USING EXPERIMENTAL “SMART GRAVELS” FOR DETERMINING COARSE GRAVEL DISTRIBUTION ALONG THE DEAD SEA SHORE DURING BASE-LEVEL FALL

Abstract. Karst groundwater systems are characterized by the presence of multiple porosity types. Of these, subsurface conduits that facilitate concentrated, heterogeneous flow are challenging to resolve geologically and geophysically. This is especially the case in evaporite karst systems, such as those present on the shores of the Dead Sea, where rapid geomorphological changes are linked to a fall in base level by over 35 m since 1967. Here we combine field observations, remote-sensing analysis, and multiple geophysical surveying methods (shear wave reflection seismics, electrical resistivity tomography, ERT, self-potential, SP, and ground-penetrating radar, GPR) to investigate the nature of subsurface groundwater flow and its interaction with hypersaline Dead Sea water on the rapidly retreating eastern shoreline, near Ghor Al-Haditha in Jordan. Remote-sensing data highlight links between the evolution of surface stream channels fed by groundwater springs and the development of surface subsidence patterns over a 25-year period. ERT and SP data from the head of one groundwater-fed channel adjacent to the former lakeshore show anomalies that point to concentrated, multidirectional water flow in conduits located in the shallow subsurface (< 25 m depth). ERT surveys further inland show anomalies that are coincident with the axis of a major depression and that we interpret as representing subsurface water flow. Low-frequency GPR surveys reveal the limit between unsaturated and saturated zones (< 30 m depth) surrounding the main depression area. Shear wave seismic reflection data nearly 1 km further inland reveal buried paleochannels within alluvial fan deposits, which we interpret as pathways for groundwater flow from the main wadi in the area towards the springs feeding the surface streams. Finally, simulations of density-driven flow of hypersaline and undersaturated groundwaters in response to base-level fall perform realistically if they include the generation of karst conduits near the shoreline. The combined approaches lead to a refined conceptual model of the hydrological and geomorphological processes developed at this part of the Dead Sea, whereby matrix flow through the superficial aquifer inland transitions to conduit flow nearer the shore where evaporite deposits are encountered. These conduits play a key role in the development of springs, stream channels and subsidence across the study area.

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GEOMORPHIC RESPONSE OF A LONG LOW-GRADIENT CHANNEL TO MODERN, DECADES-LONG AND CONTINUOUS BASE-LEVEL LOWERING: NAHAL HAARAVA, THE DEAD SEA

10.1130/abs/2017am-297297 ◽

2017 ◽

Author(s):

Yehouda Enzel ◽

◽

Elad Dente ◽

Nadav G. Lensky‬‏ ◽

Efrat Morin ◽

...

Keyword(s):

Dead Sea ◽

Base Level ◽

Geomorphic Response ◽

Gradient Channel ◽

The Dead ◽

Level Lowering

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FLUVIAL INCISION AND COARSE GRAVEL REDISTRIBUTION ACROSS THE MODERN DEAD SEA SHELF AS A RESULT OF BASE-LEVEL FALL

10.1130/abs/2019am-332857 ◽

2019 ◽

Author(s):

Haggai Eyal ◽

◽

Elad Dente ◽

Itai Haviv ◽

...

Keyword(s):

Dead Sea ◽

Base Level ◽

Fluvial Incision ◽

Coarse Gravel

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The declining but non-rejuvenating base level—The Lisan lake, the Dead Sea area, Israel

Earth Surface Processes and Landforms ◽

10.1002/esp.3290130305 ◽

1988 ◽

Vol 13 (3) ◽

pp. 239-249 ◽

Cited By ~ 21

Author(s):

D. Bowman

Keyword(s):

Dead Sea ◽

Base Level ◽

The Dead ◽

Sea Area

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Sinkholes and uvalas in evaporite karst: spatio-temporal development with links to base-level fall on the eastern shore of the Dead Sea

Solid Earth ◽

10.5194/se-10-1451-2019 ◽

2019 ◽

Vol 10 (4) ◽

pp. 1451-1468 ◽

Cited By ~ 1

Author(s):

Robert A. Watson ◽

Eoghan P. Holohan ◽

Djamil Al-Halbouni ◽

Leila Saberi ◽

Ali Sawarieh ◽

...

Keyword(s):

