DEVELOPMENT OF DISASTER INFORMATION SYSTEM IN NEPAL
Damodar Bhattarai, Badri Govind Rajkarnikar, Prakash Man Shrestha1), Takeshi Fukada, Satoru Morikawa2), Shinji Yamaguchi3)
ABSTRACT
Nepal is a landlocked mountainous country. Ecologically, Nepal can be divided into three regions such as mountains, hills, and plains. Very fragile mountains and hills cover about 80 % of its land, while 20 % is covered by plain area. Heavy monsoon rainfall causes gully erosion, landslides, debris flows etc in the mountain and hill area, while the plain areas are affected by floods. Information on the past disasters is very crucial for the disaster prediction, planning and implementation of countermeasures against such disasters in future. The GIS is one of the convenient tools for the management of such database and to prepare the potential hazard map. The GIS based District-wise Disaster Information System developed in the Department of Water-induced Disaster Prevention (DWIDP) is intended to present the graphical display of the past water-induced disasters in Nepal and the analysis of the causative factors of such disasters in future.
KEYWORDS: GIS, Information, Disaster, Database, Hazard.
INTRODUCTION
The landform of Nepal is divided into five geomorphologic regions High Himalayas, High Mountain, Middle Mountain, Siwalik, and Terai plains that can be divided hydrologically into several watershed and sub-watersheds. Due to the wrong farming practices and unplanned settlements, several types of mass movements have dominated these watersheds and sub-watersheds. The mountains, hills, foot hills, valleys and Terai plain have been suffering different types of erosions, landslides and debris flows and flooding during the heavy rain in monsoon every year. Land defragmentation is on going rapidly and the use of marginal lands of hill slopes is being made for agricultural purpose due to the increase in population every year. These human activities along with tectonic and other natural causes are triggering the processes of land erosion, landslide and debris flows at the upper catchments while the Terai and valleys are affected by floods due to the increase in bed level of the rivers. Infrastructures such as roads, irrigation canals built in the hills of Nepal are highly susceptible to landslides, while the Terai plains are susceptible to floods. These disasters usually damage major portions of the infrastructures and disrupt the normal life in a short span of time. Beside these, they claim a significant number of human lives in a short period. The disasters of 1987, 1993 and more recently, 1998, are the significant water induced disasters in the disaster history of Nepal. Information on disaster events is a primary input to disaster prevention and preparedness. The initiation of a well-maintained Disaster Information system (DIS) by using Geographic Information System (GIS) is very essential for the information on water-induced disasters and its causative factors. Several data layers of the causative factors, topographic as well as climatic information, geomorphologic data and disaster data are vital for this purpose. Analysis of these data can be used to draw the conclusion on the causative factors for countermeasure, warning for self-evacuation, disaster database for planning etc.
At present, the Department of Water Induced Disaster Prevention (DWIDP)/Disaster Mitigation Support Program Project (DMSP) has implemented GIS for the disaster information management as follows:
District wise Disaster Information System having the information of the causalities of disasters each year in 75 districts of Nepal.
Kathmandu-Naubise Road, which is the only major road linking Kathmandu Valley with the rest of the country and India.
GIS database
GIS is a tool for managing the spatial data conveniently for the analysis and the presentation of spatial data. Thus, it is very convenient to implement this system for the management of the water-induced disaster data. The system needs regular updating and maintenance. It is very convenient for data sharing also.
The procedure of construction and the contents of data in the DWIDP Disaster Information System are as follows:
For the effective use of the system, it is very important to develop the required human resources. The main process for system preparation has the following main components:
Information Compilation/Storage/Management
Promotion of Information Sharing
Management of Hazard Site and Disaster Occurrence Site
Preparation of Disaster Potential Map
Initial application after the disaster occurrence
It can be expected that the GIS system will be able to improve efficiency in analyzing disaster prevention database. Retrieval of necessary information from the map, related disaster prevention information to the public, awareness to the local government for enhancement of disaster prevention activity, the analysis of the disaster occurrence point by overlapping of the causative factors and effect due to the disaster and its occurrence should have to be analyzed through the use of GIS.
Purpose and effectiveness of developing disaster Information system (DIS)
It is clear that a lot of effects can be expected by using GIS. However, the possibility of failure because of overconfidence in the system cannot be over ruled. So the following points are considered before developing a GIS:
The Purpose is to improve the efficiency of the works and to prevent the loss of data, proper preservation and storage management of documents, photographs, drawings and investigation results etc.
Frequency of updating of Information.
Data retrieval requirements.
Cooperation with related organizations and disaster information sharing.
Required output such as distribution of disaster areas, their geographical features and the method of analysis should be clearly defined.
The output should assist to prepare the disaster prevention plan, and the hazard maps.
