BGR Bundesanstalt für Geowissenschaften und Rohstoffe

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TC Lebanon: Protection of Jeita Spring

Report of the project:

Project areaProject area

Background:
In July 2010 a German-Lebanese Technical Cooperation project started with the aim to reduce the pollution risks for the drinking water supply of Beirut through measures to be implemented in the Jeita catchment. With the rapid and uncontrolled expansion of residential areas in the catchment of Jeita spring following the end of the civil war in Lebanon, pollution of Jeita spring had become extensive. The main reason for this pollution was that wastewater was not collected and treated. At many places wastewater was even injected into wells. The main tasks of the project are to

  1. provide advice to the partner institutions and KfW Entwicklungsbank concerning the concept and environmental impact assessment for wastewater facilities to be built in the project area;
  2. delineate groundwater protection zones for Jeita spring and other relevant springs in the project area and implement them. This implies landuse restrictions in protection zones 1 and 2;
  3. establish a monitoring system for water quality and quantity;
  4. prepare a proposal for an improved water conveyance system from Jeita to Dbaye, i.e. between the source and the drinking water purification plant.

On the German side the project is implemented by the Federal Institute for Geosciences and Natural Resources (BGR). Concerning task 1, the project works closely together with KfW Entwicklungsbank and its consultant GITEC. Task 2 is done in scientific cooperation with University of Göttingen, Department of Applied Geology. On the Lebanese side the project has three main cooperation partners: the Council for Development and Reconstruction (CDR), the Water Establishment of Beirut and Mount Lebanon (WEBML) and the Ministry of Energy and Water (MoEW).

The hydro-lithostratigraphic sequence occurring in the project area is shown in this figure. The aquifer system consists of two main limestone aquifers, the Jurassic J4 and the Cretaceous C4 aquifers, separated by an aquitard. The Jurassic J4 aquifer is more than 1000 m thick, while the Upper Cretaceous C4 aquifer is up to around 600 m thick.

Jeita underground riverJeita underground river

Jeita spring emerges from the Jurassic limestone aquifer, which is highly karstified. In general karstification is especially high where limestone had been exposed since long time and where present day rainfall is high, i.e. at elevations between 1,000 m and 2,600 m. On the Cretaceous plateau, located at elevations > 1800 m asl, karstification is very intensive. The plateau shows virtually no surface water runoff features and rainfall and melting snow directly infiltrate in the groundwater through fields of dolines. This plateau, which is covered in winter by 2-4 m of snow plays an important role for groundwater recharge. It is believed that about 75 % of snow and rainfall in this area contribute to groundwater recharge. Some climate change scenarios suggest a considerable warming in this region, which would have severe consequences for the availability of water.

Task 1:
The planning of wastewater facilities is still at the beginning in Lebanon. Because of the high karstification in the Mount Lebanon and Antilebanon mountain ranges, hydrogeological criteria must be integrated into the planning process. This fact was recognized by KfW Entwicklungsbank, which is in the process to establish wastewater facilities in the Jeita catchment and elsewhere in Lebanon. Because of this fact, two projects were funded by the German Federal Ministry for Economic Cooperation and Development (BMZ), a Technical Cooperation project implemented by BGR and a Financial Cooperation project, implemented by KfW Entwicklungsbank. Both projects work closely together in finding the optimal and safest solution for wastewater facilities in the Jeita catchment. To this end a joint proposal has been made by both parties. KfW and BGR will prepare a joint environmental impact assessment (EIA) for the selected sites.

BGR will assist the partners to prepare the hydrogeological part of the EIA. Currently EIAs in the wastewater sector don't follow well defined rules and regulations. Therefore the BGR project has established a guideline for environmental impact assessments in the wastewater sector.

Treated wastewater reuse may provide additional water for irrigation when discharge of springs is not sufficient. Therefore the Ministry of Energy and Water is currently in the process to establish regulations for treated wastewater reuse. The BGR project has prepared a guideline for treated wastewater reuse which specifically addresses the following issues :

  • definition of criteria where treated wastewater reuse could be allowed,
  • definition of threshold values for treated wastewater reuse, and
  • definition of monitoring criteria.

