1.1 Background to the study
Floods are major disasters affecting many countries of the world
annually especially in most flood plain areas. Floods do not only damage
properties and endanger the lives of human and animals but also produce
other secondary effects like outbreak of diseases such as cholera and
malaria as well. Flooding is commonly caused by heavy downpours of rains
on flat ground, reservoir failure, volcano, melting of snow and or
glaciers e.t.c. Flood risk is not just based on history, but on a number
of factors: rainfall, riverflow and tidal-surge data, topography, flood
control measures, and changes due to construction of building and
development on flood plain areas.
Flooding is caused by several factors and is invariably preceded by
heavy rainfall. The other causes of flooding are moderate to severe
winds over water, unusual hightides, tsunamis due to undersea
earthquakes, breaks or failures of dams, levees, retention ponds or
lakes, and other infrastructure that retains water. Flooding can be
aggravated by impervious surfaces or by other natural and man-made
hazards which destroy soil, vegetation that can absorb rainfall.
Although flooding is a natural occurrence, man-made changes to the land
can also be a factor. Development does not cause flooding but can make
it worse. In cities and suburbs, pavement and rooftops prevent some
rainfall from being absorbed by the soil. Thus can increase the amount
of runoff flowing into low lying areas or storm drain system.
The significance of the year 2012 flood disaster in Nigeria lies in
the fact that they were unprecedented in the past forty years. Most
parts of the central states of Nigeria and other adjoining states along
the river Niger and Benue are devastated by these floods causing huge
destruction to the rural and urban infrastructures (farmlands/crops,
roads, buildings, damages, bridges, power lines e.t.c ) and
socioeconomic lives of the areas. Floods occur when the soil, stream
channels and man-made reservoirs cannot absorb or contain all the water.
A flood that occurs suddenly with little or no prior signs, is called a
flash flood and is due to intense rainfall over a relatively small
area, it us inevitable resulting from the natural rainfall runoff
process. It is a natural phenomenon and its magnitude is periodic. The
periodicity of flood implies that every year some area surrounding the
river (on both sides) is flooded.
Flood disaster management like other disasters management can be
grouped into phases; the preparedness phase where activities such as
prediction and rusk zone identification or vulnerable mapping are taken
up long before the event occurs, the prevention phase where activities
such as forecasting early warning, monitoring and preparation of
contingency plan are made before or during the event, and the response
and mitigation phase where activities are undertaken after the disaster
and these includes damage assessment and relief management (Van Western
et al., 1993).
1.2 Problem Statement
Mitigation of flood disaster can be successful only when derailed
knowledge is obtained on the expected frequency, character and magnitude
of events in an area as well as the vulnerability of the people,
buildings, I frastructures and economic activities in a potential
dangerous area (Van Western and Hosftee, 1993). However, Ifatimehin er
al., (2009); Ifatimwhin and Ufuah (2006) reported that this detailed
knowledge is always lacking in most urban centers of the developing
world especially Nigeria.
1.3 Objectives of the study
The major objective of the study is the application of geoinformatics
techniques in controlling flooding in Vulnerable Roads, Buildings and
Farmlands in Jos East LGA of Plateau State.
1.4 Research questions
(1) what is flood?
(2) what are the effects of flood ?
(3) How can flooding be mitigated?
1.5 Significance of the study
This study gives a clear insight into the application of
geoinformatics techniques in controlling flooding. It will also show how
effective geoinformatics techniques application is in controlling
flooding in vulnerable roads, buildi GS and Farmlands.
1.6 Scope
The research focus on the applications of geoinformatics techniques
in controlling flooding in vulnerable roads, buildings and farmlands in
His East LGA of plateau state.
References
Ifatimehim and Ufuah, M.E (2006). Analysis of Urban Expansion and
Loss of Vegetation in Lokoja using GIS Techniques. Zaria Geographers,
17(1): 28-36.
Ifatimehin, O.O., Musa, S.D. and Adeyemi, J.O. (2009). An analysis of
the changing land use and Its impact on the Environment, Anyingba Town,
Nigeria. Journal of Sustainable Development in Africa 10(4): 357-364.
Van Western, C.J.I., Van Duren, H.M.G. Kruse and M.T.J. Terlien
(1993). GIZZI: Training package for Geographic Information Systems in
Slope Instability Zonation. International Institute for Aerospace Survey
and Earth Science (ITC), 15(1): 245 pp. Enschede, The Netherlands