District-wise disaster information system (DIS)
Water induced disaster occurs every year in Nepal due to severe geographical and the weather conditions. A significant number of lives and properties are lost each year due to these disasters. To manage this disaster information, and to disseminate the information to the related organizations and the local government, etc., DWIDP/DMSP has implemented the construction of the GIS system for district-wise disaster information. It is quite difficult to make facilities at all disaster sites. So, it is very essential for concerned agencies to get such disaster information to execute the "Soft" countermeasures. Till now not all regions have computer facilities and system of disaster information dissemination, which are useful for the disaster management. So, it is very difficult for the DWIDP/DMSP to manage the system. Disaster information has been collected mainly from mass media such as newspaper articles, news etc. With the limited information at present, these databases were categorized into type of disaster, damage condition and so on. The content of this database is shown in the table below:
There is a causal relationship between the various parameters & characteristics and the occurrence of disaster, and in arranging this information, it is possible to analyze and predict the probable future hazard. These causative factors can be classified into three characteristics.
1.
Environmental Characteristics: Disaster versus amount of rainfall, density of vegetation, land use pattern etc.
2.
Topographical Characteristics: Disaster versus Geographical features (slope inclination and altitude, etc.), geological features (geological features which easily collapses and which is not)
3.
Socio-environmental Characteristics: Disaster versus Population distribution, Health and education religious factors, Public awareness on disaster, Settlement pattern and infrastructure density etc.
These characteristics give the overview of the occurrence of past disaster areas by overlapping disaster information and the causative factors. A regional statistical analysis of disaster occurrence of all 75 districts can be done to infer the relationship between the causative factors and the disasters. For further analysis, the system will be improved and managed accordingly. The maintenance and updating of the system will be carried out for a long-term in the future. The sample maps are given below:
An Example Of DIS Application In Road Managemane
The DWIDP is trying to develop the Disaster Potential Map (DPM) of sediment-related disasters along a national highway using GIS in addition to the District-wise Disaster Information System (DIS). Since the target sector is one of the most important road corridors, the DMSP intends to develop a GIS based road management system. The road management system should consist of 4 stages:
Extraction of hazard areas
Implementation of control-work against the disasters
Maintenance of constructed facilities
Management of the system
The DPM is the main body in the first stage of extraction of the hazard areas. Present condition of the disaster management in Nepal is mainly to carry out disaster rehabilitation works, but the implementation of an efficient road management system is indispensable not only to contribute to reduction of the budget for the enterprise of disaster mitigation but also to mitigate important infrastructures against the disasters.
Method of the DPM
The method of making the DPM is shown in Fig.5, as a flowchart. The method is roughly divided into two stages i.e. desk study stage and field exploration stage. At first, the desk study is implemented in order to classify the geomorphology and to extract the hazard sites in the target areas. After that, field exploration survey is implemented in order to confirm the results of the desk study and to collect the necessary data. Generally, topographical and geological map and aerial photographs are used, but more detailed DPM will be developed by incorporating further information such as vegetation map, land-use map, etc, where applicable. The DWIDP is using the topographical map, geological map, aerial photographs, and vegetation map at this time. Although a detailed DPM can be developed with more information, attention should be paid in two points i.e. meaningless information that does not express the actual site condition and necessity of the verification of site data. Therefore, it should be recognized that the field exploration is the main theme of the DPM.
The field exploration is indispensable to develop the DPM, but the standard formats and their manuals did not exist. So, the DMSP has developed these formats and manuals for the field exploration. The formats of the field exploration consist of 3 kinds of sheets, which correspond to the countermeasures of the sediment-related disasters, i.e. debris flow, land-creep, and slope failure. Photographs and sketches are adopted effectively to understand site condition easily. Besides, to classify the site by hazard level, the hazard rating developed by the DPTC has been adapted.
The DWIDP is collecting field data on the slope failure along the road now and then plans to implement data processing. The DWIDP intends to use the GIS technology for overlapping collected data and avoid using high-level application of it like simulation of the disasters for the time being for practical reasons and paucity of data. The DPM using GIS is shown in Fig. 6.
The Characteristics of the Method
This is the practical method based on considering the condition of Nepal. Through the simplification of the formats of the field exploration, local government officers who complete the training on DPM method can collect field data easily. Moreover, a set of formats has been designed for quick comparison between previous and present field data at the data revision period. However, hazard rating of the DPTC, which has been decided on the basis of the Japanese examples, is used because of the insufficient data at present. It is necessary to improve these ratings through the collection and analysis of field data in the future.
Future Task
It is necessary to improve the DPM method through the application for field exploration survey in the model-site. Especially, classification of the site by hazard-level should be based on a large amount of data for analysis. Therefore, the DWIDP considers that the database on the sediment-related disasters should be established first and GIS should be an efficient tool for this.
Conclusions
Presently, the DWIDP/DMSP is making two types of GIS database. One is the district wise disaster occurrence database and the other is the disaster occurrence along the Kathmandu-Naubise Road. It is needless to say that GIS is an efficient tool to manage the information basically. It is necessary for engineers to have the policy that engineers should make high quality data, and users should try to be cognizant enough in using these data effectively. GIS is just a tool used to manage the geographically related data and it is not magical software. GIS will be able to manage various data, but the basic information is to be extracted and realized by the field survey. To monitor the site, it is essential that engineers try to comprehend the changing site condition correctly. In line with the adoption of Information Technology all over the world, DWIDP/DWSP has been implementing GIS system as one of its activities in disaster information activity, but it should make an effort for adaptation of the suitable system for this country. Care should be taken not to duplicate the already available data, as it is wastage of time and investment.
