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CHAPTER IV

A BRIEF REVIEW OF GROUNDWATER RESOURCES IN COASTAL LEBANON

Amin Shaban

National Centre for Remote Sensing, National Council for Scientific ResearchP .O. Box: 11-8281, Mansourieh, Lebanon

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SUMMARY

Contrary to the general perception, Lebanon is now considered to be a water deficient country. The existing status shows acute water shortage with the per capita having been reduced by about 50% in the last few decades. The problem of water resources in Lebanon, including groundwater, has been exacerbated, notably in the absence of governmental controls and proper management approaches. The exploitation of groundwater is widespread and has been reflected through the lowering of water table; decrease in water yield, and quality deterioration. This is well pronounced in the coastal zone of Lebanon where more than 70% of population is located. The terrestrial and marine ecosystems have obviously been degraded and yet, monitoring approaches are insufficient to cope with the existing problems and challenges and to establish an integrated and sustainable water resources management plan.

Conservation and monitoring of groundwater resources are important aspects to consider for any remedial action which should also have strong elements of capacity building and structural modifications.

Keywords: Water Table, Monitoring, Pollution, Aquifer

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A REVIEW OF THE COASTAL ENVIRONMENT

BACKGROUND

Lebanon was described as the “water tower” of the Middle East; however, recently it became a poorly-supplied region, and demand for water became crucial. Thus, water shortage exists as a serious geo-environmental problem in many regions. This has been exacerbated with the increased population growth and the changing climatic regime. This is well pronounced in arid and semiarid regions of the country.

Lebanon is known for its surface and subsurface water resources (Figure 1), with rainfall averaging between 800 to 1500 mm, and an annual snow cover in the high mountains that extends to about 2000 km2 to form the major source of the water resources. There are more than 2000 major springs and 12 rivers, in addition to a large number of subsurface water-bearing conduits and aquiferous rock formations. Therefore, the naturally-available water resources can provide enough water to the present population. It is generally assumed that current resources suffice the needs of the country under the present consumption rate.

FIGURE 1. 1) AFKA SPRING, 2) ARTIFICIAL WATER LAKE

Many regions in Lebanon are witnessing severe water shortages, as domestic water supply sources keep dwindling. The country is quickly becoming to be seen as a water deficit region like most of the MENA regions, even though it has a comparatively favorable geographic setting for higher precipitation rate. Groundwater is presently over-exploited and the two principal rock aquifers, are subjected to intensive abstraction and accompanying quality deterioration. The thousands of public and privately owned wells throughout the country provide about 30-40% of water being utilized for domestic, industrial and agricultural uses (Macksoud, 1998). This chaotic state of affairs lowers the water table and can cause salt water intrusion particularly in the coastal aquifers.

ESTIMATES OF GROUND WATER RESOURCES

In Lebanon, measuring systems for water are inadequate for a comprehensive assessment of the existing water resources. Thus, there are diverse estimates on water volume from

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different sources (UN, 1992; Jaber, 1997; Comair, 1998). In addition, there is a lack of advanced monitoring systems, and yet traditional procedures are used whether in exploring groundwater or monitoring groundwater withdrawal and quality. There are no definite estimates, and contradictory information usually exist. Jaber (1995) for example gives an estimate of 1350 million m3/year, while UNDP (1970) estimates the amount to be 1500 million m3/year.

Sixty-five percent of the the Lebanese territory is covered by carbonate rocks (i.e. limestone and dolomite). They are attributed to the Jurassic, Middle Cretaceous and Eocene rocks, which are characterized mainly by extensive faults, fractures and karstification. This, in turn, enhances the infiltration rate, which may exceed 40% of the precipitated water as estimated by UNDP (1970). According to Shaban (2003), the areal extent of the major aquiferous rock formations are listed in Table 1.

TABLE 1. DISTRIBUTION OF AQUIFEROUS ROCK FORMATIONS IN LEBANON

Region Rock formation Mount Lebanon Anti-Lebanon Bekaa plain

Jurassic 550 km2 810 km2 90 km2

Middle Cretaceous 2880 km2 2350 km2 120 km2

Middle Eocene 490 km2 110 km2

Total 3920 km2 3160 km2 320 km2

AQUIFERS CHARACTERISTICS

The exposed rock succession in Lebanon, starts from Middle Jurassic to recent and reflects mainly sedimentation in the marine environment until the Middle Eocene. There are 16 geologic formations where Carbonate rocks build up the largest part of the stratigraphic column, and separated by continental sands and clastics deposits at the base of the Cretaceous, plus some intercalated volcanics up to the Pliocene. According to Beydoun (1977), the exposed rock succession totals a thickness of about 5650 m.

