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Handbook of Drought and Water Scarcity Environmental Impacts and Analysis of Drought and Water Scarcity Saeid Eslamian, Faezeh Eslamian

Environmental Impacts of Drought on Desertification Classification

Publication details https://www.routledgehandbooks.com/doi/10.1201/9781315226781-3 Dalezios Nicolas R., Eslamian Saeid Published online on: 24 Jul 2017

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Deser tification is an ecological and environmental issue and a slow-developing slow-developing a and issue environmental and ecological an is tification Drought on Desertification Referen Author 3.5 3.4 3.3 3.1 3.2 Environmental Impacts of Impacts Environmental

Summary and Conclusions Conclusions and Summary Methodology Classification Desertification Hazard Desertification Introduction Introduction of Critical Areas to Desertification Initial AssessmentRiskSeverity of Desertification of Desertification Modeling Causes and Factors of Desertification and Assessment Drought Types and Quantification Droug s ces ...... ht Quantification and Assessment Assessment and ht Quantification

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Proces ...... ses Leading to Desertification Leading ses ......

Classification •

Drought F •

Simul ation and eatures

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. Mitigat ...... Assessm ion ent 3 - - 45 60 49 45 47 57 61 61

Downloaded By: 10.3.98.104 At: 11:54 26 Sep 2021; For: 9781315226781, chapter3, 10.1201/9781315226781-3 of over 3.6 area an to corresponds which desertification, by threatened is land earth’s of one quarter Specifically, degradation. land of and worsening continuation the in resulting failed, have often desertification tocombat However, activities past drylands. of populated long-term productivity the for ensuring essential is desertification against Fighting at risk. are over people 100 countries one billion almost addition, in and, people million 250 over affects desertification Nevertheless, discontinuous. porally themajor is deficit ofprecipitation or lack since change, climate due to intensified is ification limits due to human activities [ activities due to human limits low to critically lead that parameters soil other are there restrictions, climatological despite when, only andaccelerated active become processes desertification for instance, region, Mediterranean the in Indeed, factors. environmental of other independent conditions desert causes that factor tinct dis and aunique constitutes drought meteorological where deserts, Sahara the and Kalahari the distribution. impact and in relief inequities and regional conflicts, use water issues, of life quality health, safety, refer topublic which mentioned, are impacts social Finally, sectors. related and other agriculture affect impacts economic Moreover, species. several animal and toplant damage wildfire the or process desertification the as such losses, indirect involve however, may also drought; they of consequence adirect as result that losses the involve impacts environmental particular, In impacts. social or economic, to environmental, sector, leading affected the on based classified be can impacts drought Furthermore, impacts. indirect considered are impacts direct these of consequences The habitat. fish and wildlife to damage and rates, mortality wildlife and livestock increased hazards, fire increased levels, water reduced productivity, rangeland or and forest cropland reduced include impacts drought world. of the parts other and Europe problem throughout awidespread erosion is by water soil fact, In activity. by human increased significantly been has rate natural erosion,the where to accelerated related erosion about are concerns most degradation, toland respect With formation. for soil essential is that process natural is a erosion soil Nevertheless, desertification. eventually, and, degradation, land [ activity and human change climate with circle vicious a creates desertification and degradation of land risk existing the regions, semiarid and arid in that evident it is Indeed, region. Mediterranean the as such environments, of certain protection for the threat a serious constitutes and of drought feature force and [ activities human and socioeconomic and biology, physiography, hydrology, soil, geology, climate, as such todesertification, contributing factors several are there Indeed, degradation. the first stage of the quantitative classification of desertification severity. At the second stage, mapping mapping stage, second At the severity. desertification of classification the quantitative of stage first the constitutes which classification, toquantitative leads region examined over the factors two of these maps development The composite of function. loss soil of the on modelling based considered is assessment erosion then, and indices, used widely by employing assessment drought from starting considered, is desertification physical Specifically, region. aover severity desertification of classification quantitative the for methodology two-stage on a emphasizes chapter This impacts. environmental drought from people. billion one of hoods liveli the threatens desertification that mentioning is worth it Thus, degradation. due toland year woodland. and forest, pasture, range, or cropland, gated irri cropland, of rained complexity and productivity or economic biological of the or loss reduction the in results degradation land Indeed, considered. are areas subhumid dry and semiarid, arid, lands, dry in Where, production. food andsubsistence pastoralism specifically agriculture, is of drylands use land The predominant processes. desertification triggering in decisive occasionally are activities human tosay, Needless factors. socioeconomic and climatic as such factors various between interaction the (UNCED: 46 The desertification phenomenon is distinguished from the classical concept of desert, such as such desert, of concept classical the from distinguished phenomenon is desertification The Direct indirect. and direct be can which impacts, significant have several droughts that It recognized is The objective of this chapter is to develop a desertification classification methodology, which results results which methodology, classification desertification a develop is to chapter this of objective The l causes, anthropogenic and natural of the outcomecombination of a is Desertification 34 of Agenda 21) of Agenda [ 12 Chapter ]. Specifically, prolonged drought periods result, among others, in soil exposure, erosion, exposure, soil in among others, result, periods drought prolonged ]. Specifically, ­billi on hectares. Moreover, since 1990, 6 million hectares of productive land is lost every every lost is land of productive hectares Moreover, 6million 1990, since on hectares. 1 ]. As a result, the desertification phenomenon is spatially andtem phenomenonspatially is desertification the ]. a result, As 31 ]. However, this is a general definition, which does not focus on not focus does which definition, ]. ageneral However, is this Handbook of Drought and Water and Scarcity of Drought Handbook 34 ]. Moreover, desert ­eadin g to land g toland ­ drivi ng ------Downloaded By: 10.3.98.104 At: 11:54 26 Sep 2021; For: 9781315226781, chapter3, 10.1201/9781315226781-3 drought types is complex. A brief description of the previously mentioned drought types is as follows: as is types drought mentioned previously of the description Abrief complex. is types drought [ demands environmental and societal meet to supplies water adequate toprovide on precipitation, depend that activities human and drought cal of meteorologi characteristics natural the between interaction of the terms in of drought, aspects social or human on the emphasize hydrological, and agricultural as such of droughts, types other the drought, of meteorological exception the with Specifically, sectors. hydrological and agricultural the in impacts in results quickly humidity, low relative and winds, high temperatures, above-normal with association logical drought [ drought logical meteoro as considered usually are or expected normal from of precipitation departure of accumulated stages early These time. of period over a in a region of precipitation a deficiency with begin droughts All considered. also is which of drought, impacts socioeconomic the of drought, type afourth is there tion, Environmental Impacts of Drought on Desertification Classification on Desertification of Drought Impacts Environmental 3.2 3.4 Section Finally, mitigation. and methods, assessment stages, factors, causes, features. 3.2 Section follows: as organized is chapter This classification. severity desertification scheme of final tothe 1, leading of stage mapping the produced to added is factors 2 stage of mapping composite Then, and measurements. data field ity water qual of mapping and analysis the through component desertification chemical of the sideration conthe is by followed This modelling. on groundwater based (GW) considered is levels of groundwater ­meteor namely, considered, are drought of definitions operational three literature, international the In 3.2.1 planning. and assessment drought in more useful are and of drought duration and severity the of the identification to contribute definitions operational hand, other the On of drought. concept the understand to the public and help are general definitions conceptual particular, In or operational. ceptual either con as classified be can drought of definitions Indeed, types. different into droughts classify and todefine atendency is there ahazard, as Moreover, drought sectors. by considering between vary impacts drought since specific, be application to need drought of definitions addition, In characteristics. climatic specific has region each and extent in regional are droughts Specifically, specific. or impact application [ distribution temporal and spatial diverse its and uses different for demand water increasing an as as well drought by affected of sectors variety awide is there because drought, of definition accepted universally and of aprecise absence an is there that It recognized is methodology for the quantitative classification of desertification severity. desertification of classification quantitative the for methodology Agricultural Meteorological  period of time, and by prolonged and abnormal moisture deficiency. moisture byabnormal prolonged and of time, period for some aregion in average lower than being anomaly, by aprecipitation characterized generally is drought Meteorological duration. period dry the and of precipitation deficiencies by specified dryness of thedegree as It defined is causes. multiple from resulting phenomena, of atmospheric drought-prone areas, which are more vulnerable to agricultural drought. toagricultural more vulnerable are which drought-prone areas, to typical are capacity low holding water with Soils intensity. precipitation and slope, type, soil conditions, moisture antecedent on depends infiltration fact, In soil. the into of precipitation tion infiltra and precipitation between relationship no direct is there and growth forage and crop port to sup water soil of availability the by defined is drought agricultural considerably. Specifically, reduced is yield crop that so depleted is moisture soil when occurs and of failure crop terms in described is drought agricultural Indeed, use. for agricultural availability water the in ciencies Drought Quantification and Assessmentand Drought Quantification  ological or climatological, agricultural or agrometeorological, and hydrological [ hydrological and agrometeorological, or agricultural climatological, or ological Drought Types and Quantification and Types Drought Section 3.3 Section or agrometeorological drought refers to the agricultural impacts resulting from defi from resulting impacts agricultural tothe refers drought or agrometeorological 27 or climatological drought is a region-specific natural event, due to the regional nature nature the regional event, to due natural aregion-specific is drought or climatological ]. A continuation of these dry conditions over a longer period of time, sometimes in in sometimes of time, over alonger period conditions dry of these ]. Acontinuation presents a conceptual and comprehensive description of desertification, including including of desertification, comprehensive description and aconceptual presents briefly describes drought concepts, types, quantification, indices, and indices, quantification, types, concepts, drought describes briefly 16 ]. Needless to say, the relationship between the different different the between tosay, relationship ]. the Needless 13 ]. Definitions of drought are usually region and and region usually are drought of ]. Definitions presents the two-stage two-stage the presents 6, 13 , 35 ]. In addi 47 ------Downloaded By: 10.3.98.104 At: 11:54 26 Sep 2021; For: 9781315226781, chapter3, 10.1201/9781315226781-3 mum severity. Periodicity severity. mum maxi of area the epicenter, is which so-called the of shift annual and aseasonal is there and gradually, evolve drought severe by affected The regions classes. mentioned previously the include which indices, and indicators drought through determined usually is severity The toextreme. severe, moderate, mild, follows. for the evaluation of drought indices without excessive complication. excessive without indices of drought evaluation for the framework reasonable a provide criteria the previous but condensed, or expanded be may list The fied. justi beprecisely to difficult are criteria, evaluation the of importance the relative reflect which weights, [ assessment and quantification drought in used [ of drought characteristics statistical and togeophysical related is value index how an and index the in weighted and combined is indicator howeach is, that index, an of validity and operational scientific the about [ data sensed remotely and/or conventional on based indices and indicators drought of use the