Impact of Climate Change on Water Resources of Lebanon: Indications of Hydrological Droughts

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0.1 Impact of Climate Change on Water Resources of Lebanon: Indications of Hydrological Droughts

Amin ShabanNational Council for Scientific Research, Remote Sensing Center, Riad El-Solh St., P.O. Box 11-8281, Beirut, Lebanon

Abstract

As a global meteorological process, change in climate conditions has become aserious topic that many researchers work on. However, data availability is still themajor problem to analyze this process. Lebanon, as a Mediterranean region isinfluenced by climate change, which is viewed not only from fluctuation in the cli-matic elements, but also from its influence on the regime of water resources. Theseresources show an abrupt volumetric decrease in water supply, the so-called„hydrologic drought“. Thus accusation of water shortage has become a nationalissue. The study of this phenomenon is tackled through analyzing different indicesof surface and subsurface water, thus comparing different records on graphicalillustrations and numeric values. Results of this application in Lebanon revealed anobvious decline in the amount of available water. This decline shows a variancebetween different sources. However, those which are not in a direct touch withhuman, like precipitation and snow cover, are less influenced and a decrease of 12-16 % was resulted. These two elements directly represent the climate impact onwater inputs. While, this percentage gets higher in the case of rivers and groundwa-ter, in which their decrease ranges between 23-29 %. This adds the human interfer-ence to the climatic conditions, which is due to over exploitation form groundwaterand rivers. Moreover, the number of springs and their discharge as well as thenumber of local reservoirs exhibits the most excessive influence, Consequently, itwas reduced to 43 % and 79 % for the springs and local reservoirs; respectively.This high percentage is attributed to the dependence of human on these twosources. The obtained results in this study are quite alarming and expose a dramaticexceed in the level of hydrologic drought in Lebanon that would be worth takingdecision as soon as possible to water conserve by following a wise-use of waterresources.Key words: water resources, climate change, descending tend, Lebanon

0.1.1 Introduction

Recently, climate change has been raised as a global issue that covers all regions ofthe world. It followed with different human implements to assess mitigate itsimpact on the whole globe, with particular concerns to sensitive areas. However,several explanations and scenarios have been made using different approaches ofanalysis to evaluate the status-quo of climatic trends in space and time.

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The Mediterranean region, as a typical example, is witnessing the impact ofchange in climatic components, which is mainly reflected by the decline in itswater resources. In the Mediterranean region, rapid population growth and indus-trialization are imposing rapidly growing demands and pressures on the watersources, thus the demand in the 20th century has increased by 60 % in the last 25years. Also, in a short period of one generation, in a country after the other, the pic-ture has changed from one of relative abundance to one relative sacristy (Hamdyand Lacirignola, 2005). Therefore, an obvious water shortage is essentially resultedover time and thus refereed as a „Drought“ phenomenon. It is a creeping phenome-non of natural hazard, drought makes it difficult to determine its onset and end.

Likewise for desertification, drought should not be viewed as merely a physicalphenomenon; however, it is the result of interplay between a natural event and thedemand placed on water supply by human-use systems. It has become a commonfeature of long-term natural hazards in many regions of the world. It is negativelyreflected on significant economic, environmental, and social aspects. Thus, it isamong the most complex and least understood of all natural hazards.

Normally, climatic variability expresses the initial stage of drought, thus origi-nates two major meteorological elements:

1. Precipitation deficiency over an extended period of time including volume,intensity and timing

2. Increase in temperature, wind velocity and sunshine, and decrease in relativehumidity and cloud cover

Drought should be considered relative to some long-term average condition ofwater productivity and balance between precipitation and evapotranspiration, in aparticular area. It is also related to the timing (i.e., principal season of occurrence,delays in the start of the rainy season, occurrence of rains in relation to principalcrop growth stages) and the effectiveness (i.e., rainfall intensity, number of rainfallevents) of the rains. Other climatic factors such as high temperature, wind, and lowrelative humidity are often associated with it in many regions of the world and cansignificantly aggravate its severity.

