Displacement of springs and changes in groundwater flow regime due to the extreme drop in adjacent lake levels: The Dead Sea rift (original) (raw)
Related papers
Historic Dead Sea Level Fluctuations Calibrated with Geological and Archaeological Evidence
Quaternary Research, 2002
The Dead Sea, the Holocene terminal lake of the Jordan River catchment, has fluctuated during its history in response to climatic change. Biblical records, calibrated by radiocarbon-dated geological and archaeological evidence, reinforce and add detail to the chronology of the lake-level fluctuations. There are three historically documented phases of the Dead Sea in the Biblical record: low lake levels ca. 2000-1500 B.C.E. (before common era); high lake levels ca. 1500-1200 B.C.E.; and low lake levels between ca. 1000 and 700 B.C.E. The Biblical evidence indicates that during the dry periods the southern basin of the Dead Sea was completely dry, a fact that was not clear from the geological and archaeological data alone. C 2002 University of Washington.
The effect of climate and anthropogenic sea level changes on Israeli coastal aquifers
The effects of base (sea or lake) level changes on the location and elevation of the groundwater divide were examined in the hydrological system between the Mediterranean Sea and the Dead Sea. Steadystate simulations were conducted with a 1-D analytical model and transient conditions were simulated using FEFLOW groundwater modeling software. Two hydrological scenarios were simulated: (a) a transition to a new steady-state, following the expected drop of 150 m of the Dead Sea level; and (b) the time of the precursor of the Dead Sea (Lisan Lake), some 20,000 years ago, when the lake level was about 250 m above the present-day Dead Sea level and the Mediterranean Sea level was 120 m below its present one. The results of the simulations show that the Dead Sea level drop has led to a progressive decline in the groundwater level up to several kilometers inland from the shoreline. The hydraulic gradient increases, and thus the discharge to the lake also increases at the expense of the storage, and also due to a small enlargement of the recharge zone by a $600 m shift of the divide.
2011
In this paper water and salt mass balances for the Dead Sea were modeled. Precipitation, evaporation, river discharges, ground water flows, input/output from potash companies and salt production, and brine discharge were included in the models. The mixing time in the Dead Sea was modeled using a single-layer (well-mixed) a two-layer (stratified) system. Using the single-layer approach the water level was predicted to change from 411 m below mean sea level (bmsl) (in 1997) to 391 m and 479 m bmsl (in 2097) based on water mass balances including and excluding brine discharge, respectively, and to reach 402 m and 444 m for the two cases based on a salt mass balance. In the two-layer approach the water level after 100 years was predicted to change from 411 m bmsl (1997) to 397 m and 488 m for a water mass balance including and excluding brine discharge, respectively, and to reach 387 m and 425 m for the two cases using a salt mass balance. The water mixing time using the single-layer description increased from 58 to 116 years when excluding brine discharge. Using the two-layer approach the exchange or mixing time increased in both layers, when adding brine discharge to the system, from 1.2 to 1.7 years and 11 to 15.3 years in the upper and lower layers, respectively. Good agreement was found between the models and historical data.
Water input requirements of the rapidly shrinking Dead Sea
Naturwissenschaften, 2009
The deepest point on Earth, the Dead Sea level, has been dropping alarmingly since 1978 by 0.7 m/a on average due to the accelerating water consumption in the Jordan catchment and stood in 2008 at 420 m below sea level. In this study, a terrain model of the surface area and water volume of the Dead Sea was developed from the Shuttle Radar Topography Mission data using ArcGIS. The model shows that the lake shrinks on average by 4 km 2 /a in area and by 0.47 km 3 /a in volume, amounting to a cumulative loss of 14 km 3 in the last 30 years. The receding level leaves almost annually erosional terraces, recorded here for the first time by Differential Global Positioning System field surveys. The terrace altitudes were correlated among the different profiles and dated to specific years of the lake level regression, illustrating the tight correlation between the morphology of the terrace sequence and the receding lake level. Our volume-level model described here and previous work on groundwater inflow suggest that the projected Dead Sea-Red Sea channel or the Mediterranean-Dead Sea channel must have a carrying capacity of >0.9 km 3 /a in order to slowly re-fill the lake to its former level and to create a sustainable system of electricity generation and freshwater production by desalinization. Moreover, such a channel will maintain tourism and potash industry on both sides of the Dead Sea and reduce the natural hazard caused by the recession.
