Abstract：
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.
摘要：
环境流动对于维持河流生态系统健康和保证水生生物的正常生长至关重要。由于考虑了水生生物栖息地的河流形式和最小流量，因此湿润周长方法在评估环境流量方面确实非常有用。在这项研究中,选取具有明显季节性和外部引水的河流为典型研究对象；以静乐，兰村,汾河水库,和伊塘水文断面作为控制断面，我们在三个方面改进了现有的润湿周长方法：（1）我们改进了水文数据序列的选择。选定的水文数据系列应具有一定的长度，并能很好地反映湿地的水文变化，正常,和干燥的岁月。(2)不同于传统的润湿周界法,只给出一个环境流量值，改进后的方法逐月计算环境流量。(3)改进的湿润周长法建立了原生鱼类生存与环境流量的关系。结果表明，改善的湿润周长考虑了主要鱼类的生存，斜率法计算结果与多年平均流量之比大于10%，这可以确保鱼类的栖息地不会被破坏，结果更合理。此外，获得的月环境流量过程优于现有方法确定的年统一环境流量值，与河流自然水文情况和引水情况一致。该研究表明，改进的湿润周长方法对于研究季节性强，年流量变化大的河流环境流量是可行的。
