Resource management in densely populated and technologically developed countries is faced with changing conditions, tending towards increased complexity. Some examples of these trends are: * increasing scarcity of resources and hence increased need for efficient production; * increasing number of objectives, such as those referring to ecological and environmental values and the quality of the landscape; * increasing number of actors in the decision process; * increasing rate of change of technological innovations. The tendency towards increased complexity is clearly present in spatial planning in the Netherlands. Urbanisation and economic development have led to a reduced quality of the ecological status and landscape and to an intensified agricultural landuse. As a result, conflicts of interest between socio-economic, environmental, ecological and agricultural values have become more pronounced. Public authorities and stakeholders try to protect and enforce a wide range of values and interests that are present in different types of land use, often seeking opportunities to avoid conflicts with other objectives. Groundwater protection zones are maintained by provincial authorities to ensure safe drinking water production, but are an obstacle for further urbanisation, development of industry, infrastructure and agriculture. Agriculture is limited by many regulations, in particular if urban or nature areas are nearby. Space, unpolluted groundwater, natural vegetation and clean air have become scarce and therefore changes of land use have become complex, time consuming operations, where every expected benefit of change may come with costs for a wide range of other values. The presence of multiple objectives combined with the spatial heterogeneity of landuse, geographical and hydrological conditions re sult in a highly complex system of relations. Scenarios that correspond to optimal fulfilment of objectives cannot be identified effectively by the 'unarmed' human mind. As aresult, the risk of choosing suboptimal scenarios has become more pronounced. Choosing suboptimal solutions to spatial planning problems implies that costs are higher than necessary. These higher costs are not restricted to economic values but concern a wide range of values : environmental, ecological or other.