International Journal of Modern Trends in Engineering and Research www.ijmter.com e-issn No.:2349-9745, Date: 28-30 April, 2016 Landslide Hazard Management Maps for Settlements in Yelwandi River Basin, Pune, Maharashtra 1 2 Khamkar Dattatraya, Dr. Mhaske Sumedh 1 Research Scholar, Department of Civil Engineering, VJTI Mumbai, India, djkhamkar@yahoo.com 2Associate Professor, Department of Civil Engineering, VJTI Mumbai, India, symhaske@vjti.org.in Abstract- The landslide is one of the critical geological processes, which causes enormous damages to the structures and human lives. Earthquakes, heavy rainfall, volcanic eruptions, weathering, etc. may act as triggering mechanisms to initiate a landslide. Geographic Information System (GIS), Global positioning system (GPS) and Remote sensing (RS) are very useful in the study of landslide. In this paper the landslide prone settlements are detected by the field study from Yelwandi River basin. The settlements are classified into different categories depending upon the severity of landslide. The maps are prepared for different parameters using GIS. This will help to take necessary precautions to avoid the property and live losses. It may form guidelines for further decision of development. Keywords- GIS, GPS, Landslide, Disaster Management, Settlements, Remote Sensing. I. INTRODUCTION Mass movements are important geo-ecosystemic phenomena in nature, scattered in different places ranging from mild hills to steep mountains [1, 2]. Landslide hazard is defined as the probability of occurrence of landslides within a specific period of time and within a given area [3]. Remote sensing and GIS technique play a vital role in natural disaster management, particularly for landslide studies [4]. Present study aims to study danger of landslide to settlements. The settlements in the Yelwandi river basin area are studied and they are also classified into different categories depending upon parameters responsible to landslides. This will help to take remedial steps to avoid live and property losses due to landslide. Geographic Information System (GIS) is the system that integrates stores, analyzes shares and displays geographic information for decision making. GIS applications are tools that allow users to create interactive queries, analyze spatial information, edit data in maps, and present the results of all these operations. II. STUDY AREA The study area consists of Yelwandi River basin. It lies in Bhor and Velha taluka of Pune district having latitude N 18 0 to 18 15 and longitude E 73 30 to 74 0.
Figure 1. Study Area The Bhatghar Dam built on Yelwandi River in Bhor taluka of Pune district. The area is about 331Sqkm. It consists of hills, valleys, forests, farming, settlements, etc. About 52 settlements are present in this basin. The map shows the ridge line i.e. boundary of the study area. With the help of 1:50,000 scale toposheets the map is prepared. III. FIELD EXPLORATION With help of toposheets number E43H/12 and E43H/16 with 1:50,000 scale the detail exploration is carried out. Each location of settlement is observed physically and the details are noted. The involvement of local people helped to get information regarding landslide. Some of the observations are given in the following table. The details like latitude, longitude, slope, weathering, etc. is observed physically and accordingly the prediction is noted. Table 1. Field Observations Sr. no. Site Name Latitude/ longitude/ elevation N18 10.149 E73 50.134 652m Slope angle& stability Natural50 to54 Artificial cut85 to87 1. Basarapur 2. Kutwad Vasti N18 10.165 E73 49.676 658m Bare- N18 10.480 25 to 30 due to treatment 15 to 20 3. Description Mr. Sopa Raoba Jhanjale house is constructed at the foot hill on dangers slope, SW corner of the village and N facing of ZP school. Near about 3m lower columnar, jointed basalt is removed and house is constructed. Compact basalt is deeply weathered and spheroidal concretions are exposed. slope on southern side of Kutwad Vasti covered with scanty vegetation. Some CCT, gully plugs, stone bunds and farm bunds are constructed. Village is present nearly flat plateau at the foot hill, at 463
khurd E73 49.381 643m 4. Barebudruk 30 to 35 5. Mahalewadi N18 10.772 E73 49.103 632m At the top N18 11.389 E73 48.776 665m At the bottom N18 11.309 E73 48.899 643m 62 to 65 IV. both sides of hill alluvial fans follows by Ist and IInd order stream. Stone bunds treatment is provide along the channel. Village is present on unstable surface but at the foundation level plane bunds are provided. At the foot hill a farm step is observed along the side of road. Moderate to scanty vegetation is responsible to resist landslide along deeply weathered, spheroidal, concentric jointed columnar basalt. Hillock is present western side of Mahalewadi. DATA LAYERS 4.1. Geology and Geomorphology The study region consists of multiple layers of solidified fluid basalt and is more than 2,000 meters thick. The region has basaltic base on which there are alluvial deposits in river valleys on the terraces and an old flood plains. The study area includes drainage, water bodies, lineaments, vegetation, soil etc. All the tributaries are source from Sahyadri uplands and destinate to the Yelwandi River and up to Bhatghar reservoir. Landslide activities are depending on the geomorphic setting. 