College of Water Conservancy Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.
School of Computing, Science & Engineering, University of Salford, M5 4WT, Manchester, UK.
Environ Sci Pollut Res Int. 2023 Aug;30(37):88009-88021. doi: 10.1007/s11356-023-28331-0. Epub 2023 Jul 12.
Environmental flow is vital for maintaining river ecosystem health and ensuring the normal growth of aquatic organisms. The wetted perimeter method is indeed very useful in the assessment of environmental flow due to consideration of stream forms and minimum flow for aquatic life habitat. In this study, a river with obvious seasonality and external water diversion was selected as the typical research object; taking Jingle, Lancun, Fenhe Reservoir, and Yitang hydrological sections as control sections, we improved the existing wetted perimeter method in three aspects: (1) We improved the selection of hydrological data series. The selected hydrological data series should be of a certain length and can well reflect the hydrological changes of wet, normal, and dry years. (2) Different from the traditional wetted perimeter method, which only gives one environmental flow value, the improved method calculates the environmental flow month by month. (3) The improved wetted perimeter method establishes the relationship between native fish survival and environmental flow. Results indicated that the improved wetted perimeter took the survival of the main fishes into consideration, the ratio of the calculated results by the slope method to the multi year average flow was greater than 10%, which can ensure the fishes' habitat is not being destroyed, and the results are more reasonable. Furthermore, the monthly environmental flow processes obtained were better than the annual unified environmental flow value determined by the existing method and are consistent with the natural hydrological situation and water diversion situation of the river. This study shows that the improved wetted perimeter method is feasible for research of river environmental flow with strong seasonal and large variation of annual flow.
环境水流对于维持河流生态系统健康和确保水生生物的正常生长至关重要。湿周法在评估环境水流时非常有用，因为它考虑了河流形态和水生生物栖息地的最小流量。本研究选择了一条具有明显季节性和外部引水的河流作为典型研究对象；以荆雷、兰村、汾河水库和义堂水文断面为控制断面，从三方面对现有的湿周法进行了改进：（1）改进了水文数据序列的选择。所选的水文数据序列应具有一定的长度，并能很好地反映湿、正常和干旱年份的水文变化。（2）与传统的湿周法只给出一个环境水流值不同，改进后的方法逐月计算环境水流。（3）改进的湿周法建立了土著鱼类生存与环境水流的关系。结果表明，改进的湿周法考虑了主要鱼类的生存，斜率法计算结果与多年平均流量的比值大于 10%，可以确保鱼类的栖息地不被破坏，结果更加合理。此外，获得的逐月环境水流过程优于现有方法确定的年度统一环境水流值，并且与河流的自然水文状况和引水状况一致。本研究表明，改进的湿周法适用于季节性强、年径流量变化大的河流环境水流研究。
