Geo-environmental deals with every issue that affects a living organism in the world. It is essentially a multidisciplinary approach that brings about an appreciation of our natural world and human impact on its integrity. Since last few decades the human life is being severely affected by natural hazard, therefore, it looks that the studies related to geo-environmental and hazard need to studies in details(Rawat et.al.2015) One of such approaches is to prepare regional geo-environmental appraisal for identification of areas subject to natural hazard and environmental degradation. To address a geo-environmental problem like landslide hazard one have to use different geo-environmental parameters like geology, geomorphology, rainfall, soil, surface water, ground water, land use / land cover of the study area. Indian Himalayan Region (IHR) has one of the most rugged mountain topography in the Himalaya, which is geologically one of the youngest mountain range in the world and geodynamically still active, with vast wealth of natural resources. IHR occupies 18% geographical area with 6% resident population of the country. It stretches over 2400 km from East to West and varies in width from 220 to 300 kms in North to South disposition (Agrawal et al., 1997).
As the world heads toward its urban future, the environmental problems related to municipal solid waste, one of the byproducts of an urban lifestyle became glaring. The municipal waste generally includes domestic waste (garbage, rubbish, sewage, vegetable waste etc.), commercial waste and waste from building mater ial, dead animal skeleton etc. I n order to keep the urban environment clean, solid waste management is one among the basic essential services provided by municipal authorities. However, it is among the most poorly rendered services in the basket. Disposal of waste in open have created the unpredictable and variable behavior of the geo-environment which ultimately affects the planning and management of geo-resources. Dumping of industrial and municipal wastes causes toxic substances to be leached and seep into the soil and affects the ground water course,
This State experiences the problems of landslides and other mass movements at its various locations. This is due to a combination of factors like, dominantly geological with fragile rock formation as well as unconsolidated soil material coupled with high intensity annual precipitation and steep slopes. The monsoon months play a critical role in triggering the landslide events along the roads as well as other locations of human habitations. During monsoon months (particularly June, July, August) landslides are widespread; causing collapsed, loss of life and property in the coming year’s Monsoon month receives average monthly rainfall of approximately 300-600mm. The relative humidity also remain quite high providing enough moisture to the formation particularly with clay rich soils and rocks allowing them to swell, causing unpredictable landslides at places almost round the year.
Geology of Dehradun:
Geological structure of Doon valley is characterized by two major faults, crustal and fractures along which rock slabs of mountain mass have been uplifted and moved southward. The doon valley and Shiwalik range is principally composed of the rocks of the Shiwalik groups. The rocks of the Shiwalik groups are classified into the lower, the middle and the upper Siwaliks. The southern limb of the Doon-valley and the Shiwalik. Rishikesh and some parts of Mohand is found in Doon valley, within the Himalayan ranges of mountain in the outer (Sub) Himalayan division. The southernmost zone of the outer Himalaya consists of 9500m thick piles of Tertiary sedimentary rocks (conglomerate, sandstone, mudstone, phyllites, shale, limestone ranging in age from Paleocene to lower Pleistocene. The breakdown of the rising central Himalaya has resulted in deposition of the Shiwalik group in the form of Molasses deposits, overlain by late Pleistocene Doon gravels. In the Shiwalik region a number of longitudinal valleys occur, of which one of the largest is in the Doon valley having 80 km length and 20km width.
Doon valley is situated in Uttarakhand state of India and southwest of Himalaya Shiwalik region and extends for a length of about 80 km with its average width of 20 km occupying an area of about 2245 km2 . The area lies between longitude 77035’E to 780 19’E and latitude in the north –western limit of state Uttarakhand and adjoining the state of Himachal-Pradesh. The valley is bounded in the northeast by lesser Himalayan belt and Shiwalik region on the south west. Two important rivers of north India Yamuna and Ganga demarcate the south -eastern and north –western boundaries of Doon valley. Maximum east-west length for the valley is approximately 70 km and the width varies from about 2.5 km in the extreme west, 25 km in the central part of near ly 45 km in the east. The valley comprises of mainly 6 sub watersheds: Asan (left), Asan (right), Suarna Tons, Song, Ramau and Chandrabhaga. A north -south divide divide roughly corresponding to Mussorie -Saharanpur road bifurcates the valley into the major subwatersheds of Song and Asan which flow to their master systems in the east and west respectively.
- Geo-environmental problem of Dehradun District.
- Integration of various parameters to analyze landslide and geo-environmental relation.
- Inventory of multi-hazards.
- Generate multi-hazard zonation of Dehradun District using Remote Sensing (RS) & Geographical Information System (GIS).
- The study will be carried out through the analysis of geo-environmental parameters related and responsible for landslides.
- Traverses will be taken and geological map will be prepared using traditional methods.
- Remote sensing techniques will be used for creation of different thematic map. Satellite data of IRS 1D LISS III bands 2, 3 and 4 will be used for this purpose and for input data Survey of India Top sheet No.-78A/11 of 1:50000 will be used and thus various thematic maps will be prepared in the GIS environment at required scale.
- A Multi-hazard Zonation map will be prepared considering the parameters land use/land cover pattern, slope, aspect, lithology, drainage density and rainfall.
- After obtaining the above data analysis will be done by ‘landslide index method’. In this method, a weight-value for a parameter class, such as a certain lithological unit or a certain slope class is defined as the natural logarithm (ln) of the landslide density in the class divided by the landslide density in the entire map. The ILWIS latest available software will be used for the data organization and analysis. Point, segment, polygon and raster map of all the parameters will create considering the domain as ‘classes’. In parameter maps the valued were distributed under diverse classes of equivalent class-interval.
- Efforts will be made to establish thematic maps of the geomechanics properties of the rock masses in order to be able to estimate the stability conditions in future slopes, to be excavated along new communication lines, or in isolated cases. Work will be done in a 1:25.000/1:50.000 scale, covering part of east Sikkim. Topographic data will be obtained from a “terrain digital model” and field data will be gathered in field stations. The geomechanics parameters obtained will be “regionalized” (neither interpolation nor extrapolation was convenient) in two groups of properties: rocks and joints. Criteria for designs of “regions” will be lithology, tectonic style, morphology, topography, and climate.
Tentative chapter plan:
- Geology and Geomorphology
- Interpretation of the Remote Sensing (RS), Geographic Information System (GIS) data for the study area, GPS data and RMR, SMR data.
- Multi- Hazard Zonation
- Discussion and Conclusion
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B.S. Kotlia, L.M. Joshi, R.K. Dumka and K. Kumar (2009) Vulnerablity of the Balia Nala landslide(BNL) at Nainital: preliminary GPS. pp. 136-150. In : Natuarl resource Conservation in Uttarakhand, B.L. Sah(Ed) 285 pages.
Rawat,M.S.,Uniyal,D.P.,Dobhal,R.,Joshi,Varun.,Rawat,B.S.,Bartwal,Anil.,Singh,D.,Aswal,A.,Study of Landslide Hazard Zonation in Mandakini valley, Rudraprayag district of Uttarakhand using Remote Sensing & GIS. Curr. Sci., 2015, 109(1), 158-170.
Rawat,M.S.,Joshi, Varun.,Uniyal, D.P., and Rawat, B.S., Investigation of Hill slope stability and mitigation measures in Sikkim Himalaya.Intl.J.Lsld.Env.,2015,3(1-3),8-15.