balle beganton - littoral 2010 (education centre)

8/8/2019 Balle Beganton - Littoral 2010 (Education Centre)

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Managing the microbiologicalcontamination of the Thau

lagoon

SPICOSA study site SSA13 Thau lagoonJ. Ball-Bganton1, T. Laugier2, V. Derolez2, A. Fiandrino2,M. Lample5, R. Mongruel1, J. A. Prez Agndez1, A. Vanhoutte-Brunier1,

H. Rey-Valette3, F. Valette3 and G. Brocard4

1Ifremer, UMR Amure, Marine Economics Departement, BP70 F-29280 Plouzan2Ifremer, LER-LR, Environmental and Resource Laboratory, BP171 F-34203 Ste cedex3LAMETA, Universit de Montpellier 1,C.S. 79606 F-34960 Montpellier cedex 24SMBT, Syndicat Mixte du Bassin de Thau, Route de Ste, BP18 F-34540 Balaruc les Bains5UBO, UMR Amure, Marine Economics Departement, BP70 F-29280 Plouzan


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The Thau lagoon microbiological issue

Microbiological contamination

The lagoon sees its water quality strongly

impacted by a rapid demographic growth and by

an important seasonal influx due to tourism and

failures in the water treatment system,

leading to commercial bans for the shell fish

farming activity.

SSA13

The Thau Lagoon


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Local Management of the area

The local policy framework, which has been set up during the

preparation of the SCoT defines the general objectives of Thau

lagoon management :

Economic development, including tourism and thermalism

Environment preservation, including water quality andecosystems protection

The SAGE defines several specific objectives related to the

environment policy. One specific objective is the reduction of

microbiological contamination.

Maintaining the culturalpatrimony, including traditional

activities (shellfish farming, fisheries activities in the lagoon,

recreational activities).

Territorial Management Plan SCoT

Local Water Management Plan SAGE


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Stakeholder Involvement and Policy issue of the Thau Lagoonstudy site

ManagersScience

How and how farmitigate the microbiological contamination ofthe Thau Lagoon, taking into account local development needs ?

How can this objective of contamination mitigation can be

translated into operational management options ?


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Stakeholder Involvement and Policy issue of the Thau Lagoonstudy site

What technical improvement of the water treatment system

should be made in priority with the objective of:

Lagoon sanitary classificationA with an allowed number of commercial bans

Lagoon sanitary classification B with no commercial bans

Lagoon sanitary classification B with an allowed number of commercial bans

and what would be the cost ?

OMEGA-THAU

Assessment and hierarchy of

contamination sources andtheir impact on the lagoon,

and estimate the cost of

improving their treatment.

An integrated view and

model with the watertreatment system imbedded

in the regional economy and

impact analysis to the

shellfish farming industry.


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A system view of microbiological contamination of the lagoon

contamination

sources

lagoon

reputation

-+

Water policy:

quality improvement

-technical options

-operational objectives

Relationships depending onstrategic decisions of localmanagersThe model is built to explore the ecological and economic impacts of different

combinations of technical options and operational objectives. The strategic

decisions made by local managers should reflect social preferences.

-

+

water

treatmentsystem

efficiency

microbiological

contamination

-

+

Climate:

rain & wind

Population

+ +

+ closures ofbeaches

lagoon sanitary

classification

bans of

shellfish sales

++

-

shellfish

farming

-

-

recreative

activities

External MEPP model

Regional

economy+

+


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The ExtendSim model

The model was developed using ExtendSim modelling software and

following a top-down Ecological-Social-Economical analysis.


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Watershed E.coli sources, flux treatment and transfer

Thau lagoon

E.Coli fluxes

at watershedoutlets

The model uses the detailed

database from the OMEGA-THAU

assessment to simulate for19

sub-catchments :

the watershed E.coli sources theirtreatment theiroutlet fluxes in the lagoon


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Microbiological contamination of the lagoon

Low S-SE winds100 m x 100 m grid10 level along verticaldirection

In the Thau lagoon, the IFREMER 3D

hydrodynamic model MARS (Model for

Applications at Regional Scale) has been

coupled to a biological model simulating

the transport, dispersion and mortality of

E.Coli cells in the lagoon waters.

This model has been used to simulatethe impact of E.Coli load discharge into

the lagoon by each local stream for

specific rain events. Calibration and

validation of this 3D model has been

achieved in the framework of the

OMEGA-THAU project.