Among the existing rock formations in Lebanon, 6 are aquiferous, and the rest are aquicludes or aquitards. Two out of the six are considered as excellent aquifers (Figure 1). These are attributed to the: Cenomanian (Middle Cretaceous) and Kimmerdjian (Upper Jurassic) ages (Shaban, 2010). The other 4 (of the 6 aquiferous formations) are considered as semi-aquifers.

Considering the areal extent, total rock thickness, depth to water and porosity, therefore the volume of groundwater can be accordingly assessed. For example, the estimated volume of groundwater in the largest aquifer of Lebanon (i.e. Cenomanian) is estimated at 687 million m3. Also, the Eocene rock succession, which is considered as a semi-aquifer, has a considerable amount of groundwater storage as shown in Figure 1, and estimated as 150 million m3 and much more than that in the excellent aquifer of the Kimmerdjian rock succession. However, exploitation from the later (Eocene) is almost negligible due to the depth-to-water as well as due to the quality in some cases (Figure 2).

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FIGURE 2. HYDROSTRATIGRAPHIC SUCCESSION OF LEBANON (SHABAN, 2010).

The recharge of these aquifers is principally a combination of processes from rainfall and snowmelt. However, rainfall is almost torrential, thus resulting in high run-off flow rate and losses, whilst melting snow is considered as the major feeding water (Shaban and De Jong, 2008).

MAJOR HYDROLOGIC PROBLEMS IN THE COASTAL ZONE

Seventy percent of the population of the country lives along the narrow coastal stretch (from the coast to the adjacent mountain chains) and about 70% of the GDP is produced along this stretch (ECODIT-IAURIF, 1996). The conflicting and contradictory interests for the resources of the coastal zone naturally puts a great stress on available water resources.

Quality deterioration

Water quality has been raised as a major concern in Lebanon as it affects 45-100 000 inhabitants/year (ESCWA, 2009). Groundwater quality in Lebanon is ranked at the acceptable level, where Sodium and Bicarbonates are dominant, and Nitrates lie within the international standards. However, recently, organic and chemical groundwater contamination has been well pronounced in the coastal zone. This situation has been exacerbated, notably where quality control is lacking with no sanitation systems and the increased number of chaotic landfills and waste liquid disposals (Ministry of Energy

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and Water, 2012)1. This phenomenon has been accelerated by the absence of regular maintenance of the distribution system and contamination by fertilizers used extensively in the coastal agricultural plains and in the Bekaa valley. Nitrate concentrations in groundwater in these two areas are reported as over 300 mg/L respectively (Halawani et al., 1999; Darwich et al., 2008).

Saltwater intrusion

Due to the existence of rocky formations along the coastal stretch, and the heavy pumping of ground water, salt-water seepages along the coastal areas has reached unacceptable conditions particularly as a result of uncontrolled and chaotic well drilling by private enterprises in the absence of any public control and/or monitoring. Kheir et al. (1994) have reported that salinity levels in groundwater as a direct consequence of intrusion of salt-water has increased 200 fold since 1960s. This state of affairs had a devastating impact on coastal agriculture as farmers had to look for different crops able to sustain higher salinity levels in the water and the soil. This has been a source of loss of revenue to many and a cause of socio-economic woes (El Moujabber et al., 2005).

Groundwater discharge to the sea

Water loss to the sea is a major problem in the coastal zone of Lebanon. In addition to the surface run-off along rivers and streams, groundwater discharges in the marine environment is a known hydrogeologic phenomenon. These discharges, which are also described as “submarine springs”, were classified into two major categories: coastal springs issuing water at the land/sea interface; and off-shore springs which discharge groundwater at a distance from the coast that exceeds several hundred meters in many instances (Shaban et al., 2005). The flow regime of groundwater towards the sea is along faults, karstic conduits and the tilting rock beds of the coastal aquifers. Therefore, the existing submarine springs have created a unique ecosystem in the marine environment.