on studies review several are There and/or indices. indicators todrought lead gation aggre and interpretation, analysis, Data vegetation. and snowpack, levels, groundwater storage, ervoir res moisture, soil streamflows, precipitation, and temperature as such variables, climate are indicators [ end time and onset, extent, areal periodicity, severity, duration, magnitude, as such features, drought describing variables are demand. and of supply processes spatiotemporal on the depends occurrence its since of droughts, types other from different is drought supply. water in Socioeconomic shortfall power, of aweather-related aresult as hydroelectric and transportation, water, materials, raw as such food, before, described droughts of types other three on brought by the goods of economic demand supply and gap between to the Finally, transparency, sophistication, expendability, and dimensionality [ dimensionality and expendability, sophistication, transparency, tractability, namely, robustness, index, of each properties on desirable based are which index, to each [ indicators economic and social by both measured be can 48 complex phenomenon, the assessment of start and end time is a complicated technical subject. subject. technical a complicated is end time and of start complex assessment phenomenon, the is a drought Since in months. usually time, andend start the from interval time the as defined is sode or indices. It is often difficult to determine the onset and the ending of a drought and on what criteria criteria what and on a drought of ending the and onset the determine to difficult It often is or indices. indicators of values threshold on again based drought, of termination the signifies episode a drought time End value. threshold acertain reaching or indices indicators through assessed is of adrought beginning The episode. of adrought occurrence by the determined is which of adrought, beginning the variability of several drought features in quantitative terms [ terms quantitative in features drought of several variability temporal and spatial the todelineate used be can methods and data and/or remote sensing ventional con Specifically, detected. usually are features drought several droughts, monitoring and For assessing 3.2.2 As already mentioned, quantification of drought is accomplished through drought indicators, which which indicators, drought through accomplished is drought of quantification mentioned, already As In evaluating the overall utility of indices, a set of weighted decision criteria are usually assigned assigned usually are criteria decision of weighted aset of indices, utility overall the evaluating In Hydrological surface and subsurface components of the hydrological system [ system hydrological components of the subsurface and surface in deficiencies these of the appearance and of precipitation departures between lag time nificant sig also is There supplies. water subsurface and of surface status the and amounts precipitation between relationship no direct is there drought, agricultural (watershed). region Like particular a in operations for normal supply necessary water minimum the than less or groundwater,is water supply, water surface either actual the which during aperiod tobe considered is drought Hydrological drought. meteorological from resulting period over along time conditions average  Drought Features and Assessment and Features Drought socioeconomic Severity 30 ]. Nevertheless, drought indices can provide ease of implementation and are extensively extensively are and of implementation ease provide can indices drought ]. Nevertheless, drought is normally defined by the departure of surface and subsurface water from somefrom water andsubsurface surface of departure the by defined normally is drought or intensity of drought is defined as escalation of the phenomenon into classes from the phenomenonintoclasses of escalation as defined is of drought or intensity drought is defined in terms of loss from an average or expected return and return expected or an average from of loss terms in defined is drought is considered the recurrence interval of drought. Duration of drought. interval recurrence the considered is 3 ]. Primary data for meteorological, agricultural, or hydrological drought drought or hydrological agricultural, for meteorological, data ]. Primary 19 , 21 ]. Handbook of Drought and Water and Scarcity of Drought Handbook 22 4–6 ]. Indeed, socioeconomic drought refers refers drought socioeconomic ]. Indeed, 16 ]. A description of some key features features of key some ]. Adescription ]. It is clear that the previous criteria criteria previous the that ]. It clear is 27 ]. 13 , 15 , 23 ]. There are questions are ].questions There of a drought epi of adrought Onset of of is is ------Downloaded By: 10.3.98.104 At: 11:54 26 Sep 2021; For: 9781315226781, chapter3, 10.1201/9781315226781-3 Environmental Impacts of Drought on Desertification Classification on Desertification of Drought Impacts Environmental consider multiple indicators to verify the existence and severity of drought. severity and existence the toverify indicators multiple consider to best is it summary, In scales. at different of drought characteristics and distribution temporal and tial spa of the detection for tool the important an become gradually has remote sensing that recognized is Moreover,severity. drought of it and monitoring assessment the in significant also are indicators other many indicators, drought of many basis the is precipitation Although data. on rely rainfall monitoring and assessment drought of methods traditional Indeed, and monitoring. assessment, quantification, tourism. and recreation, health, energy, transportation, economy, of agriculture, the as such sectors toseveral impacts may have serious of drought characteristics spatial the perspective, From a planning class. each in pixels of the number counting by parameter this of delineation the in significantly contributed has sensing and remote time, in varies extent Areal indices. or indicators by classes in phenomenon quantified as extent Areal made. be should determinations these tourism, and socioeconomic factors. socioeconomic and tourism, expansion, industrial and urban practices, management agricultural and forest inadequate overgrazing, intensification, agricultural fires, forest in changes use land inappropriate resources, underground and surface of overexploitation fires, forest and overexploitation urbanization, include causes pogenic anthro hand, other the On of a region. aspects historical the and balance, water of the alterations tive qualita and quantitative erosion processes, of soil geomorphology climate, dry include causes natural Specifically, anthropogenic. or natural either be can of desertification causes the mentioned, already As .13.3 to combat desertification are described. This is followed by a presentation the of stagesthat lead todesertification, and, finally,mitigation measures factors contributing to desertification, thenand assessment methods and effortsmodelling are described. land. valuable however, region; it affects Mediterranean the in extensive not it very is and plains alluvial some in is localized desertification of seawater. Chemical intrusion the causing aquifers of coastal overpumping and tables, groundwater saline or raising requirement leaching tomeet ing fail schemes irrigation thresholds, critical exceeding soluble salts containing waters with irrigation are causes main The lands. irrigated in management water irrational through of soils salinization secondary is desertification of chemical process dominant the addition, In zones. subhumid dry and semiarid the within located are cover and of vegetative 60% more have lost than that lands on marginal occurs which erosion, soil accelerated is process physical dominant the where extensive, very is and land on sloping occurs degradation physical Specifically, involved. processes on the depending or chemical, physical as characterized be can desertification Furthermore, season. growing vegetative the during temperatures high and deficit, moisture soil high of rainfall, corrosion high and intensity increased time, and space in distribution precipitation (PET), uneven evapotranspiration potential annual high depth, rainfall annual include low areas such of characteristics the Indeed, desertification. of classification quantitative in a in order to proceed areas high-risk the to identify useful and Moreover, significant areas. it is mid subhu dry and semiarid, arid, in degradation land constitutes desertification defined, already As ard. - haz environmental slow-developing and a issue andenvironmental ecological an is Desertification 3.3 There are many factors that trigger desertification, including the unpredictable effects of drought, drought, of effects unpredictable the including desertification, trigger that factors many are There deforestation, predatory exploitation, extensive cultivation, industrialization, and urbanization [ urbanization and industrialization, cultivation, extensive exploitation, predatory deforestation, change, climate as such varied, most are degradation of land originators main the out as pointed tors It is accepted that drought indices can be easily implemented and are extensively used in drought drought in used extensively are and implemented easily be can indices drought that It accepted is The identification of the factors contributing to desertification is a complex process, since the fac the since a is complexprocess, desertification to contributing factors the of The identification A brief description of desertification hazard is presentedfrom starting a presentation thecauses of and   DesertificationHazard Causes and Factors ofDesertification and Causes of drought is considered the spatial coverage of the of the coverage spatial the considered is of drought 25 49 ]. ]. ------Downloaded By: 10.3.98.104 At: 11:54 26 Sep 2021; For: 9781315226781, chapter3, 10.1201/9781315226781-3 tinuously increasing pressure. Rational management of soil resources may resources of soil management Rational pressure. increasing tinuously - con faces and destroyed, easily be can which resource, anonrenewable is soil Nevertheless, ecosystem. the in sustainability is there aresult, As losses. and of changes rates the and formation of soil rates the between abalance is there slow and are changes the conditions, Under natural environment. tothe puts out and of inputs intensity on the based rates of various changes continuous faces asystem Such that. rocks. volcanic the and fumed acid the are composition, have coarse slowlyand soils form which rocks, Other todrought. sensitive and shallow is soil the rocks, these In land. hilly of marls and limestones are rocks These corrosion. soil and of rocks, weathering rate of the permeability, their dueto process desertification the influence can of rocks The properties 3.3.1.2 is desertification. no there 0.65,than higher is ratio the when whereas desertification, 0.03, always is there ( index aridity (P) the tation as toPET, known is which precipi the annual 0.03–0.65of ratio with areas the as defined are regions, subpolar and polar than other cal, and biological soil properties, which lead to erosion, loss of its productivity ability, and, most times, times, most and, ability, productivity of its toerosion, loss lead which properties, soil biological and cal, chemi physical, the in by changes characterized is Moreover, degradation land processes. phogenesis eda through re-created tobe centuries even it may take otherwise, over along time; ability productive tion tion loss on desertification are difficult to predict [ topredict difficult are on desertification loss of biodiversity effects consequent the areas, many in risk desertification and aridity may increase change climate although addition, In species. for certain growth plant boost can atmosphere the in dioxide bon car in increase an hand, other the On drylands. in rainfall reduced and soil from of water loss increased through impact can negative have a higher temperatures first, At understood. not sufficiently yet and complex is desertification on change climate global of effect the Indeed, system. climate global for the consequences significant with of desertification, aresult as atmosphere the into released be could which carbon, a lot of contain soils dryland Specifically, losses. vegetation and soil through change climate global affects Moreover, desertification alkaline. and/or saline frequently are and content matter organic ­dryla C 3.3.1.1 text. thesucceeding in described briefly are categories perspective the and rized catego be can desertification of factors The services. supply of environmental the toreward markets of failure the and systems, research environmental and agricultural and makers by policy neglect ­landle increase, population mining, nutrient pressures, livestock erosion, geological and soils fragile 50 limate and desertification interact at a variety of scales. Indeed, climate affects the desertifica the affects climate Indeed, scales. of variety at a interact desertification and limate Soil is an open natural system, interacting with the environment and resulting in strong impact on impact strong in resulting and environment the with interacting system, natural open an is Soil ­proces d [ nds ssness and an inequitable distribution of resources, poor infrastructure and market access, access, market and infrastructure poor of resources, distribution inequitable an and ssness   Climate Geolog 10 ses through its impact on dryland soils and vegetation, as well as on hydrological cycle in in cycle on hydrological as well as vegetation, and soils on dryland impact its through ses ]. Unlike the organically rich soils of more humid regions, dryland soils often have low often soils dryland regions, of more humid soils rich organically the ]. Unlike y and Soils y and >0.65 0.50–<0.65 0.20–<0.50 Classification 0.03–<0.20 <0.03 (mm) Rainfall (PET >P) Aridity Index: P/PET TABLE 3.1