Many classifications have been done to diagnose drought types. Namely, hydrolog-ical, meteorological, agricultural and socioeconomic are the most frequently usedtypes. However, all these types are water-related and attributed, in a broad sense, toclimate change as an initial process (Fig. 0.1.1). In addition, human influence has aminor role in the process of climate change. This can be viewed from the impact ofnegative human activities, such as industries, forestation, smoke effect, etc.

Viewing it from a Meso (national) scale, water resources in some countries suchas Lebanon have more today than they are capable to manage through deficienciesexisted. Other states such as Jordan and Palestine presently are consuming about 15% more water than is annually renewable. Amery and Wolf (2000).

Impact of Climate Change on Water Resources of Lebanon ff-3

Fig. 0.0.1. The sequence of drought process and its major types

Lebanon, as a Mediterranean country is witnessing a drought condition, which isdefinitely observed from the change in its climate events and trends that followedby decrease in the amount of water from different sources. This, in combinationwith the rapid increase in population size, results in a shortage in water availabilityper capita. Therefore, obtained scenarios showed that human quota of renewablefresh water in Lebanon will be declined from 1900 m3/year to 1100 m3/yearbetween 1990 and 2025 (UN, 1994).

This study aims to quantify the hydrologic drought that conditioning Lebanon.As well as to evaluate its trend in space and time, certainly for the last few decadeswhen data started available and human interference took place. For this purpose,several tools of analysis were utilized in this study. Mainly, meteorological andhydrological records as well as remotely sensed data.

0.1.2 Concept and indices of hydrologic drought

In a simple definition, hydrologic drought is a period of time below the averagewater content in streams, reservoirs, aquifers, lakes and soils (Yevjevich et al.,1977). This period is associated with effects of precipitation (including snowfall)shortfall on surface and subsurface water supply, rather than with direct shortfallsin precipitation. The frequency and severity of hydrological drought often definedon a watershed or hydrologic system scale. Although all droughts originate with adeficiency of precipitation, hydrologists are more concerned with how this defi-ciency plays out through the hydrologic system.

Accordingly, monitoring hydrologic drought mainly needs controlling indicesof change in water storage among different hydrologic systems. These indices canbe viewed from the volumetric decrease in both surface and subsurface watersources, which are influenced by climatic conditions and human overexploitation.

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Identification of these indices helps characterizing drought condition spatially andtemporally as well as its intensity, duration, and severity (Redmond, 1991). Eachof the indices has different description with respect to water shortage.

Table 0.1.1 shows the major indices represent the hydrologic drought. Itincludes precipitation, as a major index, though precipitation often referred bymany researchers only to meteorological drought; however, it is included herebecause it is considered as an integral component of the hydrologic cycle and has amajor role in water regime.

Particular indices of hydrologic drought exist in specific regions. In other words,not all indices exist in the same region. For example, snow cover can be utilized asa drought index in some regions like Lebanon, but it would not be so where it doesnot exist like Egypt.

Several measures have been established to study drought indices. They mainlydepend on equations to attain numerical values, thus inducing the existence ofdrought and its magnitude of impact. However, most of these measures involvemeteorological components, notably precipitation as a fundamental parameter. Themajor known measures of these indices are:• Percent of Normal: and it is computed by dividing the actual precipitation by the

normal precipitation, which is typically considered to be a mean of 30-year(Manacelli et al. 2005). It is expressed by the following equation:

Where values of the index less than 100 means drought conditions exist.• Deciles: in which the distribution of the time series of the calculated precipita-

tion for a given period is divided into interval each corresponding to 10 % of thetotal distribution (decile). Gibbs and Maher (1967) proposed to group thedeciles into classes of events (Table 0.1.2)

• Palmer Hydrological Drought Index (PHDI): which integrates water supply(precipitation) with water demand (evapotranspiration as computed from tem-perature) in a soil moisture model (Palmer, 1965),

• Standardized Precipitation Index (SPI):

• Surface Water Supply Index (SWSI): is developed by Shafer and Dezman(1982) to complement Palmer index for moisture conditions, which is appliedmainly to homogenous region and does not occur for snow. SWSI is designedfor surface water as mountains-water dependant, in which snow pack is a majorcomponent.For better assessment of drought condition, notably the hydrologic type, all

available indices must be included. In addition, the assessment must be analyzedfor long term to figure out a time trend, i.e. at least several years. Whilst, applying

I P⟨ ⟩P⟨ ⟩30-------------- 100×=


it only for a couple of months as some worker stated (Sibai and Jinad, 2005) doesnot reveal a comprehensive figure, especially drought is a creeping natural hazardthat takes long time to reflect its impact.

