G.O. Enaruvbe & G.U. Yesuf

Regional Centre for Training in Aerospace Surveys (RECTAS) Obafemi Awolowo University, Ile-Ife,

Nigeria

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Introduction� Flood disasters are among the most destructive natural

disaster in history.

� Flooding has become more prevalent over the past decades in Nigeria.

� The recent incidence of flood disaster in the country has been attributed to increased rainfall and infrastructure failure.

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Introduction Contd� Coastal farming communities are the most adversely

affected as their farms and fishing implements are inundated or washed away by the floodwater

� An important aspect of flood disaster management is the provision of timely information, necessary for mitigation of the impact of the disaster.

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Introduction Contd� Maps play a vital role in the presentation and

assessment of the local flood situation. They provide information for flood management strategies

� Research indicates that the integration of Remote Sensing and Geographic Information Systems (GIS) provide valuable spatial information in the event of a natural disaster

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The Study Area� Delta State lies approximately between longitudes

5°00 and 6°45'E and latitudes 5°00 and 6°30'N

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Figure 1: Study Area

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MATERIALS AND METHODS

� To determine the vulnerability of the entire state to flooding, Digital Elevation Model (DEM) covering the entire state generated from ASTER image.

� The scenes covering Delta State were mosaickedwithin ArcGIs software environment, and transformed to the projected coordinate system -WGS 1984 UTM Zone 32N

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MATERIALS AND METHODS

� The DEM was classified into three vulnerability classes, using the variation in elevation values

� Visual image interpretation and on-screen digitisingwas used in extracting the land use land cover of the state from medium resolution images derived from Google Earth

� Their non-spatial characteristics and spatial extent were also determined

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MATERIALS AND METHODS

� The Multi-Resolution Land Characterization regional and land cover classification (MRLC) system (Vogelmann et al. 1998) is adopted in categorizing the land use types in the entire state

� On the basis of the MRLC classification systems, the state is classified into four major land use classes (Waterbody, Settlement, Bare surface and Vegetated surface).

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MATERIALS AND METHODS

� The risk map of the study area was generated from the ASTER image

� The categories are highly vulnerable, vulnerable and non-vulnerable areas. A field survey of areas affected by the flood was conducted in order to assess the extend of the flood

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MATERIALS AND METHODS

� It was observed that the flooding of the River Niger affected communities as far as 5 kilometer from the River banks

� A buffer of 5km was therefore created for River Niger and its major tributaries and 2km for minor distributaries

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Figure 2: Digital Elevation Model of Delta State 12

Figure 3: Flood Map of Delta State

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Figure 4: Flooded Farmland14

Figure 5: Flooded Settlements15

� An area of over 7,950km2 or over 49% of the coastal and riverine communities of the State was inundated.

� This affected about 39 communities and over 137.1 hectares of farmland across the State

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Conclusion and Recommendation

� Remote Sensing and Geographic Information Systems techniques were adopted in examining the extent and impact of the recent flood disaster on agriculture and human settlement in the study area

� The use of ASTER images for the generation of DEM seems effective in mapping flood prone areas in the State

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Conclusion and Recommendation

� The results of the study indicate that a large part of coastal and riverine communities in the State are affected by the flood, inundating many farmlands and washing away fishing equipment

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Conclusion and Recommendation

� This implies that climate change has far-reaching implications on agriculture, food security and social stability in the Niger Delta as food prices are likely to skyrocket as a result of low agricultural productivity and food scarcity

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Conclusion and Recommendation

� This situation is likely to result in increased threat of hunger and malnutrition in the area

� Since flooding is aggravated by obstruction to natural water channels

� it is important that urban and regional development plans be rigorously pursued and implemented to avoid a situation where buildings and other structures are constructed on natural drainages

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Thank You!!

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