6533b7ddfe1ef96bd1273f71

RESEARCH PRODUCT

Overland flow generation on hillslopes of complex topography: analytical Solutions

Cecilia CorraoGiorgio BaiamonteCarmelo Agnese

subject

brachistochroneRegular polygonGeometryConical surfaceFunction (mathematics)analytical solutionMaxima and minimaoverland flowSettore AGR/08 - Idraulica Agraria E Sistemazioni Idraulico-Forestaliconvergent and divergent hillslopeShape factorDivergence (statistics)Surface runoffoverland flow; convergent and divergent hillslopes; concave and convex profiles; analytical solution; brachistochroneconcave and convex profileBrachistochrone curveGeologyWater Science and Technology

description

The analytical solution of the overland flow equations developed by Agnese et al. (2001; Hydrological Processes15: 3225–3238) for rectangular straight hillslopes was extended to convergent and divergent surfaces and to concave and convex profiles. Towards this aim, the conical convergent and divergent surfaces are approximated by a trapezoidal shape, and the overland flow is assumed to be always one-dimensional. A simple ‘shape factor’ accounting for both planform geometry and profile shape was introduced: for each planform geometry, a brachistochrone profile was obtained by minimizing a functional containing a slope function of the profile. Minima shape factors are associated with brachistochrones; interestingly, brachistochrones associated with rectangular surfaces have a simple power-law form. For a fixed profile shape, the rapidness of overland flow increases with the degree of divergence; for a fixed planform geometry, however, the overland flow associated with convex profiles is more rapid than that associated with concave profiles. An extended analytical solution is also proposed for the instantaneous response function. Copyright © 2007 John Wiley & Sons, Ltd.

10.1002/hyp.6354http://hdl.handle.net/10447/11033