基于层次分析-蚁群算法的内蒙古大型灌区节水改造综合评价

Comprehensive assessment on water-saving renovation of large-scale irrigation districts in Inner Mongolia based on hierarchical analysisant colony algorithm

内蒙古大型灌区节水改造工程建设已开展15a,各灌区改造效果差异较大,全面系统的评价灌区节水改造效果可为灌区管理及进一步节水改造实施提供科学依据。该文针对内蒙古14个不同类型大型灌区(引黄、水库取水、河流取水、扬水灌区及井灌区)复杂条件,利用层次分析法的层次框架思维模式与蚁群算法的自适应性及人为干扰少等特点,在种植种类、灌溉方式、运行管理不同,经济效益迥异的环境中,构建了层次分析-蚁群算法。选择灌区的作物种植、节水效益、运行管理及经济效益等4个要素的14项评价指标,采用层次分析法获得权重值,再利用蚁群算法确定各灌区的优属度,对其中10个典型灌区的节水改造效益进行综合评价与分析,旨在研究各灌区节水改造效果。获得10个灌区优属度(值)的排名为:山湾子灌区(0.91)、镫口灌区(0.95)、河套灌区(0.97)、黄河南岸灌区(0.98)、甸子灌区(1.005)、察尔森灌区(1.01)、英金河灌区(1.115)、西辽河灌区(1.14)、麻地壕灌区(1.165)、莫力庙灌区(1.185)。结果表明山湾子灌区和镫口灌区的节水改造效果最好,莫立庙灌区节水改造效果最差。该评价结果符合灌区实际情况,表明该基于层次分析-蚁群算法的评价结果具有一定的可信度。因此,层次分析-蚁群算法可用于大型灌区节水改造工程综合评价。其评价结果可为管理机构进行灌区改造综合评价提供一条新的思路与方法,并为相近大型灌区节水改造综合效益评价提供参考。

Inner Mongolia Autonomous Region is located in northern China and it is characterized by dry,little rainfall, and shortage of water resource. Most farmlands in this region are distributed in arid and semiarid areas, and thus agricultural production is highly dependent on irrigation. There are 14 large-scale irrigation districts in 7 municipalities （leagues） or around 3 river basins. Most of the irrigation districts obtain irrigation water from surface water. The irrigation districts as important agricultural bases of China for spring wheat, maize and sunflower production are constructed in 50 s-70 s of 20th century. The old irrigation districts are found with problems such as disrepair, poor auxiliary works, sever canal seepage and low water use efficiency. The increased population and socio-economic development have greatly aggravated the competition for water among agriculture, industry and domestic users in these irrigation districts. In order to deal with such problems and maintain agricultural production, a project of renewed construction and water saving renovation for irrigation districts was implemented in Inner Mongolia Autonomous Region since 1998. It is necessary to evaluate the effects of the project for better managing and developing future projects of water saving renovation. However, since there is large difference in physical conditions, hydrogeology and climate among irrigation districts, the effect of water saving renovation may vary greatly in different irrigation districts, causing the difficulty in selecting indicators for evaluation. In this study, 10 typical irrigation districts （water diversion from the Yellow River, water diversion from reservoirs, water diversion from other rivers, water lifting from rivers and water lifting from wells） were selected and used for the evaluation of water saving renovation using Hierarchical Analysis-Ant Colony method. From the perspective of plant species, irrigation methods, operating management level and economic benefits of different environment, the evaluation indicator system was constructed with 4 parameters for crop cultivation, operation, management and benefit. The Hierarchical Analysis was used to assign the weights to each indicator for each irrigation district and the Ant Colony Algorithm was used to determine the optimal degrees indicating goodness of the water saving renovation in each district. The results showed that the 10 irrigation districts were ranked by optimal degree as Mountain bay （0.91）, Dengkou （0.95）, Hetao （0.97）, the South Bank of Yellow River （0.98）, Dian Zi （1.005）, Chaer Sen （1.01）, Yingjin River （1.115）, West Liaohe River （1.14）, Madi Hao （1.165）, and Moli Temple （1.185） irrigation area. It indicated that of the 10 typical irrigation districts, the water-saving renovation effect of San Wanzi Irrigation District and Dengkou Irrigation District were remarkable but that of Mo Limiao Irrigation District was not desirable. The evaluation was in agreement with the real situations of these irrigation districts, suggesting that the assessment based on the Hierarchical Analysis-Ant Colony method was reliable. The Hierarchical Analysis-Ant Colony method was simple and easy to operate and reliable for evaluation of large-scale irrigation districts. The study introduced a new method for assessment of water-saving renovation effects of large-scale irrigation districts.