A Study on Natural Disaster Impacts on Soil in Kattery Watershed Nilgiri District
Total Page:16
File Type:pdf, Size:1020Kb
International Journal of Civil Engineering and Technology (IJCIET) Volume 9, Issue 1, January 2018, pp. 407–415, Article ID: IJCIET_09_01_039 Available online at http://http://iaeme.com/Home/issue/IJCIET?Volume=9&Issue=1 ISSN Print: 0976-6308 and ISSN Online: 0976-6316 © IAEME Publication Scopus Indexed A STUDY ON NATURAL DISASTER IMPACTS ON SOIL IN KATTERY WATERSHED NILGIRI DISTRICT Kumar N Research Scholar, Department of Civil Engineering, Karpagam Academy of Higher Education, Coimbatore, Tamilnadu, India Dr. N. Balasundaram Professor, Department of Civil Engineering, Karpagam Academy of Higher Education, Coimbatore, Tamilnadu, India Dr. T. Meenambal Professor, Department of Civil Engineering, Government College of Engineering, Coimbatore, Tamilnadu, India ABSTRACT The aim of this study is to access the impacts of natural disaster on soil in watershed basis. Hence Kattery watershed of Nilgiris district-Tamil Nadu, India is taken up for this study. The methodology involves remote sensing and GIS technologies. Field study and Laboratory analysis. The present study was initiated in Kattery watershed by preparing various thematic maps from cadastral maps using GIS Technology relevant to the study. Natural disaster that occur in hilly areas are earthquakes, landslides and floods. During these disasters there is great loss for life, properties and natural resources. This paper focuses on importance of natural resources such as soil, and the virtual disasters caused due to the soil loss. Key words: Kattery watershed, natural diaster, landslides, impact and soil loss. Cite this Article: Kumar.N, Dr. N. Balasundaram, Dr. T. Meenambal, A Study on Natural Disaster Impacts on Soil in Kattery Watershed Nilgiri District. International Journal of Civil Engineering and Technology, 9(1), 2018, pp. 407-415. http://iaeme.com/Home/issue/IJCIET?Volume=9&Issue=1 1. INTRODUCTION Natural disasters such as earthquakes, tsunami’s, cyclones, landslides, fire, volcanic eruptions are a great threat to mankind and properties. A disaster happens when a hazard impacts on vulnerable population and causes damage, casualties and disruptions. India has been traditionally vulnerable to natural disasters on account of its unique geo climatic conditions. http://iaeme.com/Home/journal/IJCIET 407 [email protected] Kumar N, Dr. N. Balasundaram, Dr. T. Meenambal Nilgiri’s district is a disaster prone area, although the district falls under earthquake prone zone the major natural disasters occurred since 1865 to 2009 is of rainfall induced landslides and floods. The district is located in the north-western part of Tamil Nadu which falls within the western ghats. The district receives an annual average rainfall of 1920 mm. This district isdelineated into 75 macro watersheds drained by two major rivers namely Moyar and Bhavani draining into Bhavani Sagar Dam. The natural disaster occurred in the district has largely contributed to soil loss and henceforth siltation of this dam. This dam irrigates an Ayacut area of 582.87 sq km. In order toprecisely study the impact of natural disasters in terms of soil loss, Kattery watershed codified 7A/75 draining in to Kattery Dam is selected. 2. ABOUT KATTERY WATERSHED The Kattery watershed is one of the biggest valley’s in South India, Located on Ooty- Coonoor highway with an area of 2919 hectares at an MSL of 2100 mts. It is globally positioned at 1122”01 N, 7644”32’ E which mainly comprises of annual and perennial crops. It drains into Kattery reservoir which contributes to a major water resource for cordite factory (Govt. of India Defense Department) the watershed is part of two revenue villages namely Adigarrty and Ketty. The reasons for selecting kattery watershed it’s because of its proximity for stream gauging and various other factors such as agriculture practices different land terrains, its susceptibility for landslips, slides and its drainage pattern, which drains into the kattery dam. This watershed is further delinated into eight micro watersheds as per its natural drainage pattern. This watershed receives rainfall from both southwest monsoon and northeast monsoon. http://iaeme.com/Home/journal/IJCIET 408 [email protected] A Study on Natural Disaster Impacts on Soil in Kattery Watershed Nilgiri District 3. OBJECTIVE The paradigm shift in management of natural resources following a watershed approach requires integrated planning and implementation of works and activities. The Nilgiris have been divided into 75 macro watershed and 176 micro watershed and these have been also priorities into very high to low priority watersheds. The scope of this study is to develop a comprehensive natural disaster management plan, keeping the above views in mind with the following objectives. Prevention of loss to life & property To reduce the soil movement & erosion Reduce the siltation of the reservoir Increase the tank capacity of the reservoir Increase in crop productivity. To conduct a precise study in the watershed and the solutions to be implemented in the district. 