Dryland C Dryland (summer) 600–800 (winter) 500–700 (summer) 400–600 (winter) 200–500 (summer) <400 (winter)<200 <200 ategories 31 ]. Moreover, arid, semiarid, and dry subhumid areas, areas, subhumid dry and ]. Moreover, semiarid, arid, Table 3.1 Table Handbook of Drought and Water and Scarcity of Drought Handbook ). In general, when the ratio is lower than lower is than ratio the when ). general, In No desertification subhumidDry Semiarid Arid Hyperarid climateDesert ­ sustai n or even improve n or its even ------Downloaded By: 10.3.98.104 At: 11:54 26 Sep 2021; For: 9781315226781, chapter3, 10.1201/9781315226781-3 Environmental Impacts of Drought on Desertification Classification on Desertification of Drought Impacts Environmental whe to long dry periods followed by heavy bursts of erosive rain, falling on steep slopes with fragile soils [ soils fragile with slopes on steep falling of rain, erosive bursts by followed heavy periods to long dry subject it is toerosion, because vulnerable mostly is region Mediterranean the For example, use. land and climate toboth sensitive very is erosion rate Indeed, farmland. of natural loss toapermanent lead may shallow, are soils where and, productivity soil erosion reduces topsoil, fertile most the removing By desertification [ desertification

flow to sea, which are very critical for desertification, especially in vulnerable and sensitive areas [ areas sensitive and vulnerable in especially fordesertification, critical are very which flowsea, to groundwater and groundwater, to percolation deep infiltration, runoff, surface as such abstractions, and losses water are there Nevertheless, animals. and plants as such organisms, of living requirements the to cover insufficient are supplies water available the until extends This process to desertification. lead and impacts which may have force, driving the cycle signifies the hydrological of phase land The 3.3.1 southern Europe. in than areas extensive less affects year, and the throughout distributed evenly slopes, on gentle falls mainly rain problem, since not aserious erosion yet is soil Europe, northwest in hand, other On the water resources. water of available exhaustion the and land of to low related productivity directly is which desertification, and the soil moisture, resulting in plant growth. plant in resulting moisture, soil the replenishes which irrigation, be may desertification from areas these for solution preventing A possible sedimentation. and exploitation groundwater and rocks, limestone of permeability demand, industrial and urban pollution, cover, vegetation environmental sparse from Moreover, may occur losses water respectively, as follows: as respectively, 3.1 rate (Equation loss soil are presented, equations two Specifically, of land. shape and aspect, gradient, slope on depends desertification addition, In aridity. and erosion, salinity, namely, features, presented the previously favor which processes, desertification three the significantly Moreover, affects erodibility. physiography soil and availability, nutrient plant capacity, holding water rate, formation soil through to desertification connected is performance soil the particular, In capacity. andfield conductivity, hydraulic infiltration, matter, surface organic fertility, soil moisture, soil ture, tex soil depth, soil are indicators, risk desertification as considered are and processes and rate cation desertifi affect which characteristics, soil Indeed, erosion resistance. tosoil and toplants availability water to are related parameters These surface. soil on the fragments of rock amount the and texture, soil aspect, slope gradient, slope depth, soil parent material, are desertification affecting greatly parameters soil that have shown MEDALUS, and DESRTLINKS, DESIRE, as such projects, research European several in studies Extensive of plants. needs the of meeting not capable is balance water their when soils, even deep on proceeds desertification that cover. Moreover, vegetation cases are there minimum certain a capable sustaining of is not depth soil the rootable when desertified irreversibly becomes land the zones, subhumid and semiarid the In water, nutrients. and space, rooting with plants the vide

c, a, b, m are the empirical coefficients empirical the b, mare a, c, length slope the L is erosion the is E2 gradient slope the S is loss soil the is E1 It is accepted that desertification proceeds in a certain landscape, when the soil is ablenot to pro soil the when landscape, certain in a proceeds desertification that It accepted is re .3  Hydrol 33 ogy and Water Resources and ogy ]. Indeed, irrational land use due to human intervention leads to land degradation degradation toland leads intervention due tohuman use land irrational ]. Indeed, E E 2 1 = = bL cS a m

