The incessant occurrences of natural and human induced disasters have become a serious menace to the Nigerian society. The low level of technological know-how employed to combat disasters adds to the problem. The article looks at the implication of using crude and remote methods of managing risks and disasters in both rural and urban areas of Nigeria at the expense of cheap, reliable, precise method of GIS and remote sensing technologies
Year after year, the Nigerian landscape has been impacted by varying degrees of either man-made or natural disasters. According to a 2012 report by the United Nations relief agency, Nigeria has one of the worst records of disaster management in sub-Saharan Africa. There is a huge risk associated with the inability of people to manage hazards and disasters that may eventually lead to negative consequences like destruction of the environment, socio-economic activities, loss of property and lives.
Major causes of disasters in Nigeria
Poverty: Poverty is one of the oldest challenges for Nigerian people. On 18 October 1998, fire engulfed more than 2000 villagers who were scrambling for petrol near a ruptured vandalised pipeline in Jesse outside of Warri. It is estimated that nearly 1000 people were killed in the inferno.
Lack of political will: The fact that Nigeria as a sovereign entity never established a federal emergency body until 1990 shows how unserious successive governments view the critical issue of disaster management.
Resistance to change: In August 2011, the city of Ibadan in Oyo state witnessed one of the worst floods in Nigeria's history, which resulted in the death of scores of persons and destruction of property worth more than NGN 20 billion. It has been established that most of the country’s natural disasters were made worse by non-adherence to early repeated warnings from NEMA. Similarly, due to some cultural or socio-economic reasons, the people find it difficult to move or be evacuated to safer areas because they practically resisted movement.
Lack of proper education and enlightenment: The total absence of disaster management and response initiative in the county is worst at the level of the local council as most of the 774 local government area councils have become dysfunctional because of the undemocratic tendencies of state governors that have largely failed to respect section 7 of the constitution by ensuring that democratic structures are institutionalised at the grass root level. It is only when the local councils are democratically administered that the council officials with the mandate of the electorate can put workable disaster management infrastructure into proper use for the benefit of the people.
Inappropriate response to disaster by agencies/authorities: Eyewitness accounts stated that the Dana plane which crashed into residential buildings in Lagos in 2013 did not catch fire for over twenty minutes and that rescue operations came nearly one hour after the incident. This proves that timely rescue intervention could have saved a lot of precious lives.
Methods and techniques of combating disaster using GIS and remote sensing
Mission Control Center (MCC): The Mission Control Centre located at NEMA headquarters in Abuja is a computer based satellite facility that uses the COSPAS-SARSAT hi-tech system. The system is designed to pick distress alerts and location data to assist in search and rescue operation, using spacecraft and ground facilities to detect and locate the signals of distress beacons. When there is a distress alert from the beacon located on a ship or aircraft, the satellite system transmits the signal to the ground segment facilities from where the data is processed and transmitted to the appropriate MCC. The MCC then alerts the nearest Rescue Coordinating Centres (RCC) or Disaster Reaction Units (DRU) of the Army, Air Force, and the Navy for appropriate and immediate action.
During the disaster prevention stage, GIS is used in managing the huge levels of data required for vulnerability and hazard assessment. In the disaster preparedness stage, it is a tool for planning evacuation routes, designing centers for emergency operations, and for the integration of satellite data with other relevant data in the design of disaster warning systems.
In the disaster relief phase, GIS, in combination with GPS, is extremely useful in search and rescue operations in areas that have been devastated and where it becomes difficult to find one’s bearings. In the disaster rehabilitation stage, GIS is used to organise the damage information and post-disaster census information and in the evaluation of sites for reconstruction. Natural hazard information should be included routinely in developmental planning and investment projects preparation. They should include cost/benefit analysis of investing in hazard mitigation measures and weigh them against the losses that are likely to occur if these measures are not taken.
Disaster mapping: Disaster mapping can be done through the use of ground-based observations or through the use of remote sensing devices such as aerial photographs or satellite images. From the information gathered, it is possible to map the affected areas and provide information to the relief supplying groups.
Introduction of hi-tech search and rescue operation: Search and rescue, commonly known as SAR, is the process of identifying the location of disaster victims who may be trapped or isolated and bringing them to safety and providing them with medical attention. Due to scientific advances, it has become easier to carry out SAR operations efficiently. Techniques like acquiring high resolution satellite imageries and swift GIS manipulation and analysis help to identify areas that are disaster prone, zoning them according to risk magnitudes, severity and intensity. Modern communication systems have also proved very useful in SAR operations, which include the use of high precision geo-tag cameras, accurate GPS devices, sophisticated compasses, high sensitive walkie-talkie gadgets and thematic maps of the affected areas.
Floods: It is impossible to define the entire flood potential in a given area. However, given the best remote sensing data for the situation and a competent interpreter, the evidence for potential flood situations can be found or inferred. The most obvious evidence of a major flood potential, outside of historical evidence, is identification of floodplain or flood-prone areas which are generally recognisable on remote sensing imagery. The most valuable application of remote sensing to flood hazard assessments is in the mapping of areas susceptible to flooding.
