This chapter presents development scenarios for the Vecht area that will be used in the integrated modelling exercise reported in later chapters. These scenarios reflect choices made in physical planning, nature policy, agricultural policy and the regulation of recreation and drinking water production, which are the main political and economic interests in the area. The scenarios have a spatial disaggregation and are formulated at polder level. The hydrological parameters are defined at grid level (500 m × 500 m) and the economic parameters at polder level. This is because the hydrological model assumes homogeneity and is formulated at grid level, while the economic model is formulated at the polder level. Any information at grid level can be aggregated up to polder level.
As the static model approach is used, static scenarios are formulated. Each scenario will provide information about land use and water levels at polder level for 72 polders (Fig. 6.1). The procedure for such a spatially disaggregated approach is complicated. Land use depends on the type of activity and the type of soil. The first includes historical conditions, classified into agricultural land (grassland, cropland), nature and forestry, urban settlements and open water. The soil type is classified into sand, clay and peat.