VULNERABILITY ASSESSMENT USING REMOTE SENSING AND GIS TOOLS IN THE INDIAN PART OF KAILASH SACRED LANDSCAPE

The Indian part of Kailash Sacred Landscape (KSL) is prone to flash floods, landslides and forest fires leading to various environmental and socio-economic problems. This study aims to identify areas vulnerable to these disasters by preparing hazard maps to curtail their impact on the overall landscape. The Indian part of KSL covering seven forest ranges in Pithoragarh district which is spread over an area of 7,212 km2. This paper integrated the Geographic Information System and Remote Sensing and the multi criteria analysis through AHP to determine the disaster vulnerable areas in the landscape. All the thematic layers and final maps are prepared in ArcGIS 10.2. A total of ten variables for a landslide, six variables for flood and seven variables (topographic, climatic, and anthropogenic) were used to carry out the pairwise comparison for relatively weighting the variables through AHP. Consistency ratio (CR = 0.01) for landslide and forest fire and for flood (CR=0.06) which shows the matrix was consistent. We identified 174 km2 of the area which is highly fired prone to forest fire, 76 km2 of area vulnerable to landslide and 24 km2 of the area comes under hotspot of the flood. The sites vulnerable to key drivers identified and mapped through this study will form the basis for further conservation and development planning at landscape level by policy makers.


Introduction
Kailash Scared Landscape is known for its rich spiritual, religious, ecologically diverse and cultural ethos rooted in traditions, but it is also known for growing natural disaster incidence, and highly vulnerable-ecologically fragile, geologically unstable and tectonically and seismically active.Owing to varied topography, the landscape is vulnerable to landslides, forest fires, flash floods affecting ecosystem services.These disasters havebeen known to cause major losses to ecosystem, resources, property, and life in the region and thereby affecting its process of economic development (Kazakiset et al., 2015).Vulnerability assessment is a crucial input to comprehend the degree of loss that the built environment suffers because of the occurrence of a natural disaster (Bhat et al., 2013).* Forest fires in the Indian part of KSL have been a common phenomenon that hascontinued to increase more frequently in last few decades due to rising temperatures during March to May and less winter rainfall (Roy et al., 2013).Majority of fire incidences are reported in moderately dense and open forest patches in the landscape generally between 600 -2500m altitudes.Forest fire event may burn areas, influencing the species composition and ecosystem and promote the regional domination of chir pine at the expense of broadleaf oak forests.Winter season fire in such areas have positive effect on habitat for certain species, however uncontrolled fire during summer month especially in broad leaf forest can be detrimental.In the absence of traditional fire management practices in this landscape, more areas are coming under forest fires.Low Precipitation during the summer season in the landscape reduces the moisture in forested areas down at ground level, allowing the fire to catch more rapidly and spread quickly over the forestland.Besides, anthropogenic intervention for collection and extraction of timber, improvement of growth of grass, hunting wild animals, encroaching forestland, burning of pine needles, and burning of litter are all responsible for forest fire in the landscape (Negi et al., 2016).
Fragility, unpredictability,and activeness of terrain further highlight the landscape vulnerability (Bhatt et al 2013).The landscape is located in the center of the Indian Himalaya and one of the most fragile landscapes of the Himalayan Mountain system.Hazards like debris flow, landslides, and rock-falls are very common phenomena in the north and northwestern part of the landscape.Heavy rain during monsoon further emphasizes the intensity and frequency of these events, resulted in large-scale destruction of lives and property due to landslides as well as floods.This study deals with the first step of disaster risk management, i.e. to define the hazard area in the specific region.The objective of the study is to produce vulnerability maps of the study area with the integration of field survey data, GIS and remote sensing, which can help decision makers and government in the development and to reduce life and property loss from these disasters.

