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TC Jordan/Syria: Updating the Groundwater Contour Map of the A7/B2 Aquifer in North Jordan

Fig. 2: Groundwater contours in 2013Fig. 2: Groundwater contours in 2013 Source: BGR

Background
The groundwater resources of Jordan are overused since many years, resulting in a continuous groundwater level decline. A large share of overall groundwater abstraction in the country is taking place in the studied area, in North Jordan (42%). The influx of more than 600,000 Syrian refugees since July 2012 has exacerbated the strain on groundwater. In consequence, the groundwater levels have started declining even more rapidly, not just in the north but also in other parts of the country because water resources had to be reallocated throughout the country. The last comprehensive groundwater contour maps, prepared by the BGR projects Groundwater Resources of South Jordan and Groundwater Resources of Northern Jordan, are dating back to 1990 (south) and 1995 (north). An updating of the groundwater contour map of the A7/B2 aquifer was urgently needed in order to adapt the groundwater exploitation strategy to the changed conditions.

Fig. 3: Groundwater abstraction in 2012Fig. 3: Groundwater abstraction in 2012 Source: BGR

The current study presents the results of the Technical Cooperation Project Syrian Refugee Response, implemented by BGR and MWI between March 2014 and March 2015, related to the updating of the groundwater contour map of the main used aquifer in North Jordan, the A7/B2 - basalt aquifer. The work done by the project for updating of the groundwater contour map of the combined A7/B2 - basalt aquifer cost considerable efforts. It was necessary because this updated information provides the basis for an improved management of the groundwater resources and the adoption of an appropriate exploitation strategy for the next 20 years. The exploitation of the A7/B2 aquifer in this area is and will remain very extensive.

Fig. 4: Loss in saturated thickness 1995 to 2013Fig. 4: Loss in saturated thickness 1995 to 2013 Source: BGR

Objectives
The last groundwater contour map for the A7/B2 - basalt aquifer was prepared in 1996, building on data collected until 1995 (Fig. 1; HOBLER et al., 2001; MARGANE et al., 2002) by the BGR Technical Cooperation Project Groundwater Resources of Northern Jordan. During the course of the past 18 years water levels have significantly declined and the groundwater flow regime has dramatically changed (Fig. 2). This is noticed in particular in areas which are heavily exploited, such as North Jordan (Fig. 3). The groundwater divides between the flow components towards Azraq and Yarmouk, formerly located W of the Corridor wellfield are now located N of Azraq. This means a shift by more than 40 km towards E. The former local groundwater recharge mound SW of Corridor, forming a separate groundwater flow component from where groundwater flow was directed towards Sukhneh has disappeared. Instead, due to the decline of water levels by 40-60 m, it appears that groundwater is not anymore flowing out towards Seil Zarqa near Sukhneh but leaves the system towards Yarmouk.

The change in the flow regime brings about changes in the hydrochemical composition because now practically all water is drained towards Yarmouk and much of this water has a fairly high mineralization due to irrigation return flows. It must therefore be expected that mineralization will strongly increase along the current groundwater flow path, i.e. in the Za'atari, W-Aqeb, Somaya and Jaber wellfields.

Fig. 5: Graph of groundwater level declineFig. 5: Graph of groundwater level decline Source: BGR

The findings of the report (MARGANE et al., 2015) have major consequences for the development of water resources in N Jordan. Groundwater level declines have been more severe than thought, often exceeding 60 m (Fig. 4). The average water level decline over the past 18 years is around -45 m (-2.5 m/yr), while in the NW (Irbid area) they even reach -70 m (-3.9 m/yr). Also the area around Mafraq experienced water level declines of 60 m and more. Water level declines have surged in the past 5 years (Fig. 5). In many areas, especially east and southeast of Mafraq and in the Dhuleil-Hallabat area, the A7/B2 has run dry (Fig. 6), forcing the local population and farmers to look for alternatives. The unsaturated zone of the aquifer is expected to increase significantly, if no action is taken (Fig. 7). Many irrigation wells have already been deepened to the A4, A1/2 or Kurnub aquifer. Here the water level is generally deeper and salinity is higher. Based on statements of drilling companies, salinity in the Kurnub is mostly higher than 2,000 µS/cm. In order to use the water for irrigation it is therefore necessary to desalinate the water, which is what most farmers in these areas probably already do.

