The water coming from the soil surface after the saturation of the soil stratum over the groundwater table at field saturation raises the groundwater level. The soil structure and the soil texture characterize the infiltration process. The resultant of the gravitational force and the capillary forces gives the energy to the water molecules to push the air entrapped out of the pores, reaching a full saturation of the soil and raising then up the phreatic level. There is a complex interac-tion between the agent forces on the water and the air resistant forces in the soil micro-pores. In paddy fields irrigation a groundwater level stable condition is reached when there is equilibrium between the capil-lary forces. A stable soil stratum with pressured air is always present in the soil over the phreatic level. From the collected data it seams that the soil stratum thick-ness from the soil surface to the groundwater table is proportional to the modulus of the capillary force. In a stable surface ponding depth, during the groundwater table rising, the level growing velocity may be assumed proportional to a medium hydraulic conductibility of the soil stratum. When the phreatic level is approaching the saturated soil surface, the rising rate gradually changes until it gets to a point of equilibrium where the groundwater table is stationary at stable surface condi-tions. In this condition, by changing the surface water depth the phreatic level changes with it.
|Titolo:||Infiltration process and groundwater table raising in a paddy field area|
|Parole Chiave:||Groundwater ; level trend ; Soil conductivity ; Monitoring ; Equations ; Aquifer contamination|
|Settore Scientifico Disciplinare:||Settore AGR/08 - Idraulica Agraria e Sistemazioni Idraulico-Forestali|
|Data di pubblicazione:||nov-2004|
|Appare nelle tipologie:||01 - Articolo su periodico|