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LAND DEGRADATION IN LEBANON: VULNERABILITY OF SOIL RESOURCES TO DESERTIFICATION

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LAND DEGRADATION IN LEBANON: VULNERABILITY OF SOIL RESOURCES TO DESERTIFICATION Darwish, T. Khawlie, M. Faour, Gh. Masri, T. Shaaban, A. and Bou Kheir, R. – PowerPoint PPT presentation

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Title: LAND DEGRADATION IN LEBANON: VULNERABILITY OF SOIL RESOURCES TO DESERTIFICATION


1
LAND DEGRADATION IN LEBANON VULNERABILITY OF
SOIL RESOURCES TO DESERTIFICATION
  • Darwish, T. Khawlie, M. Faour, Gh. Masri, T.
    Shaaban, A. and Bou Kheir, R.
  •  
  • National Council for Scientific Research.
    National Center for Remote Sensing. Beirut,
    Lebanon. P.O. Box 11-8281.

2
Introduction
  • Lebanon is an eastern Mediterranean country
    lying in the midst of a tectonically active
    region.
  • Structurally, Lebanon consists of three units,
    two of them constitute the uplifted steep
    mountain ranges (Mount Lebanon and Anti-Lebanon),
    separated by the Bekaa depression.
  • Land resources of the Mediterranean region, with
    a long history of civilization, have been put
    under pressure for several centuries.

3
Location
4
  • Therefore Lebanon is distinguished by
  • Complex geomorphology
  • Diverse Climate
  • Biodiversity in land cover including vegetation
    and soil types.
  • Land use in Lebanon date to the old Phoenician
    times.

5
  • Human interference and mismanagement together
    with climate change created increasing pressure
    on the limited natural resources.
  • This lead to increasing risks of erosion,
    deforestation, soil and water pollution, and a
    reduction of soil quality and productivity.
  • Landscape changes have not been always associated
    neither with rehabilitation nor with remediation
    measures.

6
  • There are no exact estimates of the extent and
    severity of this historical damage.
  • The presence of large areas of very shallow
    soils, and rock outcrops points to periods of
    serve erosion and land degradation.
  • Is land degradation, which reduces the natural
    beauty and harmony of landscapes an irreversible
    fact?

7
  • Did scientists develop and do decision-makers use
    appropriate early warning indicators of land
    quality to be able to monitor and prevent land
    deterioration?
  • What is the role of research bodies and NGOs in
    the bottom up approach to tackle land
    degradation?
  • What is the level of our knowledge on soil
    resilience and how regional and international
    organizations can contribute to protect this non
    renewable resource?

8
  • Geomorphology of Lebanon in relation to
    environmental risk hazards
  • The major faults of the Lebanese tectonic regime
    are the Yammouneh fault and Roum Fault.
  • These are the northern continuation of the Jordan
    fault and are continued North word by the Ghab
    fault.
  • This setting and fracturing system are a
    structural result of the major tectonic framework
    of the Dead Sea fault system.
  • This makes Lebanon vulnerable to earthquakes.

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10
Geology Can be grouped into
  • Quaternary marine deposits
  • Quaternary colluvial deposits
  • Fluvial deposits
  • Tertiary sedimentary rocks
  • Clastic mesozoic rocks
  • Non-clastic sedimentary rocks
  • Volcanic rocks

11
Geology
12
  • All mentioned peculiarities lie behind the
    complex orography of Lebanon with gt75 of its
    territory consisting of sloping and steep lands
    that adds to the fragility of the ecosystems.
  • The coastal area and inner Bekaa plain represent
    level lands with a slope gradient lt8.
  • The mountains and hills represent mainly slopping
    and steep lands with gradient between 20 and 60.
  • Small intermountain plains are always present
    filled by tertiary and quaternary sediments.

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  • Mean annual precipitation ranges from 700 mm on
    the coastal area to 1200 mm on the high mountain
    (with a snow cover for 2-3 months).
  • It drops down until 500mm in Central Bekaa and
    150 mm in the North east Bakaa.

15
Mean annual precipi-tation
16
Land cover/use
  • Mountain
  • Pine and oak forests and copies, shrubs and
    grasslands alternating with rock outcrops.
  • Apple, Olive and Grape production.
  • Plains
  • Cash field crops, vegetable inland
  • Citrus and banana cultivation on the coast.
  • Greenhouses tomatoes, cucumber and flowers.

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18
Soil cover
  • 1. Petric Calcisols in the northeastern Bekaa
  • 2. Eutric Fluvisols, Vertic Cambisols and
    Vertisols in the Central Bekaa.
  • 3. Eutric Luvisols, Rendzic Leptosols and Lithic
    Leptosols in the Lebanese Mountains.
  • 4.Calcaric Cambisols, Eutric Vertisols, Calcaric
    Arenosols and Eutric Fluvisols on the coast.

