Search results for "Soil saturation"
showing 3 items of 3 documents
Effect of cultivation techniques on the hydrodynamic and mechanical behaviour of the "Lauragais-terreforts"
1993
The effect of various seed bed preparations on hydrodynamic and mechanical parameters was studied experimentally by simulated rainfall on clayeyloamy soils Lauragais, which had developed on chalky molasse on a slope greater than 12 %. The level of soaked up rain ("pluie d'imbibition", Pi) is closely connected to the inital degree of saturation of the soil ; it varies from 10 to 24 mm when the soil is humid and increases when the soil is dry (14 to 47 mm). But when the soil surface is crusted the Pi is less and seems to be no longer controlled by the degree of water in the soil. Treatments with fine structural elements show the fewest possibilities of infiltration during the soaking up stage…
Saturation excess runoff numerical simulation
2005
Saturation excess runoff is a relevant process which needs additional experimental and modeling efforts. This work is focused on its numerical modeling. The final objective is the successive interpretation of ongoing experimental monitoring results in two watersheds in different areas of Italy where the saturation excess runoff formation mechanism seems to be important. The numerical solution of the two-dimensional Richards’ equation allows the evaluation of the sensitivity to the various influent parameters : rainfall intensity, soil properties, depth and initial water content, slope and hillslope length. Also the subsurface flow is simulated at the same time, allowing the evaluation of th…
A model of dunnian flow at hillslope scale
2005
The development of a thin stream above the soil surface (overland flow) is associated to two mechanism of runoff generation on the hillslope: the infiltration excess (hortonian flow) and saturation excess (dunnian flow) mechanism. The first one is typical of arid and semi-arid regions, usually characterised by high rainfall intensities on soil exhibiting low permeability. The second one, firstly introduced by Hewlett and Hibbert, constitutes the main mechanism of runoff generation in humid regions, characterised by high groundwater table. In the last mechanism runoff is produced by contributing areas of restricted extent that expands with time, where near to the bottom of the hillslope a hi…