Study Area
KSL-India forms the study area having a larger part of Pithoragarh District (30.0815˚N, and 80.3659˚ E) and a small part of Bageshwar District of Uttarakhand having an area of 7212 km², altitudinal gradient from 350 m to 7,000 m.Present study was focused in 12 selected villages in 'Horizontal Transect' (ICIMOD.2010, KSL India Feasibility Report 2010) selected for various studies in KSL-India (figure 1).Agriculture is the primary occupation in most of the area.The landscape predominates in diverse forests (broad leaved in lower altitudes to temperate forests in higher elevation areas while extensive alpine pastures in areas between 3000-3500 m asl).The landscape has experienced rapidity of environmental changes and the global natures of socio-economic forces those have not only influenced the whole landscape but most of the ecosystems and associated elements have been notably transformed (ICIMOD. 2010, KSL India Feasibility Report 2010, Robert J. Z. et al. 2014).

Materials and Methods
Vulnerability maps can be utilized in all steps of disaster management: prevention, mitigation, preparedness, operations, relief, recovery, and lesson learned.Landscape vulnerability analysis for KSL -India was performed in three steps: (i) Identification of natural and anthropogenic risks and hazards (ii) Assessment of vulnerable areas and (iii) mapping of hotspots and validation of results.Based on the literature review and extensive field observations we identified three major risks and hazards affecting ecosystem services in the KSL-India.These areLandslides, Forest Fires, and Floods.Landslides are among the most destructive geological processes that cause enormous damage to roads, bridges and housesand also lead to loss of human life in the landscape (UDR, 2014).Major routes to inner valleys and pilgrims trail to Holy Kailash are particularly vulnerable due to recurrent landslides.The forested tracts in KSL-India are more vulnerable to forest fires.Integratingthe remote sensing data, GIS and AHP are quite effective tools to generate vulnerability data (Rimba et al., 2017).The overall method of vulnerability assessment is given in figure 2. All the raster layers of parameter considered is prepared using ArcGIS 10.2.table 1and figure 3.
The degree of slope and elevation: Degree of the slope is an important parameter for landslide hazard prediction (Bhatt et al. 2013.The slope class from 30˚ -90˚ covered most of the area in the landscape where the frequent landslide occurred.Slope angle map was prepared from DEM with using DEM surface tool.(Rimba et al.,2017;Ouma et al., 2014;Kazakis et al., 2015): -elevation and slope are the important factor for flood as well.Slope influences the amount of surface runoff and infiltration as Water flows from higher to lower elevations.Flat areas in low elevation may flood quicker than areas in higher elevation with a steeper slope (Kazkis et al., 2015).In the studied area, high-elevation appears in most of the area, where the slope is also steeper.Naturally, low slope and low elevation has been assigned the highest rating, as prone areas.
Distance to motor roads and settlement -Construction of roads using heavy machines and dynamite make undercutting of the slope, cracks on the surface and loss of soil, which makes the area more prone to landslide.Similarly, more fire incidences were observed closer to roads and human settlement due to accidents/negligence or deliberate actions of human beings.Hence, proximity to roads and settlements were an important predictor of landslides and forest fires.

Distance to thrust and faults:
The rocks forming slopes in Himalaya have been reduced to successive deformation due to geological evolution of the terrain and present day tectonic activity along the edge of thrust and fault (Kazakis et al., 2015).The slope with multiple joint sets fail particularly during monsoon, when this region receives heavy rainfall.The slopes become saturated with water, destabilizing the slope beyond thestability limit.Rock fall, debris flow and complex landslides are various types of slope failure that occur.

Normalized difference vegetation index (NDVI):
Changes in land cover conditions triggers change in the level of vulnerability of land.It is obvious that densely vegetated areas are departed from landslide events.The value is in range from -1 to 1, -1 represents less and 1 represent dense vegetation cover.