Equation 3.2 (Equation erosion and ) (3.2) (3.1) 51 9 3 ), ), ]. ]. ]. ]. - - - Downloaded By: 10.3.98.104 At: 11:54 26 Sep 2021; For: 9781315226781, chapter3, 10.1201/9781315226781-3 52 evapotranspiration demands. Furthermore, low amounts of annual rainfall negatively affect plant cover. plant affect negatively rainfall of annual low amounts Furthermore, demands. evapotranspiration high promotecover low to due plant temperatures air annual high cover. Indeed, plant affects greatly climate addition, In stress. water by affected areas in especially desertification, of land indicator cial acru cover is Plant conservation. water soil and temperatures surface soil summer of the increase the prevents cover significantly plant mentioned, already as Furthermore, impact. raindrop reducing [ reduced significantly erosion is soil and impact raindrop from protected adequately are soils value this above since value, acritical as considered is order of 45%–50% cover of the Avegetation Mediterranean. the in species est for many of the regeneration for is andnecessary it temperatures surface soil thesummer significantly decrease exponentially with an increasing percentage of vegetation cover [ of vegetation percentage increasing an with exponentially decrease surface. ground at the sity inten rainfall effective prevent cannot cover by vegetation protection the reduced since desertification, ( crops rainfed with areas addition, In land. soil bare in resulting gradually water availability, of reduction suffer rate evapotranspiration high and mm P <280 precipitation annual with areas Indeed, area. an in vegetation and soil, climate, between relationships cover. existing of on vegetation Moreover, the cover depends vegetation variability increased in result also drylands in (P) variability rainfall and seasonality cautiously, since treated be should indicator this trend. However, desertification a signifies continuously, this increase areas barren and observed are cover in vegetation changes persistent When for desertification. indicator possible best the also is which 3.3.1.4 periodically. occur may salinization severe or moderate climates, subhumid or in humid whereas to desertification, lead could accumulation salt continuous climates, dry in Furthermore, uptake. water root lowering and potential osmotic ing increas by indirectly and toxicity their by directly both growth plant affect bicarbonates, and sulfates calcium and magnesium and chloride sodium for example, salts, of various concentrations high Indeed, and productivity. growth plant affect can layers topsoil the in levels salt Moreover, increasing nization. sali tosoil leads conditions climatic and soil certain under for irrigation quality water of poor use the mentioned, already As uses. for multiple demands water increasing from results which overexploitation, impacts. strongest the faces sector economic the time same at the although degradation, chemical water and consumption water high major role by causing a plays agriculture cases, such In Europe. in of hectares millions affects world and over the problem all growing is a salinization soil coast, the along areas the plain in Indeed, todesertification. lead could that processes key one is of the quality, water poor from resulting salinization, Soil erosion. soil and alkalinization, logging, water salinization, from resulting degradation for soil responsible cases many in are intrusion, seawater for example, quality, water of poor use the and systems, of drainage lack the costs, production high to meet intensification Moreover, for agriculture need uses. water the tothe ing Th Water resources are under severe physical, social, economic, and environmental stresses, compound stresses, environmental and economic, social, physical, severe under are Water resources Many studies have demonstrated that in a wide range of environments, both runoff and sediment loss loss sediment and runoff both of environments, range awide in that have demonstrated studies Many due to intrusion seawater the is aquifers in of salts amounts of the increase for the reason main One e most dominant biotic land component that affects desertification is the vegetative cover of land, land, cover of vegetative the is desertification affects component that land biotic dominant e most  Biology Dry subhumidDry Semiarid Arid Hyperarid lsiiainGrowingSeason (Days) Classification TABLE 3.2

