The Calculation And Analysis Of Irrigation Efficiency And The Evaluation Water-saving Reconstruction At The South Bank Irrigation District Of The Yellow River In Inner Mongolia

This paper focuses on the accurate field measurements in the Yellow River South Bank Irrigation District of Inner Mongolia in2013, as well as the indoor experiments. The typical irrigation areas were selected basing on the different associated scales, water intaking types (artesian diversion, pumping), engineering status and management levels, thus, the measurement and analysis of irrigation water efficiency and the assessment on water-saving transforms were conducted in this district. Based on the field tests been conducted to the typical channels and fields in the Yellow River South Bank Irrigation District of Inner Mongolia to measure the water efficiency of irrigation, water efficiency of canal system and water efficiency in field. Later, the current irrigation water application status, the water-saving potential after saving transforms and the water saving effect of water-saving engineering implements in the district were assessed, accompanied by the TOPSIS model integrated evaluations on the water-saving benefits in gravity irrigation districts. Results indicated that:(1) The irrigation water efficiency of general main canal in gravity district of the Yellow River South Bank Irrigation District is0.7920; the efficiency for branch canal is0.9418; the lateral canal efficiency is0.9370. For the pumping irrigation district, the efficiency of trunk canal is0.8339; the branch canal one is0.9179and the lateral canal efficiency is0.86. The water efficiency of canal system in gravity irrigation district derived from Head-Tail calculation method is0.6820. The water efficiency of canal system in pumping irrigation district is0.6988; the water efficiency of canal system in irrigation district derived from Head-Tail calculation method is0.6885. The field tests calculated water efficiency in field are0.7759and0.7912separately for gravity irrigation and pumping irrigation districts. By field measurement method of water at the southern bank of the Yellow River irrigation area water use in the field is0.7818. Based on the Head-Tail calculation method of the field measured average method and water balance method, measured gravity and pumping irrigation area of irrigation water use coefficient value are0.5291and0.5530, and then measured at the southern bank of the Yellow River irrigation area of irrigation water use coefficient is0.5384. (2) The water-saving potential of canal system under conditions of lining was evaluated through an integrated assessment basing on the canal system method, the calculated amounts of saved water for gravity irrigation and pumping irrigation districts are0.1212and0.06785billion m3, and the total amount in the Yellow River South Bank Irrigation District of Inner Mongolia is0.189billion m3. The comprehensive assessment approach associated results showed that, the calculated amounts of saved water for gravity irrigation and pumping irrigation districts in crop growth period are0.0315and0.0175billion m3respectively; the cumulative saved water for crops in the Yellow River South Bank Irrigation District is0.103billion m3. All the aforementioned assessments on canal and field system illustrate that, the Water-saving outstanding achievements and the total water-saving potential of the whole district is0.292billion m3.(3) Through the application of the improved TOPSIS model, an analysis on the integrated benefits after the water-saving transformation, covering the period of2000-2012was conducted. Generally, the water efficiency of irrigation and integrated benefits of the district follows an increasing order with the enlargement of investigations on the water-saving transformation. Additionally, results also illustrated the improvements on management levels and the further consummations on fundamental conditions of the irrigation and water conservancy in this irrigation district, as well as the significantly improved social benefit, economic benefit and ecological benefit. Thus, making the district to a mode of highly efficiency, less waste and satisfying irrigation quality. Besides, the irrigation water efficiency in2000ranks last which is resulted from the just beginning of water-saving transformation this year. Prior to2000, all the canals in this district were earth ones, the corresponding conveyance loss was huge and the management system was not complete, resulting in the lower irrigation water efficiency and the relatively bad integrated benefits. After the water-saving transformation applied in this district, majority of the canals were lined, along with the enlarged integrated benefits, the improved management system and the drastically enhanced irrigation water efficiency and comprehensive water-saving benefits. All these results are consistent with the practical status and, the related methods are simple. The evaluation results are visual and reliable.