The appraisal of the water-'shed'

According to current social theory, global economic, political, social-cultural driving forces are reshaping the way we organize our production and consumption. This would result in the dawn of the era of the New Geography. This might explain that in Western Europe the countryside is changing rapidly into an arena in which many different stakeholders compete for the land and the countryside becomes multifunctional in time and space. In this contribution, we will focus on one challenging planning aspect of these dynamics: the combination of an attractive developed (pseudo) countryside, housing development and water-retention in the urbanized Netherlands. Water safety has become an important spatial and economic planning topic since the greenhouse-effect will lead to more water excess in the Netherlands due to more heavy rainfall, riverwater and a rise of the sea-level. Especially in the economic core of the Netherlands, The Randstad-Holland, huge investments seem necessary to protect the people, the built environment and our economy. The challenge is to design an attractive, multifunctional and safe area that is affordable for the state, for developers and the final consumer. Each of these stakeholders makes costs-benefit analyses as a part of a general risk-assessment procedure. This assessment has become important in the Netherlands due to deregulation politics. So, the questions become: what are the positive valued externalities of public investments for private users, how can validly quantify and monetarize them, and finally how can we apply these private excessive gains to reduce the unprofitable public investments. To ex-ante evaluate the externalities of investments models (spatial) models are applied. Especially in spatial and economic planning models are necessary to understand the many recursive rules that exist within economic and spatial systems. The National Institute of Public Health and the Environment (RIVM) is a state agency that develops and uses GIS-based evaluation land-use models to assess risks. It noticed that the appraisal of housing nearby water was lacking in its models. It commissioned the Research Institute for Housing, Urban and Mobility studies to review literature on the methodological aspects of the assumed relationships and to estimate the part-utility/part-valuation of water nearby housing location as a first step to improve its models. This paper presents some of the results of these studies.