The Western Mountain Aquifer is one of the most important water resources for both Israel and the Palestinian territories. It provides people with their drinking water. They use it to irrigate their fields and their food production. It is also essential for nature. 30 percent of rainfall ends up in the aquifer, contributing significantly to the recharge of ground water. Calculations now predict that groundwater recharge will fall by 16 percent by 2070. We need to bear in mind that the Western Mountain Aquifer provides 20 percent of the required drinking water in Israel and the Palestinian territories.
This prediction is one of the most important findings to emerge from the “MedWater” international research project, coordinated by hydrogeologist Professor Dr. Irina Engelhardt. “This aquifer has been exhibiting problems for a number of years now, such as falling groundwater levels and springs drying up, as was the case with the Yarkon Springs at the start of the 1970s. These problems are mainly attributable to an ever increasing population, more intensive agriculture, and climate changes. “Our climate predictions forecast a temperature rise of two degrees Celsius in winter as well as a reduction in precipitation of about 60 percent in autumn for the groundwater recharge zone by 2070,” says Engelhardt, head of the Chair of Hydrogeology at TU Berlin. Approximately 6 million people live in the Western Mountain Aquifer region.
If the aquifer continues to dry up, this would have serious consequences for the people living in the region as well as nature. Using data regarding population growth, use of land for agriculture, the water required by the ecosystem, and climate change, the “MedWater” project’s goal was to develop forecast models to predict how water levels will change in the aquifer over the next 50 years. “We are developing these forecast models as a basis for retaining the Western Mountain Aquifer as a reservoir, for developing strategies for a more efficient and sustainable use of water and most importantly to provide fair access to water both now and in the future for all population groups living in the area,” Engelhardt explains. In addition to reduced groundwater recharge by 2070, the models also show that an intensive use of water could see the groundwater level sink by two meters over the next five years and by a further three meters by 2040. A more resource-efficient use, however, could help the aquifer recover, enabling the groundwater level to rise by up to 12 meters by 2040.
The Western Mountain Aquifer covers an area of 9,000 square kilometers in Israel and the Palestinian territories, from Haifa in the north to the Negev Desert in the south, and from Jerusalem in the east to the Mediterranean coast in the west. The Western Mountain Aquifer is a karst aquifer. This term describes aquifers which consist of carbonate rock and which contain many subterranean caves, linked by karst pipes and fissures. The rate of flow in karst aquifers is high, whereas the karst pipes and fissures mean that their storage capacity is low. When it rains, the ground water rises quickly, but then drains off equally quickly. “This low storage capacity means that karst aquifers are affected by climate changes, which are likely to result in not only fewer episodes of rainfall but also a stronger concentration of extreme episodes,” says Philipp Nußbaum, research associate at the Chair of Hydrogeology and “MedWater” project manager. This was one of the reasons why the researchers developed a concept for a sustainable use of the Western Mountain Aquifer.
On the one hand, the concept developed by the international research team consists of various models, such as a flow model to gain a deeper understanding of the complex functioning of a karst aquifer, a high resolution regional climate model to predict changes in temperature and precipitation by 2070 as well as a model for calculating the ecosystem services of the drainage area, such as food production. The other focus of the project is on developing a concept for a web-based decision-support system based on these models. “This decision-support system enables local decision makers to apply the developed models of fictive changes to the management of groundwater. Possible solutions could include creating new springs and adapting pumping rates,” says Nußbaum: “It is important that the groundwater level does not sink below a certain level, the 'red line' as we call it, as this could lead to saltwater from the Mediterranean infiltrating the aquifer, resulting in long-term negative impacts on the water quality.
Alongside other cooperation partners from Germany, the “MedWater” project also includes teams from Israel, the Palestinian territories, France and Italy. The project receives 2 million euros from the Federal Ministry of Education and Research (BMBF). The scientific work in the “MedWater” project was carried out in cooperation with Professor Dr. Martin Sauter of the University of Göttingen and Professor Dr. Thomas Köllner of the University of Bayreuth. "MedWater" is based on many years of German-Israeli-Palestinian cooperation, funded by the BMBF in the previous "SMAT" and "SMART Move” projects.
Author: Sybille Nitsche