基于频率法的河道最小生态流量计算

摘要

Adopting polynomial fitting method to fit flow frequency curve of each period,this paper established the function relationship between flow and frequency and calculated the minimum ecological flow of river channel by using the dry season frequency based on meeting ecological hydraulic el-ements such as ecological water depth and ecological flow velocity. The ecological flow with above method could reflect the concept of guaranteed rate, so could easily evaluate the river ecological water requirement. Temporal distribution could reflect wet and dry characteristics in different period. Tak-ing Chahe section of Xiaoqing River as a calculation example,this paper confirmed that the minimum ecological flow during January to March,April to June,July to September,and October to December controlled by 4. 8,3. 2,10. 0,5. 7 m3/s respectively were reasonable.%采用多项式拟合法拟合各时段的流量频率曲线，建立流量与频率的函数关系，在满足生态水深、生态流速等生态水力要素要求的基础上，以某枯水期频率计算该时段的河道最小生态流量。该法计算的生态流量具有保证率的概念，便于对河道的生态需水满足情况进行评价；时程分配能反映出不同时段的丰枯特性。对小清河岔河进行实例计算，经分析确定1-3月、4-6月、7-9月、10-12月的河道最小生态流量分别以4．8、3．2、10．0、5．7 m3/s进行控制比较合理。