Application of Large Sscale Pipeline Irrigation System in Northwest China
A single irrigation system exceeding 200 hm2 can be defined as a large system.The selection of water source location usually takes meeting the minimum working pressure requirements of the most unfavorable area as a prerequisite.The storage pond is calculated based on a one-time irrigation quota,with a volume ranging from 20000 to 50000 cubic meters.For one irrigation season,every 667 hectares require a storage volume of 400000 to 500000 cubic meters.For pipeline layout,the length of pipeline per hectare in plain areas should be controlled at 120 to 150 meters,while in hilly areas,it should be controlled at 195 to 225 meters.System flow calculation is based on the formula given in the micro-irrigation engineering technical specifications for areas of 1,333 hectares or less,and the method of irrigation rate is used for areas above 1,333 hectares.Whether the pipeline is depressurized and the type of depressurization method used mainly depends on the working pressure of the pipeline network and the specific pressure level of the selected pipe material.