我国河流众多,径流量的年内分配很不均匀,多数集中于夏季。有些河流如新疆和田河的支流玉龙喀什河,每年7、8两个月,就集中了全年径流量的80%以上,因此,全国的洪涝灾害频繁发生。据统计,从1950年至1983年,平均每年水灾面积1.1亿亩,成灾面积0.6亿亩。 There are many rivers in our country. The distribution of runoff during the year is very uneven, mostly concentrated in the summer. Some rivers, such as Yulong Kashi River, a tributary of the Hetian River in Xinjiang, concentrate more than 80% of the annual runoff during July and August every year. As a result, floods and disasters throughout the country frequently occur. According to statistics, from 1950 to 1983, the average annual flood area was 110 million mu and the affected area was 0.6 million mu.