## Abstract

We are solving a problem of salinization of coastal aquifers. As a test case example, we consider the Henry saltwater intrusion problem. Since porosity, permeability and recharge are unknown or only known at a few points, we model them using random fields. The Henry problem describes a two-phase flow and is nonlinear and time-dependent. The solution to be found is the expectation of the salt mass fraction, which is uncertain and time-dependent. To estimate this expectation we use the well known multilevel Monte Carlo (MLMC) method. The MLMC method takes just a few samples on computationaly expensive (fine) meshes and more samples on cheap (coarse) meshes. Then, by building a telescoping sum, the MLMC method estimates the expected value at a much lower cost than the classical Monte Carlo method. The deterministic solver used here is the well-known parallel and scalable ug4 solver.

Original language | English (US) |
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State | Published - 2023 |

Event | 5th ECCOMAS Thematic Conference on Uncertainty Quantification in Computational Sciences and Engineering, UNCECOMP 2023 - Athens, Greece Duration: Jun 12 2023 → Jun 14 2023 |

### Conference

Conference | 5th ECCOMAS Thematic Conference on Uncertainty Quantification in Computational Sciences and Engineering, UNCECOMP 2023 |
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Country/Territory | Greece |

City | Athens |

Period | 06/12/23 → 06/14/23 |

## Keywords

- density driven flow
- groundwater
- Henry problem
- saltwater intrusion
- two-phase
- uncertainty

## ASJC Scopus subject areas

- Computational Theory and Mathematics
- Computer Science Applications
- Modeling and Simulation
- Statistics and Probability
- Control and Optimization
- Discrete Mathematics and Combinatorics