HR: 0800h
AN: H21A-0188    [Abstracts]
TI: An analytical model of the effects of catchment hypsography on the flood frequency distribution
AU: * Allamano, P
EM: paola.allamano@polito.it
AF: Dept. of Hydraulics, Transports and Civil Infrastructures, Corso Duca degli Abruzzi 24, Turin, 10129, Italy
AU: Claps, P
EM: claps@polito.it
AF: Dept. of Hydraulics, Transports and Civil Infrastructures, Corso Duca degli Abruzzi 24, Turin, 10129, Italy
AU: Laio, F
EM: francesco.laio@polito.it
AF: Dept. of Hydraulics, Transports and Civil Infrastructures, Corso Duca degli Abruzzi 24, Turin, 10129, Italy
AB: The role of the temperature regime on the flood frequency distribution in alpine basins is examined through a minimalist analytical model of the flood formation mechanisms. We represent rainfall as a marked Poisson process of storm arrivals in time with rate λ in which the depth h of each storm is modelled as an exponentially distributed random variable with mean α. Each rain event occurs in a liquid form over a fraction of the basin area, the contributing area, while in the upper part of the basin the precipitations are in a solid form and do not contribute to the discharge at the outlet. The contributing area depends on the elevation of the snow line at the date when the event occurs. As a consequence, the watershed elevation characteristics, which are represented through a simple hypsographic curve, play a role in the derivation of the flood frequency curve. Under these assumptions the probability distribution of the annual maxima of discharge is analytically derived. Reasonable representations of the relations between moments of the distribution and mean basin elevation are obtained. They are in good agreement with the experimental trends and prove the ability of the model to mimic the dependency of flood formation on elevations. The relevance of this work derives from its simple structure, that allows the user to characterize each basin with a set of fundamental descriptors. Behaviour of basins in transition regions and mountainous basins sensitivity to climate change are possible interesting applications of the model.
DE: 1829 Groundwater hydrology
DE: 1835 Hydrogeophysics
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
DE: 1847 Modeling
DE: 1879 Watershed
SC: Hydrology [H]
MN: 2007 Fall Meeting