Topographic Wetness Index (TWI):
The topographic wetness index (TWI) has been used extensively to describe the effect of topography on the location and size of saturated source areas of runoff generation (Pourghasemi et al., 2012).TWI is calculated using Eq (2.1), proposed by moore et al. (1991), with the assumption that condition is steady and soil properties are uniform.TWI = ln(AS / tanß) Eq(2.1) where AS is the specific catchment's area (m2/m), and b is slope gradient (in degrees).
Stream Power Index : The stream power index (SPI) is a measure of the erosive power of water flow based on the assumption that discharge (q) is proportional to specific catchment area (As) (Eq.2.2) (Pourghasemi et al., 2012;Moore et al.,1991).
where AS is the specific catchment's area (m2/m), and b the slope gradient in degrees.As the specific catchment's area and gradient increase, the amount of water contributed by upslope areas and the velocity of water flow increase; hence, the SPI and slope-erosion risk increase (Pourghasemi et al., 2012;Moore et al.,1991).Moore et al. (1993) stated that the SPI controls the potential erosive power of overland flow (Pourghasemi et al., 2012).Therefore, these processes can be considered as one of the components of landslide occurrence (Pourghasemi et al. 2012;Lee and Min 2001;Gokceoglu et al. 2005;Nefeslioglu et al. 2008;Yilmaz 2009;Akgun and Turk 2010).Aspect: It is also considered as a landslide-conditioning factor and this factor has been considered in several studies.Some of the meteorological events such as the direction of the rainfall, amount of sunshine, the morphologic structure of the area affects the slope stability (Pourghasemi et al. 2012;Mohammadi, 2008).lower order.
Rainfall: -Heavy Monsoon Rainfall, cloudburst in the landscape increases the intensity of flash flood along riverbanks, which makes rainfall one of the main contributing factors for flash flood in the landscape.Seasonal rainfall plays important role in forest fire.Less rainfall during winter season (December-January), causes low precipitation and humidity in the forest, which makes the forest prone to fire.

Landuse and:
-Land use influences infiltration rate, the interrelationship between surface and groundwater as well as debris flow.The value is in range from -1 to 1, -1 represent very sparse and 1 represent dense vegetation cover.

Plan curvature:
The term plan curvature is the theoretically defined as the rate of change of slope gradient or aspect, usually in a particular direction.The slope affects the overall rate of movement downslope based on the shape of the slope (convex, concave or plain).The steep slope with convex and concave curves contribute more to landslides than the plain slopes and aspect defines the direction of flow of the rainwater.
Table 1: Data sets used for in landscape vulnerability analysis in KSL-India.
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLII-5, 2018 ISPRS TC V Mid-term Symposium "Geospatial Technology -Pixel to People", 20-23 November 2018, Dehradun, India

Analytical Hierarchy Process (AHP)
AHP is a decision-making technique utilized for solving complex problems, with many parameters of interrelated objectives or concerned criteria (Rimba et al., 2017).The level of the each of the contributing factor is not same; some parameters are dominant over others.Factors are compared with each other to determine the relative preference of each factor in accomplishing the overall goal.Rankingis assigned to each pair of the factors using the guidelines established in fundamental Satty 'sscale (Table 2).The relative importance has a range from 1 to 9 where 1 means an equal contribution of the pairwise parameter and 9 means a very important parameter.The number of parameters influences the matrix.The comparisons of parameters were generated from the expert judgment and literature review.The output of AHP has to be consistent for all the pairwise comparisons measured by Consistency Index (CI) and Consistency Ratio (CR).The CI follows Equation Wheren is a numberof parameters and λmax is calculated to normalize and find the relative weight of the matrix.The final calculation is consistency ratio; it is a ratio of the CI and random index (RI).The maximum threshold of CI is ≤0.1 and CR ≤ 10%; the rational value is when the CI and CR have fulfilled the maximum threshold value.The consistency ratio (CR) followed Equation.

