Exposure of tourism development to salt karst hazards along the Jordanian Dead Sea shore

Abstract

The Dead Sea shore is a unique, young and dynamic salt karst system. Development of the area began in the 1960s, when the main water resources that used to feed the Dead Sea were diverted towards deserts, cities and industries. During the last decade, the water level has fallen by more than 1 m per year, causing a hydrostatic disequilibrium between the underground fresh waters and the base level. Thousands of underground cavities have developed as well as hectometre-sized landslides. Despite these unfavourable environmental conditions, large tourism development projects have flourished along the northern coast of the Jordanian Dead Sea. In this work, which is based on a multi-method approach (analyses of radar and optical satellite data, in situ observations, and public science), we show that a 10 km long strip of coast that encompass several resorts is exposed to subsidence, sinkholes, landslides and flash floods. Geological discontinuities are the weakest points where the system can re-balance and where most of the energy is dissipated through erosional processes. Groundwater is moving rapidly along fractures to reach the dropping base level. The salt that fills the sediments matrix is dissolved along the water flow paths favouring the development of enlarged conduits, cavities and then the proliferation of sinkholes. The front beaches of the hotels, the roads and the bridges are the most affected infrastructure. We point out the importance for the land planners to include in the Dead Sea development schemes the historical records and present knowledge of geological hazards in the area.