0.1.3 Data Requirements and Availability

In accordance with the indices in Table 0.1.1, the following approaches and toolsare typically applied to assess and monitor hydrologic drought indices:1. Locating rainfall gauges in several representative sites and with a uniform geo-

graphic distribution,

Table 0.1.1 Major indices of hydrologic droughts

Index Elements Criteria

Precipitation Volume Long-term decrease

Intensity Intensive spills of rainfall

Rivers and Stream Stream course Shallow running waterHigh chlorophyll contentLow transported bed load

Discharge Decrease in discharge at mouthLow water velocity

Length Decrease in total tributaries lengthsIntermittency in water flow in courses

Spring Discharge Decrease in dischargeQuality deterioration

Permanency Total disappearance of some springsDischarge intermittency

Lake and reservoirs Water level and quality Lowering in water levelSurrounded mud cracks and sedimentsQuality deterioration

Snow Areal coverage Decrease in snow areal coverageLow dissipationLower frequency

Thickness & density Lowering in thicknessLowering in density

Groundwater Pumping Decrease in yield from wellsFlow intermittency

Water table High depletion in water level

Water quality Saltwater intrusion

Soil moisture Water content Decrease of water content below normal level

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Table 0.1.2. Tools and data availability of hydrologic droughts indices in Lebanon

*TRMM: Tropical Rainfall Mapping Mission extended by NASA.

2. Mounding hydrographs and flow-meters on rivers and springs to record waterdischarges measures,

3. Fixing scale-levels to measure water level in lakes and ponds,4. Using remote sensing data (NOAA, AVHRR, MODIS, etc) to monitor snow

coverage. This can be also applied to monitor changes in the areal extent oflakes and wetlands,

5. Monitoring groundwater level in aquiferous rock formations, using manometersand water table measures in drilled wells,

6. Using available equipments and laboratory testing to measure soil moisture. In order to attain reliable measures, human interference must be avoided. For

example, measuring stream flow should not influenced by water pumping fromstream courses, especially if this pumping changes from year to another. Therefore,measures on source sites would be more creditable, since it has a least influence byhuman impact.

Index Elements Tool Available out-put

Date Creditability

Precipitation Volume Gauge sta-tions

Records & graphs

1967-2006 Reliable

Intensity Gauge sta-tions & TRMM

Records & maps

1998-to date

Rivers Discharge Flow-meters Records & graphs

1965-2006 Reliable

Spring Number of springs

Topographic maps

Desk study 1963-2005 Reliable

Discharge Flow-meters Records & graphs

1965-1999 Reliable

Lake and res-ervoirs

Number of lakes

Topographic maps and aerial photos

Desk study 1963-2005 Partially reli-able

Areal extent Satellite images

Non-contin-ues measures

1973-2005 Partially reli-able

Snow cover Areal Cover-age

Satellite images

Maps 1973-2007 Reliable

Groundwater Pumping Well testing and measure records

Discharge, depth and steady state flow

No regular and continues measures

Partially reli-able

Water table

Water quality

Submarine springs

Airborne sur-vey

Radiometric images

1973 & 1997 Reliable


In Lebanon not all favorable measures for drought indices have prefect records.Lack of sequential records and limitations of dates often exist (Table 0.1.2).While, some data are not available at all, like that for soil moisture except for lim-ited sites and specific times.

In this study, the assessment of hydrologic indices was obtained depending ongraphical analysis of records on time series. This enables to show a complete andcomprehensive figure of trends for different hydrological indices.The approachesof data collection (tools) are different from one index to another (Table 0.1.2).They combine between conventional methods of measures through gauging sta-tions and new techniques of remote sensing. However, they are integrated in someinstances, like that in the case of precipitation.

