去年砂石开采期，我们河道管理人员在制止乱采滥控现象中，问一个村民：“你们这样挖砂，洪水来了怎么办？”“挖了砂才有利于泄洪嘛！”在这不妨讨论一下挖砂与泄洪的关系：取某一段河道为研究对象，我们把日常水位以上、危险水位以下能容纳洪水的那部分库存容，称作为有效净 During the gravel mining period last year, our river managers asked one villager to stop indiscriminate and indiscriminate floods: “If you dig sand, what should you do when the floods come?” “It is good for flood dredging if you dig sand!” Discuss the relationship between sand dredging and flood discharge: take a section of the river for the study, we will be above the daily water level, the danger level below that part of the inventory to accommodate the flood, known as the effective net