Eastern Outskirts Of Xi'an Loess Aquifer Conditions And Controlling Factors

The ancestors have done a large number of studies about climate changes and soil pedogenesis of the Loess Plateau, and have obtained wealth of research results. However, the research on enrichment conditions and enrichment discipline of groundwater of loess Plateau is still less. Therefore, the research of Enrichment situation and enrichment discipline of groundwater of loess Plateau has important scientific and practical significance for revealing the enrichment discipline, development of water resources and ecological construction of groundwater of loess Plateau. In this paper, a complete profile was chosen in the western of Bailu tableland after detailed field research, and many samples were collected and infiltration experiments from L1-S5 of the profile were done. According to the determining results of the porosity, magnetic susceptibility, CaCO3 content and theoretical analysis, the following conclusions were obtained:(1) The average of stability infiltration rates of the loess layers at Renjiapo profile in Bailu tableland is 1.49mm/min, and which of the paleosol layers is 0.91mm / min. The former is greater than the latter. The stability infiltration rate of S4 calcium carbonate nodules is only 0.19 mm / min, which is the lowest in all experimental points of the profile.(2) The average infiltration rate and the stability infiltration rate from L1 to S5 at Bailu tableland has showed the reducing trend, but sometimes there are anomalies.(3) The loess layers have more coarse particle size composition, larger porosity and better aquifer space than the paleosol layers.(4) The loess layers have higher porosity and better aquifer space which benefits for forming the aquifer layers. The paleosol layers have lower porosity, smaller infiltration coefficient and weaker aquifer space which benefits for forming of the water-resisting layers. The infiltration coefficient of the calcium carbonate nodules in the bottom of the paleosol is the smallest, and its water-resisting capability is the best.(5) The infiltration characteristic of the loess layers of the Loess Plateau is determined by the cold-dry climate of that time, and that of the paleosol layers is determined by the warm-humid climate of that time. The better water-resisting capability of the calcium carbonate nodules is caused by eluviate and illuvial in a stronger pedogenesis process.(6) The average and standard deviation for every parameter of three experience formula can provide important reference for hydrological and agricultural sector using the seeping experienceformula.