内蒙古河套灌区节水对区域水盐平衡的影响分析

Influences of Water Saving on Regional Water and Salt Balance in Hetao Irrigation District,Inner Mongolia

内蒙古河套灌区实施大型节水改造以来,渠系衬砌、田间节水和种植结构调整等节水措施影响了该区域原有的水盐平衡。通过比对灌区节水措施从1990年到2013年的实施历程和灌区引水量、排水量和耗水量等水盐循环要素在同时期的演进情况发现,随着节水措施的实施,多年平均引黄水量从1998年之前的49.7亿m3减少到1999—2013年的45.3亿m3;进一步分析了灌区地下水位和盐分变化情况,发现年平均地下水埋深从1990—1994年的1.70 m下降到2010—2013年的2.09 m;灌区长期处在积盐状态,但积盐量呈下降趋势。分析结果表明:节水最直接的结果是导致灌区水循环通量减少;随着节水措施的不断加强,地下水埋深不断增大;节水导致灌区引盐量减少、排盐量增加;节水对灌区生态的影响还有待进一步研究。

Since the large-scale water-saving projection of Hetao Irrigation District of Inner Mongolia was implemented, water-saving measures like canal lining, field water conservation and planting structure adjustment have been affecting the region＇s original water and salt balance. In this paper, through the comparison of the implementation process of water saving measures from 1990 to 2013 in the ir- rigation area and the evolution of water and salt circulation factors such as water volume, displacement and water consumption at the same time period, it was found that the average annual water diversion from the Yellow River reduced from the level of 49.7×10^8m^3 of before 1998 to the level of 4.53×10^8m^3 from 1999 to 2013. Furthermore, the changes of groundwater level and salinity in irrigation area were analyzed. The results showed that annual mean groundwater buried deep dropped from the level of 1.70 m from 1990 to 1994 to the level of 2.09 m from 2010 to 2013, and the irrigation area was in the state of salt accumulation for a long time, but the amount of salt accumulation was decreasing. Comprehensive results show ： the most direct result of water saving is the decrease of water circula- tion flux in irrigation district; with the constant implement of water saving measures, the depth of groundwater is increasing; water sav- ing also leads to the decrease of the amount of salt cited irrigation and the increase of the amount of salt discharge; the effect of water saving on the ecological environment in the irrigation area should be further studied.