Groundwater in Jordan: status and new developments

Groundwater in Jordan: status and new developmentsNizar Abu-JaberGerman Jordanian University

1IntroductionAccording to the national water strategy of 2009, the demand for water in Jordan stands at 1500 million cubic meters per year.The supply available for the country currently is 867 million cubic meters per year (42% deficit).Of the supplies available, 366 million cubic meters are from groundwater (42% of the total).Of these, 91 million cubic meters are non renewable.2

3PaleogroundwaterBy definition, paleogroundwater is non-renewable, and thus any extraction of it is unsustainable.Isotopic studies of various ground waters in Jordan show that numerous aquifers contain waters that were not recharged under modern climatic conditions.4Star signs are modern precipitation, closed triangles represent the Azraq basin waters, open diamonds represent the Mafraq area waters, open squares are Disi waters, closed squares are from the Sirhan waters, closed triangles are from the Dhiraa waters and the open circle is the S-90 sample described by Bajjali (1994), plus signs are Ashqaf waters and the closed circles are Hammad waters

5Renewable aquifersOn the other hand, it is estimated that the amount of precipitation falling over the country ranges from 6-8 billion cubic meters per year, and that only 5% of that (300-400 MCM) goes to recharge the groundwater.These numbers are crucial in understanding and effectively managing the water resources of the country.6Studies of modern rechargeIn order to better manage groundwater in the country, it is crucial that the process of recharge be well understood and quantified.Because of the gap of solid knowledge in this regard, two important studies have been conducted in Jordan to improve the knowledge on this issue.These studies were conducted in the Tulul al Ashaqif area in the northeastern desert and in the Yarmouk Basin area of northwestern Jordan.7Recharge at Tulul Al AshaqifThe Tulul al Ashaqif highlands consist of a volcanic ridge in northeastern Jordan, half way between the towns of Safawi and Ruwaishid. It extends 80 km in a NS direction with a maximum width of 40 km, and the maximum elevation reaches 950 m above sea level. The area is climatically arid, with average annual rainfall only reaching 90 mm (Al Qudah, 2003). 8

9Shallow aquifersLocal inhabitants have tapped shallow aquifers in these highlands for many generations. Simple pits dug to depths of a few meters accessed water within the shallow alluvium in the area. The water is of acceptable quality, used for domestic and livestock purposes. It is available all year round. 10

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14What do the shallow aquifers tell us about recharge?1- The waters in the aquifers are recharged locally. 2- The recharge occurs during annual runoff events.3- There are no sources of other recharge to interfere with the signals derived from the local runoff.

15RechargeGeochemical and isotopic data indicate that recharge occurs rapidly in these areas, with little or no evaporation.This suggests that most recharge occurs in coarse-grained alluvium, rather than in the terminal playas.This suggests that delaying the arrival of water to the playas will enhance recharge.16

Types of pavement surfaces17RunoffGeomorphological studies show various types of surface cover lead to different runoff characteristics.Study of the drainage basins by GIS can lead to better understanding of flow accumulation and runoff

18Can other shallow aquifers be found in the area?Remote sensing data suggest other areas with similar plant cover characteristics.The DTM of the area shows some of these sites have similar slope characteristics.Ten sites were chosen for detailed geoelectrical surveys.19Location of the geoelectrical survey lines (2001), by George Haddadin

20What did this suggest?The remote sensing and geophysical data suggested four sites which may contain shallow water. These are at Ghussein, Shwaiti, Misma and Abiad.21

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23Results of drillingDrilling of these locations has been completed. Water is found at Ghussein and Abiad at depths between 15-20 m.

24The Yarmouk BasinLies in the northwestern corner of the country, with an area of about 1426 km2.Estimated recharge of the basin is about 40 Million Cubic Meters.25

27BeginningDetailed base maps using geographic information systems (GIS) were prepared.These include topography, drainage, geology and land use layers.28

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33A more detailed look at much smaller scales is herein attempted.These will give a better idea about where, how and how much recharge is occurring in the study area.

34Rainfall distributionBecause rainfall tends to be heterogeneous, a number of small rainfall tipping gauges were distributed near the locations of the detailed investigations.In all, four of these gauges were installed.35

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40Rain runoff responsesA special system was designed and built to conduct rain-runoff simulations.Such simulations will allow for a better idea of how much infiltration occurs at various locations and under different rainfall intensities and soil moisture conditions.41

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46Soil moisture and chemistrySoil pits are dug throughout the dry season in order to monitor the propagation of moisture and salts.This data was used to evaluate the moisture budget in the soil.Specifically, the amount of moisture seeping into the groundwater as opposed to evapotranspiration (ET) was evaluated.ET was also evaluated based on mass balance calculations of the labile salts in the soil.47

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52Geophysical methodsMonitoring of deeper infiltration using geoelectrical techniques is attempted.Both Schumberger and Wenner arrays were used in order to monitor deeper moisture movement through the summer season.53

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55ConclusionsThere is significant variability in moisture behavior in the subsurface through the study area.Greater recharge seems to be occurring in the area than previously thought.Perched aquifers seem to exist throughout the flat areas of the Houran plains, especially in the Um Rijam formation.Recharge in the area seems to be 15-20% of the rainfall.56

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