0.1.3 Method of Analysis

For the case of Lebanon, likewise many regions of the world, a detailed analysis ofthe available data was obtained to assess the majority of trends in water resources.Therefore, out of the 7 indices of hydrologic drought (Table 0.1.1), six ones couldbe analyzed as follows:

Precipitation

Available data on precipitation in Lebanon are found to be reliable to build a com-plete figure on rainfall trends over more than 40 years, i.e., since 1966, (Fig. 0.1.2). In this study, the precipitation trend was built for the whole Lebanon and not forselective sites. These data were primarily (i.e., until year 1978) from 70 gaugingstations distributed over Lebanon, where 64 % of them were in the western part.However, after this date the number of gauge stations was reduced to 11, until1997, and then increased to 24 ones.

Fig. 0.1.2. The cumulative precipitation rate in Lebanon between 1967 and 2006

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Fig. 0.1.3. Measuring precipitation rate and rainfall peaks using TRMM data in graphicand mappable forms


Fig. 0.1.4. Discharge from Lebanese rivers between 1965 and 2006 (LRA, 2006)

Obviously, the major trend is descending and the first decline in precipitationstarted around the1980s (Fig. 0.1.2). Before this time, the average precipitation ratewas 1043 mm, thus it declined to 917 mm (up to 2006), which is equivalent to 12%

For rainfall intensity, normal graphic plotting was also carried out from theavailable climatic data till the year 1998 when TRMM (Tropical Rainfall MappingMission) was extended by NASA to introduce daily climatic information as imagesand graphs (Fig. 0.1.3). The accuracy of the TRMM data was verified by compari-son between these data and ground data from gauging stations in Lebanon. A clearcorrelation was observed for the timing of events, although there was some vari-ance in the amount of precipitation recorded, presumably arising from varying geo-graphic coverage and accuracy of measurement.

The number and rates of rainfall peaks were of utmost concern, since they influ-ence flooding events and water losses to the sea. An obvious increase in the num-ber and rate of rainfall peaks was reported, notably in the period after 1980s.Therefore, the average number of rainfall peaks was <15 peak/year and 24 peaks/year for the periods before and after the1980s; respectively. Moreover, the averagerate of torrential water from these peaks was between 15-20 mm/day before the1980s and 18-22 mm/day after.

Rivers

Lebanon occupies 12 permanent watercourses (rivers). Besides, there is about 60major streams (Wadis) that occupy rain water for few months. Lately, all thesewatercourses have witnessed an obvious decrease in water level and some arereduced to about 50 % of their normal level.

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In a simple method to assess rivers discharge, the available data on rivers flowwere graphically presented for the period between 1965 and 2006 (Fig. 0.1.4).However, some measures were lacking due to the damage in hydrographs, whichhave not re-activated until the beginning of the 1990s.

The hydrographs mounted along the primary courses of the Lebanese riverswere fixed at different confluences and diversions. In addition, many hydrographsfixed on river mouths (outlets). In this study, the interpolated measures of riversdischarge were obtained only for hydrographs along the river mouths.

Even though, there is much turbulence in the discharge rate for each of thelocated rivers, yet the overall discharge rate is obviously in a descending trend forall issuing rivers (Fig. 0.1.4). It is found that the average discharge rate of the Leb-anese rivers was 246 million m3/year in the year 1965, thus reduced to about 186million m3/year in the year 1965, which is equal to 23 % over 40 years.

Springs

Lebanon is known by a big number of springs, which are mostly of the karstic,overflow and fault types. For example in western Lebanon (~ 5000 km2) there are853 major springs, in which 60 % are located at altitudes over 750 m (Shaban,2003). They are, on average, mostly of the 4th class (6.31-28.3 l/sec) of knownmagnitude according to Meinzer classification (1923), but 3rd class is frequent andthere 22 springs with 2nd and 1st magnitude (0.283- >2.83 m3/sec) Meinzer classifi-cation.

Two approaches were followed in this study to assess water discharge from theLebanese springs. First, depends on a comparative analysis for the number ofspring over the past four decades, while the second deals with a graphic illustrationof the major spring.

