NPSSecond Reader: Steven D. Haeger,NAVOCEANO

Outlines

Geographic location

Hydrodynamic model used in this study

Forcing mechanisms and Sensibility study

Hydrochemical model and naval applications

Conclusion and recommendations

Geographic location - overview

Northeastern Gulf of MexicoPart of the Intracoastal highwayFed by Deer Point Lake dam

Deer Point Lake dam

Geographic location - bathymetry

Panama City BeachPanama City

West boundaryEast boundaryWest PassEast Pass

Point APoint B

Geographic location - bathymetry

Panama City BeachPanama City

West boundaryEast boundaryWest PassEast Pass

Point APoint B

City Beach

Geographic location - bathymetry

Panama City BeachPanama City

West boundaryEast boundaryWest PassEast Pass

Point APoint B

West boundary

East boundary

Geographic location - bathymetry

Panama City BeachPanama City

West boundaryEast boundaryWest PassEast Pass

Point APoint B

West Pass

East Pass

Geographic location - bathymetry

Panama City BeachPanama City

West boundaryEast boundaryWest PassEast Pass

Point APoint B

A

B

Hydrodynamic model – WQMAP

General equations:

Momentum equations

Continuity equation

Transport equation

Stability condition

222 11 11 222

11 22

1 u D g uvD g g guD uuvD v fDv

t g g

0

011

1v

gD D D ud A

D DR g

(1)

22 11

11 12 11 12 0uD g vD g

R g g R g gt

(2)

2 2

2 2 2 2 211 2211 22

1 1 1h h v

S u S v S S S S Sw D D D

t R g R g DR g R g

(3)

2 22 211 2211 22

12 2h h

tD D u v

R g R gR g R g

(4)

Hydrodynamic model – grid generation

Hydrodynamic model – bathymetry smoothing effects

Hydrodynamic model – WQMAP

Approximations:Shallow watersBoussinesqIncompressibility

Boundary conditions:No flow through surface or bottomNo flow perpendicular to the shorelineNo transport of salt at closed boundaries

Study configuration:3D-version with 10 layersRectangular 550m-wide cells grid2m-minimum cell depth applied after bathymetry smoothingTime step of 0.1min

Sensibility study - methodology

The control run featured with:Tidal time series at all open boundaries

Tidal residual time series at Gulf entrances

Wind time series

Fresh water supply from drainage sub-basins

21˚C constant water temperature

Constant salinity values of 22, 20 and 35 psu at West Bay, East Bay and West Pass open boundary respectively

293214

151

642

476257

242

55

All values in m3/s

Data analysis – fresh water supply

Bay county sub-basins flow

number flow [m3/s]1 0.5

2 0.8

3 ------

4 1.3

5 1.4

6 0.4

7 1.4

8 1.7

9 1

10 1.2

11 1.2

12 1

13 3.8

14 -------

15 0.7

16 0.9

17 38.1

Salinity impact and steady state

Model is featured with salinity only

Surface layer Bottom layer

Hydrodynamic model – steady state

Fresh water impact

This case was featured with a doubled river runoff.

-8+4

-1

-28

+21-7

-1

+55

Flux differences (m3/s) between this case and the control run

West Bay (top) – West Pass (middle) – Point A (bottom)

Data analysis – sea surface temperature

Data set collected at Panama City Beach Panama City Station

Averaged between2000-2004

Varies from 15˚C in winter up to 30˚C in summer

Well-mixed through the water column

Data analysis – wind

2004 average:0.12m/s

northwesterlies

May through September average:

4m/s from 155.

Can easily reach 20m/s and more during hurricane events

Jan. Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

dir. N N SSE S S WSW WSW E ENE N N N

speed 3.5 3.5 4 3.5 3 3 3 2.5 3 3 3 3.5

Wind values (m/s) averaged over the past 60 years.

Wind impacts

25m/s 20m/s

09/16 at 05:00 AM 09/16 at 01:20 PM

West PassWest BayEast Bay

Wind impact

We featured two cases:wind removeda normalized error (μ=0, σ=1m/s) applied on both u and v-components.

0-24

+21

-49

-24-6

-23

0

Flux differences (m3/s) between this case and the control run

Surface layer

Bottom layer

-90

-3

-2

-4-5

-13

0

Flux differences (m3/s) between this case and the control run

West BayWest Pass

Wind impact

We featured two cases:wind removeda normalized error (μ=0, σ=1m/s) applied on both u and v-wind components.

Surface layer

Bottom layer

East Bay

Data analysis – tides from NOAA

NOAA website provides:

Tidal gauge time seriesTidal constituents

Panama City Beach station:amplitude in cm phase

in deg.K1: 15.89 (0.3) 296.2 (1)O1: 15.84 (0.3) 284.8 (1)Q1: 3.4 (0.3) 270.7 (5.5)

M2: 3.4 (0.1) 287.4 (1.5)S2: 2 (0.1) 303.1 (2.5)

Data analysis – tides from NOAA

NOAA website provides:

Tidal gauges time series Tidal constituents

 

Panama City Beach

collected data studyNOAA

prediction data

amplitude [cm]

phase [deg]

amplitude

phase

K1 15.89 (0.3) 296.2 (1) 14.5286.