4.2. Soil and Drainage Depending on the source and thickness it is categorize into five category i.e. thickness from 0.3m to 1.5m, 1.5m to 2m, 2m to 3m, 3m to 4m and above the 4m. At the source area of streams the thickness of soil is low but as go down the thickness of soil is increases. The study area is sources from the Sahyadri uplands. The most of the tributaries are sources from very high elevated region. To know the density, frequency, catchment area, the calculation of the drainage is important. The given map shows the first, second, third, fourth and fifth orders. The Yelwandi River is fifth orders i.e. very big river with high density of drainages. 464
Figure 2. Drainage map with ordering 4.3. Lineament The two types of lineaments are drainage lineaments and ridge lineaments. With the help of lineament study the hill trending can be known. In the given area most of the ridge lineaments are trending E-W, NE-SW, and NW SE. The drainage lineament indicates the major fractures occurred in the area. The major lineaments are trending NE-SW, few are NW-SE. To know the topographic settings the lineament analysis is important. 4.4. Forest The study area include hilly region which having very good rainfall rate. Depending on the favorable condition the variation in the vegetation and their density occurs. The map shows open scrub, open jungle, fairly dense mixed jungle, dense scrub and dense mixed jungle 4.5. Settlement map With the help of detail exploration the following map is prepared. The map shows the Drainage of Yelwandi River basin and the villages are present surrounding the drainages. 465
Figure 3. Settlement map 4.6. Landslide prone villages On the basis of field investigation the map is prepared. Total 52 villages are explored during the field exploration. Out of these 23 villages are including in the landslide prone area. This map shows the two categories i.e. landslide prone villages and already landslide occurred villages Figure 4. Landslide prone Villages 466
The field exploration shows that there are 15 villages where the chances of landslide are more. The map shows the location of these villages. The map also shows the 8 villages where the landslide already occurred. The causes of landslide may be steep slope, weathered rock, cracks, heavy rainfall, etc. The landslides occurred at villages are of types like subsidence, sliding, and creeping. V. CONCLUSION Landslides are significant natural hazards in many areas of the world as it causes property and live losses. If we get some pre-indication of landslide it shall help to take precautionary measures to avoid losses. By using GIS map making and geographic analysis is faster and with more sophistication than any traditional manual methods. The field condition of the Yelwandi river basin area along the road cutting clearly indicate that most of the area is having stiff to vertical cut i.e. 70-85º slope. Therefore, when any loose, separated, unsupported rock mass of basaltic rock when comes in the movement, then such movement is most of the time landslide or subsidence category. Therefore, due to the above situation in this terrain the mass movements which are occurred in the past and future will be the landslides or subsidence type. The settlements present in Yelwandi river basin are classified into different categories according to landslide severity. The different maps are prepared for the study area. The landslide hazard maps shall be useful for getting pre-indication of landslide so that proper care should be possible to avoid property and live losses. The number of locations is subjected to landslides in hilly area. The detail investigations are required for further conclusion. The preventing measures like micro-piling and soil nailing reduced the hazard of landslides. It also helpful to take proper policy decision for planning the different construction activities. REFERENCES [1] [2] [3] [4] Krishnan, N., Subramani, T., Land slides hazardous Zones by using Remote sensing and GIS, International Journal of Application in Engineering and Management, 4, P-211-222, 2015. H. Shahabi, B.B. Ahmad, and S. Khezri, Landslide susceptibility mapping using image satellite and GIS technology, International journal of engineering research and technology, vol.1, Issue-6, P-1-5, 2012. Varnes, D. J., Landslide hazard zoantion: A review of principles and practice, United Nations International, Paris, P. 1-55, 1984. S.Anbazhagan, A. Chatterjee, A. S. Sethupathi, Guru Balamurugan and V. Ramesh., Remote sensing and GIS for landslide hazard mapping- Case study from Mumbai, India, Landslides and Environmental Degradation, P.89-106. 467