11 Typical Ra ]. Moreover, both runoff and sediment loss are greatly affected by plant cover plant by affected greatly are loss sediment and ]. Moreover, runoff both infed Crops Grown inDrylands 2–7 Maize, beans, groundnut, barley, peas, wheat 120–179 60–119 1–59 0 Bulrush millet, sorghum, millet, Bulrush sesame No crops, marginal pasture No crop, no pasture Table 3.2 Table Handbook of Drought and Water and Scarcity of Drought Handbook ) [ Typical Crops 10 ] are very sensitive to erosion and to erosion and sensitive very ] are 8 ]. Forest vegetation reduces reduces vegetation ]. Forest ------Downloaded By: 10.3.98.104 At: 11:54 26 Sep 2021; For: 9781315226781, chapter3, 10.1201/9781315226781-3 trigger desertification. trigger could that change land of pathways up specific make use, land regional and mechanisms feedback with combination in factors, of causal aset location, For each extension. infrastructure and overgrazing, expansion, cropland rise to give factors These desertification. drive remote influences, and growth, population policies, national institutions, factors, economic and climatic are prominent most the desertification [ desertification affect factors on yet how human no consensus is there that mean researchers among views varying and paradigms Changing understood. fully are not of desertification causes human the summary, In failures. institutional and of outcomes policy as recognized been have all salinization erosion, and soil depletion, tosay, groundwater problemsscarcity, of water Needless salinity. tosoil water,gated leading irri of and losses in redundancy results planning irrigation ineffective Furthermore, aquifers. coastal in of seawater intrusion and aquifers of groundwater salinization in resulting resources, available the of toa reduction leads water resources, of and overexploitation deforestation to due sea, the to runoff of surface increase addition, In degradation. to land lead tourism development and land irrational and abandonment, land areas, sensitive of overgrazing cover due fires, to forest of vegetative reduction and Moreover, erosion. soil in deforestation result lands of hilly cultivation irrational and biomass plant of factor,overexploitation since another is intervention human through agriculture of Intensification pollution. to environmental also leading consumption water in increase continuous the and growth consi are factors human main The .1.53.3 conditions. climatic or arid semiarid cover under plant and growth plant therefore, and, capacity storage water soil affect outcrops greatly of rock exposure and texture, soil depth, soil Furthermore, promote lowcover percentages. plant usually indices seasonality rain high In addition, preventing desertification, improving the knowledge about desertification processes and understanding understanding and processes desertification about knowledge the improving desertification, preventing and include monitoring among others, efforts, Such trends. and needs order tocover current in ducted con be to and work remains effort much research degradation, of land impacts the from at risk ently people pres six worldwide in one nearly With areas. sensitive in schemes classification desertification anddevelopment of assessment, severity drought during imagery satellite of analysis desertification, causing processes main the representing of maps production areas, (DSR) sensitive in risk severity tion desertifica of the modelling spatial techniques, remote sensing and systems information geographical (PET > deficits water P). large with areas in conditions cation desertifi to evaluate indices composite and of multiple use and methods; downscaling high-resolution on influence and geomorphology of topography assessment effects; on small-scale emphasis with events extreme and variability climate of simulation conditions; desertification future understand to scenarios climatic of use gases; greenhouse of andemission use land in changes as such conditions, specific under parameters climatic in of long-term changes prediction forecasting; short-term atmosphere–ocean; and atmosphere–continent between exchange energy and oceans, atmosphere, of the dynamics of the tion - simula scenarios; climatic for future models development of include numerical methodologies Such desertification. to related activities research within implemented havebeen that efforts modelling and of methodologies range large DEMON.is a EFEDA; There and III; and MEDALUS II, I, as such tinue, con still and conducted have been projects integrated multilevel and multiscaling, Interdisciplinary, mitigation. and extent, spatial impacts, causes, on its research supported has and Europe Mediterranean the majorin as a problem desertification recognized has Commission European the Indeed, tion. to desertifica susceptible of drylands area largest the considered is Europe level, global At the 3.3. Environmental Impacts of Drought on Desertification Classification on Desertification of Drought Impacts Environmental Summarizing this section, according to [ according section, this Summarizing Existing desertification assessment and monitoring methods are also considered that incorporate incorporate that considered also are methods and monitoring assessment desertification Existing 2   Simulation and Modeling and Simulation Human A 7 ]. ctivities dered to be of socioeconomic nature. One factor is the population population the is factor One nature. of socioeconomic to be dered 12 ], a limited number of recurrent core variables, of which of which core variables, of recurrent number ], a limited 53 ------Downloaded By: 10.3.98.104 At: 11:54 26 Sep 2021; For: 9781315226781, chapter3, 10.1201/9781315226781-3 and oxidative stress on plants, imposes ion toxicity [ ion toxicity imposes on plants, stress oxidative and K, Ca, (N, Zn) nutrient P, Fe, deficiency, stress, osmotic except salinity, soil therefore, on plants; effects toxic independent boron,andhave chlorine, sodium, as such ions, specific Some nutrients. and of water shallow soils very sensitive to erosion [ sensitive very soils shallow with lands hilly to confined mainly are olives, and almonds, vines, cereals, as such crops, rainfed with cultivated areas Mediterranean Extensive horizon. soil surface the in especially aggregation, soil and infiltration water affects activity Moreover, year. of the microbial period the the and conditions matic cli on depending areas hilly in altered be readily can which by vegetation, controlled greatly is runoff water Surface activity. microbial the and soil, the within over and redistribution sion water control, [ solution of soil potential osmotic the increases zone root [ Europe in sustainability and quality tosoil major threats eight the among included is Salinization desertification. toland lead can that zones arid in processes degradation land. on arable those lower than magnitude one order of by at least losses sediment soil cover generate vegetation permanent with soils that trating out [ carried phenomenonbeen have desertification the for quantifying efforts recent Indeed, orchards. olive steep moderately in loss soil limiting in vegetation understory plant annual role of the significant the highlighted it also and olives, with cultivated areas hilly in occurred loss sediment and [ found It also is erosion occurs. soil accelerated which under and platforms. and schemes technological several through knowledge scientific distributing and mechanisms, feedback and schemes evaluation institutional developing implications, environmental and interactions causal 54 in runoff and sediment yields. Specifically, the key limit of plant [ coverplant of limit (40%) identified been key has the Specifically, yields. sediment and runoff in variation tothe management use land cover and role of vegetation important the have reported studies Several erosion. tosoil susceptible generally is erodibility, soil high and erosivity rainfall by high ized character region, Mediterranean European The desertification. consequently, and, degradation land of process asignificant erosion is soil addition, In surface. the reach ground on the falling raindrops the that the result has which area, an over coverage the vegetation of the reduction is issue main The 3.3.3.1 presented. are briefly todesertification lead that processes the and stages the todesertification, furthermore and todrought contribute that factors and causes the Following 3.3.3 to bushfires. subject or areas areas burned and areas; over large erosion patterns water large paths; animal around low-cover as grasslands such features, overgrazing schemes; irrigation in patterns salinization include images satellite from detected be can that features Other features. degradation land and acteristics, char soil features, cover, land landscape use, of land assessment for the used be can data sensing remote Furthermore, maximum. at its cover is vegetation when period growth the during ducted con be should and importance of crucial is observations vegetation of the Moreover,tion. timing of desertifica indicative not necessarily are data yield the thus and use, of fertilizer by alack caused have been could yields However, data. decreasing yield crop is degradation land toidentify used been has that indicator Adifferent degradation. land of ongoing indication aclear there is increases storms the of magnitude the and rises storms of dust frequency the when Only desertification. experiencing is area the that to conclude not sufficient is area a certain erosion in of wind observation an Hence, erosion. water and wind as such processes, todegradation subject are areas dryland Many data. ity As already stated, vegetation is a crucial factor, which affects soils in all its dynamics, including ero including dynamics, its all in soils affects factor, which a crucial is vegetation stated, already As According to the United Nations Environment Program [ Program Environment Nations United tothe According Needless to say, from these assessment studies, it is evident that there is a need for high-qual aneed is there that evident it is studies, assessment tosay, these from Needless   Processes Leading to Desertification Leading Processes Stage 1: So Stage il Degradation il 20 ]. These areas become vulnerable to erosion and desertification, anddesertification, erosion to vulnerable become areas ]. These 28 ]. Handbook of Drought and Water and Scarcity of Drought Handbook 29 ] and consequently the normal absorption absorption normal the consequently ] and 20 32 ] that the lowest rates of annual runoff of annual lowest rates the ] that ], soil salinization is one of the main main one is of the salinization ], soil 24 ]. The concentration of salts in the in salts of ].concentration The 2 ] illus ] 11 ], ], ------Downloaded By: 10.3.98.104 At: 11:54 26 Sep 2021; For: 9781315226781, chapter3, 10.1201/9781315226781-3 3.3.3.3 salinization. by affected tobe more likely are soils fine-textured and fine moderately therefore, porosity; soil and texture soil as such properties, soil tovarious related is capacity storage water Soil salinization. tosoil more vulnerable are capacity storage water high of Soils capacity. storage water soil by affected be can desertification and salinization soil ing water stress andrisk desertification is gradient.slope gradientsUnderslope high (greaterthan25%), tourism, and and institutional social characteristics. The most important indicator relatedsoils to - affect related to climate, soil, water and water use, vegetation, land use, fires, waterrunoff, land management, water stress as most recognized the has important been degradation process. The defined indicators are indicators12 havethe defined as most important been affecting desertification risk in field sites, where Moreover, studies out carried during execution the of EUresearch the project DESIRE have shown that of available the depth root in the zone, as there is depletion of organic the matter and nutrients. the afterthe rainfall. Indeed, erosioncan resultthe in reduction the of biomass production the and decrease processthe canto runoff, lead surface as expected. In addition,gradient erosion be mayobserved also This processbasically depends on rainfall, but occur due thewind. canto it also With to rainfall, respect 3.3.3.4 growth. for used plant water of expense the at increases consumption water urban since desertification, to more vulnerable density, are population or tohigh changes tourism tohigh subjected areas, dry Furthermore, plants. growing