Fiandrino, A., Martin,Y., Got, P., Bonnefont, J.L., Troussellier, M., Bacterial contamination of

Mediterranean coastal seawater as affected by riverine inputs: simulation approach appliedto a shellfish breeding area (Thau lagoon, France). Water Research, 37, 1711- 1722, 2003

N

S E

O

5

10

15

20

25

Waterflow-Pallas(m

3/s)

hour

C = 1913*[E.coli].100mL-1

Flux = Q * C

E.Coli load from a rain event


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Microbiological contamination of the lagoon

[E.coli] concentration at REMI

monitoring Station

The contribution of watershed outlets

fluxes to microbiological concentration

are additive and allowed us to usetransport functions to simulate the

impact of E.coli discharge at each REMI

monitoring station.

Daily E.coliload from eachwatershed outlet

For a fixed wind condition and a fixed meteorologicalcondition, the transfer function depends on 4 parameters

5

10

15

20

25

Waterflow

hour

E.Coli load from a rain

event


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Monitoring and commercial bans regulation

The lagoon sanitary

classification (currently B) gives

the allowed E.Coli concentration

thresholds at defined monitoring

stations.

For various lagoon sanitary

classifications (A or B), the model

simulates the occurrence of

commercial bans according to the

different water treatmentscenarios planned by local

agencies.


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Shellfish farming vulnerability

The model calculates two economic indicators for shellfish

farms:

The global revenue losses of companies potentially impacted by

commercial bans. The distribution of companies depending on theirdegree of

vulnerability to commercial closures. Vulnerability is a multi-factorial

status, which refers to the whole different shocks than individuals

may support depending on exposure, sensibility and coping

capacity.


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Regional economy

MEPP

EXTEND

0

Population

Specification of demographic scenariosaccording to the evolution of the regional

economy : successive 5 years runs

5 years

Shellfish farming development

and environmental amenities ,

according the most efficient

water treatment systems

Forcing variables

into EXTEND

Interactive use : calibration ofsuccessive complex 5-years scenarios

10 years 15 years 20 years

Partially constrained

trajectory of the

forcing variables

MEPP -EXTEND

INTERFACE

MEPP

EXTEND

0

Population

Specification of demographic scenariosaccording to the evolution of the regional

economy : successive 5 years runs

5 years

Shellfish farming development

and environmental amenities ,

according the most efficient

water treatment systems

Forcing variables

into EXTEND

Interactive use : calibration ofsuccessive complex 5-years scenarios

10 years 15 years 20 years

Partially constrained

trajectory of the

forcing variables

MEPP -EXTEND

INTERFACE

The regional economy dynamics

is represented using the outputs of

a Prospective Macro-EconomicModel (MEPP) developed by the

LAMETA under the Excel

software.


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Model status today

contamination

sources

lagoon

reputation

-+

Water policy:

quality improvement

-technical options

-operational objectives

Relationships depending onstrategic decisions of localmanagers

-

+

water

treatmentsystem

efficiency

microbiological

contamination

-

+

Climate:

rain & wind

Population

+ +

+ closures ofbeaches

lagoon sanitary

classification

bans of

shellfish sales

++

-

shellfish

farming

-

-

recreative

activities

External MEPP model

Regional

economy+

+


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Stakeholder Feedbacks

OMEGA-THAU

Assessment and hierarchy of

contamination sources and

their impact on the lagoon,

and estimate the cost of

improving their treatment.

Stakeholder feedback :

The cost to reach the

objectives are not

sustainable for the policy

makers. The project gives a

better view of priorities butdoes not offer a tool to test

the necessary compromises.

The managers expect from

the SPICOSA project a

decision support tool to test

the various options

diagnosed by OMEGA Thau.

This demands a highly

complex modelling tool to

test the cost/efficiency of all

the possible technical

options at the detailed scale

of towns and counties.


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System Approach Framework Process

A first SPICOSA SAF cycle hasbeen run. The SPICOSA-Thau

experiment has built the basis of anintegrated model that simulates the actualcontamination and commercial bans in the

lagoon and their short-terms impacts.

To answer broader concernsof local water management

bodies, the next cycle consists in:

However, it does not supply the localplanning agencies with a complete

decision support-tool for watertreatment management.

developing a tool able to testnew water treatment options

also for other pollution sources

integrating the dynamics ofshellfishfarming industry and regionaleconomy in order to reconcile

the SAGE and SCoT

E-S-E objectives.


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In conclusion

In the Thau lagoon study site, the dynamics of the lagoon allowed us to build

and use transfer function in the integrated Ecological-Social-Economical model.

But what if.

Opened question : Integrated model versus model integration

Thank you for your attention

SPICOSA

www.spicosa.eu

Johanna Ball-Bganton

[email protected]

Rmi Mongruel

[email protected]

balle beganton - littoral 2010 (education centre)

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