19
The new soil map of Lebanon
20
  • Soil Vulnerability to desertification
  • The contribution to the framework of the
    National Action Program to Combat
    Desertification was to analysis factors leading
    to soil desertification in Lebanon.
  • The approach used RS and GIS to identify,
    classify and produce the layers related to soil
    genesis and evolution within the context of main
    characteristics.

21
  • Because the dry climate, with few exceptions, is
    dominant in Lebanon. The soil temperature regime
    is mainly hyperthermic.
  • Rainfall distribution, characteristic for the
    Mediterranean Sea, promotes a xeric soil
    moisture regime.

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  • 1.    Soil related data
  • 1.1. Soil depth. Five classes 1. lt10 cm
    2.10-50 cm 3. 50-100 4. 100-150 5. gt150
    cm.
  • 1.2.   Soil texture. Five classes 1. Coarse,
    2-medium 3. Medium fine 4. Fine 5. Very fine.
  • 1.3. Organic matter content Five classes 1.
    lt0.5 2. 0.5-1.0 3. 1.0-2.0 4. 2.0-3.0 5.
    gt3.0.
  • 1.4.  Water reserve Five classes 1. Very low
    2. Low intermediate 4-relatively high 5. High.
  • 1.5. Structural stability 1. Unstable 2. Very
    low stability 3. Low stability 4. Intermediate
    stability 5. Stable.
  • 1.6.   Soil index (combination of layers
    1.1-1.5).

24
  • Therefore, soil characteristics like depth,
    organic matter content and texture are important
    factors for water storage capacity.
  • These and others were the basis for the creation
    of soil index.
  • 1. Soil depth affecting root penetration and
    nutrient and water reserve
  • 2. Organic matter content influencing aggregate
    stability, porosity and fertility

25
  • 3. Soil texture that is responsible for soil
    water retention capacity, aeration and
    infiltration rate
  • 4. Aggregate stability characterizing the
    resistance of soil aggregate to disintegration as
    a result of rain drops, promoting soil coherence
    against erosion and
  • 5. Water storage capacity responsible to
    maintain natural vegetation during the dry
    season, which limits forest fires and affects
    irrigation scheduling.

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  • 2.    Climatic data
  • 2.1.   Annual precipitation
  • 2.2.   Potential evapotranspiration (ET0)
  • 2.3. Ratio precipitation/ET0. Two classes 1.
    Vulnerable lt0.65 of the ratio 2. Not vulnerable
    gt0.65 of the ratio.
  • 2.4.  Climatic index Four classes 1. Very high
    2. High 3. Moderate 5. Low.

29
  • 3.    Vegetation data
  • NDVI. Five classes 1. None 2. Low 3.
    Moderate 4. High 5. Very high.
  • 4. Desertification prone areas. Five classes 1.
    Very low 2. Low 3. Moderate 4. High 5. Very
    high.
  • Combination of layers 1.6, 2.3 and 3.1.

30
  • Classification using these factors, merged with
    information on climate and land cover revealed
    several hot spots.
  • The climatic index revealed more than 50 of the
    Lebanese territory to be highly prone to
    desertification.
  • The final classified layer indicated the more
    vulnerable to desertification areas to be
    distributed in the underdeveloped Baalbek-Hermel
    area.

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  • The moderate vulnerable areas are spread in
    Central and West Bekaa Valley and along the
    coastal plains.
  • The low vulnerability areas are located in the
    Central Mount Lebanon.
  • These categories of land degradation are subject
    to change with time if mismanagement of natural
    resources continues unchecked first of all water
    erosion.

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35
  • The assessment of water erosion using remote
    sensing (Landsat and Spot images) in the central
    Lebanese karstic Mountains (Qartaba- Jbeil area,
    200 km2) showed that 6 of the territory is very
    high erosion risk, 88 as moderate and 6 as low
    erosion risk.
  • This indicates the extent of the problem and
    pressure put on land resources leading to
    ecosystem degradation in Lebanon.
  • This process commences with soil erosion and ends
    with soil degradation and desertification.

36
Image Landsat TM
september 1997
37
Soil vulnerability to erosion in the Central
Lebanese Mountains
38
  • The western aspects of the Central mountain
    chain, which were distinguished by a low
    vulnerability to desertification are expected to
    become the most populated area.
  • A proper settlement policy and a gradual
    introduction of more tolerant wood species, which
    are less susceptible to dryness, and
  • The improvement of water harvesting practices
    appear to be prominent in view of greening
    efforts combating soil sealing, pollution and
    desertification.

39
Urban expansion detected from Landsat on the
Northern Lebanese coast 1984 1997
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42
Recent detailed soil information for Lebanon
43
Risks of soil pollution
  • Heavy metals in the soil
  • 1. Pedogenesis release of metals from the parent
    material by weathering
  • 2. Anthropogenic sources agricultural activity,
    manures, paints, mining activities, batteries,
    medical usages, and automobile aerosols

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Conclusion
  • Implementing appropriate land use planning based
    on soil capability and land suitability is
    important for soil and water conservation.
  • Limiting the risks of desertification and
    ensuring economic and social development based on
    sustainable production and safe environment.
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