View of NATURE-BASED SOLUTIONS FOR LANDSLIDE RISK MANAGEMENT IN UTTARAKHAND

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Vol. 04, Issue 02,February 2019 Available Online: www.ajeee.co.in/index.php/AJEEE

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NATURE-BASED SOLUTIONS FOR LANDSLIDE RISK MANAGEMENT IN UTTARAKHAND Pooja Kukreti

Associate Professor, Department of Botany

Pt. L.M.S. Government Post Graduate College, Rishikesh, Uttarakhand

Abstract - The Himalayan region of India is situated in one of the most geo-tectonically active and ecologically sensitive zones of the world. Landslides are one of the most important types of natural hazards during monsoon in this mountainous region. Indian Himalayan state of Uttarakhand because of its geography and topography is particularly vulnerable to climate induced disasters. These affect adversely both human and animal lives, cause enormous damage to properties, and blocks communication within and outside the region and lead to an additional financial burden on the state and national economy.

Climate change, deforestation, damming of rivers (hydel projects) and other tourism driven unplanned constructions along the towns and riverbeds has caused massive flooding and landslides with large scale destruction over past few decades. Landslide occurs in high frequency especially along the hill cut roads. It is thus imperative to initiate effective and innovative landslide risk reduction and management plans in the state. Landslide risk reduction involves a series of activities that include landslide susceptibility mapping, risk evaluation, landslide monitoring, forecast etc. There has been an increasing interest in non- structural and Nature-based Solutions (NbS) in many countries including India. NbS has emerged as a sustainable and efficient approach for rehabilitating degraded ecosystems and reducing climate and disaster risks. Extensive research and the successes of the many applications, has now established that NbS can be effectively used to replace or complement the conventional engineering measures for landslide risk management.

Keywords: Climate Change, Himalayan ecosystem, Landslides, Nature-based Solutions, Risk Management

1 INTRODUCTION

Different countries experience different disasters because of their geographical location as well as topographical features.

The developing countries are more vulnerable to disasters than developed countries as more developmental pressure exists in the developing countries.

Further, the mountain habitats of these countries share similar bio-climatic features and are prone to natural hazards of landslides, earthquakes, avalanches and diseases etc. and also manmade disasters that have devastating impacts causing death and destruction.

India is one of the ten most disaster prone countries of the world. In India, most of its landmass is affected by disasters like earthquakes (58.6%), floods (12%) and landslides (15%) which are due to number of factors– adverse geo-climatic conditions, topographic features, environmental degradation, urbanisation and non-scientific development. With close to 11,000 deaths due to landslides in 12 years, India tops a global list of nearly 56,000 deaths from 4,800 landslides around the world between 2004 and 2016. India not only accounts for 20% of global landslide deaths but also has the dubious distinction

witnessing the fastest rise in human- triggered fatal landslides in the world (Deccan Herald, 2018).

1.1 Indian Himalayan State of Uttarakhand

Uttarakhand has attained its place among the first five states in reverence of natural hazards. Uttarakhand‟s geography and topography makes it particularly vulnerable to climate-induced disasters.

The state is predisposed to earthquakes, landslides, flash-floods, cloud-bursts, avalanches as well as drought. These disasters have taken heavy tolls on life, property, livelihoods and have caused severe damage to environment and ecology. According to the state records of Disaster Management and Mitigation Centre (DMMC) there have been 20 landslides in the state over 11 years from 2001 to 2012. The disaster of 16-17 June, 2013 was a grim reminder of colossal devastation in terms of large number of casualties and widespread damage to the houses, property, roads, bridges, buildings, forests, plantation, crops and agriculture land. The devastation caused by the disaster was so huge that it has been termed as Himalayan Tsunami.

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2 The faster growing economic sectors of the state economy have brought some growth to the mountain areas but have also seriously endangered ecological sustainability and livelihood security in the process. Uttarakhand‟s governments have pushed roads, dams, tunnels, bridges, mining and unsafe buildings even in the most fragile mountain regions (Chopra, 2014).

In eco-sensitive region like Himalayas, roadway network serve as arteries for swift and hassle free progression of transportation and communication activities of the region.

The route of „Char Dham Mahamarg Vikas Pariyojna‟- a highly ambitious project of Uttarakhand, launched in 2016, is extremely prone to landslides. It is a project of central government to improve the existing conditions of highways in Uttarakhand, maintained by National Highways Authority of India. In this project, the government will upgrade and develop the road of around 889 km having Mana and Rishikesh as north and south end junctions respectively. It connects all four dhams i.e. Gangotri, Yamunotri, Kedarnath and Badrinath. Though, this project is economically beneficial but creates a great sense of alarm to environmentalists as around 27,300 trees were cleared.