The implementation of GIS database for disaster mitigation is used for information dissemination and management. The data related to the geography of the area is used for all kinds of analysis and designs. A planner, designer, and engineer can use the data related to geology, rainfall and so on of the area for the design of all kinds of mitigation activities of disaster. Rainfall pattern and its intensity give an overview of the characteristics of disasters of that area.
The system developed for the disaster database management in Nepal through GIS is a sample database and it could be used in other countries as an example. These maps are an effective means of data presentation in graphical form. The data and information managed in DWIDP/DMSP also help for new project intervention. The area based disaster information and its buffer helps for a sustainable plan preparation and implementation. It can be expected that the development of this system will be useful for the disaster mitigation activities in Nepal.
References:
1.
Disaster Data (1996 to 2000), Ministry of Home Affairs, His Majesty's Government of Nepal.
2.
Geological Map of Nepal (1984), Department of Mines and Geology, His Majesty's Government of Nepal.
3.
Disaster Data Publications (1996 to 2001), National Daily News Paper Publications of The Kathmandu Post and The Rising Nepal.
4.
Digital Data of District Maps (2001), National Planning Commission
5.
Rainfall Data (1996 to 2000), Department of Hydrology and Meteorology, His Majesty's Government of Nepal.
1)
Department of Water Induced Disaster Prevention, Ministry of Water Resources, His Majesty's Government of Nepal.
2)
Long-term expert, Japan International Cooperation Agency (JICA) Nepal office.
3)
Ministry of Land Infrastructure and Transportation, The Government of Japan.
Tuesday, March 27, 2007
Monday, March 19, 2007
DISASTER MANAGEMENT
The Role of Mapping in Disaster Management
- Kalyan Gopal Shrestha
Abstract: Every year Nepal suffers from many kinds of disasters such as floods and landslides. In recent years, the increasing numbers of natural disasters in Asia like Tsunami and series of South Asian quakes are a matter of serious concern to us. At this crucial period, we should be conscious about our status of disaster management situation in Nepal. What will happen if a strong earthquake or any other natural disaster strikes Nepal, particularly in the capital city of Kathmandu? Though we cannot avoid disaster, but by implementing the effective prevention schemes, we can reduce damages from severity, if sufficient information for disaster forecasting is given timely. This paper attempts to evaluate the critical role of mapping for all stages of the disaster management cycle: prevention, mitigation, preparedness, response and recovery.
1.0 Introduction
Disaster is a sudden and accidental event that causes many deaths and injuries. Most disasters result in significant property damages. Common natural causes of disasters include earthquakes, floods, landslides, hurricanes, and tornadoes. Volcanic eruptions, fires, and avalanches rank among the other natural forces that sometimes create disasters.
Not all disasters are produced by the forces of nature. Many modern-day disasters involve accidents aboard passenger-carrying airplanes, ships, or railroads. Other “man-made” disasters can be traced to the collapse of buildings, bridges, tunnels, and mines, as well as to explosions and fires triggered by humans. War and terrorist events, which also cause death and destruction, are intentional rather than accidental, and therefore are not considered disasters.
In recent years, the increasing number of natural disasters in Asia that include Tsunami and series of South Asian quakes are a matter of serious concern to us. At this crucial stage, it is useful to make aware our status of Disaster Management situation in Nepal. What will happen if such a strong earthquake or any other natural disaster hits Nepal, particularly in the capital city of Kathmandu? Hundreds of thousands of people will be buried and yet other thousands and thousands of people will be killed because of poor post-Disaster Management. Country will face severe panics of road blockade, failure of water supply system, medical services and food supply failure and eventually upsurging epidemic so on.
2.0 Disasters in Nepal
Natural disaster is common in Nepal. The country is geologically young and still evolving. Therefore landslides and earthquakes are common and frequent. Given its mountainous topography and the fact that the country comes under the spell of the monsoon every summer, flash floods, regular floods and flood- and earthquake-triggered landslides are also quite common.
Tectonic-induced disasters (Earthquake disaster) could be most catastrophic. The earthquake of 1934, 1980, and 1988 were the most devastating natural disasters, which not only caused heavy losses of human lives and physical properties but also adversely affected the development process of the country as a whole. A massive earthquake registered 7.9 on the Richter scale struck Nepal in Jan 1934. Thousands of peoples were killed and hundreds of thousands were left homeless. A powerful earthquake is said to strike Nepal every 80 to 100 years. As Nepal falls in most vulnerable seismic zone, geologists have warned that a major earthquake may strike at any time.
