The Value of Environmental Base Flow in Water-Scarce Basins: A Case Study of Wei River Basin, Northwest China

Siyu Yue,Huaien Li,Bo Cheng,Zhiyue Gao

doi:10.3390/w10070848

Abstract

In the perennial river, environmental base flow, associated with environmental flow, is the base flow that should be maintained within the river channel throughout the year, especially in the dry season, to sustain basic ecosystem functions and prevent the shrinkage or discontinuity of a river. The functions of environmental base flow include eco-environmental functions, natural functions, and social functions. In this study, we provided a method based on these functions; this method estimated the function values per unit area, introduced the scarcity coefficient, multiplied by the corresponding water area, and summed over to quantify the value of environmental base flow from 1973 to 2015 in the Wei River Basin, the largest tributary of the Yellow River in Northwest China. We observed that there was a positive correlation between the total value of environmental base flow and its water yield, whereas this outcome was completely different in the benefit per unit discharge of environmental base flow, which was closely associated with the shortage of environmental base flow. This method can thus present the considerable value of environmental base flow in monetary terms in a simple and effective way and lay the foundation for further reasonable protection levels of environmental base flow.

Highlights

We focused on the e-flow within the river channel, which can be referred to as environmental base flow (EBF)
“waste treatment”, “nutrient transport” to “nutrient cycling”, “hydrologic cycle” to “water regulation”, “recreation and landscapes” to “recreation” and “fishery production” to “food production”; (2) We believed EBF can maintain the normal functioning of wetland ecosystems connected with the natural river channel, so all functional values of a wetland could be included, that is, “sustaining wetland ecosystems” to “wetland”; (3) We converted all prices to 2015 RMB based on the exchange rate and discount rate for the sake of more comparable evaluation; (4) Qualitative analysis was not compared here
Both of them are associated with social function in the dry season of water scarce basins; EBF still provides for humans, supporting human recreation and fisheries, even if it is very costly for the ecosystem, and that is why the value of these two functions is high

Summary

Introduction

Humans have chosen to live near rivers, which are the main birthplaces of human civilization, since ancient times [1]. [2], which has caused the remaining water in the river channel, known as environmental flow (e-flow) [3], which had been appropriated in the long term, to decrease in amount, followed by irreversible impacts on riverine ecosystems [4]. This phenomenon is intensified in water-scarce basins Since the Industrial Revolution, with continuously burgeoning populations and rapid urbanization, flow extraction from rivers has been increasing in terms of feeding, drinking, irrigation, industry, hydropower, etc. [2], which has caused the remaining water in the river channel, known as environmental flow (e-flow) [3], which had been appropriated in the long term, to decrease in amount, followed by irreversible impacts on riverine ecosystems [4].

Methods

Results

Discussion

Conclusion