• For the number of spring with low discharge, they were found to be reducedsince four decades. Even though, many of the existing springs on the topo-graphic maps (plotted in 1963) are now being totally disappeared.

• For the major springs, which are fed from deep aquiferous formations, theincrease in the number of well has a role in reducing the number of thesesprings. Whilst, those springs, which capture water from shallow water-bearingstratum, they merely affected by the decrease in the rate of rainfall. In this study,Lebanon is divided into three areas according to its geomorphologic units.These are: occidental, oriental and the Bekaa plain. In each area the number ofsprings was counted at the time when the topographic maps were produced in1963 and recently in 2005 as obtained from field survey data. Table 0.1.3 showsthe results of this comparison. It reveals a regression in springs yield reaching toabout 50 %.


Table 0.1.3. Comparison between the number of springs in 1963 and 2005

* Springs of all magnitudes according to Meinzer Classification (1923)

Fig. 0.1.5. Discharge from major Lebanese springs between 1965 and 1999 (LRA, 2006)

For the graphic illustration, no complete records for springs discharge are known.However, for some major ones, discharge measures were obtained in spite of thenon-continues recording. Therefore, in this study, nine major issuing springs wereinvestigated. They are typical of the spring type in Lebanon, since they representthe three major types of springs (karstic, overflow and fault springs).

Fig. 0.1.5 shows the trend in discharge from these springs, which is clearlydescending and abruptly changed since three decades. The average discharge fromthese springs was 104 million m3/year, and reduced to 49 million m3/year between1965 and 1999. This is equivalent to 53 % over 34 years.

Lakes and reservoirs

No natural lakes have been occurred in Lebanon, but all known ones are man-madeones and were selected according to their geomorphic setting, which is almost adepression-like shape, thus constructing (local reservoirs). The unique large-scaleone is the Qaraoun Lake, which was made in 1962 (Shaban and Nassif, 2007).Thus, human contributed in adapting these localities for surface water storage.

Geomorphologic unit /Year

Number of spring *

Occidental Lebanon Bekaa plain Oriental Lebanon

1963 853 345 237

2005 419 196 158

Decrease (%) 52 43 33

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Recently, most of know local reservoirs (Berrkah) have been neglected sincethey became unable to store water due to the less amount of rainfall if comparedwith last decades. In addition, the only large-scale (4.5 km2) lake of the Qaraounhas undergone a decrease in its normal area. • For the local reservoirs, they we assessed by counting them at two different

times. First was from topographic maps and aerial photos (Fig. 0.1.6), whichwere made in 1963, then in 2005 as obtained from high resolution satelliteimages and field survey.

Results show that: out of 234 known reservoirs in Lebanon during 1963, only 48are still in use until 2005. While some other ones are remain, but no water storagehas been noticed among these reservoirs. This is other than the new built reservoirswith new approaches, the so-called „hill lakes“.• The large-scale reservoirs, and more certainly the unique one in Lebanon the

Qaraoun Lake, has undergone many fluctuations in its dimensions. This can benoticed from one year to another according to precipitation rate. However, ageneral decrease in the lake size is recorded and obviously noticed by the inhab-itants. In this respect, a comparative analysis has been applied using the avail-able satellite images to induce these changes with time.

The analyzed satellite images were not in a complete sequential time series andattributed to different dates as follows: 1973, 1984, 1985, 1987, 1989, 1992 and1997-2005. These dates were adapted from different available satellite images (i.e.,Landsat MSS, TM, ETM+, SPOT and ERS) to compose the most continues timeorder. These images with different resolution (5-120 m) were processed using dif-ferent software types dedicated for this purpose. Namely, Erdas Imagine ENVI-4.2and PCI. Therefore, several optical and digital advantages were applied to measurethe exact areal extent of the lake at different dates.

Fig. 0.1.6. Identification of local reservoirs from topographic map and aerial photo


The selected images for processing were of close times, which often in winter torepresent the maximum storage in the lake of Qaraoun. Consequently, the widthand length of the lake were calculated to measure its area for these years.

Fig. 0.1.7 shows the change in the area of the Quaroun Lake at different years ofthe period between 1973 and 2005. Even though, the time series is not complete;however, the general trend exhibits reduction in the area of the lake through theinvestigated dates.