Water-induced disasters, e.g. Flood, Landslides etc. are most common natural disasters in Nepal. Besides, heavy precipitation, high wetness and steepness of watersheds contribute to flood magnitudes. Mainly, the middle hills are prone to landslides and the Tarai to flood and fire. Thus, flood, landslide and fire are the most frequent natural disasters in Nepal. These disasters occur almost every year in one part of the country or the other causing loss of life and heavy damage to physical properties. In July 1993, Nepal experienced the worst recorded natural disaster in history due to two days of torrential rainfall in central Nepal. More than 1300 lives lost and over millions of property and infrastructure were destroyed.
Apart from that, the region is also quite vulnerable to disastrous hazards due to glacial lake outburst floods. Since a few years, Tsho - Rolpa Glacial Lake has been a burning issue and becoming potentially dangerous. Among the 2323 glacial lakes of Nepal, 20 glacial lakes are identified as potentially dangerous. A monitoring system for lakes with outburst risk should be established to avoid flood hazards.
It is a great challenge to the nation to protect infrastructure and property from frequent landslide and floods. Each year flood, landslide, fire, epidemic, avalanche and various other natural and man made disasters cause the casualty of thousands of human lives and destruction of physical properties worth billions of rupees.
2.1 Disaster Management in Nepal
Immediate rescue and relief works as well as disaster preparedness mitigation activities are governed by the Natural Disaster Relief Act 1982 of His Majesty’s Government of Nepal. The Natural Disaster and Floods Division of the Ministry of Home Affairs is the central unit responsible for managing/coordinating emergency response.
Disaster mitigation efforts of the government so far are confined to rescue operation and post-disaster recovery. In the absence of information about the nature of flood events, exposure of life and properties and capabilities to cope with disasters, it is difficult to prepare and implement pre-disaster activities. Lack of information is a major constraint in implementing and coordinating the rescue and post-disaster management activities effectively.
So far there are no established guidelines in Nepal that facilitates policy and program development in disaster reduction and efficient response. The efficient exchange mechanism of relevant information to establish a central database is the most important factor to be encouraged. There is an urgent need to prepare a consolidated Natural Disaster Management Policy. There are still several fundamental unanswered questions before us. How to do? When to do? Who will do?
3. Role of Mapping
Maps have been used for centuries as tools for providing detail information about the area concerned. The remarkable developments in computer technology, space technology and GIS applications in mapping during the recent decades have enhanced the design, quality and utility of maps. Subsequently these developments provided important tools for change analysis, programming and monitoring for results and impacts, and policy making agencies to address issues related to sustainable development more effectively. The results obtained through the use of satellite data have stimulated major environmental policy decisions around the world.
Maps are essential at all stages of the disaster management cycle: prevention, mitigation, preparedness, response and recovery. It is important to undertake a range of activities such as: risk assessment; scenario analysis or analysis of consequences; forecast and projection; dissemination of information; allocation of personnel, equipment and other resources; reaching relief personnel at various affected areas; damage assessment and so on. Maps play a critical role in all these activities. The role of mapping for disaster management can be analyzed with reference to the following phases:
3.1 Hazard Assessment and Vulnerability Analysis
Hazard assessment and vulnerability analysis are fundamental to disaster management planning. It is necessary to identify geographical areas that are likely to be affected by hazards such as earthquakes, landslides and floods. Vulnerable and risky areas in the context of various types of disasters need to be identified and mapped with a view to planning of prevention, mitigation and emergency response measures. If we had geographical information systems, which link maps with database, it would be possible to have simulation models that can be useful at various stages. With the help of GIS, one can analyze disasters over time and space.
3.2 Mitigation and Preparedness
Though we cannot avoid disaster, but by implementing effective prevention plans, its impact can be reduced through a proper disaster management, including disaster prevention (hazard and risk assessment, land use planning and legislation, building codes), disaster preparedness (forecasts, warning, prediction) and rapid & adequate disaster relief.
Mitigation measures will have to be taken in areas that are more prone to hazards like earthquake, cyclone, flood and drought. Maps and GIS can facilitate such activities. With the help of GIS, one can have a dynamic system of mapping. In other words, maps can be updated as soon as the linked database is updated. Based on the above analysis mitigation and preparedness activities can be planned.
3.3 Pre-disaster phase
During the pre-disaster phase (the period after a warning or an early warning of a disaster and before the actual occurrence of a disaster), scenarios can be analyzed and response measures can be planned with the help of maps and GIS. Evacuation routes can be planned and displayed for use by emergency managers. We take an example of a system of early warning of a drought. During the monsoon season, the rainfall situation is monitored closely. With the help of maps and GIS, it is possible to have a detailed assessment of areas with excess, normal and deficient rainfall.
3.4 Loss and Damage Assessment
The role of maps in loss and damage assessment does not need any emphasis. In the event of a disaster, the assessment of damage may have to be done in phases. Immediately after the disaster, questions are asked regarding the number of deaths, the number of injured persons, loss of property etc. With the help of GIS one can have broad and quick estimates of area, population and the vital installations affected. At a later stage when a detailed survey and damage assessment are carried out, the consistency and reliability of the data can be checked with the help of GIS based analysis.
