Study On Evaporation By Field Test In The Weining Plain

The vadose zone is an important part of natural ecological environment, and thelink between groundwater and surface water. Through the research of unsaturatedzone soil moisture migration rule, accurately determine rainfall, irrigation ongroundwater recharge and soil evaporation, to improve the calculation precision ofgroundwater resource.WeiNing plain is the core area of ningxia along the yellow zone planning anddevelopment, and also is the key area of ningxia "twelfth five-year" developmentplanning. Previous studies have shown that ningxia groundwater circulation along theyellow zone is given priority to with vertical alternation, irrigation, drainage andatmospheric precipitation infiltration around accounted for about90%of the totalrecharge, evaporation discharge is plain are the main way of discharge of groundwater,account for more than50%of total emissions. Therefore, the research on the rules ofthe vertical drainage of groundwater, the correct evaluation WeiNing plaingroundwater recharge resources and recoverable resources, the rational developmentand utilization of groundwater, and scientific management, has important significance.Based on the understanding of domestic and abroad achievements of research onvadose zone, in this paper, With the method of vadose zone in situ experiments, ToWeiNing plain different vadose zone thickness, lithology combination and the surfacevegetation, precipitation, irrigation water to the rule of groundwater recharge andgroundwater evaporation quantity are discussed.Based on the comprehensive analysis of WeiNing plains of hydrogeologicalconditions, choose the typical geomorphic units, respectively, in the city of Li Yuanvillage, seven teams using DLS ZhongNingXian field DLS-Ⅱ negative pressuregauge, the SM1rain gauge equipment such as soil temperature recorder establishedtwo vadose zone moisture migration test station, in June2013to November2013were tested. Each test station are divided into the bare land, vegetation group contrastexperiment was carried out, at the same time the two sites of underground water level,ground temperature, rainfall, evaporation were observed. Using the observation data, the test period by applying the method of soil water flux of surface evaporation wascalculated, ZhongWei test station bare land evaporation for331.80mm, cornevaporation for619.15mm, Zhongning test station bare land evaporation for332.16mm, Chinese wolfberry evaporation for670.93mm. Will test station carries outa comparative analysis on the observed meteorological data and calculatedevaporation, calculate the test station surface evaporation capacity empirical formula.On this basis, of different meteorological conditions, different thickness and differentlithology combination belt, different vegetation, and under the influence of differentfactors such as water level, the infiltration law of soil water evaporation is analyzed.