In this respect, quantitative measures of the lost (discharged) water have been carried out. El-Qareh (1967) applied imperial investigation for water volume from Chekka off-shore springs (the largest marine-freshwater sources in Lebanon), and he estimated the discharge from these springs at about 1.5 m3/sec in dry season. Whilst, CNRS (1999) applied thermal airborne survey to identify these sources. Thus, it was estimated around 400 million m3/year of groundwater discharges into the sea along coastal Lebanon.

MONITORING STATUS AND CHALLENGES FOR LEBANON

The undesirable situation in the water sector in Lebanon is attributed mainly to mismanagement which continues to deteriorate in the absence of any remedial action. This state of affairs was also influenced by the lack of information and data required to

1 http://www.lebarmy.gov.lb/article.asp?+=ar&id=24769

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figure out the status-quo. It is also a direct result of an obvious absence of monitoring and measuring tools.

DATA AVAILABILITY

There is a paucity of data on groundwater in Lebanon, and no adequate and reliable hydrologic measures on water table, groundwater withdrawal, hydrogeologic characteristics of aquifers, regime of saltwater intrusion and even on water quality are available. Most available records and other hydrogeologic information in Lebanon imply principally intermittent and incomplete hydrological and meteorological time-series records within the public sector. No data on boreholes from the private sector is available, as these boreholes were chaotically dug. Availability of date on water resources in Lebanon is given in Table 2.

TABLE 2. PUBLIC AND PRIVATE ORGANIZATIONS CONCERNED WITH GROUNDWATER IN LEBANON

Entity concerned with groundwater

Legal status Major concerns

Ministry of Energy and Water Public sector Data from wells, springs and supply; constructions of water tanks and lakes

Litani River Authority Data on water supply and discharges from channels and lakes

Ministry of Agriculture Data on irrigation rate from wells; construction of water ponds

Lebanese Agronomical Research Centre

Data on water consumption by crop; irrigation channels & climate records

Universities and Research Centres1 Private sector Research on groundwater resources

Private companies Field data1 Except the Lebanese University and CNRS.

MONITORING TOOLS

The majority of monitoring tools for water resources include the hydrologic and climatic systems. There are three aspects of tools to monitor groundwater quantity and quality. Some of these tools follow conventional methods of analysis and others, such as laboratory testing, have been recently developed. In Lebanon however, old instrumentation is commonly used for monitoring and measuring purposes with the addition of some simple electronic equipments. These tools can be classified as follows:

Portable tools

These are practical tools for water monitoring in Lebanon. These are usually utilized by public organizations and research institutes, but rarely used by private companies.

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These include in-situ measurements in water wells to estimate water table depth, using manometers, and sometimes well-logging devices to induce hydrogeologic characteristics of rock sequence in boreholes. Also, flow-meters and water metering are used to measure the discharge of groundwater in wells. In addition, electronic probes and in-situ measuring kits are used to apply direct water quality analysis, including chemical and physical properties of water.

Fixed probes

Fixed tools to measure groundwater in Lebanon are rare, thus regular and periodic measures are still lacking. They follow mainly conventional approaches to measure the pumping rate in wells, such as diverting water into channels with identified cross-section, which usually results in erroneous values.

Laboratory tools

These generally consist of basic laboratory equipment for bacteriological and chemical analysis of water quality. They are often used in times of emergencies and for very limited periods of time. Consequently there is a marked absence of long-term monitoring data.

ANTHROPOGENIC AND PHYSICAL CHALLENGES

Over-exploitation of fresh water aquifers along the coastal zone has resulted in intrusion of brackish water (ESCWA, 2001). The increase in population size in Lebanon is estimated at 2.7% annually, which is relatively high compared to many countries worldwide. This is accompanied with increasing demand for water, which has been reached to about 300 L/day/capita according to the Ministry of Energy and Water2. This is the situation in the densily populated areas of the coastal zone. Thus, excessive pumping of groundwater has become widespread in most of the Lebanese regions; notably in the absence of official control. This excessive pumping is not due only to population growth, but also due to the ever increasing patterns of water use. For example, the consumption of water in Beirut was 30, 50, 84, 112 and 200l/day/capita for the years 1870, 1912, 1944, 1959 and 2007; respectively (Fawaz, 2007). This indicates a yearly increase of about 1.2 L/day/capita. Another example is given by Mahfouz (2010) on Beirut, the capital, that has more than half of the country population, where by by he estimates about 250 L/day/capita of water to be extracted primarily from the two major aquifers.