3.5 Rehabilitation and Reconstruction
Mapping is essential even during relief, rehabilitation and recovery phases after a disaster. In the event of a major disaster affecting vast areas and a large population, it is necessary to plan relief and rehabilitation activities with the help of maps. The task becomes easier and more systematic if maps are linked to database.
The above examples illustrate how critical the role, relevance and utility of maps and imageries is in disaster management.
4.0 Roles of Remote Sensing and GIS as a Natural Hazard Management Tool
A complete strategy for disaster management is required to effectively reduce the impact of disaster, which is referred to as disaster management cycle. Disaster management consists of two phases that takes place before disaster occurs, disaster prevention and disaster preparedness, a three phases that happens after the occurrence of a disaster i.e. disaster Estimation, relief, rehabilitation and reconstruction.
Mapping has become an integral part of a modern decision support system. Remote sensing and GIS provides a data base from which the evidence left behind by disaster that have occurred before can be interpreted, and combine with the other information to arrive at hazard maps, indicating which area is potentially dangerous. Using remote sensing data, such as satellite imageries and aerial photos, allows us to map the variabilities of terrain properties, such as vegetation, water, geology, both in space and time. Satellite images give a synoptic overview and provide very useful environmental information, for a wide range of scales.
Dynamic use of GIS integrated with RS provides useful measures towards disaster preparedness and to provide warning for the people to take initiative to evacuate people to the safe places in time and also planning for operational activities, immediately before, during and after disaster.
Finally, the impact of the disaster event leaves behind an area of immense devastation. Remote Sensing can assists in damage assessment monitoring, providing a quantitative base for relief operation. After that it can be used to map the new situation and update the database used for the reconstruction of an area. It can help to prevent the occurrence of such disasters again in future.
The multidisciplinary approach of the study is fully benefited by application of remote sensing and GIS techniques combined with field studies. The current scenario of Base map and related records in disaster management is as follows:
4.1 Base Map Preparation
Survey Department of Nepal has already prepared the topographical base maps covering the entire country. The scale of the maps for mountainous and tarai area is 1:25,000 and the map scale for Himalayan region is 1:50,000. Survey Department has also prepared a set of digital topographical data base from the topographical base maps. The department has also initiated updating of topographical maps with the help of satellite images.
4.2 Hazard Mapping
Hazard map and disaster data play an important role to predict and foresee the possible trends of likely disasters. So, hazard map and reliable data is the need of the day. The lack of meteorological and hydrological records in the country makes accurate projection of possible flood damage beyond our target.
However, recognition of the past damages and potential hazards are one of the key elements to be studied. The primary stage is to plot out the exact location and degrees of damages in the previous major disasters are to be recorded through interviews and field surveys. This information will enable us to suggest particular locations, and human activities of significant vulnerableness, which are to be mapped and shared by the residents and researchers as a basis of discussion and learning toward strengthened protection of life and assets.
4.3 Nodal Point for Disaster Management
Survey Department is a member of Asia Pacific Regional Space Agency Forum (APRSAF). In 1995, APRSAF appointed the Survey Department as a nodal point for disaster management for Nepal. In this connection, Geoinformatics Center of Asian Institute of Technology (AIT), Thailand provided trainings to Staffs of Survey Department with the sponsor from Japanese Aerospace Exploration Agency (JAXA). The trainings so far provided are on study of Change in Urban Land use, Flood Disaster Mitigation and Earthquake Disaster Mitigation.
5.0 Concluding Remarks
Persistent occurrences of earthquakes, floods, landslides and forest fires need to be studied using today’s advanced technology to find effective preventive measures. Being a resource-poor country, Nepal faces a gigantic managerial task to provide adequate support to the natural disaster victims.
Nepal lacks organized data collection network, even though several governmental as well as non-governmental International agencies have been providing support for disaster victims from time to time. Despite all these provisions and assistance, there are many challenges for an effective disaster management system - such as system of hazard mapping, vulnerability assessment, risks analysis, low-level of public awareness, lack of cooperation and coordination, poor system of data collection and dissemination, remote and inaccessible topography.
There are no institutions that deal with hazard mapping for serious natural disaster threats in Nepal. Survey Department of Nepal, being a national mapping agency, should kick-off a disaster mapping unit to optimal utilization of its resources for the sake of enhancing country’s disaster mitigation efforts. It could work as a coordinating agency for various other institutions dealing with various types of disasters in the country so as to produce disaster hazard maps. Investment towards making use of the space technology is worth because improvement in instrumentation and time prediction will bring about reduction in disaster damages; and improved decision making in planning stages.
REFERENCES:
ADPC, 1991, Disaster Mitigation in Asia and the Pacific, Manila: Asian Disaster Prevention Center.
Lanza, L. and Conti, M. (1994) Remote Sensing and GIS: Potential Application for
Flood Hazard Forecasting. http://www.odyssey.maine.edu/gisweb/spatdb/egis/eg94208.html
OAS (1990).Disaster, Planning and Development: Managing Natural Hazards to Reduce Loss. Dept. Regional Development and Environment. Organizaion of American States. Washington, USA.
