Abstract
It is of great significance for the watershed management department to reasonably allocate water resources and ensure the sustainable development of river ecosystems. The greatly important issue is to accurately calculate instream ecological flow. In order to precisely compute instream ecological flow, flow variation is taken into account in this study. Moreover, the heuristic segmentation algorithm that is suitable to detect the mutation points of flow series is employed to identify the change points. Besides, based on the law of tolerance and ecological adaptation theory, the maximum instream ecological flow is calculated, which is the highest frequency of the monthly flow based on the GEV distribution and very suitable for healthy development of the river ecosystems. Furthermore, in order to guarantee the sustainable development of river ecosystems under some bad circumstances, minimum instream ecological flow is calculated by a modified Tennant method which is improved by replacing the average flow with the highest frequency of flow. Since the modified Tennant method is more suitable to reflect the law of flow, it has physical significance, and the calculation results are more reasonable.
Highlights
As known, river ecosystems play a significant role in watershed ecosystems, whose primary functions are purification, water storage, landscape, shipping, maintaining biodiversity, offering habitats for aquatic animals, and so on [1, 2]
Since the annual runoff in the Wei River Basin has nonlinear and nonstationary characteristics, the heuristic segmentation method introduced in Section 3 is employed to detect the change points of the annual runoff
It can be obviously seen that the frequency of monthly flow satisfying the maximum instream ecological flow before the flow variation is extremely larger than that after the flow variation, especially for the Beidao station; the frequency of half of the months after variation is zero, implying that the river ecosystem is subject to severe damage after the flow variation
Summary
River ecosystems play a significant role in watershed ecosystems, whose primary functions are purification, water storage, landscape, shipping, maintaining biodiversity, offering habitats for aquatic animals, and so on [1, 2]. The key step to improve river ecosystems is to reasonably calculate the instream ecological flow. The Guanzhong Plain is designated as a state key economic development zone, which will greatly promote the economic development of surrounding area. The flow of the Wei River is seriously polluted on a large scale, leading to severe ecological damages, which will greatly restrict the economic and social development of this basin and will even affect national economic development strategy. For this reason, it is necessary for the local watershed management department to accurately calculate the instream ecological flow in the Wei
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