The Ministry of Energy and Water in Lebanon has allocated optimal water consumption rates as follows:

• 10 000 m3/ha/year in the year 2000• 8 000 m3/ha/year in the year 2015• 6 000 m3/ha/year in the year 2020

2 http://www.lebarmy.gov.lb/article.asp?+=ar&id=24769

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There are several estimates on the number of wells in Lebanon. Khawlie et al (2003) assumed between 400 and 500 wells/km2, most of them being privately owned and chaotically located. The estimated total number of these wells is around 100 000; constantly pumping groundwater in the whole Lebanese territory from different levels. Considering an average pumping rate of about 10 L/day/well; however, an annual estimate of around 1310 million m3 of groundwater is exploited. There presently exist about 100 000 wells pumping water from different levels at an average rate of 10 L/day/well as a conservative estimate of annual ground water use.

Climate change

Changes in climatic conditions in Lebanon are well pronounced through the slight decrease in the precipitation rate, variability in rainfall regime with a forwarding shift in rainy periods. This is accompanied with an increase in temperature (i.e. 1.5 to 2.0°C), as confirmed from the recorded meteorological data over the last few decades. Accordingly, available records show that rainfall rate has decreased only by about 50 mm, but there is an increase in the number of torrential rainfall peaks, which is not favorable for potential groundwater recharge (Shaban, 2011).

In addition, the snow cover, which is an essential groundwater-feeding source (Abd El-Al, 1953), has been recently monitored using remotely sensed data. It was found that the average spatial coverage of snow has been reduced from 2500 km2 to about 1900 km2 in the last three decades. This highly affected the recharge rate for groundwater (Shaban, 2009).

These changing climatic regimes directly affect the volume of surface water and then groundwater. A decrease in the amount of water in rivers and springs is estimated at 10% to 30% over the last few decades. As a result the replenishment process of ground water is greatly decelerated. In this respect, 193 water wells in the Cenomanian aquifer and 122 in the Kimmerdgian aquifer were investigated in different Lebanese regions between 1984 and 2005. In both cases a clear decrease in the pumped water rate was recorded, notably in the coastal regions due to the existing over-exploitation. The average decline in the discharge was estimated at 32% and 26% from the Cenomanian and Kimmerdgian aquifers respectively (Figure 3).

THE NEED FOR CAPACITY BUILDING AND INSTITUTIONAL REFORM

GROUNDWATER SUSTAINABLE DEVELOPMENT

In order to achieve a sustainable groundwater development, there must be in place an adequate management plan considering all problems and challenges facing the water sector. This should be based on scientific, technical knowhow with public control to improve the staus of water resources particularly in the densely populated coastal zone.

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FIGURE 3. CHANGE IN THE DISCHARGE IN WELLS FROM MAJOR AQUIFERS

FIGURE 4. PROPOSED IMPLEMENTATIONS FOR SUSTAINABLE GROUNDWATER DEVELOPMENT IN THE LEBANESE COASTAL ZONE

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Figure 4 shows the major elements for a sustainable groundwater development along the coastal zone of Lebanon. This concerted effort should engage all sectors of society particularly the private sector. Any remedial action in view of establishing a master plan for sustainable exploitation of groundwater resources should consider the following:

1. Adequate and periodic monitoring and control equipment and systematic well developed analytical procedures

2. Proper legislative measures to follow up implementation of groundwater monitoring and enforcement

3. Improving infrastructure and distribution systems4. Capacity building and equitable balance between supply and demand 5. Promotion of public private partnership as regards of exploration, exploitation and

distribution6. Implications of climate change to serve as the background to these approaches

A successful implementation calls for complementarity and parallel action with the involvement of all stakeholders particularly the organizations involved in coastal and marine issues and continental water resources (Figure 4).

Data and information as a vital component of such an approach needs to be harvested and collected with proper quality control. In this regard, a centralized data bank on water resources becomes imperative. Transparency, exchange of experiences and information as the ultimate goal. This calls for the active involvement of all tiers of society and in particular the NGOs and the media in all of its forms.

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