Developing Rainfall Intensity Duration Curve for Selected Towns in Western Part of Ethiopia
Jemal Ibrahim Mohammed,
Getachew Rabo Kumsa
Issue:
Volume 9, Issue 3, September 2021
Pages:
56-65
Received:
3 May 2021
Accepted:
24 June 2021
Published:
2 August 2021
Abstract: Rainfall and Its Intensity is needed for planning and designing of various water resource projects including infrastructure such as the design of urban drainage works, Storm Sewers, Culverts and etc. The main aim of this research was to develop Rainfall intensity duration curve for the selected towns in western part of Ethiopia. Gumbel and the Log Pearson Type III Probability distribution (LPT III) were used to develop rainfall intensity duration curves for the selected towns in western part of Ethiopia. The IDF curves developed by Gumbel’s Extreme value distribution shows, the pattern similarity for all return period, duration and all considered stations but the rainfall intensity shows an increasing with increase in the return period and decrease with rainfall duration increase in all return periods and also show high Rainfall intensity (mm/hr.) so that it was used to derive Empirical equation using Logarithmic transformation method to determine the constants (C, m, a) considered to derive the equation. Then the comparison was made between rainfall developed by using Gamble’s Probability distribution and computed by Empirical equation. In all return period and duration of time it shows good relation which approximately equal to unity (R2) but for 1000 return period differs which is still acceptable without any uncertainty for further application. So, the developed Rainfall intensity duration curves and derived empirical equations can be used for the planning and design of any Water Resources projects and infrastructure in the towns related to water resources.
Abstract: Rainfall and Its Intensity is needed for planning and designing of various water resource projects including infrastructure such as the design of urban drainage works, Storm Sewers, Culverts and etc. The main aim of this research was to develop Rainfall intensity duration curve for the selected towns in western part of Ethiopia. Gumbel and the Log ...
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Flash Flood Risk Assessment of Wadi Degla Basin Protected Area, East of Maadi, Cairo, Egypt Based on Morphometric Analysis Using GIS Techniques
Abdel Galil Abdel Hamid Hewaidy,
Mohamed Abu El Hassan,
Ahmed Salama,
Ragab Ahmed
Issue:
Volume 9, Issue 3, September 2021
Pages:
66-73
Received:
15 July 2021
Accepted:
5 August 2021
Published:
13 August 2021
Abstract: The Wadi Degla basin is amongst the most important basins in the north-eastern part of the Eastern Desert, east of Maadi, Cairo, which drains into River Nile. It covers an area of about 177.6 km2. Although it located in an arid region, the basin could receive a huge amount of rainwater during heavy rainstorms which in turn lead to initiate flash flood hazard and causing catastrophic effects on existing infrastructure of main gate and tracks of protected area, also threatened visitor's life and surrounding environments. The present study aims to evaluate of flash flood risk in Wadi Degla and possible mitigation. The morphometric parameters investigation were carried out using ASTER Digital Elevation Model (DEM), GIS, and geomorphic field observations. Using a technique given by El-Shamy, the risk degree for the Wadi Degla basin's vulnerability to flash flooding risk was calculated. The first technique focuses on the relationship between drainage density and bifurcation ratio, whereas the second relies on the relationship between drainage frequency and bifurcation ratio. For the examined basin of the watershed, the third morphometric parameter (the bifurcation ratio, drainage density, and stream frequency) were obtained and calculated. The bifurcation ratio, stream frequency, and drainage density all have values of 1.7, 6.05, and 2 according to morphometric study. The bifurcation ratio, stream frequency, and drainage density have morphometric values of 1.7, 6.05, and 2 respectively, as per morphometric analysis. The Wadi Degla has elongated shape. According to the computed metrics (e.g., stream frequency, bifurcation ratio and drainage density), the Wadi Degla basin catchment area falls into category (A). This means that there is expected high susceptibility of flash flooding possibility in the area under consideration. This expected risk leads the Ministry of Water Resources and Irrigation to establish three dams on the pass of Wadi Degla to work as an obstacle for decrease the flash flood velocity flow. Consequently, from an environmental hazards point of view, the Wadi Degla Protected Area should be closed during heavy rainfall for visitor safety and also avoid the establishment of any basic infrastructure in the vicinity of the Wadi pass.
Abstract: The Wadi Degla basin is amongst the most important basins in the north-eastern part of the Eastern Desert, east of Maadi, Cairo, which drains into River Nile. It covers an area of about 177.6 km2. Although it located in an arid region, the basin could receive a huge amount of rainwater during heavy rainstorms which in turn lead to initiate flash fl...
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