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العنوان
HYDROLOGICAL PARAMETERS AFFECTING FLASH FLOODS: CASE STUDY WADI AL-BAROUD EL-ABIAD, SAFAGA CITY, RED SEA GOVERNORATE
المؤلف
Esraa Mohamed Abdel Goad؛ Taha
هيئة الاعداد
باحث / اسراء محمد عبدالجواد طه
مشرف / جمال ابوزيد عبدالرحيم
مناقش / محمد فكري
مناقش / نشأت عبداللاه على
الموضوع
al baroud.
تاريخ النشر
2020.
عدد الصفحات
103 p.
اللغة
الإنجليزية
الدرجة
ماجستير
التخصص
الهندسة المدنية والإنشائية
الناشر
تاريخ الإجازة
1/11/2020
مكان الإجازة
جامعة أسيوط - كلية الهندسة - Department of Civil Engineering
الفهرس
Only 14 pages are availabe for public view

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from 129

Abstract

Flash flood is one of the most important natural hazards all over the world. It is very dangerous due to its effect on the life of people and may lead to death. So, hydrologists are aware of flash flood by predicting and studying the factors affecting its occurrence. In this Thesis, hydrological parameters affecting flash floods in arid or semi-arid areas are studied.
The study area is Wadi Al-baroud El-abiad which is located to the north west of Safaga city on the red sea coast that is frequently subjected to severe flash flood. Wadi Al-baroud El-abiad dam (1) was constructed at the outlet of the basin to protect Safaga city from flash flood disasters. Three types of parameters affecting floods are considered i.e. meteorological (climatic), morphological, and geological factors. Rainfall data from rain gauge station near the area are used. Climatic data are analyzed by using Hyfran-plus program to reach the design storm values for different return periods for 5, 10, 25, 50, 100 and 200 years. The mean monthly rainfall values of Safaga meteorological station from 1994 to 2018 is used and the annual maximum values of rainfall rates are extracted from it.
Digital elevation model (DEM) and digital terrain data of the catchment are obtained from the USGS EathExplorer website and inserted into WMS and AcrGIS software. Morphological characteristics of the basin could be calculated as area of the basin (A), its length (L), and circumference (C) by addition to other morphologicalbasin characteristics as Circularity ratio (Rc),Elongated Ratio (Re), Form Factor (R.f), Compaction coefficient (Cc) andLemniscate Factor (K).El-Shamy’s approach is used to evaluate the hazard degree for Wadi Al-baroud El-abiad basin using three morphometric parameters (drainage frequency, drainage density and bifurcation ratio).
Hydrological characteristics such as unit hydrograph, concentration time, storage coefficient, and delay time are estimated using soil type and land use in the study area. SCS and Curve Number methods are used for estimating soil type and land use of thebasin.
Many software and tools are used in data analysis and watershed delineation among of them, GIS, WMS, SURFER, HYFRAN andGoogle Earth. As a result, flood hydrograph curves are estimated.
ArcGIS software (Arc Map+ Arc Scene) is used for the three-dimensional simulation of Wadi Al-Baroud El-Abiad watershed by adding a virtual layer of water as a raster. Animation tool for tracing the flood and how the lake storage of the dam is filled with water is used.
Water budget method is applied to estimate the time required for storage water in the lake to evaporate and infiltrate into the subsurface soil based on storage area elevation curve of Wadi Al-baroud El-abiad dam (1).
The finding may have practical applications and may be useful for the developer, planners and decision makers for flood management in arid areas, especially when it is required to deal with Wadi El Baroud El Abiad watershed. The main conclusions may be drawn as:
1) Maximum daily rainfall at different return periods of 5, 10, 25, 50, 100 and 200 years is estimated with a range from 6.3 to 26.9 mm/day by using Gamma type which is considered the most appropriate graph of statistical probability distributions for HYFRAN-PLUS program.
2) For return period equals to five years, the rainfall intensity is less than the infiltration capacity which resulted in no runoff.
3) The analysis of morphological characteristics of Wadi El Baroud El Abiad watershed such as (Rc, Re, Rf, Cc, and K) revealed that the studied basin deviates from the circular nature to elongation with lower peak flow of longer duration of time.
4) from Stream system analysis with Strahler’s method, the estimated values of Rb, ,Dd, Fs, and Rh indicated weak structural disturbance and high permeability with mild general slope of studied basin.
5) Evaluation of hazard degree probability for the basin using El-Shamy’s approach, clarifies that the final hazard degree of Wadi El Baroud El Abiad basin is moderate hazard degree as the basin is located in zone B of El-Shamy diagrams No. (1&2).
6) According to Soil Conservation Service’s Curve Number and hydrological group of curve number 85, the studied basin falls into the type of soil C.
7) from the calibration curve for Wadi Al-Baroud El-Abiad dam (1) and flood hydrograph curves for different return periods 10, 25, 50, 100 and 200 years, it is found that the dam is safe up to 100 years, while for time period of 200 years precautions should be taken to increase the storage capacity of the dam.
8) As SURFER program results,the volume of water collected in storage lake of the contour line 200 (top of the dam) is approximately 10 Mm³,while the design capacity of Wadi Al-Baroud El-Abiad Dam (1) is 1.8 Mm³ at same level as the top of the dam.
9) Using water budget method, the maximum period of time required for stored water to evaporate and to infiltrate into the subsurface soil and for the survival of water in the dam storage lake is 28 days.