Recommendations
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Identification of landslide prone regions : Considering the level of devastations, landslide susceptibility mapping should be carried out to delineate potential zones of instability, to minimize the loss of human lives and damages to properties. If any indication of slope instability is noticed in an area which has major risk elements, the fact should be shared with the society in a proper way with the implementation of mitigation measures. This suggestion has two major implications.
⦁ the risk posed by natural hazard must also be evaluated on priority considering the existing large scale environmentally unsound development activities in the region. This is well-exemplified by a series of natural hazards (landslides) in the region. Considering rainfall-intensity and changes in climate / hydrologic regimes (due to global warming) stochastic relationships must be explored to assess high-risk areas.
⦁ Secondly, with the successful establishment of relationship between rainfall and landslide activity, analysis of palaeo landslides would provide insights based on the past variation in rainfall patterns. Equally, such relationships aid in predicting changes in mass movement activities based on modelled regional impacts of global climate change.
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Arresting deforestation : Analyses of land use dynamics highlights of widespread removal of native vegetation in all districts of central Western Ghats. Tree cutting amounts to removal of a protective mantle. Moreover, after interval of some years when the root network disintegrates the compaction of soils and rocks by root mass weakens causing slope failure. The hollows created by stump and root disintegration become a major cause for water seepage into the soil and trigger off landslides during spells of heavy rainfall.
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Planting of native vegetation on hilltops and slopes : The roots of the native vegetation, especially of certain chosen tree species, can act as good soil binders, thereby providing slope stability. The removal of trees (with deep tap roots) and subsequent taking over of secondary vegetation, planting of monoculture species on hill tops by removing earlier natural tree cover, most of them with shallow roots has reduced the soil binding properties. At present many hill tops are barren or with highly inadequate tree cover.
Restoration of vegetation cover: A replanting programme should be undertaken giving priority for strong and deep-rooted species which check erosion and withstand water-logging. Pongamia pinnata, Calophyllum inophyllum, Ficus racemes, Thespesia populnea, Barringtonia spp., Terminalia arjuna etc. may be considered for lower slopes bordering the estuarine areas. Middle and upper slopes in landslide prone areas should be planted with tree having lower biomass but stronger and deeper root networks. Minimum of 350 trees/ha would be ideal number for the hills. Location specific species of the natural vegetation should be given priority. The general practice of afforestation with the exotic species of monoculture of trees has to be discontinued in all hazard zones.
Enhancing the scope of VFCs : The scope of the already existing village forest committees may be expanded to landslide/natural resource management as well. Necessary awareness and training programmes may arranged for members of VFCs in landslide prevention and management.
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Enhance structural stability of fragile hills : Apart from reforestation of barren hill slopes and hill tops, sealing of cracks, slope-grading, proper drainage measures, soil reinforcement using geo-grid and biotechnical measures must be done. However, appropriate selection of these measures along with their design is only possible after an in-depth geological and geotechnical study of the slide area.
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Restoration of natural drainage network : Alteration in hydrological regime due to changes in drainage network consequent to deforestation due to unplanned anthropogenic activities. Inappropriate locations of human habitations on the first and second order streams has hindered the natural water path. Heavy pressure of rainwater along the natural water path (within the hill) removing all blockages and resulting in mudslide and collapse of houses.
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Eco-restoration of Drainages and buffer zones : Natural drainage patterns should be investigated and maintained to ensure free flow of water without any blockages. Riparian plant species or stream-side species are to be promoted for stream-bank protection, flood plain protection, to enhance the water retention capability and ecology.
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Improving drainage connectivity : The sustained rainfall of many days would enhance the pore water pressure. This with lateral pressure due to swelling of oversaturated clay rich horizon has set the driving force resulting in burial of houses, human’s displacement and loss of properties.
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Discouraging monoculture plantations: The land given to commercial plantations in ecologically fragile regions should be taken back and the afforestation has to be carried out with the native species of flora according to suitably designed planting programmes.
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Restrictions on large scale developmental projects particularly in ecologically fragile regions in Central Western Ghats . The implementation of large number of mega projects in ecologically sensitive regions, has already surpassed the carrying capacity of the region and further implementation of any mega projects would prove detrimental with the recurring instances of disasters leading to the loss of life and property. The regions prone to hazards needs to be mapped and designated as hazard hotspot.
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Banning of large scale illegal quarrying of granite stones and mineral mining in ecologically fragile regions of central Western Ghats , considering the hazards proneness of the region and presence of ecologically sensitive pockets.
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Banning soil and rock mining in ecologically fragile hills - Landslide prone areas should not be leased out for soil or stone removal. All illegal mining and quarrying must be stopped immediately.
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Restrictions on slope cutting and deep excavations : Natural slope of hills have been cut in many locations for linear projects. Toe support of vulnerable hills has been cut by the residents for housing, resorts, etc. There has been also digging of the hill for soil. This necessitates stringent regulations on slope cutting. Indiscriminate slope cuttings must be strictly regulated and engineering or ecological solutions to be deployed depending on the level of hazard. Bio-protection is by far most important. Quarrying for stones and soils to be strictly regulated in vulnerable regions prone to landslides.
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Need to investigate the suitability of human habitations in regions prone to landslides and rehabilitating all affected families at appropriate locations without affecting their current livelihood dependence.
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Considering the hazard proneness of the region it is necessary to set up 'Disaster management centre (DMC)’ in each district of central Western Ghats to assist in regional planning, management of disasters and also to assist the administration in rehabilitation measures in case of eventualities. Also, need to setup a seismic
monitoring cell (within DMC) in the district to assist the district administration in the predication and mitigation measures. Disaster management centre shall house seismic monitoring cell and shall have the state of the art gadgets to predict calamities due to natural as well as human induced causes.
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Setting up special packages to restore ecosystems in all districts affected by recurring disasters (landslides): Many districts in central Western Ghats have transgressed its limits of growth, beyond the carrying capacity - Series of landslides consequent human tragedies and property loss is the indication of the lack of integrated approaches in planning and the region has crossed the thresholds of carrying capacity. Large scale land cover changes have resulted in alterations in hydrological regimes evident from the conversion of perennial streams to seasonal streams, enhanced siltation in the catchment evident from increased sedimentation in reservoirs in recent years. Many large-scale projects implemented already in this region have played significant role in degradation the ecosystems which have been affecting the livelihood of local people.
These projects shall also make provision to provide a recurring grant to sustain the proposed Disaster Management Centre and also for research in these regions.
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Constitution of Western Ghats Authority to regulate development within carrying capacity and to ensure integrated sustainable management of natural resources : Numerous development projects implemented during the post-independence period and commercial establishments have transgressed the region’s ecological carrying capacity. Need to formulate measures for safeguarding ecological stability of the region as well as recommend cluster based developmental path that are compatible with the rich biodiversity, natural resources availability and ecological fragility of the region.
Sahyadri ENews: I - LXXVII