The developmental activities in hilly areas are essential- (i) for improving people‟s living standard, (ii) for state as well as country‟s growth via better tourism opportunities, (iii) for connecting urban and rural areas which will provide better educational, medical and transportation facilities. But when mountain perspective is disregarded in development planning and execution of projects and programmes, it has severe implications to the ecology, environment and livelihoods of people in the region (Awasthi, 2014). These threats may be taken as loopholes of developmental projects, if these projects are not integrated with sustainable developmental methods.

The paper emphasizes on ecological approach of mitigation and management of landslides using the Nature-based Solutions (NbS).

2 LANDSLIDES AND ITS MITIGATION MEASURES

The term landslide as presented by Varnes (1978) and Cruden and Varnes (1996) includes all types of gravity- induced mass movements, ranging from rock falls through slides/slumps, avalanches, and flows, and it includes both sub aerial and submarine mass movements triggered mainly by precipitation (including snowmelt), seismic activity and volcanic eruptions.

The factors of great significance which are indicators of degree of landslide severity are magnitude of slope movements;

volume of the landslide mass displaced;

suddenness of a landslide, its recurring nature and history and its momentum dynamics. Deforestation adds to the fragile geological environment and adverse climatic conditions to cause degradation of inter bedded quartzite and phyllites.

The slopes without vegetation cannot hold soil cover together and widespread erosion occurs (Bhandari, 2006).

Landslides of different types occur in geo-dynamically active domains of Uttarakhand. They occur due to - (i) mountainous slopes with rugged topography as well as high seismic activity, (ii) seasonably wet period, (iii) rapid erosion, (iv) human activity, (v) earthquakes, volcanic eruptions, floods etc. Massive deforestation and unplanned developmental activities in the mountainous regions of Uttarakhand has robbed the land of the protective vegetal cover and increased the number and frequency of landslides, over the period of past few decades.

Landslide control methods include combination of slope dressing and treatment, surface and subsurface drainage and provision of restraining structures (such as nailing, bolting, and anchoring). The other courses adopted to avoid landslides are tunnelling, bridging the landslide-affected area or re-routing.

Border Roads Organization is the premier agency in the country to manage landslides and is also the repository of experience on technological developments.

The technologies for slope treatment such as the Asphalt mulch technique of vegetative turfing and jute and coir netting were first developed by the Central Road Research Institute in the late seventies and the early eighties. CRRI also promoted the technology of subsurface drainage using horizontal drains to synergise with surface drainage

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3 measures. Construction of gabion walls as an element of landslide remediation package is common in India (Bhandari, 2006).

Bioengineering is another re- emerging way of improving slope stability.

It entails the use of living plants and other auxiliary materials for stabilization of hill slopes, works as an integrated technique to protect slope against surface tension, to reduce the risk of planer sliding and to improve surface draining.

3 LANDSLIDE RISK MANAGEMENT USING NATURE-BASED SOLUTIONS To mitigate the hazards caused by landslides, nature-based solutions are used by many countries. Nature-based Solutions (NbS) are defined by the International Union for Conservation of Nature (IUCN) as “actions to protect, sustainably manage and restore natural or modified ecosystems, that address societal challenges effectively and adaptively, simultaneously providing human well-being and biodiversity benefits”. Sendai Framework for Disaster Risk Reduction 2015-2030 highlights NbS as an effective technique to reduce disaster risk, adapt to climate change and strengthen community resilience. Plants species/vegetation constitutes the major component in nature-based landslide risk management practices. Numerous studies carried out in many Asian Countries confirm the crucial role of plants/

vegetation in minimizing the risk of landslides, reducing the erosion and in supporting vulnerable communities to cope with associated risks.

Nature-based solutions play an effective role in reducing the hazards of landslide by including-

(i) Soil engineering, effective for surface erosion and shallow landslides, include living plant material to build structures that provide slope support. It includes: (a) Bio- engineering for landslide mitigation- trees or shrubs are preferred to herbaceous species for slope stabilization in steep slopes because of dual effect of roots in reinforcing soil and in reducing water content by transpiration process. Grasses are preferred against soil erosion because they have a good turf and dense root system. (b) Bio-

engineering for flood mitigation- live fascines, brush layers, live staking, vegetated geo grids and gabions can be applied.

(ii) Landslide Risk Mitigation Toolbox- both living and non-living approach should be used to minimise the losses caused by landslides.