Sea Water ◽

Dead Sea ◽

Eastern Coast ◽

Temporal Development ◽

Evaporite Karst ◽

Base Level ◽

Theoretical Predictions ◽

The Dead ◽

Spatio Temporal ◽

Karst Landscapes

Abstract. Enclosed topographic depressions are characteristic of karst landscapes on Earth. The developmental relationship between depression types, such as sinkholes (dolines) and uvalas, has been the subject of debate, mainly because the long developmental timescales in classical limestone karst settings impede direct observation. Here we characterize the morphometric properties and spatio-temporal development of ∼1150 sinkholes and five uvalas formed from ∼1980 to 2017 in an evaporite karst setting along the eastern coast of the hypersaline Dead Sea (at Ghor Al-Haditha, Jordan). The development of sinkhole populations and individual uvalas is intertwined in terms of onset, evolution and cessation. The sinkholes commonly develop in clusters, within which they may coalesce to form compound or nested sinkholes. In general, however, the uvalas are not defined by coalescence of sinkholes. Although each uvala usually encloses several clusters of sinkholes, it develops as a larger-scale, gentler and structurally distinct depression. The location of new sinkholes and uvalas shows a marked shoreline-parallel migration with time, followed by a marked shoreline-perpendicular (i.e. seaward) growth with time. These observations are consistent with theoretical predictions of karstification controlled by a laterally migrating interface between saturated and undersaturated groundwater, as induced by the 35 m fall in the Dead Sea water level since 1967. More generally, our observations indicate that uvalas and the sinkhole populations within them, although morphometrically distinct, can develop near-synchronously by subsidence in response to subsurface erosion.

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Extreme rates of channel incision and shape evolution in response to a continuous, rapid base-level fall, the Dead Sea, Israel

Geomorphology ◽

10.1016/j.geomorph.2009.07.004 ◽

2010 ◽

Vol 114 (3) ◽

pp. 227-237 ◽

Cited By ~ 40

Author(s):

D. Bowman ◽

T. Svoray ◽

Sh. Devora ◽

I. Shapira ◽

J.B. Laronne

Keyword(s):

Dead Sea ◽

Shape Evolution ◽

Channel Incision ◽

Base Level ◽

The Dead

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

10.5194/hess-2018-479 ◽

2018 ◽

Author(s):

Najib Abou Karaki ◽

Simone Fiaschi ◽

Killian Paenen ◽

Mohammad Al-Awabdeh ◽

Damien Closson

Keyword(s):

Sea Water ◽

Warning System ◽

Dead Sea ◽

Northern Coast ◽

Karst System ◽

Base Level ◽

Geological Discontinuities ◽

The Dead ◽

Remote Sensing Techniques ◽

The 1960S

Abstract. The Dead Sea shore is a unique young and dynamic evaporite karst system. It started developing in the 1960s, when the main water resources that used to feed the terminal lake were diverted towards deserts, cities and industries. The Dead Sea water level started to lower at an accelerating pace, exceeding 1 meter per year during the last decade, causing a hydrostatic disequilibrium between the underground fresh waters and the base level. This battery-like system provides the energy needed for the development of underground cavities, hectometre-size landslides, and vertical erosion of channels during flash-floods. The 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 these discontinuities to reach the dropping base level. The salt that soars the sediments matrix is dissolved along the paths favouring the development of enlarged conduits, cavities, and the proliferation of ground collapses (sinkholes). Despite these unfavourable environmental conditions, large touristic projects have flourished along the northern coast of the Jordanian Dead Sea. In this work, thanks to the application of remote sensing techniques combined with repeated field observations, we show that a 10 kilometres-long strip of land along the Dead Sea shore that encompass several touristic infrastructures is exposed to subsidence, sinkholes and landslides. Furthermore, we point out the importance of setting up an early warning system to warn the authorities prior to the triggering of hazardous events, limiting or preventing possible disastrous consequences related to hydrogeological hazards.

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Sinkholes, stream channels and base-level fall: a 50-year record of spatio-temporal development on the eastern shore of the Dead Sea

10.5194/se-2018-105 ◽

2018 ◽

Cited By ~ 3

Author(s):

Robert A. Watson ◽

Eoghan P. Holohan ◽

Djamil Al-Halbouni ◽

Leila Saberi ◽

Ali Sawarieh ◽

...

Keyword(s):

Remote Sensing Data ◽

Dead Sea ◽

Eastern Coast ◽

Stream Channels ◽

Shoreline Retreat ◽

Base Level ◽

Close Range ◽

The Dead ◽

Spatio Temporal ◽

Karst Systems

Abstract. The fall of hydrological base-level is long established as a driver of geomorphological change in both fluvial and karst systems, but few natural occurrences occur on timescales suitable for direct observation. Here we document the spatiotemporal development of fluvial and karstic landforms along the eastern coast of the hypersaline Dead Sea (at Ghor al-Haditha, Jordan) during a 50-year period of regional base-level decline from 1967 to 2017. Combining remote sensing data with close-range photogrammetric surveys, we show that the 35 m base-level fall has caused shoreline retreat of up to 2.5 km, and resulted in: (1) incision of new meandering or straight/braided stream channels and (2) formation of > 1100 sinkholes and several salt-karst uvalas. Both alluvial incision and karst-related subsidence represent significant hazards to local infrastructure. The development of groundwater-fed meandering stream channels is in places interlinked with that of the sinkholes and uvalas. Moreover, active areas of channel incision and sinkhole development both migrate seaward in time, broadly in tandem with shoreline retreat. Regarding theoretical effects of base-level fall, our observations show some deviations from those predicted for channel geometry, but are remarkably consistent with those for groundwater-related salt karstification. Our results present, for the first time in the Dead Sea region, the dual response of surface and subsurface hydrological systems to base level drop as indicated by fluvial and karst geomorphological analysis.

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