The average area was 5.14 km2 in the period before 1990 and thus decreased to4.35 after 1990 until 2005, which is equivalent to 15 % of the normal area of thelake.

Snow cover

Lebanon, as a junction between Europe and Asia and located in the Eastern Medi-terranean region, receives a considerable amount of snow that covers about 25 % ofits terrain (Shaban et al., 2004). Normally, snow covers the regions above 1200 m,thus shapes the mountain chains of Lebanon.

No creditable measures on snow cover have been done in Lebanon; only localmeasurements for snow depth were obtained for different dates and regions. How-ever, the development of remotely sensed techniques helped estimating the area ofsnow cover. Yet, this estimation depends on satellite imagery availability.

In this study, the same images used to analyze the Qaraoun Lake were utilized,plus MODIS-Terra images and SPOT 4-Veg., which have 1 km resolution (Fig.0.1.8). The data on the area of snow cover could be obtained at different periodssince 1973 and thus from 1998 until February 2007. The depth and density ofsnow were not estimated as they need field verification. Nevertheless, the arealextent of snow cover is indicative to the intensity of snow, thus to the amount ofwater derived from snowmelt (Shaban et al., 2004).The processed MODIS-Terra

Fig. 0.1.7. Change in Qaraoun Lake area at different years, between 1973 and 2005

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images were on a daily basis, but in this study the maximum snow cover was con-sidered for each year (Fig. 0.1.8). The same approaches and softwares, as for theQaraoun Lake, were used in the case of snow cover.

Analysis of satellite images for different periods show a noticeable decrease inthe area of snow cover. This accompanied with a decrease in the residence time(i.e., melting) of dense snow cover as a reflection of the increase in temperaturelevel (Fig. 0.1.9). In this study, dissipated snow cover was not considered, becauseit does not represent a dense snow, and this was applied for all the analyzed satel-lite images.

Even though, the number of the analyzed years is not pretty much enough toinduce a complete figure of snow cover change, yet they show a general and obvi-ous changing trend. Thus, before 1990s, dense snow often covers more than 2000

Fig. 0.1.8. Different satellite images at different dates showing the change in snow coveron Lebanon


km2 of the Lebanese mountains and averaging about 2280 km2. Lately, it declinedto less than 2000 km2 with an average area of about 1925. In addition, the time thatdense snow remains, before melting processes have taken place, was alsodecreased from 110 days to 93 days.

Groundwater

Groundwater is an important index for hydrologic drought and can give more accu-rate results, since it is not affected by climatic conditions after the time water per-colates downward into aquiferous rock formations. Besides, the chaotic andimmeasurable pumping from dug wells into potential aquifers misleads the accu-rate records of the pumped quantities of water.

In Lebanon, no creditable records for discharged water from dug wells havebeen made, but decline in water quantity from wells as well as the non-steady statein water pumping are well observed and remarked by wells owners. In addition, thecoastal aquifers are witnessing obvious saltwater intrusions that exceeded theknown limits (El Moujabber et al. 2005). These intrusions are found even in somecoastal stretches where no groundwater exploitation by human exists, like that nearNaquora area.

All these elements if mangled together; however, they obviously indicate aregression in groundwater volume with time. In this view, human influences ongroundwater regime have an essential role as much as the change in climatic condi-tions, notably with the excessive exploitation of groundwater that created with pop-ulation increase.

In this study, a comparison for water discharge from wells has been applied andbased on available data from different dates and regions (Fig. 0.1.10). It tackles themajor water reservoirs in Lebanon (Cenomanian Limestone aquifer and JurassicLimestone aquifer) that exist in different regions, even where no groundwater

Fig. 0.1.9.Areal extents of snow cover on Lebanon and their residence time

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extraction by human is known, like that near Rachaya area. In the Cenomanianaquifer, 193 water wells were investigated from four different regions to induce thechange in water yield between two dates (1984 and 2005). While for the Jurassicaquifer, 122 wells were studied and from another four regions in Lebanon (Fig.0.1.10).In both cases, a clear decrease in the pumped water was recorded, notably in thecoastal regions, thus reflecting the human over exploitation. The average dischargefrom wells of the Cenomanian aquifer in 1984 in the four studied regions was 29.5l/sec. It was decreased to 20 l/sec. While the in the Jurassic aquifer, the dischargewas 31.75 l/sec and 23.5 l/sec, for 1987 and 2005; respectively.