NbS are eco- friendly, cost effective and can generate employment and economic opportunities for local people, thus reducing the need to import technical expertise labour as in case of engineering techniques (IUCN, 2017).

4 ROLE OF NATIVE VEGETATION IN LANDSLIDE MANAGEMENT

The role of native vegetation is quite significant in prevention of landslides as well as for stabilizing the landslide. Plant cover not only protects the surface from weathering due to direct impact of rain and winds but its intricate root system works as a cohesive in binding the loose soil and preventing it from erosion. When properly installed and maintained, vegetation could protect slopes by reducing erosion, strengthening soil, and inhibiting landslides which increase general slope stability (Rawat et al., 2012) The selected species should have deep and large root system and preferably be hardy, fast-growing and suckering (Sastry and Kavathekar, 1990). The native vegetation could be more useful and efficient in the restoration and bioengineering programmes as they have fewer competitors than other species and the disturbances permits the germination and development of non-seeded species (Munshower, 1993).

The factors affecting slope stability were grouped by Varnes (1978) into those tending to increase shear stress and those tending to reduce shear resistance. The primary factors of vegetation that affect mass movements in slopes, particularly shallow sliding in slopes includes (Gray and Leiser, 1982):

1. Root Reinforcement: Roots mechanically reinforce a soil by transfer of shear stress in the soil to tensile resistance in the roots.

2. Soil Moisture Modification:

Transpiration and interception by the foliage limit build up of soil moisture stress. Vegetation also

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4 affects rate of snowmelt, which in turn affects soil moisture regime.

3. Buttressing and Arching:

Anchored and embedded stems could act as buttress piles or arch abutments in a slope, counteracting shear stresses.

4. Surcharge: Weight of vegetation on a slope exerts both a down slope (destabilizing) stress and a stress component perpendicular to the slope which tends to increase resistance to sliding.

5. Root Wedging: Alleged tendency of roots to invade cracks, fissures, and channels in a soil or rock mass cause wedging action.

6. Wind Throwing: Destabilizing influence from turning moments exerted on a slope as a result of strong winds blowing downslope through trees.

Root reinforcement, soil moisture modification (reduction), buttressing and arching increase slope stability.

Surcharge, root wedging and wind throwing have a net destabilizing effect.

The stabilization of slopes by vegetation depends on the depth to which roots grow. The more the roots penetrate a potential shear plane, the greater is the chance that vegetation will increase slope stability (Abe et al., 1990).

Trees regulate the water balance through rainfall interception, evapotranspiration and soil water storage reducing the formation of pore water pressure or the decrease of suction stress in soils, thus lowering the probability of slope failure (Dhakal et al., 2003; Keim et al., 2003).

Vegetation plays many beneficial roles like- (i) reduction in potential peak of groundwater pressures, (ii) roots reinforce the soil by increasing the soil shear strength, (iii) roots of trees may anchor into firm strata, providing support to the up-slope soil mantle through buttressing and arching (Popescu et al., 2009).

4.1 Case Studies: Application of NbS at Landslide Damaged Sites in Uttarakhand

 In 1981, HESCO, Himalayan Environmental Studies and Conservation Organisation launched a programme to botanically control an intense landslide zone between Kotdwara-Dugadda roads in district

Pauri of Uttarakhand. In this zone, 17 out 21 major landslide sites were under control by eight years. The areas are no more under threat of landslides and present green lush forest (Joshi et al., 2001).

 Forest Research Institute, Dehradun and State Forest Department, Uttarakhand undertook a joint venture for the biological stabilisation of Varunavat landslide using bioengineering technique in 2006-07 (Vasistha et al., 2011). The Varunavat landslide in Uttarkashi on September 23, 2003 had affected a large area (about 5 ha) of Varunavat Parvat and damaged/uprooted about 2,050 trees of Chir pine (Pinus roxburghii), the dominating tree species. Apart from this, about 450 trees of Chir pine were slashed to transport heavy machinery used for geological treatment of Varunavat landslide area and about 600 trees were slashed down for various other purposes. The sum total of chir pine reduction was about 3,100. About 13 species, including 5 species of shrubs and 8 species of herbs and grasses, had disappeared from the Varunavat Landslide areas. Most of these species were ecologically and ethnobotanically important (Rawat et al., 2007). A combination of slope dressing, surface and subsurface drainage and provision of retaining structures (gabion wall, breast wall) were prepared out to check further mass movement and debris flow in the landslide damaged sites. Further, geo-jutes were also spread out to arrest the loose soil. Space was made in between the geo-jute at a regular interval for germination of seeds and planting tufts of grasses and seedlings.