the in stress water promote exploitation, groundwater of rates increasing as such activities, Human stress. water toMay, October enhances from period the during occurring fall rain of the most with conditions climatic semiarid under one observed the as such ofbution rainfall, distri irregular An year. anormal during of rainfall distribution tothe related is seasonality Rainfall seasonality. rainfall high with areas in of desertification process important an as considered be can stress water Specifically, water foramount of plants. of asignificant loss subsequent the and production of biomass the reduction from starting effects, of negative achain produces structure surface soil the th of as a result ones intosmaller separated are particles soil The sumption per sector, are more vulnerable to soil salinization and land desertification [ desertification land and salinization to soil more vulnerable sector, are per sumption con of water terms in scarcity, water by high characterized Areas tooccur. more is likely salinization soil demands, consumption/water of water rates high under Furthermore, salinization. tosoil nerable more vul are resources water surface and of groundwater by overexploitation accompanied availability of water low Areas pronedesertification. to areas in salinization soil affecting greatly are scarcity, water and land, arable of percentage irrigation demands, consumption/water water exploitation, groundwater as such exploitation, resources towater related actions human indices, aridity high mm) 650 and than (lower rainfall of low annual characteristics climate important the Except areas. coastal especially and conditions drainage poor with areas plain mainly affects salinization Soil production. biomass of the reduction the in resulting agglomerates, soil of the weakening the may cause matter of organic lack 3.3.3.2 desertification. erosion and from areas hilly protecting ecosystems, natural some than higher even fauna, and of flora diversity aremarkable support conditions seminatural under [ rate adecreasing in tillage minimum under groves olive and shrubland, cereals, byfollowed eucalyptus, loss, sediment and of runoff amount highest the generates vines uses that land the agement practices, - man land existing the under MEDALUS that have shown projects EU research of the execution the ing dur and Portugal Europe the Mediterranean along conducted erosion measurements soil Specifically, rains. heavy during impact raindrop from cover the vegetation of effect protection decreased due to the Classification on Desertification of Drought Impacts Environmental Orga 20 ]. Moreover, olives present a particularly high adaptation and resistance to long-term droughts and and tolong-term droughts resistance and adaptation high ]. Moreover, presentaparticularly olives nic matter is the connecting factor between the soil particles. The reduction and, eventually, eventually, and, The reduction particles. soil the between factor connecting the is matter nic    and Deterioration oftheSoilStructure Matter Stage 2:ReductionoftheOrganic Stage 4: Ru 4: Stage Stage 3: Di 3: Stage spersion of the Soil Agglomerates Soil the of spersion noff and Sediment Transfer Sediment and noff e falling raindrops. The degradation of degradation The raindrops. e falling 14 ]. Furthermore, ]. Furthermore, 55 - - - - - Downloaded By: 10.3.98.104 At: 11:54 26 Sep 2021; For: 9781315226781, chapter3, 10.1201/9781315226781-3 2000 m theof level 1000– uses Organization The capita. per World Health year per meters cubic in expressed sectors, economic by all water water, cooling and water, water, process irrigation for drinking demands the total includes capita per consumption water The demand. increasing an from resources of available thesupply and/oron pressure change, climate as to due such resources, diminishing means definition, Moreover, by scarcity, water survive. can environment, its and human for the useful is which organism, of form living any that extent tothe moisture soil of the decrease and volume soil of the Reduction 3.3.3.5 andrisk desertification are diminished. population density. Finally, ifexisting on policies environmental protection are implemented, water stress charge of water for used plant growth.same The trends with tourism change are found forthe indicator stays last inthe 10 years) are more vulnerable to water stress, since urban water consumption increases in than(higher 5%—number of overnight stays destination inaspecific in one year averaged by overnight tion risk are Tourism high. change is positively related to water stress. Areas tourism under high change measures. If no or low erosion soil control measures are water then undertaken, stress- and desertifica reducing water demands and water stress risk. Water stress is negatively related to erosion soil control In addition, ratesunder high of deforestation or firefrequency, thegrowing plants are mainly removed, growingthe plants are subjected to water higher stress, since water surface be higher. to runoff is expected 56 analysis, diagnosis, and understanding of the causes and potential effects at specific areas. specific at effects potential and causes of the understanding and diagnosis, analysis, accurate an and on involved the processes of the proper identification on depend must to desertification, leads which degradation, problem of for land of choice the solutions preventionand the Indeed, cation. desertifi of stage first the from even effective be must to say, mitigation Needless actions. necessary the of some constitute protection forest erosion, and soil from protection resources, of water management and use rational resources, of natural exploitation for the systems alternative plan, use land integrated An and measures. actions direct and requires problem global as a considered be must Desertification 3.3.4 stress and soil salinization. Areas under high water scarcity are subjected to higher desertification risk. desertification tohigher subjected are scarcity water high under Areas salinization. soil and stress water is degradation land of cause main the where areas in risk desertification for assessing indicator important an especially is Water scarcity. water scarcity experiencing as considered are areas year, then overgrazing, overexploitation of plants, and unsustainable irrigation practices, that intensify intensify that practices, irrigation unsustainable and plants, of overexploitation overgrazing, as such activities, human address can use land Moreover,sustainable preventdesertification. effectively degradation of soil forms other and erosion, salinization, from soils protect that measures All vention. activities. or mining woodcutting, plants, of medicinal overharvesting overgrazing, due toovercultivation, lost is cover vegetation if induced may be rainfall Reduced episodes. drought during services of ecosystem loss prevents also cover vegetative maintained Properly desertification. against measure preventive akey is erosion water and wind from soil cover to protect vegetative Maintaining prevention of desertification. for amajor tool be the cover can Moreover, of vegetative protection periods. drought during for use water of reserves provide can spreading floodwater and revegetation, upstream conservation, soil–water through recharge groundwater improving addition, In topsoil. moisture-holding fertile, thin, away the carrying from runoff helps toprevent surface also episodes rainfall intensive during for capture water practices management Maintaining measures. conservation water and soil diverse and storage, water techniques, water-harvesting of traditional use may include which water-related services, enhance can practices management improved water Nevertheless, composition. species diverse and of ecosystems, capacity carrying tothe matched rates stocking sites, well and of rangelands use rotational as such activities, of human pressures the tospread measures include strategies Management vulnerability. Integrated methodologies for land and water management are key measures for desertification pre for desertification measures key are management water and for land methodologies Integrated  3  Mitigation of Desertification /person/year to identify risk on water scarcity. When these values drop below 1000 m below 1000 drop values these When scarcity. on water risk toidentify /person/year Stag e 5: Soil Degradation and Desertification and Degradation Soil e 5: Handbook of Drought and Water and Scarcity of Drought Handbook 3 /person/ ­ dry land land - - Downloaded By: 10.3.98.104 At: 11:54 26 Sep 2021; For: 9781315226781, chapter3, 10.1201/9781315226781-3 (D SPIvalues) (D)(negative drought classes are study.four There under or watershed area over the basis cal drought index [ index drought cal meteorologi common the as Services Hydrological and Meteorological National by the globally used computed and to be index drought the as recommended and by SPI WMO adopted is the that Indices” on Drought Declaration “Lincoln the via (November2009) 8–11, announced of Nebraska University the at workshop expert international an that mentioning It step. worth is time for each area the examined 3.3 Table in shown are of SPI classes Seven used. is period a12-month application, current For the or less. months of 24 ods peri used for mostly is but it from 1to 72 months, periods for calculated be can and The SPIflexible is positive. the SPIbecomes of when−1.0 event Theends intensity or less. an reaches and negative ously SPI continu is the anytime event occurs Adrought deviation. by standard mean long-term seasonal its and precipitation seasonal the normalized between difference the dividing The computedSPIis by the SPI ( from (intensities)resulting severities drought define to used is system A classification parameters. distribution gamma of the estimation likelihood of maximum a process through tribution dis gamma toa are fitted station the of data rainfall historical The preferred. and more optimal being (or years more) 50–60 with needed are values complete monthly of serially years 20–30 at least Ideally, [ historically months same tothe relative periods for 12-month 3-, 6-,9-, as and such timescales, [ (SPI) index precipitation standardized of the use the with conducted is assessment severity Drought 3.4.1.1 risk. desertification of classification initial the and assessment, degradation soil the assessment, severity drought the involves subsection this Specifically, methodology. classification desertification development the the of stage for first the of steps the presents section This 3.4.1 presented. is briefly adopted procedure The steps. several has stage each and stages two includes methodology This is presented. severity desertification of classification for quantitative A methodology 3.4 normal class (−0.49 to +0.49). The ideal spatial resolution is usually 1 km 1 (−0.49 class usually is normal resolution to+0.49).spatial The ideal −2.0).the near- than also (less is There dry (−1.5 to −1.99); 4, extremely dry 3,class severely and class Environmental Impacts of Drought on Desertification Classification on Desertification of Drought Impacts Environmental and groundwater, subject to the number of rain gauges. of rain number to the groundwater,subject and 20 i ], which is based only on precipitation data. The SPI quantifies the precipitation deficit for multiple multiple deficit for the precipitation The SPI quantifies data. on precipitation only based is ], which , i = 1–4) (   Desertification Classification Methodology Classification Desertification  Initial Assessment of Desertification Severity Risk Severity ofDesertification Assessment Initial Drought Table 3.3 Severity Assessment Severity 36 American Meteorological Society, Anaheim, CA,1993, pp. 179–184. duration Preprints, to timescales, Eighth Conference on Applied Climatology, −2.0 and less −1.5 to −1.99 −1.0 to −1.49 to 0.99 −0.99 +1.0 to 1.49 +1.5 to 1.99 +2.0 and greater Standardized Precipitation Index Value TABLE 3.3 ), namely, class 1, mild dry (−0.50 to −0.99); class 2, moderately dry (−1.0 (−0.50 dry dry to −0.99); moderately 1, 2, mild ),to −1.49); namely, class class ]. In quantitative terms, the outcome is digital mapping of SPI values on a pixel on apixel of SPI mapping values digital outcome is the terms, ]. quantitative In . Geostatistical analysis is used for spatial interpolation to derive digital maps of maps digital toderive interpolation for spatial used is analysis . Geostatistical Source:

