Application of Remote Sensing and Gis In Flood Hazard Assessement and Mapping in Itang Woreda of Gambella Region, Ethiopia
No Thumbnail Available
Date
2017-05-30
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
In the past decades, a large number of human life and enormous properties have been lost in
different parts of the world due to flood hazard. Flooding is a common problem in different
parts of the world including Ethiopia. Itang Woreda, which is located in Gambella Region of
Ethiopia is one of the areas affected by flood of different frequency and magnitudes. This thesis
is proposed with the aim of assessing and mapping flood hazard of Itang Woreda. Heavy
rainfall from the region and surrounding highland areas is the major cause of flooding in Itang,
by increasing the discharge level of streams and big rivers and making them overflow into
adjacent flood pains. Baro River, which cross the study area from east to west and flow down
to South Sudan is the major cause of flooding in this Woreda. Flood frequency of different
recurrence intervals was calculated through the use of the most commonly used flood frequency
analysis, i.e. Gumbel and Log-Pears type III. After obtaining the discharge level from the
method with Chi Square test, flood inundation area of the 5, 10, 25, 50 and 100 year recurrence
intervals were mapped. By using of remote sensing and GIS as a tool and slope and elevation,
land-use/land-cover, rainfall data, discharge data and the soil type as input, the nature and
characteristics of the flooding in Itang was analyzed. Finally, after evaluating and giving weight
for the above mentioned criteria based on Analytic hierarchy process, flood hazard zones were
mapped. Based on the results, the study area was classified into zones such as very high, high,
medium, low and very low flooding and these zones were mapped. Majority of the land surface
of the study area fall in the medium hazard zone (29.7%), followed by high flood hazard zone
(27.8%), very high (12.7%), low (18.5%) and very low (11.4%), respectively. These maps are
very useful to reduce the damages and losses that might arise from flooding. It is also
inhabitants, and floodplain management authorities to minimize flood damage and loss of
human lives in the study area.
Description
Keywords
Analytic Hierarchy Process, Flood Frequency, Flood Hazard Zone, Remote Sensing, GIS