7

O1 15.84 (0.3) 284.8 (1) 14.1284.

5

Q1 3.4 (0.3)270.7 (5.5) 3.1

273.4

M2 3.4 (0.1)287.4 (1.5) 3.4

277.1

S2 2 (0.1)303.1 (2.5) 2

274.5

form ratio 5.90 --- 5.30 ---

Data analysis – tides from Wxtide32

Embedded tidal software Wxtide32Uses open data only Almost Worlwide

Provided time series for all open boundaries

 

Panama City BeachNOAA prediction

dataTide and current

software

amplitude [cm]

Phase [deg]

amplitude [cm]

Phase [deg]

K1 14.5 286.7 15.53 (0.1)313.9

(1)

O1 14.1 284.5 15.95 (0.1)302.3

(1)

Q1 3.1 273.4 3.5 (0.1) 295 (4)

M2 3.4 277.1 2.3 (0.1)329.5

(1)

S2 2 274.5 0.7 (0.1)325.2

(3)

form ratio 5.30 --- 10.50 ---

Tidal impact on speed

West Pass

West Bay

Tidal impact on salinity

East Bay

West Bay

Tidal impact on salinity at point A

Two remarks:salt propagates trough two different processesebb and flood tides are not equally long

Tidal impact

-4-1

0

-2

-3-2

-1

0

Flux differences (m3/s) between this case and the control run

This case was featured with a modified K1-coefficient amplitude (14.5cm in stead of 15.5) at West Pass.

Data analysis – tidal residuals

Due to:Wave setup

Storm surge

Averages 7.73 cmwith a 13.6 cm standard deviation

West PassWest Bay

Residual impact

-123-104

-72

-392

-289-177

-180

0

Flux differences (m3/s) between this case and the control run

East Bay

Surface layer

Bottom layer

This case was featured without residual time series

WQMAP coupled rapid response models

CHEMMAP overview

Use of Ethylene GlycolSinkerHighly solubleNon volatile

10 tons released within 10 hoursRelease at bottom

Wind impact:3% of wind speed20˚ drift to the right

Chemical database:international referencesphysical properties (solubility, volatility, floatability)

Chemical fate model:Lagrangian approachspreading, entrainment, evaporation, dispersion, dissolution, sedimentation and degradationvertical velocity relies on Stoke’s Lawmass transported with wind field and WQMAP issued currents.

Release the 1st of June – 12:00am

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30

Mass Balance for ethylene glycol

%

Time (days)

Surface Water Column Ashore Evaporated

Decay Sediment Cleaned

Spill dispersion after 3 weeks

Release the 1st of June – 12:00am

0

50

100

150

200

250

300

0 5 10 15 20 25 30

Maximum Dissolved Concentrations85.6890W, 30.1497N for ethylene glycol

Con

cent

ratio

n (m

g/m

3)

Time (days)

0

5000

10000

15000

20000

25000

30000

0 1 2 3 4 5 6 7 8 9

Maximum Concentration at any Location (Horizontally and Vertically) for Dissolved

Co

nc

en

tra

tio

n (

mg

/m3

)

Time (days)

0.0

2.5

5.0

7.5

10.0

12.5

15.0

0 5 10 15 20 25 30

Maximum Dissolved Concentrations85.7426W, 30.1863N for ethylene glycol

Con

cent

ratio

n (m

g/m

3)

Time (days)

0

1

2

3

4

5

6

0 5 10 15 20 25 30

Maximum Dissolved Concentrations85.7337W, 30.2207N for ethylene glycol

Con

cent

ratio

n (m

g/m

3)

Time (days)

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2.00

0 5 10 15 20 25 30

Maximum Dissolved Concentrations85.8237W, 30.2742N for ethylene glycol

Con

cent

ratio

n (m

g/m

3)

Time (days)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0 5 10 15 20 25 30

Maximum Dissolved Concentrations85.8409W, 30.2785N for ethylene glycol

Con

cent

ratio

n (m

g/m

3)

Time (days)

0

1

2

3

4

5

6

7

0 5 10 15 20 25 30

Maximum Dissolved Concentrations85.7608W, 30.2908N for ethylene glycol

Con

cent

ratio

n (m

g/m

3)

Time (days)

Wind effects on spill propagation

No wind simulation Inversed wind simulation

Release time influence – stochastic model

Run number for worst case scenario

50 cases from1st of June

to31st of August

Release location influence

Time response delay

Minimum time to exceed a threshold

Conclusion

The hydrodynamic model:shows the baroclinicity of St Andrew Bay system,proved the fresh water input accuracy not to be essential,proved the tidal residual to run the fluxes in the whole basin,confirmed the wind influence on stratification,allowed the salt diffusion process to be identified.

The hydrochemical model:enhanced the aforementioned conclusions,emphasizes the importance of wind in driving pollution.

Future improvements and recommendations

The hydrodynamic model:Is underground seepage realistically modeled by river cells ?Are the open boundaries correctly located ?the smoothing process effects should be further investigated,strong weather events impact should be evaluated.

The hydrochemical model:Should include vertical salinity distribution.

Please offer OC 4212 – Tides.

Questions