Method for estimating seepage analysis model including boundary condition using merging particle filter

Seepage analysis models have been estimated based on field measurement data using the merging particle filter, which is a data assimilation method. In previous studies, one-dimensional seepage analysis models were assumed, and unsaturated seepage behaviors were simulated by setting the free drainage boundary condition at the bottom of the one-dimensional models. During heavy rain, however, owing to the rising groundwater level at the field slope, the simulation setting of the free drainage boundary condition could not reproduce the field measurement data. In this study, the authors propose a new method for estimating the seepage analysis model, including the boundary condition at the bottom of the one-dimensional model using the merging particle filter. The applicability of the proposed method is also discussed. Using the proposed method, the estimated seepage analysis model could reproduce the measurement data of not only numerical experiments but also the field slope. Therefore, the ability of the proposed method to simulate unsaturated conditions under saturated conditions was verified.