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一、海河流域农田灌溉的成就海河流域属于温带半湿润半干旱的季风气候区,冬季寒冷而雪少,春季多偏北或偏西北风,往往形成干旱天气流域多年平均降水量约560毫米,但年内分配不均匀,年际变化也很大,年雨量的70～81％集中在7、8、9三个月,以致时常洪涝为患。而在冬小麦生长期的10～5月降雨量稀少,作物最需水的4～6月降水量一股只有30～60毫
I. Achievements of Farmland Irrigation in the Haihe River Basin The Haihe River Basin belongs to the temperate semi-humid and semi-arid monsoon climate zone. It is cold and snowy in winter, with more northerly or northwest winds in spring, often forming a mean annual precipitation of about 560 mm in dry weather basins. However, during the year Uneven distribution, interannual changes are also great, 70 ~ 81% of annual rainfall concentrated in 7,8,9 three months, so often floods. In the winter wheat growing season, 10 to May rainfall is scarce, the most water-sensitive crops in April to June rainfall of only 30 to 60 milliliters