The Dead Sea hydrography from 1992 to 2000
2002
The modern hydrological regime of the Dead Sea is strongly affected by anthropogenic activity. The natural fresh water budget has changed mainly due to the drastic reduction of runoff. Since 1977, the surface level of the Dead Sea has been lowered by an average rate of about 60 cm/year and for the period from 1998 to 2000, the lowering rate has reached about 100 cm/year. As a result of the runoff reduction, the upper layer salinity of the Dead Sea has increased and the gravitational stability of the water body was diminished. Eventually, during the winter of 1978 -1979, the lake waters overturned, bringing to an end the long-term stable meromictic 1 hydrological regime. The lake entered a new phase in which its hydrological regime switches between holomictic and meromictic regimes, depending on the size of the runoff into the lake (i.e. the amount of precipitation in the lake's watershed). The first holomictic period, 1979 -1980, lasted for 2 months only. It was succeeded by a 4-year meromictic period (1980 -1983). The second holomictic period lasted for 9 years (1983 -1991). The rainy winter of 1991 -1992 resulted in an almost 2-m sea level rise. The upper layer with a relatively low salinity was restored and a new meromictic period persisted for 4 years, until winter 1995 -1996. During the last meromictic period, the hydrological regime of the Dead Sea was characterized by following long-term trends: the depth of the summer thermocline increased from 12 -15 to 25 -30 m; the quasi-salinity of the upper layer, initially of about 164 kg/m 3 , increased rapidly at a rate of about 16 -18 kg/m 3 /year; the quasi-salinity of the deep water, initially of about 235 kg/m 3 , decreased slowly at a rate of about 0.08 -0.10 kg/m 3 /year (for the sake of comparison, a quasi salinity of 235 kg/m 3 is the equivalent of 280x ''usual'' salinity); and the winter minimal temperature of the upper layer, initially of about 16 jC, increased rapidly at a rate of about 2 jC/year. In November 1995, the latest meromictic period of the Dead Sea came to an end. During the present holomictic period, 1996 -2000, the hydrological regime of the Dead Sea is also characterized by long-term trends: the quasi-salinity of the entire Dead Sea increased at a rate of about 0.5 kg/m 3 /year, with practically no decrease during the winters; the temperature of the deep water mass increased with a rate of about 0.25 jC/year; and the period of vertical convection of the entire water column, initially about 3 months, increased at a rate of about 1 week/year. Moreover, we observed that the temperature and salinity of the bottom layer in the deepest part of the Dead Sea raised by about 0.5 -0.6 jC and 0.15 -0.25 kg/m 3 during each holomictic summer. D
Fluvial adjustment of the Lower Jordan River to a drop in the Dead Sea level
Geomorphology, 2002
Water utilization in the upper part of the Jordan Basin has led to a significant reduction in inflow to the Dead Sea. Over the last 70 years, a drop of about 22 m in mean sea level has occurred and has resulted in a continual adjustment of the Lower Jordan River. The impacts of this lowering on the channel morphology of the Lower Jordan River were examined using aerial photographs. Until the late 1970s, the drop in the sea level was small but still led to channel extension. Since the early 1980s, a rapid drop in sea level took place leading to major changes in channel morphology and deep incisions. The greatest change in channel width was recorded near the river mouth. Between 1850 and 1980, there were only insignificant changes in channel sinuosity, but subsequently, a 25% increase of channel sinuosity has been recorded. Most of changes in the channel sinuosity were recorded in the newly exposed area. Over the last 30 years, the active channel width has narrowed by almost four times. Until the late 1980s, the channel was relatively stable with minor bank collapses and only one bar detected near the Jisr Abdallah. During the 1990s, a number of bars developed along the channel. The downcutting is in parallel with the sea level drop resulting in the development of terraces along the lower part of the study reach. In 1983, the channel incision reached 8 km upstream and by 1993 it was about 11 km. D (M.A. Hassan), m.klein@geo.haifa.ac.il (M. Klein). www.elsevier.com/locate/geomorph Geomorphology 45 (2002) 21 -33
Landslides along the Jordanian Dead Sea coast triggered by the lake level lowering
Environmental Earth Sciences, 2010
The level of the Dead Sea lowers 1 m/year and this rate is in acceleration. The decline is causing one of the major environmental disasters of the twenty-first century. The freshwater resources management policy of Israel, Jordan, and Palestine controls the phenomenon. Since the 1960s, the level of this terminal lake dropped by 28 m and its surface shrunk by one-third. In the 1990s, international builders created major tourist resorts and industrial plants along the Jordanian shore while, during the same period, geological hazards triggered by the level lowering spread out. From the very beginning of the year 2000, sinkholes, subsidence, landslides, and river erosion damaged infrastructures more and more frequently: dikes, bridges, roads, houses, factories, pipes, crops, etc. Until present, scientific articles about this ongoing disaster concerned only sinkholes and subsidence phenomena. This paper focuses on the landslides issue along the Jordanian coast. Based on a set of ground observations collected since 1999, the dynamics of the triggering factors in relation to the evolution of the hydro-geological setting is discussed. It is inferred that the recent industrial and tourist infrastructures never took into consideration the very important geotechnical constraints resulting from the Dead Sea lowering.