Document Details
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Document Type |
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Thesis |
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Document Title |
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EVALUATING THE STABILITY OF QAA HADODA DAM (AL-MADINAH, SAUDI ARABIA) تقيم ثباتيه سد قاع حظوظا المدينة المنورة، المملكة العربية السعودية |
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Subject |
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Faculty of Earth Sciences |
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Document Language |
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Arabic |
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Abstract |
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Floods are the most frequent natural hazard in Saudi Arabia especially when there is a potential to affect cities. The local authorities are more concerned if the flood is flowing toward the holy city of al Madinah. Qaa Hadoda dam was built more than 40 years ago to protect the northern part of al Madinah. Unfortunately, there is no known published report about the detailed design or historical performance of this important dam.
Based on this study, the dam is an earthfill type of low height (7 m) and made up of compacted sand. The flood water in this area is collected and drained from five large-scale sub-basin, a total area of 35,652 km2 with a maximum flood peak flow for 100 years is 13,818 million m3/s. In addition, the surrounding rock slopes are sharp enough for the flood to flow at high speed toward its natural reservoir (Qaa Hadoda). The dam is composed of three adjacent parts including a large spillway. The water reservoir is huge (107 million cubic meters) making it capable to accommodate the tremendous water flood volume. It was found that the dam was designed with an efficient hydrologic system to regulate the water flood toward al Madinah with a safe flow.
The essence of this investigation is to compare the dam dimensions and estimate the related soil and rock properties to evaluate the dam's stability. The flood volume is significant, the lateral water pressure on the dam's upstream face is 240 kN/m2, and the calculated maximum pore water pressure is about 53 kN/m2. The soil unit weight of the dam body is measured to be 21.6 kN/m3. The dam weight per one-meter length created a stress of 3,855 kN/m2, and this vertical stress is high on the foundation soil (γ = 18 kN/m3).
When taking the moment of those forces around the dam toe, the dam is found to be adequate to resist the water effect. The flood peak discharge is 13,083 m3/s, which can be easily handled by the spillway capacity which is 19,465 m3/s (1,681 x 106 m3/day), greater than the estimated maximum flood peak flow by 48%. While the dam is resisting, so the spillway can drain flood water fast enough to avoid the dam overtopping. The water seepage (q) through foundation soil is q ≈ 6 m3/day/m (which is low), and the critical hydraulic gradient (icr) is under control (icr = 0.2, less than 1).
Keywords: Dam, Flood, Runoff, Spillway, Watershed |
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Supervisor |
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Prof. Abdullah A. Sabtan |
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Thesis Type |
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Master Thesis |
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Publishing Year |
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1444 AH
2023 AD |
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Added Date |
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Friday, May 5, 2023 |
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Researchers
| أنس مجدي المدني | Almadani, Anas Majdi | Researcher | Master | |
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