Prediction and Research on the Change of Groundwater Environment on the Conditions of Different Diversion Level in Hetao Irrigation District of Inner Mongolia
|School||Inner Mongolia Agricultural University|
|Course||Agricultural Soil and Water Engineering|
|Keywords||Groundwater environment Water-saving transformation Diversion level Forecast|
Water resources are an important natural resource for human survival and development, is also an important natural ecological environment constraints. With the rapid economic and social development, the contradiction between supply and demand of water resources have become increasingly prominent, solve the water crisis has become one of the strategic issues worldwide. The Hetao irrigation water issue has become a bottleneck restricting the economic development of Inner Mongolia, how to solve the problem good Hetao Irrigation District in the efficient use of the water resources and the rational allocation of proposed maintaining the threshold of the Yellow River water irrigation groundwater environment virtuous circle, become the key to the rapid economic development of Inner Mongolia Autonomous Region technology. This study Hetao background, the use of field trials, research means a combination of numerical simulation and theoretical analysis, analysis of groundwater levels, groundwater quality factors discussed mu typical area before and after the Hetao Irrigation District project area kinds of groundwater level and groundwater quality scale variation forecast of different the Diversion level of the groundwater environment. Experimental studies have shown that the groundwater level is mainly affected by the impact of irrigation, rainfall and evaporation. Smaller changes in evaporation, groundwater levels affected by irrigation and rainfall is more obvious, but large changes in evaporation, groundwater level changes at the same time by the interaction of the three factors. The main factors of the underground water quality for irrigation water quality, groundwater depth and external contamination, underground water quality and irrigation water quality factor of 0.73 (moderate correlation), groundwater depth correlation coefficient of 0.46 (had low correlation). The variation of the typical district project area groundwater levels have a strong two rising twice a downward trend due to changes in the irrigation amount and time. Declining groundwater levels in the period of fertility, crop consumed some groundwater storage. Groundwater table presents the descending trend from upstream to downstream. Each of the years groundwater levels in the water-saving transformation than water-saving reduced in varying degrees in the transformation of the former Long wins after the transformation of the demonstration area, which reduce the range between 0.29 ~ 0.58m reduction in six project areas in the range of 0.02 ~ 0.55 m between. The total water-saving irrigation district groundwater salinity distribution law transformation trend from upstream to downstream salinity increases gradually, gradually increased the upper limit of the project area during the year underground water quality from 2007 to 2009, increased by an average of 3.78g / l, groundwater quality during the year dynamic can be classified as the thaw period, the crop growing period, crop harvesting period, autumn irrigation period, the freeze period groundwater salinity relative increase in the dissolved phase groundwater salinity is reduced accordingly, crop growth period groundwater salinity with irrigation will fluctuate, crop harvesting period evaporation strength Ambassador groundwater salinity increases, the autumn the pouring period of irrigation played salinity reduce leaching dilute the role of leaving. Mean groundwater depth in the numerical simulation results show that Option One (40 billion m ~ 3 / a) of the groundwater table mean local scale is close to the lower limit of the appropriate depth, program II (3.6 billion m to 3 / a) about 2.50m, and the growth period will be lower than this mean groundwater freshwater regions of the two programs have decreased, but programs to reduce significantly, less than 1/6 of the total area. A program on the irrigation district scale groundwater level changes gently, the program two average groundwater level is about 1m lower than the status quo, the upstream groundwater salinity of the two programs have increased in the second scheme increased significantly. Shows that Option II will make the region's groundwater environment deteriorated significantly. Therefore, initially proposed in Hetao maintain a the groundwater environment virtuous cycle of the Yellow River water threshold value of 4 billion m3 / a. Due to a shorter series of field trial data, the the paper simulation predicted results have yet to verify further on the basis of a long series of tests and boundary information.