Zoet-zout inversie, enkele modelresultaten

Gualbert Oude Essink

Unit Soil and Groundwater Systems

Deltares, The Netherlands

Grid convergence

Time step

Salt water pocket in a fresh environment

Salt water pocket in a fresh environment (I)

cases

Effect of discretisation on a ‘salt lake problem’

Salt water pocket in a fresh environment (I)

cases

Effect of discretisation on a ‘salt lake problem’

Salt water pocket in a fresh environment (II)

cases

Effect of discretisation

Salt water pocket in a fresh environment (II)

cases

Effect of discretisation

Salt water pocket in a fresh environment (III)

cases

Effect of discretisation

Salt water pocket in a fresh environment (III)

cases

Effect of discretisation

Salt water pocket in a fresh environment (IV)

cases

Effect of discretisation

Salt water pocket in a fresh environment (IV)

cases

Effect of discretisation

Salt water pocket in a fresh environment (V)

cases

Effect of discretisation

Salt water pocket in a fresh environment (VI)

cases

Conclusion:

• For some physical processes, a large number of cells is necessary

• Check always grid convergence!

Sri LankaSome days after December 26th, 2004

Impact of the 26-12-04 Tsunami on groundwater systems

Impact of the 26-12-04 Tsunami on groundwater systems

Impression of relevant salinisation processes by conceptualmodels of salt water intrusion in coastal aquifers:

1. Fingering processes in the subsoil2. Evolution of a freshwater lens after flooding by sea water3. Freshwater lens in a coastal aquifer with a brackish lagoon

Next step: quantifying processes in real situations, using topographic and hydrogeological data, and ending up with vulnerability maps

Concept 1: Fingering processes in the subsoil

Case Sri Lanka: lagoon setting fingering processes

Concept 1: Fingering processes in the subsoil

Concept 1: Fingering processes in the subsoil

Concept 1: Fingering processes in the subsoil

Concept 1: Fingering processes in the subsoil

Concept 1: Fingering processes in the subsoil

Concept 1: Fingering processes in the subsoil

Concept 1: Fingering processes in the subsoil

Concept 1: Fingering processes in the subsoil

Concept 2: Evolution of a freshwater lens after flooding

Concept 2: Evolution of a freshwater lens after flooding

Concept 2: Evolution of a freshwater lens after flooding

Concept 2: Evolution of a freshwater lens after flooding

Concept 3: Freshwater lens in a coastal aquifer

with a brackish lagoon

Case Sri Lanka: lagoon setting

Concept 3: Freshwater lens in a coastal aquifer

with a brackish lagoon

Concept 3: Freshwater lens in a coastal aquifer

with a brackish lagoon

Impact of the 2004 Tsumani on the salt concentration in a coastal groundwater system, Sri Lanka

0

100

200

300

400

500

600

-0.4 0.1 0.6 1.1 1.6 2.1 2.6 3.1 3.6 4.1 4.6

Time (years)

Sol

ute

conc

entr

atio

n (m

g C

l-/l)

A. 0.7m -MSL,x=1987.5m

B. 4.9m -MSL,x=1987.5m

C. 0.3m -MSL,x=2112.5m

D. 0.3m -MSL,x=2237.5m

Tsunami characteristics: height 3 m, duration 2 hours

Concept 3: Freshwater lens in a coastal aquifer

with a brackish lagoon