干旱区扬水灌溉对灌区地下水盐演化的影响

Influence of pumping-irrigation on ground water and salt transport in arid area

利用甘肃景电灌区15年地下水水位动态及水质监测资料,分析了干旱区扬水灌溉对封闭型水文地质单元和开敞型水文地质单元地下水盐演化的影响.结果表明:高扬程提水灌区内的水盐运移主要受控于灌溉水入渗,呈径流滞缓、水盐积累的特点;灌溉水入渗带、溶质迁移带和潜水排泄带的地下水矿化度受入渗—溶滤过程的影响呈振荡变化型;封闭型水文地质单元的汇水聚盐带地下水矿化度和土壤含盐量均呈逐年上升趋势,是灌区内土壤次生盐碱化形成的主要原因.

Using the 15 years monitoring data of groundwater dynamic and water quality in Jingtai power pumping-irrigation area,the effects of pumping-irrigation on water-salt transport both in closed hydrology geology unit and unclosed hydrology geology unit were analyzed.The results showed that the water-salt transport in the pumping-irrigation area was mainly influenced by the infiltration of irrigation water,associated with stagnated run-off and salt accumulation in groundwater.Mineralization of groundwater in water infiltration zone,solute transportation zone and drainage zone present an oscillating type of change,and it was affected by the infiltration and leaching of groundwater.Mineralization of groundwater and soil salinity content in the poly salt zone of closed hydrology geology unit were both increased year by year,which was the main reason of soil secondary saline-alkalization.