基于Tennant方法的河流生态基流应用现状及改进思路

Tennant法作为国内外应用最为广泛的水文方法,在生态基流研究中起着重要作用。但是,作为一种经验方法,具有局限性,在参考或应用某种方法时应该对其进行合理性分析。系统总结了Tennant法普遍存在的时空变化大、流量适宜性较弱、普适条件较差的3个关键问题,基于3种改进形式的变量:特征流量、用水期、百分率,深化研究Tennant方法的改善战略,进而归纳出3种改进方法:年均值法、同期均值法、改进百分系数法。最后,对Tennant法进行展望,提出选取具有年内和年际丰枯变化性的低流量指标、建立基流百分比与水生生物栖息地之间的适应曲线簇、有针对性地修正具体河流中水生生物的生物和物理需求、确定生态基流阈值时需考虑到流量与河流生态系统之间的关系等发展趋势,以期拓宽Tennant法的使用范围、完善不同地区河流生态基流的技术支持。

Application status and improvement ideas of river ecological base flow based on Tennant method

As the most widely used hydrological method at home and abroad, the Tennant method plays an important role in the study of ecological base flow; however, as an empirical method with limitations, we should analyze its rationality when refer to or apply it. We systematically summarized the three key problems of the current ubiquitous spatial and temporal changes, weak flow suitability, and poor general conditions. Based on three improved forms: characteristic flow, water-use period, and percentage, we studied the improvement strategy of the Tennant method, and further summarized three improvement methods: the annual average method, the simultaneous mean method, and the improved percentage coefficient method. Finally, we selected low-flow indicators with annual and inter-annual variability to establish a cluster of adaptation curves between the percentage of base flow and aquatic habitats, and to target the correction of aquatic organisms in specific rivers. Physical needs and the determination of the ecological base flow threshold need to take into account the development trend between the flow and the river ecosystem, in order to broaden the scope of use of the Tennant method and improve the technical support of river ecological base flow in different regions.