Proxies and Scenarios for the Development of Water Demand

The project’s task is to analyze and assess the development of water abstractions and backflows in German river basins and their bordering international territories on various spatial and temporal scales. To this end, water management-related auxiliary variables (proxies) on socio-economic and meteorological influencing factors will be used in order to retrospectively interpolate data from the official environmental statistics and to extend them into the future by means of scenarios. The overarching goal is to create an expanded knowledge foundation on the human influence on the natural water balance in the past and future.

Research Approach

Based on the official environmental statistics, ISOE will interpolate and complement the existing database in order to estimate the influence of water abstractions and subsequent backflows into the natural water balance. Transfer functions based on statistical methods and hypotheses on functional relationships are developed to ensure the best possible estimation of society's water demand, which is made up of abstractions and backflows. These transfer functions thus make use of the connections between suitable socio-economic proxies and the water demand. Proxies could for example be population and employment numbers, or the added value of economic sectors. The deduction of transfer functions is based on extensive data work which comprises data acquisition and preparation as well as data storage and quality control. Once suitable transfer functions are developed for different sectors and also administrative and temporal scales, they will be used to add missing data for those periods of time that have so far not been statistically covered within the data series of the environmental statistics. Additionally and with the help of scenarios, the plan is to develop a forecast for the future water demand taking demographic, technical and economic developments into account.

Background

The availability of water is essentially determined by the natural water balance and the water demand of society with its abstractions and backflows. Frequently, an interaction of dependencies can be observed: the prosperity and development of households and economy are tied to the availability of water while the water resources in turn are influenced by the population development, urbanization, life style changes, technological innovations and ecosystem conservation. For a better understanding of the dynamic changes in the availability of water, natural and climatic factors and particularly socio-economic, political and legal influences have to be taken into consideration. Such an understanding of system interrelationships is a decisive precondition for assessing the possible consequences of measures taken by water management on the water balance.

Guided by this motivation, the Federal Institute for Hydrology (BfG) is aiming to expand the knowledge basis on the structural dynamics of change regarding water balance as observed in German river basins and their bordering international territories. As part of the overall project “Wasserwirtschaft2050” (in German) this will take place within the framework of a number of individual projects investigating particular aspects of the topic. The project “Proxies and Scenarios for the Development of Water Demand” is part of the overall project and creates the basis for the further development of models on the water balance taking the influences of society into account.