McKee, T.B

Standa rdized Precipitation Index ClassificationScale . etal., The relationship of droughtfrequency and Extremely dry Severely dry Moderately dry Near-normal–mild dry Moderately wet Very wet Extremely wet Moisture Level 2 to be compatible with erosion with compatible tobe Table 3.3 30 57 ). ). ]. ]. - - - - Downloaded By: 10.3.98.104 At: 11:54 26 Sep 2021; For: 9781315226781, chapter3, 10.1201/9781315226781-3 [ equation general following by the given soil, topography, and vegetation, climate, on dependent primarily are which of terms, aproduct as obtained t/ha, in loss soil amean as estimated event is rainfall each after transported sediment amount of The respectively. runoff, erosion and both on impact havestrong a properties and vegetation soil that water, recognizing runoff erosion by the classes. four the from one value assigned is or watershed area examined the in The raster maps of SPI values (D maps of SPIvalues raster The 3.4.1.3 resolution. 3D at 1km in erosion risk of soil estimation for the applied is model Union this level, European At the 100 m×100 m. for example, format, agrid in prepared is database sions (3D) the where awatershed, in dimen dimensions (2D),catena alongtwothree a form), (excel in in or used be can model The PESERA Asses 3.4.1.2 58 The model repeats these estimates at every 1 × 1 km 1× every at estimates these repeats The model change. use land of effect the showsand point forrates asingle anderosion runoff toestimate used be can model the mentioned, already As grid. a1km within cell for each conducted are model PESERA the of stages three the of computations The erosion rates. average durable toestimate rainfall of daily distribution frequency over the rates of daily integration an and erosion loss, average as hillside of the base the at transport sediment interpret and to gradient and runoff from transport sediment estimate a power law to runoff, flow overland total todaily rainfall daily toconvert model threshold a storage stages: three of consists model PESERA The type. soil and of topography,climate, effect the combining by Europe erosion by in water caused losses soil annual toassess developed model distributed spatially and based isa physically model PESERA The conditions. toEuropean adapted specifically a model with model, equation loss soil universal the as such methodologies, used widely previous Union toreplace [ model (PESERA) Assessment Risk Erosion Soil PESERA output values (SE, soil erosion) can be grouped into four classes (SE classes four into grouped be erosion) (SE, soil can outputvalues PESERA of range the SPI mapping, with compatible tobe terms, quantitative In format. ARC-grid in resolution whe PESERA model) through the overlay analysis, classify the study area based on the desertification risk. risk. desertification on the based area study the classify overlay analysis, the model) through PESERA able PESERA model output map provides modeled soil erosion rates in t/ha/year and at a1km and t/ha/year in erosion rates soil modeled provides outputmap model able PESERA The PESERA model follows the physically based conceptual separation into runoff generation and generation runoff into separation conceptual based the physically follows model The PESERA L is the mean slope length slope mean the L is relief slope mean the H is threshold flowpower erosion the Θ is threshold runoff the above of runoff proportion the p is threshold runoff the h is r (mm) rainfall monthly total the R is indicator erosion bioclimatic the is Ω indicator erosion topographic the is Ψ erodibility soil the k is (t/ha) loss sediment the Y is 0 re is the mean rain per rainy day rainy per rain mean the is sment of the land degradation in the study area is conducted from the output of the Pan-European Pan-European outputof the the from conducted is area study the in degradation land sment of the   Soil Degradation Assessment Initial Classification of Desertification Risk Y == L S kH 2 i ex ) combined with simulated annual soil loss rates (SE rates loss soil annual simulated with ) combined p/ () - () L Q rH 0 mo 2 18 å in the examined area or watershed. The latest avail latest The or watershed. area examined the in nths ]. PESERA has been developed by the European European by the developed been has ]. PESERA ë ê é 2 Handbook of Drought and Water and Scarcity of Drought Handbook pr 0 R ex p è ç æ - r h 0 ø ÷ ö û ú ù = k YW i , i = 1–4); thus, each pixel pixel , i=1–4); each thus,

17 ]: i ) (using the ) (using the 2 grid grid (3.3) - - Downloaded By: 10.3.98.104 At: 11:54 26 Sep 2021; For: 9781315226781, chapter3, 10.1201/9781315226781-3 be grouped into four classes (GW classes four into grouped be can outputvalues modelling of groundwater range the mapping, PESERA SPI and with compatible be to terms, quantitative in erosion (SE) (D) Similarly, soil and rates. severity of drought sets data raster trations are classified into four severity classes (WC classes severity into four classified are trations (WC) concen chemical water parameters, previous the in as pattern same the Following cell. grid 1 km at variability concentrations, water of the produced are maps Finally, considered. is parameters lyzed ana of (WC) the concentrations chemical of water variability spatial of the assessment Furthermore, situ in conducted is conductivity pH water and of the Moreover,determination desertification. consequently and soils sensitive in salinization cause can which considered, is water irrigation of the salinity of the assessment K). addition, In and Ca, Mg, (Na, cations bare and for pH, conductivity, conducted is boreholes the from analysis and Water sampling 3.4.2.2 classes. four the from zation [ zation optimi aquifer’s pumping for the used also is tool optimization An heads. hydraulic groundwater and runoff observed against period historical the for calibrated is system MODFLOW The modelling model. tothe seepage reservoir computes the model LAK3 the Finally, model. LAK3 tothe reservoir of the als withdraw water and evapotranspiration, inflows, the passes and reservoir the of and outflows inflows the balances model one to MODFLOW, second the UTHRL theand Then, respectively. able to UTHRL vari first the andpasses recharge groundwater and runoff surface basin computes the model UTHBAL The scheme: the following to according other each to MODFLOW. as such model, linked are The models agroundwater and UTHRL; as such model, operation areservoir LAK3; as such model, a lake-aquifer [ or reservoir alake including possibly watershed, of a water resources the of the simulation for models interlinked of series of a consists system This used. of volume wa extracted optimum the order toassess In 3.4.2.1 risk. desertification of tion classifica quantitative the and analysis, data spatial the analysis, chemical water the levels, groundwater of assessment the involves subsection this particular, In severity. desertification of classification titative the quan for the methodology developmentthe of for stage second the of steps the includes section This 3.4.2 scenario. risk desertification a“worst-case” torepresent highest, the is cit defi water the when considered, is months summer during conditions of hydrological assessment Then, desertification. and salinization soil of potential indicator an as salinity on water focusing chemistry, water and levels namely, groundwater conditions, hydrological local order toinvestigate in conducted is classes sensitivity at different of orcells group of cells selection for the techniques sampling tistical sta Use of desertification. to sensitivity of intoclasses cells assigns scheme aclassification Invention of discretized intodiscretized an orthogonal consisting grid spacing cells, of usually×200 m withof agrid several 200 it is purposes, and for simulation assessed, also is or reservoir lake the of aquifer the phreatic of The size Classification on Desertification of Drought Impacts Environmental tion of the spatial variability of groundwater levels in the study area or watershed. area study the in levels of groundwater variability spatial of the tion representa accurate most for the examined are analysis on geostatistical based techniques interpolation Several produced. are maps level groundwater and created, is values depth and borehole coordinates the of Adatabase levels. of groundwater indicator an as used is cells selected the in of crops irrigation for the boreholes of operating depth The zones. irrigated creating area over the mapped is for irrigation demand water the and model, UTHBAL by the obtained are data recharge aone-layer Groundwater aquifer. and The produced groundwater (GW) level maps are at a 1 km are at a1 maps groundwater level (GW) The produced  26  Assessment of Critical Areas to Desertification Areas ofCritical Assessment  Assess Water Ch ]. Moreover, the impact of climate change on precipitation and temperature can be assessed. assessed. be can temperature and on precipitation change ]. of climate Moreover, impact the ment of Groundwater Levels Groundwater of ment emical Analysis emical i , i = 1–4); thus, each pixel in the examined area is assigned one value one value assigned is area examined the in pixel , i=1–4); each thus, 26 i ], namely, a hydrological model, such as UTHBAL; UTHBAL; as such model, ], namely, ahydrological , i=1–4). using a portable pH and conductivity meter. conductivity pH and aportable using ter, a groundwater modelling system can be be can system modelling ter, agroundwater 2 grid resolution to be consistent with the the with consistent tobe resolution grid 59 ------2

