Evaluation of The Multilevel Coordinate Search Inverse Modelling Algorithm For Identifying Soil Hydraulic Properties of Undisturbed Soil Columns

Although very promising, the identification of partially saturated subsurface water transfer parameters using inverse modeling procedures remains a difficult task. This is particularly due to uniqueness and stability issues, and also to the inherent topograph- ical complexity of the objective functions to optimize. In this context, we present an inverse procedure that appears to be appropriate for practical applications and which uses an accurate and efficient optimization technique, namely, the Global Multilevel Coordinate Search algorithm combined sequentially with the Nelder Mead Simplex algorithm. The applicability of the method relies on the fact that only soil moisture time series at different depths, under natural infiltration conditions, are required as model input. This gives therefore the opportunity to include soil moisture monitoring programs in effective parameter identification procedures. We applied the method on laboratory soil columns representing different textural classes. General difficulties en- countered in obtaining hydraulic properties using inverse modeling are illustrated and discussed.