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Statistical analysis of flash flood events for designing water harvesting systems in an extremely arid environment
  • Koichi Unami,
  • Osama Mohawesh,
  • Rasha Fadhil
Koichi Unami
Kyoto University
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Osama Mohawesh
Mutah University
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Rasha Fadhil
University of Mosul
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Abstract

A water harvesting system for research purposes has been established in the Lisan Peninsula of the Dead Sea in the middle of the Jordan Rift Valley, where no authorized guideline is available for designing water harvesting systems. Rainfall and runoff, which occurs as flash floods, are being observed at the downstream end of a gorge having a 1.12 km2 barren catchment area since September 30, 2014. Due to the extremely arid environment, water current as the runoff from the catchment is ephemeral, and the flash flood events can be clearly distinguishable from each other. Thirteen flash flood events with total runoff volume more than 100 m3 have been successfully recorded during five rainy seasons. The duration, the total rainfall depths at two points, the total runoff volume, the maximum runoff discharge, and the bulk runoff coefficient of each flash flood event are considered as the random variables to be analyzed. Correlation analysis among the variables is conducted in terms of the classical methods of Pearson’s correlation and Spearman’s rank correlation, revealing that there is no straightforward relationship between rainfall and runoff. The performance of the conventional SCS runoff curve number method is also deficient in reproducing any rainfall-runoff relationship. Therefore, probability distributions are fitted to the empirical distribution of each variable. The lognormal distribution with three parameters and the generalized extreme value distribution serve well. The results support the design of the water harvesting system and provide quantitative information for designing similar systems in the future.

Peer review status:UNDER REVIEW

08 Sep 2020Submitted to Hydrological Processes
09 Sep 2020Assigned to Editor
09 Sep 2020Submission Checks Completed
09 Sep 2020Reviewer(s) Assigned