Synoptic satellite sensor coverage of a planning study area is the practical alternative to aerial photography because of cost and time factors. The application of Landsat MSS imagery to floodplain or flood-prone area delineation has been demonstrated by comparing pre-flood scenes with scenes obtained at the height of the flood, using Landsat MSS band 7 (near IR) images in a color additive viewer. This temporal comparison can now be done with pixel with the aid of a computer. Landsat TM, with its greater spatial resolution than MSS data (30m versus 80m) and its additional spectral coverage (7 bands versus 4 bands), can be used for more detailed mapping of floodplains and flood-prone areas on larger scale maps of 1:50,000 or greater. TM data have been used for discriminating land cover classification and to provide useful input to flood forecasting and flood damage models for urban and agricultural areas.
This approach to floodplain delineation has its limitations. The area of potential flooding delineated in this manner may represent a flood level that exceeds an acceptable degree of loss. Also, no floods may have occurred during the period of the sensor operation. In this case, indirect indicators of flood susceptibility are used. There are large parts of tropical humid ecosystems where adequate Landsat or other similar imagery is not available due to cloud coverage or heavy haze. In some instances the heavy tropical vegetation masks many geomorphic features so obvious in drier climates. In this case the use of available radar imagery from space or previously acquired from an aircraft survey is desirable. The radar imagery, which has a resolution comparable to Landsat TM and SPOT from both space and sub-orbital altitudes, can satisfactorily penetrate the clouded sky and define many floodplain features.
Fire: Nearly all countries operate a reactive approach to fire, which a major concern is given the limited resources usually deployed to put out a fire. About 7% of Nigeria burns annually mostly caused by human actions. However, there is very little capacity for fire monitoring and management in the country. Existing fire management approaches are ineffective and spatially limited. Trends in fire occurrence are poorly documented and this makes it difficult to assess changes in fire regimes and relate this to natural resource productivity in the region.
SAFNet is exploring possibilities for establishing satellite based active fire monitoring system in Southern Africa. One such system is the MODIS Rapid Response Fire Monitoring System that is being developed by NASA and the University of Maryland. The NASA MODIS R ordinates of burning fires and the date and time when the fire was captured. The latitudes and longitudes can be plotted on a map to determine the actual location of the fire on the ground. One of SAFNet's role is to make such near real time information on fire known to policy makers and fire managers for use in preparation for putting out a burning fire. The near real time system also provides information that is useful for locating fire scars.
Disaster management in Nigeria: Challenges ahead
There is need to create a Disaster Management Information System Bureau (DMISB) to effectively manage occurrences in terms of emergency.
Contingency stockpiling: To ensure prompt and efficient response to disasters, the agencies should establish warehouse in every local government headquarters (774) and the Federal Capital Territory, Abuja and stock them with relieve and rehabilitation items. This is to ensure timely intervention in response.
Search and Rescue (SAR) / Epidemic Evacuation Plan: An active plan should be prepared to allow for a system where all stakeholders can draw on collective strength of one another and build a formidable group of highly mobile, motivated, dedicated and trained workforce of disaster managers.
Collaboration with security agencies: Security agencies constitute the major stakeholders of the emergency agencies. Successful collaboration should be ensured with security agencies through regular meetings, workshops, simulation exercises and training utilising every opportunity to advance the cause of disaster management in the country.
National Disaster Response Plan: There should be a workable plan document approved by the Federal Executive Council, which should be emphasise the roles of stakeholders and the call out plan in response to disasters.
Training and capacity Building: NEMA should be responsible for preparation of human resources. Therefore, with the appropriate approval, the department of training should be established in the six geo-political zones which will develop the curriculum and coordinate the human resources development of the agency in addition to catering for the training needs of the stakeholders.
Summary and Conclusion
Mitigation of natural disasters can be successful only when detailed knowledge is obtained about the expected frequency, character, and magnitude of hazardous events in an area. Many types of information that are needed in natural disaster management have an important spatial component. We now have access to information gathering and organising technologies like remote sensing and geographic information systems (GIS), which have proven their usefulness in disaster management. Remote sensing and GIS provide a data base from which the evidence left behind by previous disasters can be interpreted, and combined with other information to arrive at hazard maps, indicating the potentially dangerous areas. The zonation of hazards must be the basis for any disaster management project and should supply planners and decision-makers with adequate and understandable information. Remote sensing data, such as satellite images and aerial photos allow us to map the vulnerability of terrain properties, such as vegetation, water, and geology, both in space and time. Satellite images give a synoptic overview and provide very useful environmental information, for a wide range of scales, from entire continents to details of a few meters.
Apart from that, many types of disasters, such as floods, fire, drought, cyclones, volcanic eruptions, etc. will have certain precursors. The satellites can detect the early stages of these events as anomalies in a time series. Imagery is available at regular intervals, and can be used for the prediction of both rapid and slow disasters. Many disasters may affect large areas and no other tool than remote sensing would provide a matching spatial coverage. Remote sensing also allows monitoring the event during the time of occurrence while the forces are in full swing. The vantage position of satellites makes it ideal for us to think of, plan for and operationally monitor the event. GIS is used as a tool for the planning of evacuation routes, for the design of centers for emergency operations, and for integration of satellite data with other relevant data in the design of disaster warning.
When used in combination with GPS, GIS is extremely useful in search and rescue operations in disaster affected areas. Remote sensing can assist in damage assessment and aftermath monitoring, providing a quantitative base for relief operations. In the disaster rehabilitation phase, GIS is used to organise the damage information and the post -disaster census information, and in the evaluation of sites for reconstruction. Remote sensing is used to map the new situation and update the databases used for the reconstruction of an area.