黄河下游水情变化特征与引黄灌溉的可持续发展

自 2 0世纪 70年代以来 ,黄河下游年径流量逐渐减少 ,年最大流量亦在减少 ,1 990～ 1 995年本区引黄水量达到 1 0 7.8亿 m3 ,实灌面积达到 2 2 2 .3万 hm2 。1 995～ 1 999年全区用水量为 1 3 0 .5亿 m3 ,其中 ,流域内占3 1 .7% ,流域外占 68.3 %。本区河南段以引黄渠系自流灌溉为主 ,井灌为辅 ;山东段则是渠系自流、河网调蓄提灌和机井提灌相结合的综合引黄模式。本区作物灌溉定额 ,小麦为 2 66～ 3 3 5 mm,玉米为 1 1 5～ 1 3 9mm,大豆为 1 75～ 2 0 3 mm,棉花为 1 96～ 2 49mm,水稻为 699～ 75 4mm。引黄灌溉的发展潜力为 1 1 5 .8亿 m3 ,冬春占3 3 .4% ,夏秋占 66.6%。通过发展工程节水 (将综合节水率提高 7.6% )、实施适水种植 (将小麦播种面积下调1 0 .1 % ) ,则可节水 1 4.8%。

Water Regime Change Characteristics and Sustainable Development of Irrigation Areas Diverted Water from Lower Reach of the Huanghe River

Annual runoff volume and maximum discharge has decreased, and the absence of flow has become frequent at the lower reach of the Huanghe River since 1970. The total amount of water diverting from the river was 10.78 billion m 3, and controlled irrigation area was 2022 million hm 2 in entire Huanghe basin in 1990～1995. The averagely irrigation caused yield increment for fields irrigated with water from the river was 2650 kg/hm 2 for grain, and 558 kg/hm 2 for cotton. The total water amount diverted from the river was about 13.05 billion m 3 in 1995～1999. The ratio of water volume used inside the basin and that used outside the basin was 31.7:68.3. The main irrigation model is gravity irrigation with canal system in Henan reach, and is the combination of gravity irrigation with canal system and well irrigation in Shandong Reach. The irrigation quota in the basin is 266～335 mm for winter wheat, 115～139 mm for summer maize, 175～203 mm for summer soybean, 196～249 mm for cotton, and 699～754 for paddy rice. The development potential of irrigation area with water diverted from the river is about 11.58 billion m 3, 33.4% of which is for winter wheat and spring wheat. A water saving rate of 14.8% can be achieved with implementing water saving measures included building water saving irrigation projects (increasing comprehensive water saving rate of 7.6%) and selecting water suitable crops (decreasing 10.1% of winter wheat area).