UNDRO (1991). Mitigating Natural Disasters. Phenomena, Effects and Options. United Nations Disaster Relief Co-ordinator, United Nations, New York, USA
Pokharel, Lekh Nath. Disaster Management System in Nepal, the Spotlight magazine, Vol. 23, No. 44, May 21 - 27 2004, Kathmandu, Nepal, http://www.nepalnews.com/
Chheetri and Bhattarai D., (2001), Mitigation and Management of Floods in Nepal, Kathmandu, HMG, Ministry of Home Affairs
Mool, P.K., Bajracharya, S.R., and Joshi, S. P.(2001). Inventory of glaciers, glacial lakes, and glacial lake outburst flood monitoring and early warning system in the Hindu Kush-Himalayan Region, Nepal. International Centre for Integrated Mountain Development (ICIMOD) Kathmandu, Nepal.
- Kalyan Gopal Shrestha
Abstract: Every year Nepal suffers from many kinds of disasters such as floods and landslides. In recent years, the increasing numbers of natural disasters in Asia like Tsunami and series of South Asian quakes are a matter of serious concern to us. At this crucial period, we should be conscious about our status of disaster management situation in Nepal. What will happen if a strong earthquake or any other natural disaster strikes Nepal, particularly in the capital city of Kathmandu? Though we cannot avoid disaster, but by implementing the effective prevention schemes, we can reduce damages from severity, if sufficient information for disaster forecasting is given timely. This paper attempts to evaluate the critical role of mapping for all stages of the disaster management cycle: prevention, mitigation, preparedness, response and recovery.
1.0 Introduction
Disaster is a sudden and accidental event that causes many deaths and injuries. Most disasters result in significant property damages. Common natural causes of disasters include earthquakes, floods, landslides, hurricanes, and tornadoes. Volcanic eruptions, fires, and avalanches rank among the other natural forces that sometimes create disasters.
Not all disasters are produced by the forces of nature. Many modern-day disasters involve accidents aboard passenger-carrying airplanes, ships, or railroads. Other “man-made” disasters can be traced to the collapse of buildings, bridges, tunnels, and mines, as well as to explosions and fires triggered by humans. War and terrorist events, which also cause death and destruction, are intentional rather than accidental, and therefore are not considered disasters.
In recent years, the increasing number of natural disasters in Asia that include Tsunami and series of South Asian quakes are a matter of serious concern to us. At this crucial stage, it is useful to make aware our status of Disaster Management situation in Nepal. What will happen if such a strong earthquake or any other natural disaster hits Nepal, particularly in the capital city of Kathmandu? Hundreds of thousands of people will be buried and yet other thousands and thousands of people will be killed because of poor post-Disaster Management. Country will face severe panics of road blockade, failure of water supply system, medical services and food supply failure and eventually upsurging epidemic so on.
2.0 Disasters in Nepal
Natural disaster is common in Nepal. The country is geologically young and still evolving. Therefore landslides and earthquakes are common and frequent. Given its mountainous topography and the fact that the country comes under the spell of the monsoon every summer, flash floods, regular floods and flood- and earthquake-triggered landslides are also quite common.
Tectonic-induced disasters (Earthquake disaster) could be most catastrophic. The earthquake of 1934, 1980, and 1988 were the most devastating natural disasters, which not only caused heavy losses of human lives and physical properties but also adversely affected the development process of the country as a whole. A massive earthquake registered 7.9 on the Richter scale struck Nepal in Jan 1934. Thousands of peoples were killed and hundreds of thousands were left homeless. A powerful earthquake is said to strike Nepal every 80 to 100 years. As Nepal falls in most vulnerable seismic zone, geologists have warned that a major earthquake may strike at any time.
Water-induced disasters, e.g. Flood, Landslides etc. are most common natural disasters in Nepal. Besides, heavy precipitation, high wetness and steepness of watersheds contribute to flood magnitudes. Mainly, the middle hills are prone to landslides and the Tarai to flood and fire. Thus, flood, landslide and fire are the most frequent natural disasters in Nepal. These disasters occur almost every year in one part of the country or the other causing loss of life and heavy damage to physical properties. In July 1993, Nepal experienced the worst recorded natural disaster in history due to two days of torrential rainfall in central Nepal. More than 1300 lives lost and over millions of property and infrastructure were destroyed.
Apart from that, the region is also quite vulnerable to disastrous hazards due to glacial lake outburst floods. Since a few years, Tsho - Rolpa Glacial Lake has been a burning issue and becoming potentially dangerous. Among the 2323 glacial lakes of Nepal, 20 glacial lakes are identified as potentially dangerous. A monitoring system for lakes with outburst risk should be established to avoid flood hazards.
It is a great challenge to the nation to protect infrastructure and property from frequent landslide and floods. Each year flood, landslide, fire, epidemic, avalanche and various other natural and man made disasters cause the casualty of thousands of human lives and destruction of physical properties worth billions of rupees.
