期刊名称：Cuadernos de Investigación Geográfica = Geographical Research Letters
印刷版ISSN：0211-6820
电子版ISSN：1697-9540
出版年度：2014
卷号：40
期号：1
页码：119-145
DOI：10.18172/cig.2507
出版社：Universidad de La Rioja
摘要：Bridges are usually built when traffic or the importance of the road network justifies the cost. Most road bridges are permanent structures and are vulnerable to extreme hydrologic events. Streams, particularly in semiarid regions, can significantly overflow their banks and may change course, defying the bridge’s ability to perform its intended function. This article proposes a way of assessing flood hazards at bridge crossings over ephemeral streams. Two hazard indices associated with floodwaters at bridge crossings have been tested for ephemeral channels on the South-East coast of Spain: a Flood Hazard Index for bridge crossings (FHI BC ), and a Geomorphological Hazard Index (GHI BC ). FHIBC is based on the exposure and effectiveness of drainage works for dealing with floods of different return period. The second index, GHI BC , integrates parameters related to hydraulic resistance and potential bed erosion in large floods. Variables such as granular bed susceptibility to incision, critical velocity and transitory scouring have previously been estimated based on field data. The results show that FHI BC is an appropriate index for obtaining an overall evaluation of the flood hazard at this crossing type, while GHI BC provides useful information on the main hydromorphological factors which endanger the stability of the bridges over ephemeral streams. The joint implementation of both indices may also be an efficient tool for identifying high-risk crossings and improving the planning of future infrastructures over channels in the study area.
关键词：floods; bridge crossings; ephemeral channels; hazard index; South East Spain