Downloaded By: 10.3.98.104 At: 11:54 26 Sep 2021; For: 9781315226781, chapter3, 10.1201/9781315226781-3 (GW), and water chemicals (WC), as described earlier. (WC), described as (GW), chemicals water and (D), namely,erosion (SE), drought soil groundwater parameters, four are there presentation, this In where scheme takes the following form: following the takes scheme the quantitative Specifically, of parameters. number by the divided parameters or four three mentioned previously of the sum the as basis on apixel value composite average of the of DSR consists scheme tion classifica quantitative resulted The methods. statistical standard using defined are classes risk and ered consid is area study the the DSR of of classification Then, analyses. multivariate of the results the using desertification, for causing process of each importance relative on the depending considered is layers map tothe of weightings map. Application of each values raster original on the based is which scheme, classification common a using conducted is classes risk intodesertification maps of Reclassification 3.4.2. of desertification. risk the quantitatively for assessing model aspatial and mapping composite produce to techniques mapping using conducted is maps (WC) concentrations chemical water required, if and, (GW) erosion (SE) depth, groundwater soil maps, rates, (D) drought severity of the A combination area. study the in of desertification severity on the processes main of the importance relative of the ity, loss, soil hydrological and selected variables data. Moreover, quantitative assessment is considered sever drought the using conducted is sets data raster of Grouping the of variability. sources identify Multi 3.4.2.3 60 and capacity building. capacity and interactions, causal understanding desertification, preventing and of monitoring terms in work remains much degradation, of land impacts the from at risk presently worldwide people six one in nearly with say, to Needless measures. mitigation effective potentially to leading causes, and factors desertification of understanding better a allows it since contribution, useful a very constitutes severity desertification of classification This methods. statistical standard using defined are classes risk and considered is shed water area or study the the DSR of of classification Then, of desertification. risk the quantitatively for model assessing a spatial and mapping composite to produce techniques mapping using conducted is concentrations chemical water required, if and, depth, groundwater erosion rates, soil maps, severity drought the of a combination Specifically, classification. severity desertification in resulting ment and assess drought quantitative from chapter, starting core of this the constitutes which presented, is ity sever desertification of classification the quantitative for methodology two-stage a Then, mitigation. and methods, assessment stages, factors, causes, including of desertification, prehensive presentation com and isconceptual bya followed This is presented. assessment and features, indices, tification, quan types, concepts, drought of description brief a first, severity. At desertification of classification toa quantitative leading drought of impacts theenvironmental of analysis an of consists chapter This 3.5 D i is the severity class index taking values within each class (from 1 to 4 classes) for each parameter, as as parameter, for (from each 1to4classes) class each within values taking index class severity the i is methodology the in or components involved of parameters number the N is SR is the desertification severity risk to be estimated be to risk severity desertification the SR is  variate statistical analysis is used, namely, principal component analysis and cluster analysis, to analysis, cluster and component analysis namely, principal used, is analysis statistical variate explained previously explained Summary and ConclusionsSummary 4   Quantita Spatial Data Analysis Data Spatial ( DS tive Classification of Desertification Risk R ) ii = è ç æ N 1 ø ÷ ö å ë é () DS i + () EG + () WW ii + () Handbook of Drought and Water and Scarcity of Drought Handbook CN ++ () i û ù , i = 14 -

(3.4) ------Downloaded By: 10.3.98.104 At: 11:54 26 Sep 2021; For: 9781315226781, chapter3, 10.1201/9781315226781-3 Handbook athree-volume(2015), Handbook of Drought and Water Scarcity (2017), and Underground Aqueducts Hydrology (CRC Press). Athree-volume Engineering of Handbook Professor Eslamian has editorshipstarted the of handbooks published several by Taylor & Francis Group Engineering Flood of International both Journal of Hydrology Science and Technology (Scopus, Inderscience) of and Journal publicationsthan 500 injournals and or books as reports. technical He is founder the and chief editor aresearchstarted partnership from 2014 with McGill University, Canada.He has contributed to more University, New Jersey, and University the of ETH Zurich, Switzerland. research Onthe side, he has environmental hydrology inachanging climate. Formerly, he was avisiting professor at Princeton HisPilgrim. research mainly focuses on water resources planning and management and statistical and his PhD from Universitythe of New South Wales, Australia, of under supervision the Professor David Water Engineering at Isfahan University of Technology, Iran, where since he 1995. has He received been Eslamian Saeid assessment. and monitoring analysis, on drought projects and articles research of numerous or coauthor author and chapters, book of 25 Journals Scientific of several reviewer regular and editor reports, technical and publications refereed 280 of over or coauthor author the He is variability/change. climate and assessment, risk hazards, ronmental envi modelling, remote sensing, agrohydrology, agrometeorology, in research recordin long-standing (1982). of Waterloo, University a Canada the He has from engineering civil in PhD his received and 1974)Netherland, The Delft, of Delft, (University engineering 1972) hydrological (Athens, and rology in meteo degrees of Thessaly, University (1991–2011).atVolos the postgraduate Hellas his He received of Agrometeorology Laboratory the in director (2014–2016).Greece founding and Professor also He is of Athens, University Agricultural Volos of the (2011-present), Greece Council at the President and Dalezios R. Nicolas Authors References Environmental Impacts of Drought on Desertification Classification on Desertification of Drought Impacts Environmental 4. 6. 2. 7. 5. 3. 1.

(NHESS) Science System Earth and Hazards Natural agroecosystems. for sustainable drought cultural Dalez 3139–3150. Dalez Dalez ­erosio Cerda Arna In: ecosystems. rangeland in change and disturbance Stress, 2000. C. Stokes, Archer, and S. Darkoh (Accepted). and Technology of Journal Hydrology Science International analysis. drought composite based Dalez agriculture. vulnerable in features Journal Hydrological Science Greece. in periods wet and of droughts analysis pp. 17–38.MA, Desertification Control Bulletin Africa. Desertification (2017) are published ones. lds, O. and Archer, O. (eds.), and S. lds, ios, N.R., Dercas, N., and Eslamian, S. 2016. Water scarcity management: Part 2: Satellite- 2: Part 2016. management: S. Water scarcity Eslamian, N., and Dercas, N.R., ios, N.V.,agri of Spyropoulos, identification A., 2014. Risk Blanta, A.M. Tarquis, and N.R., ios, Severity-duration-frequency 2000. H. Liakopoulos, and L., Vasiliades, A., Loukas, N.R., ios, ios, N.R., Blanta, A., and Spyropoulos, N.V. drought Spyropoulos, and of sensed remotely A., Assessment Blanta, 2012. N.R., ios, n plot data. Geomorphology data. plot n n, O. et al. 2010. Rates and spatial variations of soil erosion in Europe: A study based on based Astudy Europe: erosion in of soil variations spatial 2010. and O. Rates n, al. et , M.B.K. 1994. Population, environment and sustainable development: Desertification in Desertification development: sustainable and environment Population, 1994. , M.B.K. , 14: 2435–2448. 14: , is a full professor is a full of hydrology and water resources engineering in Departmentthe of . Currently, author the he has been of more chapters than book 100 and Recently, books. , author of two recent books, editor or coeditor of about 20 edited books and coauthor coauthor and books edited of 20 about or coeditor editor books, recent of two , author is Professor of agrometeorology and remote sensing at the University of Thessaly, of Thessaly, University at the remote sensing and of agrometeorology Professor is Rangeland Desertification Rangeland , 122: 167–177., 122: Natural Hazards and Earth System Science (NHESS) Science System Earth and Hazards Natural , 25: 20–26., 25: , Kluwer Academic Publishers, Boston, Boston, Publishers, Academic , Kluwer (2014), Urban Water Handbook Reuse , 45(5): 751–770. International International , 12: 12: , 61 - - -

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