Households in Germany consume about 120 liters of water per capita, per day. Furthermore, industry, power plant cooling and agricultural irrigation require significant amounts of water. In many parts of the world, however, water scarcity is the order of the day. That is why forecasts about the amount of water to be expected in dry regions of the earth are of vital importance. No less pressing is the question of how storage reservoirs, hydro power stations and the irrigation of farmland can be controlled and coordinated. In the joint project “Seasonal Water Resources Management in Dry Regions, Regionalized Global Data and Transfer to Practice” (SaWaM), funded by the Federal Ministry of Education and Research (BMBF), more than 20 researchers are looking for answers to these questions. Among them are environmental scientists at the University of Potsdam. Their objective is to tap into global and regional satellite data, as well as simulation models, to facilitate regional water management and seasonal water forecasting.
The vital resource of water is distributed very unevenly between regions of our Earth and over the seasons. According to estimates by the United Nations, water scarcity may impact some 1.8 billion people by 2025. The growth of the world’s population, the increase in water consumption by households, in agriculture and industry, as well as climate change in some regions, are the three main reasons for the imminent scarcity. To remedy the situation, we need a clearer picture of hydrological cycles and resources. But in many cases, there are not enough observation data available, or they are insufficient. This is why researchers increasingly depend on satellite data or specific simulation models. However, such data and model results are often quite inaccurate and thus fraught with considerable uncertainties. The objective of the SaWaM project is to investigate the potentials of hydro-meteorological data and simulation models, optimize them with newly developed methods, and thereby help improve regional water management in many places. A total of seven research institutions in the fields of climate, hydrology, and ecosystem research, as well as remote sensing, are involved in the project, plus two private sector companies from Germany.
Axel Bronstert, Professor of Hydrology and Climatology, coordinates the sub-project “Regional modelling of water management and hydro-sedimentological processes and statistical downscaling for seasonal forecasting” at the University of Potsdam. “We want to contribute our share to the comprehensive simulation of hydrological processes, soil erosion, and the shrinkage of storage reservoir volumes for large catchment areas in dry regions of the world,” he explains. “To achieve this, we use specifically developed model systems and new, sometimes globally available information.” The combination of specific simulation systems and data analysis methods is expected to facilitate an efficient and sustainable use of scarce water resources in these regions. Regionally valid seasonal forecasts of climatological conditions and the resulting water availability are a particularly innovative instrument used in this connection.
The researchers are testing and developing their methods in five regions: Brazil, Ecuador, Iran, Sudan, and western Africa. At the University of Potsdam they are focusing on the catchment areas of two large rivers, the Sao Francisco in Brazil and the Karun in Iran. These are semi-arid regions with only limited water reserves, which means that demand often exceeds the available supply. Besides, these regions are particularly important for countries with growing populations and increasing levels of industrialization. Above all else, agriculture requires water. Demand is rising, while the supply remains constant, at best, or is decreasing. Consequently, the gap between supply and demand is widening here, too. Seasonal water forecasts for these regions would be tremendously important as they would enable sustainable water use.
As a rule, the required data are not collected by the researchers themselves, but made available to them by cooperating universities and local energy and water management authorities. Water scarcity is a problem more regional than global in character. “Nevertheless, there is a host of global data, information, and models that could help in finding solutions. For instance, we use water level measurements for rivers and storage reservoirs obtained by remote sensing from space,” Bronstert points out.
Over the past 15 years, researchers at the University of Potsdam have gained a lot of expertise in this field. They have developed computer models specifically for regional hydrological cycles in dry environments. To do this, they use classical meteorological data such as precipitation and temperature, as well as information on soil and vegetation. To interpret them in a meaningful way, they have to take into account that the accuracy of the data varies depending on local conditions. “A tolerance of plus/minus 20 percent is desirable. Only then can the models provide a reasonably certain result, on the basis of which water resource management becomes plannable,” Bronstert explains. Long-term seasonal weather forecasts are another important set of tools for researchers. In dry regions with dry and rainy seasons, it is particularly important for the population to know when the rainy season will start and when particularly wet or dry spells are to be expected. “Our project is testing how reliable this information is.” In general, the storage reservoirs in these regions are managed in such a way that they fill up during the rainy season to provide water for irrigation and electricity generation in the dry season. If it were known, for instance, that the upcoming rainy season would bring just a little rain, then existing water reserves could be used sparingly during the dry season.
Far-sighted water management relies on relevant information and forecasts to facilitate efficient and responsible management of storage reservoirs, also in the dry season. To develop their models, the researchers need extensive data and new weather models preferably looking forward for up to three months. As a result, the project network will provide an online prototype to support water management in dry regions all over the world.
Prof. Dr. Axel Bronstert studied hydrology and water resources at the University of Karlsruhe. Since 2000, he has been Professor of Hydrology and Climatology at the University of Potsdam.
Seasonal Water Resources Management in Dry Regions: Practice transfer regionalized global information (SaWaM)
Funding: Federal Ministry of Education and Research (BMBF) in the framework of the Global Resource Water (GROW) research initiative
Cooperation partners of the University of Potsdam: University of Stuttgart, Karlsruhe Institute of Technology (KIT), Philipps-Universität Marburg, Technische Universität Berlin, Helmholtz Centre for Environmental Research UFZ, Helmholtz Centre Potsdam – German Geo Research Centre for Geosciences, Lahmeyer International GmbH (Bad Vilbel) and GAF AG (Munich), as well as a number of local partner institutions in the respective countries
Text: Dr. Barbara Eckardt
Translation: Monika Wilke
Published online by: Alina Grünky
Contact to the online editorial office: onlineredaktionuni-potsdamde