The development of knowledge about the mechanism in the delta has had a high dependency on projects and techniques available. During the period from 1930 to 1939, there is a consolidation of the achievements and further development of hydraulic engineering techniques, based on model-based and mathematical analyses and prognoses (Schot et al., 1998). In this time two of the physical models were built, the Waterloopbos in the Netherlands and the Mississippi River basin in the USA. Both models have been used extensively to expand knowledge and build projects, but both became out of use when computers appeared in the 1980s. Then the calculation models were favoured, as they can be done faster, and are also capable of handling complex problems. Computer technology became increasingly dominated by measurement, prognosis, calibration, verification and validation. For this project section, the current state of the two models is brought forth as a new technique in which maybe the Longue Duree of the relation between humans and nature can become evident.
- Water Models