渭干河平原绿洲灌区合理灌排比探讨

Rational Ratio of Irrigation to Drainage in Weigan River Irrigation District

根据灌区盐量平衡原理 ,采用实际监测资料 ,对渭干河及其所属的库车、沙雅、新和县平原绿洲灌区进行盐均衡分析 ,深入探讨了临界灌排比的影响因素及其确定方法。研究结果表明 :(1)灌排比的概念简捷明了 ,体现了干旱区水利建设、灌溉农业的特点 ,可作为衡量干旱区绿洲灌区水盐运动状况的一个指标 ,同时亦是进行灌排管理、规划设计的科学依据。 (2 )临界灌排比与灌溉引水量、排水量、河水含盐浓度、排水含盐浓度等因素有关。渭干河、库车、沙雅、新和灌区临界灌排比分别为 10 .80 ,6 .5 5 ,2 0 .0 9,2 1.48。若没有特殊的地形地貌 ,干旱区绿洲灌区临界灌排比为 2 1左右。 (3)在干旱区进行水量平衡计算 ,制定灌溉制度以及进行灌溉排水管理时 ,应保证有一定量的深层渗漏 ,便于淋洗盐分 ,同时应完善排水系统 ,使灌区在小于临界灌排比下运行。

Based on the principle of salt equilibrium in irrigation districts, the salt equilibrium of Weigan river irrigation district is analyzed by using measured data. The factors of affecting critical ratio of irrigation to drainage and the method of determining critical ratio of irrigation to drainage are also discussed profoundly. The results show that: (1) The conception of the ratio of irrigation to drainage is brief, embodies the characteristics of water conservation construction and irrigation agriculture, which can be used as the criterion of estimating the dynamics of moisture salt movement in plain oasis irrigation distract in arid area,and can also used as the scientific basis of management of irrigation and drainage ,planning and designing.(2)Critical ratio of irrigation to drainage is related to the irrigation water volume, drainage water volume ,salt content of irrigation water and drainage water and so on. The critical ratio of irrigation to drainage for Weigan river, Kuche county , Xinhe county, Shaya county are 10.8,6.55,20.99,21.48, respectively. If there is no special topography, the critical ratio of irrigation to drainage in oasis irrigation distract in arid area is about 21. (3) The seepage is necessary to leach salt, carrying out calculating of water balance, making irrigation schedule and managing the irrigation and drainage .At the same time, the drainage systems need improving to have the irrigation district operated under the condition that actual ratio of irrigation to drainage is less then critical ratio of irrigation to drainage.