The project also prepared a best management practice guideline for treated wastewater and sludge reuse.

Tracer test in the Msheti wellTracer test in the Msheti well

Task 2:
The second main task is the delineation of groundwater protection zones. In karst areas this is not an easy task. In order to establish a groundwater protection zone 3, i.e. the groundwater contribution zone of Jeita spring, several tracer tests were done using organic dyes (uranine, amidorhodamine G, sodium naphthionate and eosin). These tracer tests revealed that the groundwater contribution zone is considerably different than previously assumed. The extent of this contribution zone is mainly controlled by the geological structure. Tracer tests were conducted and interpreted in cooperation with University of Göttingen, Department of Applied Geology. Because the existing geological maps dated back to the 1940s and were not accurate enough, a new geological map of the groundwater contribution zone was prepared.

Groundwater protection zone 2 is delineated using groundwater vulnerability mapping. Two methods specifically developed for karst areas were selected: EPIK (Epikarst, Protective cover, Infiltration, Karst network) and COP (Concentration of flow, Overlying layers, Precipitation). For this purpose soil and karst feature mapping had to be conducted. The groundwater vulnerability maps were prepared in cooperation with the University of Göttingen/Department of Applied Geology.

In order to be able to propose water resources management options in the catchment, a WEAP model (Water Evaluation And Planning System) is being established. Base data for all components of the water balance are being collected through new monitoring stations provided by the project (meteorological stations, surface water runoff gauging stations, acoustic doppler current profiler).

Task 3:
Jeita cave is an underground river which has been explored over more than 5,500 m. At places this river is more than 6 m wide. Discharge from Jeita spring was measured in the late 1960s and early 1970s and is about 200 million cubic meters per year. Most springs in Lebanon are not regularly monitored due to lack of equipment and staff. The BGR project has set up a monitoring system to measure discharge and quality of four major springs in the project area using multiparameter probes: Jeita spring, Kashkoush spring, Assal spring and Labbane spring. This system alerts the Dbaye purification plant in case of pollution peaks via telemetric data transfer so that the water supply could be switched to another source of supply.

Water supply installations at Jeita springWater supply installations at Jeita spring

Task 4:
The water supply system based on Jeita spring is extremely fragile. In case of a damage of the canal or the tunnel the entire system would be out of operation for a long time and Beirut would be practically without water. Therefore alternatives are urgently needed. Together with KfW Entwicklungsbank, the project will prepare a concept how to improve the conveyance system.

The drinking water purification plant at Dbaye, which is, like many of the water supply facilities very old (built in 1896), currently only consists of chlorination and sand beds and is therefore not able to eliminate organic contaminants such as pesticides or hydrocarbons. An extension of the treatment plant is not possible due to lack of space. If hydrocarbons were present in the raw water, there would even be a risk of the formation of chlorinated hydrocarbons through treatment. The conveyor bringing water from Jeita to Dbaye is partly 140 years old and leaky. The canal is partly open and people have drilled into the canal. Thus there is also a high pollution risk emanating from the conveyor itself and the treatment. The tunnel drilled through the mountain north of Dbaye is too small and limits the capacity of the water supply system to 255,000 cubic meters per day. A damage to the tunnel by tectonic movements or earthquakes would have disastrous consequences.

Not just the quality but also the quantity of water provided by the conveyor is more and more becoming a problem. In December 2010 water supply from Jeita and Kashkoush was critically low. A solution to overcome periods of water shortage would be to build one or more dams. The project is looking into such and other water resources management options for the project area.


Literature:

List of reports prepared by the Technical Cooperation Project "Protection of Jeita Spring" (PDF, 32 KB)

Reports:

Maps:

Presentations:

Presentations of Final Project Workshop, July 11, 2014:

Presentations for Awareness Campaigns on Groundwater Protection:

Films:

Brochures:

Fact Sheets:

Calendar:


Contact:

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

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