Combined palaeoflood and rainfall-runoff assessment of mountain floods (Spanish Pyrenees)

JOURNAL OF HYDROLOGY

卷:245

Article

Rico, M ; Benito, G ; Barnolas, A

关键词: palaeofloods;    palaeohydrology;    rainfall-runoff methods;    mountain stream;    Pyrenees;    Spain;   

DOI  :  10.1016/S0022-1694(01)00339-0

来源: Elsevier

【 摘 要 】

This paper reports a comparative study of the use of palaeohydrological and hydrological techniques to estimate magnitude and frequency of floods applied to two high-gradient, small catchments located in the Spanish Central Pyrenees: the Aras basin, 18.6 km(2); the Montardit basin, 15.2 km(2). Palaeohydrological (palaeoflood) techniques, based on palaeostase indicators and the application of both Manning's equation and critical how equation, were used to estimate discharge values corresponding to seven cross-sections of the Montardit stream. This method yielded discharges ranging from 7 to 112 m(3) s(-1). Palaeoflood and historical hood analyses indicated a greater frequency of high magnitude events for both the Aras and Montardit basins than suggested by the application of two different methodologies based on precipitation data (the rational and the unit hydrograph methods). The 1996 Ara's basin flood was modelled using the unit hydrograph method, with most reliable results (217 m(3) s(-1)) obtained using a semidistributed basin model. For small, ungauged mountain basins, palaeoflood reconstruction provides an excellent tool to obtain past flood discharges on which to base the calibration of parameters (e.g. runoff threshold) used in rainfall-runoff methods. It is proposed that the combined results of long-term flood record analysis (based on palaeoflood and historical data) and of standard hydrometeorological methods will aid in the assessment of flood risks for application to the design of emergency measures and floodplain management in ungauged mountain streams. (C) 2001 Elsevier Science B.V. All rights reserved.

【 授权许可】

Free