Species used in bioengineering measure in Varunavat landslide were:

Economically important grass species- Napier grass (Pennisetum purpureum), Java Grass (Cymbopogon nardus), Lemon grass (Cymbopogon citratus), Golda grass (Chrysopogon fulvus), Palmarosa grass (Cymbopogon martinii), Ginni grass (Panicum maximum).

Trees- Albizia odoratissima, Aesculus indica, Alnus nepalensis, Cedrus deodara,

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5 Prunus padus, Quercus leucotrichophora, Toona ciliata, Trema politoria.

Shrubs- Agave sisalana, Buddleja asiatica, Coriaria nepalensis, Debregeasia hypoleuca, Mimosa himalayana, Rubus ellipticus, Vitex negundo, Rumex hasatus, Woodfordia fruticosa.

 A non-governmental organisation, Green Hills Welfare Society in Nainital, working in collaboration with the Bareilly-based Indian Veterinary Research Institute, has suggested that Bilayat grass, also called trap grass, has a rich potential to prevent landslides. According to Krishna Kaushal Shah, founder of the NGO, this fast-spreading variety of grass grows into soil and rocks, thus protecting rocks from breaking down. It does not get destroyed in forest fire, since its roots grow deep into rocks. Cattle that graze on this variety of grass also yield more milk.

The first test of trap grass was conducted in Naina village, about 10 km from Nainital town. Positive results there led the NGO to plant the grass in landslide prone areas of Nainital and Pithoragarh. Landslides which were once common in these areas were reduced by 70% (Times of India, 2014).

 The Fodder Bank Model used fast growing high biomass yielding fodder trees, shrubs and grasses in upper Kedarnath valley in Uttarakhand, India, to reduce rural women‟s drudgery and the region‟s deforestation by aiding slope stabilisation, reducing land and mudslides during the 2013 Himalayan Tsunami (Dhyani and Thummarukuddy, 2016).

 Vetiver, a type of grass, provides practical and inexpensive way to minimise landslides. It helps in stabilising slopes as it grows very well in different environmental conditions.

Following considerable research and the successes of the many applications, it is now established that Vetiver, is a very effective, economical, community based and environmental friendly sustainable bioengineering tool that protects infrastructure and mitigates natural disasters (Ghosh and Bhattacharya, 2018).

5 CONCLUSION

Climate change will escalate Uttarakhand‟s existing vulnerabilities to natural and manmade hazards. There are indications that the daily temperature extremes are rising and the intense rainy days are likely to increase in the coming years. The past years have shown a globally increasing trend in the number of events and consequential destruction from natural hazards. Uttarakhand, due to its rugged topography and high seismic activity, is prone to natural disasters like landslides, earthquakes, floods and flash floods. Thousands of lives were lost with immeasurable damage to property and environment since 2001due to landslides in Uttarakhand. The Kedarnath Tragedy of June 2013 caused irreparable losses of precious human and animal lives (around 6000 people died), damage of private and public properties, infrastructures, and many others. More than nine million people were affected by the disaster.

Deforestation and cut slope due to unplanned developmental projects, typical of urbanisation process are known to increase the incidence of landslides. A landslide calamity may be avoided or at- least minimised by applying remedial measures at the initial stage of any development project. One such remedial measure is application of Nature-based Solutions (NbS); the concept involves use of local natural materials, plants that binds the soil and improve surface drainage. Such biotechnical slope stabilization, are cost effective, increases environmental compatibility and is economically beneficial for local people. It includes the use of vegetation and bioengineering techniques for slope stability, thus reducing the risk of not only landslides but also other challenges as they make the degraded ecosystem more resilient. The application of such measures in Uttarakhand will not only reduce loss of lives and livelihoods but also make tourism more successful and more revenue can be generated. This kind of approach will lead to the sustainable development as developmental projects will not affect the integrity and functioning of ecosystem, thus help in achieving real goal of developmental project.

All types of landslides may not be mitigated through NbS, but essentially there are number of potential application

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6 areas. It can be effectively used for mitigating risk in larger areas susceptible to landslide hazard, where applications of conventional mitigation options are less cost effective. Applications of NbS at landslide damaged sites in Uttarakhand have successfully reduced landslides in the landslide prone areas. The use of native plant species is advocated by the research investigations in the field. This ecological approach of mitigation and management of landslides holds a promising future and requires urgent action to avoid further loss of life due to such preventable calamities.

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