Rivers Function Zoning And River Training Mode

With the rapid socio-economic development, the ability to transform nature of human becomes stronger and stronger, so the ecological and environmental needs and expectations have been increased accordingly. River regulations not only play the important roles in flood control, disaster mitigation and water supply, but also in social and ecological environment, which affect the development and progress of entire regions. The traditional river regulation is mainly for forecasted flood. Now, with the update of people's concepts, "creating harmonious riverside environment between human and nature" and "finding a balance between rational utilization of water resources and ecological health" have becoming new the ideas in river regulation. The resulting problem is that rivers environmental protection and construction need to find an appropriate theoretical system and the technical methods to provide support for engineering practice.In this study, a set of techniques and methodologies of river functional assessment, functional zoning and the governance model of typical functional areas has been presented to balance the utilization and protection of river resources. River ecological restoration are detailed in this paper. The main contents and research results are summarized as follows:(1) Comprehensive evaluation method of river function is established used the multiple-indicators evaluation method to support the functional zoning. The indicator systems of natural and societal functions are built separately. According to scoring method, the indicator grading and grading standard are set. From the temporal and spatial scales, the index scores are calculated. A case study is offered to prove the feasibility of the evaluating method. The results indicate that the condition of natural function is "Marginal" and societal function is "Good" in studied region, so the restoration of riverbank vegetation and the habitat construction for rivers species should become the main goal of river regulation in future.(2) Rivers function zoning method is proposed on the basis of the status of regulated rivers and functional requirements, in which the regionalization objectives, principles, classification system, division method and zoning procedure are systematically researched. For the ecosystem continuity and river functions integrity and considering the intensity of human utilization and river functional requirements, the functional areas are divided into five types: Ecological Protection Area, Habitat Restoration Area, Development and Utilization Areas, Buffer Area and Transition Area. The qualitative descriptions and the quantitative distinguishing method of these functional areas are given. The latter is based on two criteria to establish functional zoning map, which are evaluating scores of natural and societal functions. Summarized above the mentioned, the zoning procedure of rivers function is offered eventually.(3) As governance model of different functional areas, this study focuses on the Habitat Restoration Area, including eco-revetment engineering and the improvement of habitats. For an eco-revetment project of urban river, various factors must be considered, such as the economic, ecological, recreational and social. Based on that, this paper first gave several typical structure designs meeting with the different functions such as ecological function, aesthetic function and recreational function. Then, an assessment system of revetment work, consisting of eight indicators, is established. Applied this assessment system, a fuzzy multi-attribute decision-making method based on TOPSIS is proposed to prioritize the alternatives. In the case study of the Hunhe River, the data both the indicator relative importance, surveyed by pair comparison, and the relative preference of projects, surveyed via linguistic variables, are collected from ten experts through Delphi method. The former is processed by AHP, and the latter is dealt with TOPSIS after the preference data is converted into the quantitative used the Fuzzy Set theory. The sensitivity analysis both indicator weights and different calculation methods indicates that Construction Cost and Maintenance Cost are dominant indicators, and the distance calculation method and normalization technique are insensitive to the projects prioritization. The proposed methodology is effective and feasible method for managers to evaluate and choose the optimal engineering measures for riverbank protection.(4) In the study of habitat improvement, the habitat classification and assessment methods are reviewed firstly. Then, the quantitative method of habitat based on numerical simulation technology is established, which assumes that the diversity of habitat affects biodiversity. So, the flow regime is used to denote the types of habitat, which can be solved by hydrodynamic model. From the contour maps of the flow regimes, habitat area can be calculated, by which the habitat diversity can be evaluated and the habitat distribution map can be developed to help the engineers for planning. A case study is offered to demonstrate the study process and the results indicate that the quantitative method proposed by this paper is simple and feasible in river ecological restoration.Finally, a summary of the paper contents is given and some problems needed to be further studied are discussed.