Regional flood frequency analysis in the High Atlas mountainous catchments of Morocco

详细信息    查看全文

• 作者：Wiam Zkhiri ; Yves Tramblay ; Lahoucine Hanich ; Brahim Berjamy
• 关键词：Floods ; Regional frequency analysis ; GEV ; Tensift ; Morocco ; Mountains
• 刊名：Natural Hazards
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：86
• 期：2
• 页码：953-967
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Natural Hazards; Hydrogeology; Geophysics/Geodesy; Geotechnical Engineering & Applied Earth Sciences; Civil Engineering; Environmental Management;
• 出版者：Springer Netherlands
• ISSN：1573-0840
• 卷排序：86

文摘

In semi-arid catchments, the contribution of floods to annual runoff is important. The High Atlas Mountain catchments (N’Fis, Rheraya, Ourika, Zat and R’dat) located in the south of Morocco, upstream of the city of Marrakech, are an example of those basins where floods provide the main contribution to surface water resources. The goal of this study is to evaluate whether a regional flood frequency analysis could improve the estimation of the magnitude and the occurrence of floods in these mountainous catchments. The database considered is long-term measurement of daily discharge at the outlets with record length varying from 35 to 45 years. The index flood method is considered to build a regional model based on the generalized extreme values distribution. The results showed a contrasted seasonal behavior, with floods caused by either rainfall during the autumn season or a mix of rainfall and snowmelt for spring events. As a consequence, two distinct regional models have been computed, one for autumn and one for spring events. No significant trends have been found for seasonal maximum discharge in all the catchments. The results of the regional frequency analysis show that the regional model provides better flood quantiles estimates than a standard at-site model. However, there is a much greater uncertainty for both local and regional estimates of floods occurring during the autumn than during spring events, which are estimated with a good level of accuracy. This research provides insights into how to improve the estimation of flood return levels useful for water resources management in these semi-arid mountainous catchments.