4. METHODOLOGY As the objective of this study is to access the impacts of natural disaster such as landslides in terms of soil loss, a suitable watershed which drains into a reservoir is selected. The watershed area was delinated from village cadastral maps and digitized. Various thematic maps such as present land use, drainage, land capability and soil texture was prepared using GIS and remote sensing techniques.Data’s relevant to the study such as rainfall, cropping pattern and sedimentation were collected. Field study was done to ascertain the factors contributing for soil loss apart from natural disasters. Field study regarding the present land use, slope, agricultural practices, physical interpretation of water bodies and impacts due to natural disasters already occurred was done. Stream gauging was done to access the sedimentation in the watershed http://iaeme.com/Home/journal/IJCIET 409 [email protected] Kumar N, Dr. N. Balasundaram, Dr. T. Meenambal 5. PRESENT LAND USE The present land use in this Watershed is as follows, Cultivable area = 944.72 ha Estate land = 1307.55 ha Forest Land = 319.94 ha Road = 43.71 ha Rock = 41.76 ha Settlement = 220.27 ha Water body = 40.39 ha --------------- 2918.33 ha --------------- 6. NATURAL DISASTERS OCCURRED IN THE WATERSHED In the year 1979 landslides and flash floods at ketti had caused major loss for life and property. In the year 2009 a series of landslides had occurred in Achanakal hamlet of ketti village causing major loss of life and property. These natural disasters had contributed to a major soil loss resulting in siltation of the reservoir which was inevitable. Apart from natural disasters induced by rainfall anthropogenic activities has contributed to natural disasters and thereby soil loss. http://iaeme.com/Home/journal/IJCIET 410 [email protected] A Study on Natural Disaster Impacts on Soil in Kattery Watershed Nilgiri District 7. RAINFALL DATA The rainfall in Kattery watershed since 2007 is as follows Year Rainfall Received S.No. (Jan - Dec) (in mm) 1 2007 2921.00 2 2008 2116.00 3 2009 3288.40 4 2010 1744.00 5 2011 1523.60 6 2012 850.80 7 2013 1083.80 8 2014 1671.70 9 2015 1482.60 10 2016 648.70 8. IMPORTANCE OF SOIL Soil is considered to be one of the most important natural resource to all living organisms including mankind. Top soil formation takes more than 100 years by various agents of deterioration. Soil is made up of 45% minerals 25% water 25% air and 5% of organic materials. Soil facilitates Vegetative growth Water conservation Microbial activities Conserves natural resources Healthy soil is the fundamental element for all living being. http://iaeme.com/Home/journal/IJCIET 411 [email protected] Kumar N, Dr. N. Balasundaram, Dr. T. Meenambal 9. EFFECTS OF SOIL EROSION Soil is considered to be one of the important natural resource, hence loss of soil inherits the following Loss of fertile and precious top soil Reduction of crop productivity Sedimentation of aquatic Systems Water pollution Clogging of waterways Destruction of infrastructure Desertification 10. SLOPE STUDY The Slope study in the Watershed reveals the slope is from 5% to 60% average. http://iaeme.com/Home/journal/IJCIET 412 [email protected] A Study on Natural Disaster Impacts on Soil in Kattery Watershed Nilgiri District 11. SEDIMENTATION STUDY Sedimentation studies were carried in the silt monitoring station located at the drainage point of the watershed, to access the actual soil loss. One litre water samples were collected and analyzed in the laboratory, sedimentation rate was interpreted based on the rainfall, runoff and silt weight per litre. Rainfall Runoff Sediment Data Rain Sediment Run off fall rate in Ha Soil loss Name Year Ha. M in mm m/100 Sq.km tonnes/Ha. (Q) (P) (S) KATTERY 1979-80 1467.30 3049.670 10.4500 14.63 1980-81 787.70 449.670 0.7522 1.05 1981-82 744.20 204.882 1.1674 1.63 1982-83 970.10 613.132 0.8473 1.18 1983-84 1027.00 73.897 0.9247 1.29 1984-85 1215.70 235.580 0.3336 0.46 1985-86 1175.80 172.680 0.0617 0.08 1994-95 666.80 450.560 0.8394 1.17 1995-96 427.70 482.328 1.5814 2.21 1996-97 971.00 645.043 2.8270 3.95 1997-98 1331.96 1142.797 2.5426 3.55 1998-99 1309.91 789.287 2.9722 4.16 Study 2014-15 1482.60 1052.640 3.6300 5.09 period Sedimentation study reveals that soil loss was more during natural disaster in 1979-80 and present soil loss due anthropogenic activities 12. RESULTS AND DISCUSSION Lab Study reveals the following Soil loss monitored in the gauging station is very high in comparison with the previousdata’s. Though the permissible soil loss is 4 Tons/Hec.