Fig. 6: Remaining saturated thickness in 2013Fig. 6: Remaining saturated thickness in 2013 Source: BGR

The residual brine is assumed to be dumped in nearby wadis. Deepening of wells to aquifers below the A7/B2 aquifer and dumping of brines should therefore not be allowed because it negatively affects the quality of the water that is left in the A7/B2 aquifer and thus other downstream users.

Another major finding of this study is that the true groundwater abstraction rates must be much higher than the official figures. The reason is that these figures do not match with the observed landuse. While official values of groundwater production in many wells are below the limit of 150,000 m³/yr, for which no fees have to be paid, irrigation needs must be much higher to explain the observed landuse. It must be critically reviewed why there is such an obvious discrepancy between both. We assume that overall groundwater abstraction could be almost double, and groundwater abstraction in private wells between 2 and 3 times higher than the official number, which would explain the strong groundwater level decline. These findings are in line with other recent studies on this subject (AL BAKRI, 2014; USAID/ISSP project, pers. comm.).

Fig. 7: Areas that have run dryFig. 7: Areas that have run dry Source: BGR

Cooperation among all involved water sector institutions must be improved to ensure a better management of wells (wellfields) and water resources. Currently, most pumps are not installed at the appropriate depth and do not have the suitable capacity. This is why water well pumps are damaged frequently and production is highly uneconomic. Moreover, many water supply wells are not built appropriately (location, depth, casings, material, etc.) so that the yield is low. Well rehabilitation is commonly not done. A better well design and frequent rehabilitation would ensure a much higher yield and thus a more economic operation. The proposed measures of improved wellfield management would significantly reduce costs for operation and maintenance of water supply wells.

BGR will implement a new project, probably starting in the second quarter of 2015, that, among others, aims to improve wellfield management.

Based on the findings the BGR project suggests to implement the following water resources management measures:

  • Curb exploitation of groundwater for irrigation in North Jordan, especially in the project area, which is of utmost importance for drinking water supply;
  • Not allow drilling into the deeper aquifers (A4, A1/2, Kurnub) in the studied area (as this will damage the A7/B2 aquifer);
  • Focus future groundwater development in the Eastern Aqeb wellfield area (Fig. 9 and Fig. 10; two parallel galleries of 15 km each, allowing flow to the W by gravity). No groundwater abstraction for irrigation should be allowed here. To this end the prospective area should be declared a water conservation area.

Fig. 8: Depth to groundwater in 2013Fig. 8: Depth to groundwater in 2013 Source: BGR

Proposed new wellfield
In the eastern part of the Aqeb wellfield conditions for groundwater exploitation are currently highly favorable (saturated thickness > 200 m, depth to groundwater < 300 m; compare Fig. 6 and Fig. 8). Due to the absence of agricultural landuse and settlements there are no pollution sources yet and natural groundwater mineralization is low. Furthermore, saturated thickness is very high and pumping lifts comparably low. Due to the limited number of boreholes in this region it is not known what the thickness of basalt is and whether much of the basalt would be saturated. If this is the case, transmissivities would be high and thus drawdown can be expected to be low. It is suggested to position a new wellfield (Basalt Wellfield; Fig. 9 and Fig. 10) with three parallel lines of borehole galleries (approx. 23 wells) in the area south of the Baghdad road. Elevation in this area is between 750 and 650 m asl, while groundwater level currently is more than 500 m asl.

Fig. 9: Location of proposed area of future groundwater exploitationFig. 9: Location of proposed area of future groundwater exploitation Source: BGR

From the proposed wellfield area water could be conveyed by gravity either to Khaw or to the Somaya area (650 m asl) using new pipelines (dotted lines in Fig. 9) or using the existing pipeline, which is, however, located at an elevation of up to 840 m asl so that from the borehole galleries water would need to be pumped up by around 100 m. The proposed wellfield would consist of around 23 production wells and could provide 10-15 million m³/yr. Further details would need to be elaborated.
MWI and BGR intend conducting jointly the new Technical Cooperation Project Improved Groundwater Resources Management in Northern and Central Jordan in Response to the Syrian Refugee Crisis. In the framework of this project wellfield management plans will be established for two to three wellfields in North Jordan, probably Aqeb, Corridor, and Wadi al Arab. Also the planning for a new wellfield, probably located E of Aqeb wellfield, would be jointly done.

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Dr. Georg Houben
Phone: +49-(0)511-643-2373
homepage: www.bgr.bund.de/houben

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