Results
The main use of AHP is the ranking and prioritizing of multi-criteria parameter.The weight is given to the design factors with the following procedure (Saaty T. L., 2008): (1) Determine each factor percentage to distinguish the weight.
(2) Assign the least important factor from step 1 and assume the importance scale among the objective is linear.
(3) The importance of factor should be ranked from 1 to 5, where 1 represents the least important factor and 5 is the most important.
Ranking of each parameter was done by using pairwise comparison and the results are shown in table (3,4,5) for landslide, flood and forest fire respectively.Thereafter, we normalized the matrix, shown in table (6,7,8).The standardized raster layers were given weight by using the priority (Table 6), also called normalized principal eigenvector.Then, CI and CR are calculated to determine if comparisons are consistent.The CR ratio is designed in such a way that if CR <10%, the ratio indicates a reasonable level of consistency in the pairwise comparison.
Since the CR value for all the three pairwise comparisons is less than 10%, the comparisons are consistent.CR value for forest fire and landslide is 0.01 and for flood it is 0.06.The relative weight value is given in percentage.Ranking of parameters, their relative weight is listed in table (9,10,11) for landslide, flood and forest fire respectively.The ranking of various parameters is based on literature review.The range of ranking was between 1 and 5, where 5 signify highest influence and the lowest influence factor was 1.
The highest contributing factor for landslide was slope (32%), followed by distance to thrust and fault (16% each).
Least contributing factor is distance to river (3%).The highest contributing factor in case of flood is also slope (42%), Followed by rainfall and flow accumulation contributing 20% and 16% respectively.Slope influence the flow direction.In case of forest fire, temperature is the most important governing factor, contributing 27%, then come distance to road and settlement (14% each).Once the weight is given, weighted overlay is performed in ArcGIS 10.2and maps for vulnerability are prepared   6).For mitigation and management of flood prone areas,it has become important to identify the villages vulnerable to flash flood in the landscape.For that, we extract the hotspots area from the map and we found that 33 villages come under flood hotspots area covering 24km² along Maha kali, and Gori river in Dharchula, Bin, and Munshiyari block in the landscape which is shown in Figure 6.
In vulnerable sites, such as areas with very steep slopes, where natural disaster likely occurs, which can cause huge loss to life and property.In order to prevent the predicted outcome of these disasters, decision maker and planners should keep development at highly prone areas in check.

Conclusion
Disaster can occur anywhere anytime.We cannot stop the occurrence of disaster but we can minimize their impact.
The main aim of the present study is to develop a methodology that identifies disaster prone areas for disaster mitigation and development.Areas vulnerable to flood, landslide and forest fire are identified in this study using integrated approaches of remote sensing, GIS, and spatial multi-criteria evaluation through the Analytical Hierarchy Process (AHP) approach.The AHP is the most frequently used multi-decision criteria based on the expert judgement and we can check the consistency of the rating, as well and pair-wisecomparison of parameters is quite appealing to the users.However, AHP too has a drawback, as it mostly relies on the input of experts, and to find experts is the difficult task.

Figure 1 :
Figure 1: Map of the study area.

Flow accumulation :
High values of accumulated flow indicate areas of concentrated flow and consequently higher flood hazard (Oman et al. 2014).The flow accumulation values vary in a range between 0-404 (Table10), with the highest values occurring in the out flow of

Fig 4 :Fig 5 :Fig 6 :
Fig 4: Landslide Prone Areas in Indian part of KSL Thus, the contribution of LULC in flood mapping is important.LULC is one of the important parameters to know the extent of forest fire in the landscape, because forest fire mostly occurs in moderately dense and open forest.Such forest patches mostly share its boundary with human settlement and agriculture.The initial fire starts with surface fire and ground fire.NDVI Factor: -Changes in land cover conditions triggers change in the level of vulnerability of land and forest fires.NDVI is a vegetation index developed by Rouse et al 1973.It shows the level of greenness of vegetation and the litter.

Table 4
Matrix showing the parameters of flood hazard: Analytical Hierarchy Process.

Table 5
Matrix showing the couple comparison of the factors for fire vulnerability

Table 6
Normalized Landslide Hazard Parameters: Analytical Hierarchy Process

Table 7 :
Normalized flood hazard parameters: Analytical Hierarchy Process

Table 8
Normalized forest fire parameters: Analytical Hierarchy ProcessThe vulnerability map of landslide is shown in figure4.The vulnerability map of landslide depicts three vulnerability classes' viz., low, medium and high.The analysis reveals that nearly 73 km 2 of the landscape are highly vulnerable to landslides.Of the various blocks, Munsyari has the highest landslide prone area (37.61 km 2 ) followed by Askot (15.44 km 2 ) and Dharchula (12.8 km 2 ).

Table 11
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, VolumeXLII-5, 2018ISPRS TC V Mid-term Symposium "Geospatial Technology -Pixel to People", 20-23 November 2018, Dehradun, India Classes of the parameters and according weights for Forest Fire Vulnerability analysis.