2.1 Disaster Management in Nepal
Immediate rescue and relief works as well as disaster preparedness mitigation activities are governed by the Natural Disaster Relief Act 1982 of His Majesty’s Government of Nepal. The Natural Disaster and Floods Division of the Ministry of Home Affairs is the central unit responsible for managing/coordinating emergency response.
Disaster mitigation efforts of the government so far are confined to rescue operation and post-disaster recovery. In the absence of information about the nature of flood events, exposure of life and properties and capabilities to cope with disasters, it is difficult to prepare and implement pre-disaster activities. Lack of information is a major constraint in implementing and coordinating the rescue and post-disaster management activities effectively.
So far there are no established guidelines in Nepal that facilitates policy and program development in disaster reduction and efficient response. The efficient exchange mechanism of relevant information to establish a central database is the most important factor to be encouraged. There is an urgent need to prepare a consolidated Natural Disaster Management Policy. There are still several fundamental unanswered questions before us. How to do? When to do? Who will do?
3. Role of Mapping
Maps have been used for centuries as tools for providing detail information about the area concerned. The remarkable developments in computer technology, space technology and GIS applications in mapping during the recent decades have enhanced the design, quality and utility of maps. Subsequently these developments provided important tools for change analysis, programming and monitoring for results and impacts, and policy making agencies to address issues related to sustainable development more effectively. The results obtained through the use of satellite data have stimulated major environmental policy decisions around the world.
Maps are essential at all stages of the disaster management cycle: prevention, mitigation, preparedness, response and recovery. It is important to undertake a range of activities such as: risk assessment; scenario analysis or analysis of consequences; forecast and projection; dissemination of information; allocation of personnel, equipment and other resources; reaching relief personnel at various affected areas; damage assessment and so on. Maps play a critical role in all these activities. The role of mapping for disaster management can be analyzed with reference to the following phases:
3.1 Hazard Assessment and Vulnerability Analysis
Hazard assessment and vulnerability analysis are fundamental to disaster management planning. It is necessary to identify geographical areas that are likely to be affected by hazards such as earthquakes, landslides and floods. Vulnerable and risky areas in the context of various types of disasters need to be identified and mapped with a view to planning of prevention, mitigation and emergency response measures. If we had geographical information systems, which link maps with database, it would be possible to have simulation models that can be useful at various stages. With the help of GIS, one can analyze disasters over time and space.
3.2 Mitigation and Preparedness
Though we cannot avoid disaster, but by implementing effective prevention plans, its impact can be reduced through a proper disaster management, including disaster prevention (hazard and risk assessment, land use planning and legislation, building codes), disaster preparedness (forecasts, warning, prediction) and rapid & adequate disaster relief.
Mitigation measures will have to be taken in areas that are more prone to hazards like earthquake, cyclone, flood and drought. Maps and GIS can facilitate such activities. With the help of GIS, one can have a dynamic system of mapping. In other words, maps can be updated as soon as the linked database is updated. Based on the above analysis mitigation and preparedness activities can be planned.
3.3 Pre-disaster phase
During the pre-disaster phase (the period after a warning or an early warning of a disaster and before the actual occurrence of a disaster), scenarios can be analyzed and response measures can be planned with the help of maps and GIS. Evacuation routes can be planned and displayed for use by emergency managers. We take an example of a system of early warning of a drought. During the monsoon season, the rainfall situation is monitored closely. With the help of maps and GIS, it is possible to have a detailed assessment of areas with excess, normal and deficient rainfall.
3.4 Loss and Damage Assessment
The role of maps in loss and damage assessment does not need any emphasis. In the event of a disaster, the assessment of damage may have to be done in phases. Immediately after the disaster, questions are asked regarding the number of deaths, the number of injured persons, loss of property etc. With the help of GIS one can have broad and quick estimates of area, population and the vital installations affected. At a later stage when a detailed survey and damage assessment are carried out, the consistency and reliability of the data can be checked with the help of GIS based analysis.
3.5 Rehabilitation and Reconstruction
Mapping is essential even during relief, rehabilitation and recovery phases after a disaster. In the event of a major disaster affecting vast areas and a large population, it is necessary to plan relief and rehabilitation activities with the help of maps. The task becomes easier and more systematic if maps are linked to database.
The above examples illustrate how critical the role, relevance and utility of maps and imageries is in disaster management.
4.0 Roles of Remote Sensing and GIS as a Natural Hazard Management Tool
A complete strategy for disaster management is required to effectively reduce the impact of disaster, which is referred to as disaster management cycle. Disaster management consists of two phases that takes place before disaster occurs, disaster prevention and disaster preparedness, a three phases that happens after the occurrence of a disaster i.e. disaster Estimation, relief, rehabilitation and reconstruction.
