ABSTRACT
Modeling is the art of translating relatively complex things into simpler ones. A useful model may be as simple as a modest and concise oral explanation, i.e., a recorded description, or obscure as a complex differential equation. The following item gives a few practical examples to show how preliminary factual models may be constructed, even from inadequate information. The deepening of the groundwater level, probably due to the climatic change and the rock permeability reduction at low levels, slightly modified the predicted seasonal cycles. When unforeseen difficulties arise, and costs increase, and deadlines failed, it is almost impossible to change the project conception. Thus, one of the essential activities to be conducted before proposing a factual model is to make a selective survey of the past geological-geotechnical issues that have occurred in the project region. Check all sources of useful information: old newspapers, event registers, risk registers, as-built of old civil works and mine extraction, personal or group testimonials.