Of course, the decrease in the discharge from wells in the two aquifers wasaccompanied with depletion in water table level. This is well recorded in all sur-veyed wells as well as in several other wells in different regions. Nevertheless, noprécised measurable values have been plotted since there is noticeable fluctuationin the depletion in water table. Only, estimates were obtained by several authors.For example, an average drawdown in water table was reported as 20-25m and 5-10 m in the Cenomanian and Jurassic aquifer; respectively in the area of the LitaniRiver watershed in the last fifteen years (CNRS, 2007).

Accordingly, and as an index of hydrologic drought among the change ground-water regime, in the coastal area of Lebanon has undergone the problem of saltwa-ter intrusion. This phenomenon has been known since three decades, but lately ithas got a dramatic increase, notably in areas with high population rate, such asJbeil, Jounieh, Beirut, Choueifat and Saida.

Fig. 0.1.10. Change in the discharge from wells in the major aquifers in Lebanon at differ-ent dates


In this concern, different studies were done for different coastal segments, andall reported an increase in the salinity ratio as well as stretching in the saltwaterboundaries to several kilometres on-land. Mainly of these studies those obtained byLababidi et al. 1987; Hachache, 1993; Khawlie et al. 2003 and El Moujabber et al.2005.

In addition, the decrease in the number of the groundwater discharges into thesea (i.e. submarine springs) is another index for hydrologic drought in Lebanon,and is it relates to saltwater intrusion. These springs were found to be in andescending trend since three decades. A comparative study was applied to thesesprings along the coastal stretch between Beirut and Anfeh (North Lebanon). It wasfound that in 1972 the number of the springs along this stretch was 46 anddecreased to 27 in 1997. These results were obtained by FAO (1972) and NCRS,1997 through airborne survey using thermal infrared.

Conclusion

Likewise, several regions in the world, the Mediterranean countries are witnessingthe impact of climate change on different physical processes. In this regard, themost effected process is that related to water resources regime and volume. Thus, aclear decrease in the amount of water has been recognized and affected the socialliving.

The decrease in water can not be attributed only to climate change, but also tothe human interference, either by the increase in population or the improper use ofwater resources, thus affects the behaviour and the quantity of water and inter-rupted water budget in many areas.

Even though, the lack of insufficient/or non-continues data on climate and waterin Lebanon, yet the decline in water resources is obvious and well sensed. How-ever, different approaches of analysis were applied, but all end up with the sameconclusion though the variance in the resulting numbers.

In this study, the major elements of hydrologic droughts were analyzed throughcomparative assessment of the available data and records on time series. All theseelements obviously showed a remarkable decrease in water quantity. However, thisdecease varies from one element to another, but all are considerable and alarming.Therefore, since the last four decades, the amount of available water in Lebanon isin a descending trend as a result from combination between climate change andhuman interference.

For the climate, the decrease in the amount of waters is quite similar in precipi-tation and snow cover, which ranges between 12 to 16 %. While, the decrease iswidened in the case of rivers and groundwater and ranges between 23 and 29 %.Thus reflects the human interference as a direct pumping from rivers an overexploitation form groundwater. Besides, the most usable and dependant conven-tional water resources were highly affected by hydrologic droughts. Thus, the num-ber of springs and their discharge as well as the number of local reservoirs has the

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most excessive influence, as they were a major source of water in before 1960s.Consequently, it was reduced to 43 % and 79 % for springs and local reservoirs;respectively.

This study, though of lack of some data, exposes a clear figure of hydrologicdrought, the phenomenon the spread over vast areas in the world, notably in aridand semi-arid regions. In this regard, sudden implements must be taken to conservewater resource; however, by applying water resources management approaches ona large-scale application.

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Impact of Climate Change on Water Resources of Lebanon: Indications of Hydrological Droughts

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