The Dualism And Characterization Of Environmental Flow

Water plays an irreplaceable role on the socio-economic development and on the natural ecosystems which are the survival necessities for humanity. The issue on how to obtain a reasonable allocation of the limited water resources and maintain good ecological environment among higher socio-economic benefits must be taken into fully account for the sustainable development purpose. With an overexploitation of the water resources, the river ecosystem problem is increasingly prominent nowadays, which lead to the construction of the concept of environmental flow to coordinate the conflicts between socio-economic development and river ecosystem protection. According to the subsistent discordance of the environmental flow assessment criteria, methods and even the concept itself, the present paper proposed the concept of environmental flows from the perspective of the conflict theory, elaborated its connotative and denotative meanings, as well as its features. The contradictory duality coordination model of environmental flows was built in the present work with an improved indicator system of environmental flow characterization.Specific content and main findings are as follows:i) Based on ecological ethics, ecology and watershed dualistic water cycle theory, the relationship between the river flow and socio-economic systems, as well as natural ecosystem were described:a) As one of the driving forces of the dualistic water cycle, the socio-economic system development would affect the river flow through the watershed "natural-artificial" dualistic water cycle, which could cause the change of the river flow on the quantity, quality and the time; b) The river flow, a part of the river ecological processes, has indirect effects on the river biological processes through the impacting on other processes, thereby affecting the river ecosystem health and ecosystem services; c) The relationship between the river ecosystem and socio-economic systems could be identified as dialectical.ii) The concept of environmental flows was proposed from the perspective of conflict theory, the connotation, denotation and characteristics of the environmental flows were also described. The definition of environmental flow is based on the proper quantity, quality and the time of river flow, which could fulfill the coordination of the dualistic conflict between socio-economic development and river ecosystem protection. This concept can be converted into the existing concept of environmental flow under the circumstances where different coordinated principles and contained elements were taken into account. The connotation of environmental flow refers to certain river flow which could maintain the health of river ecosystem under the disturbance of human activities, while its denotation is defined as the threshold or the thresholds domain of the quantity, quality and time of river flow. Environmental flows have duality. Drive of environmental flow possesses a natural-social dual attributes, of which the natural attributes reflected in the respect that the formation of river hydrology and water quality is accomplished in a natural circulation of materials and the forming process of rivers, while the social attributes are embodied in that river hydrology and water quality processes are disturbed by human activities. The function of environmental flows has an ecological-social dual attributes, which can be defined and distinguished by the different value subjects of the functions:human being itself and other issues related to human are defined as the value subjects of the social and ecological functions, respectively. Moreover, the drive and function of environmental flow possess the properties of spatiotemporal dynamics and scale diversity.iii) The index system including the quantity, quality and time of the flow was built to characterize environment flow. The quantity element of the system contained two characteristic factors:runoff and base flow; while the quantity element contained four characteristic factors:water environmental quality levels, water function zones compliance rate, specific temperature indicator and dissolved gases; and finally, the factors of volume, time of occurrence, duration, frequency and rate of high flow, small floods and large floods were taken into the element of time.iv) Based on the methods and principles of the DSR conceptual framework, the dualistic contradiction coordination model was constructed. This model framework can be divided into three sub-models:one was named the drive sub-model, in which the relationship between the dualistic drive and the three elements of environmental flow was described and expressed as D(X, Y)→｛RD|(αq,βc,γt)}= Q; another is the functional sub-model that described the relationship between the three elements of environmental flows and the dualistic functional, expressed as G(E,S)→｛RG|(αq,bc,ct)}= T; the third is the coordination sub-model:in the case of Q ∈ T, Q is considered as the environmental flow under the current conditions of the protection environment and the socio-economic development, as Q (?) T, the contradictory between socio-economic development and ecological protection needs to be coordinated, expressed as L= (L1,L2,L3, …)→p RL∈T, for which there are four main principles to be followed, namely, sustainable development, bottom line guarantee, functional zoning adaptation and the principal contradiction.v) A case study was carried out on the basis of trunk steam of the upper reaches of the Yangtze River in the national reserve of the rare and endemic fishes. The mainly social driving factors of environmental flows in the trunk steam of national reserve is the cascade reservoir operation in the lower reaches of the Jinsha River, and the confluence of Minjiang River could effectively mitigate the impacts of the cascaded reservoirs on eco-hydrology of the downstream of the confluence. The ecological function is to protect the rare and endemic fishes and their habitat, the main demand including high-flow process and specific temperature conditions. In accordance with the principles of sustainable development, the functional zoning requirements and the principal contradiction, the current flow of protected areas meet the conditions of rare and endemic fish thrive, however, after cascade reservoirs operation, some measure will need to slow down the flow process change, such as ecological operation, stratified water, joint scheduling, integrated watershed management, adapting management, etc.From the view of the conflict between socioeconomic development and ecological environmental protection, a new concept of environmental flows with wide universality was proposed in the present article. A dualistic contradiction coordination model was constructed innovatively, and the index system of the environment flow characterization was further improved. Taking the reserve in the upper reaches of the Yangtze River as a case study, theoretical and technical supports were provided for the future management of environmental flows.