Sedimentary formations that compose most aquifers are difficult to model
as a result of the nature of their deposition. Their formation generally
involves multiple processes (alluvial, glacial, lacustrine, etc.) that
contribute to the complex organization of these deposits. Representative
models can be obtained using process-based or rule-based methods.
However, such methods have several drawbacks: complicated
parametrization, large computing time, and challenging, if not
impossible, conditioning. To address these problems, we propose a new
hierarchical surface-based algorithm, named EROSim. First, a predefined
number of stochastic surfaces are simulated in a given order (from older
to younger). These surfaces are simulated independently but interact
with each other through erosion rules. Each surface is either an erosive
or a deposition surface. The deposition surfaces represent the
boundaries of depositional events, whereas the erosive surfaces can
remove parts of the previously simulated deposits. Finally, these
surfaces delimit sedimentary regions that are filled with facies. The
approach is quite simple, general, flexible, and can be conditioned to
borehole data. The applicability of the method is illustrated using data
from fluvio-glacial sedimentary deposits observed in the Bümberg quarry
in Switzerland.