Mapping has become an integral part of a modern decision support system. Remote sensing and GIS provides a data base from which the evidence left behind by disaster that have occurred before can be interpreted, and combine with the other information to arrive at hazard maps, indicating which area is potentially dangerous. Using remote sensing data, such as satellite imageries and aerial photos, allows us to map the variabilities of terrain properties, such as vegetation, water, geology, both in space and time. Satellite images give a synoptic overview and provide very useful environmental information, for a wide range of scales.
Dynamic use of GIS integrated with RS provides useful measures towards disaster preparedness and to provide warning for the people to take initiative to evacuate people to the safe places in time and also planning for operational activities, immediately before, during and after disaster.
Finally, the impact of the disaster event leaves behind an area of immense devastation. Remote Sensing can assists in damage assessment monitoring, providing a quantitative base for relief operation. After that it can be used to map the new situation and update the database used for the reconstruction of an area. It can help to prevent the occurrence of such disasters again in future.
The multidisciplinary approach of the study is fully benefited by application of remote sensing and GIS techniques combined with field studies. The current scenario of Base map and related records in disaster management is as follows:
4.1 Base Map Preparation
Survey Department of Nepal has already prepared the topographical base maps covering the entire country. The scale of the maps for mountainous and tarai area is 1:25,000 and the map scale for Himalayan region is 1:50,000. Survey Department has also prepared a set of digital topographical data base from the topographical base maps. The department has also initiated updating of topographical maps with the help of satellite images.
4.2 Hazard Mapping
Hazard map and disaster data play an important role to predict and foresee the possible trends of likely disasters. So, hazard map and reliable data is the need of the day. The lack of meteorological and hydrological records in the country makes accurate projection of possible flood damage beyond our target.
However, recognition of the past damages and potential hazards are one of the key elements to be studied. The primary stage is to plot out the exact location and degrees of damages in the previous major disasters are to be recorded through interviews and field surveys. This information will enable us to suggest particular locations, and human activities of significant vulnerableness, which are to be mapped and shared by the residents and researchers as a basis of discussion and learning toward strengthened protection of life and assets.
4.3 Nodal Point for Disaster Management
Survey Department is a member of Asia Pacific Regional Space Agency Forum (APRSAF). In 1995, APRSAF appointed the Survey Department as a nodal point for disaster management for Nepal. In this connection, Geoinformatics Center of Asian Institute of Technology (AIT), Thailand provided trainings to Staffs of Survey Department with the sponsor from Japanese Aerospace Exploration Agency (JAXA). The trainings so far provided are on study of Change in Urban Land use, Flood Disaster Mitigation and Earthquake Disaster Mitigation.
5.0 Concluding Remarks
Persistent occurrences of earthquakes, floods, landslides and forest fires need to be studied using today’s advanced technology to find effective preventive measures. Being a resource-poor country, Nepal faces a gigantic managerial task to provide adequate support to the natural disaster victims.
Nepal lacks organized data collection network, even though several governmental as well as non-governmental International agencies have been providing support for disaster victims from time to time. Despite all these provisions and assistance, there are many challenges for an effective disaster management system - such as system of hazard mapping, vulnerability assessment, risks analysis, low-level of public awareness, lack of cooperation and coordination, poor system of data collection and dissemination, remote and inaccessible topography.
There are no institutions that deal with hazard mapping for serious natural disaster threats in Nepal. Survey Department of Nepal, being a national mapping agency, should kick-off a disaster mapping unit to optimal utilization of its resources for the sake of enhancing country’s disaster mitigation efforts. It could work as a coordinating agency for various other institutions dealing with various types of disasters in the country so as to produce disaster hazard maps. Investment towards making use of the space technology is worth because improvement in instrumentation and time prediction will bring about reduction in disaster damages; and improved decision making in planning stages.
REFERENCES:
ADPC, 1991, Disaster Mitigation in Asia and the Pacific, Manila: Asian Disaster Prevention Center.
Lanza, L. and Conti, M. (1994) Remote Sensing and GIS: Potential Application for
Flood Hazard Forecasting. http://www.odyssey.maine.edu/gisweb/spatdb/egis/eg94208.html
OAS (1990).Disaster, Planning and Development: Managing Natural Hazards to Reduce Loss. Dept. Regional Development and Environment. Organizaion of American States. Washington, USA.
UNDRO (1991). Mitigating Natural Disasters. Phenomena, Effects and Options. United Nations Disaster Relief Co-ordinator, United Nations, New York, USA
Pokharel, Lekh Nath. Disaster Management System in Nepal, the Spotlight magazine, Vol. 23, No. 44, May 21 - 27 2004, Kathmandu, Nepal, http://www.nepalnews.com/
Chheetri and Bhattarai D., (2001), Mitigation and Management of Floods in Nepal, Kathmandu, HMG, Ministry of Home Affairs
Mool, P.K., Bajracharya, S.R., and Joshi, S. P.(2001). Inventory of glaciers, glacial lakes, and glacial lake outburst flood monitoring and early warning system in the Hindu Kush-Himalayan Region, Nepal. International Centre for Integrated Mountain Development (ICIMOD) Kathmandu, Nepal.
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