Construction Diversion Risk Assessment for Hydropower Development on Sediment-Rich Rivers

Hydropower is an important renewable energy, and Construction Diversion Risk (CDR) should be highlighted and assessed during hydropower development. Since sediment-rich rivers are widely existing around the world and have great hydro-energy potential, assessing CDR for hydropower development on sediment-rich rivers in terms of engineering feasibility is of significance. This paper proposes a CDR assessment method for the sediment-rich hydropower development environment. The method is concise and practical, reflects diversion uncertainties and correlation, and mainly adopts the Gumbel–Hougaard Copula and the Monte Carlo Simulation. Through simulating flood evolution and sediment impact during diversion, the method can assess CDR basing on the cofferdam overtopping probability. Case results show that the proposed method can achieve CDR assessment on a sediment-rich river and highlights sediment impact on the diversion risk. Through results discussion, the risk feature of construction diversion on sediment-rich rivers is revealed, that sediment impact causes the dynamic and yearly-risen CDR. Hence, our conclusions are: (1) the proposed method is feasible, effective and has industrial potential, and (2) a diversion scheme on sediment-rich rivers is suggested that adopts the design with high or yearly-heightening cofferdams, based on the advanced CDR assessment to cope with the risk features of sediment-rich diversion environments.

Risk analysis of construction diversion scheme

The determination of diversion risk in the construction of water conservancy and hydropower projects is a key problem related to the guarantee of project safety, saving project investment, giving full play to benefits in advance and facilitating construction. According to the design data, considering the influence of the uncertain factors such as hydrology and hydraulics, this paper analyses the relationship between the elevation of the upstream cofferdam and the upstream design water level, uses the Monte Carlo method to simulate the construction flood process and the discharge capacity of the diversion buildings, makes statistical analysis and determines the risk corresponding to the upstream water level distribution of the cofferdam and the water retaining height of the cofferdam, and establishes the calculation model of the construction diversion risk.

Multi-Attribute Group-Decision on a Construction Diversion Scheme for Hydropower Projects Based on Perception Utility

The multi-attribute and group-decision problem in the selection of a construction diversion scheme for large hydropower projects often involves multi-decision subjects and schemes. Each scheme includes multiple attributes, and the attribute values and weights are multi-attribute group decision-making problems with interval numbers. In this study, a new method for solving the multi-attribute group-decision problem is proposed by integrating regret theory, negotiation gathering theory, and the Monte Carlo simulation technique. Firstly, decision-makers’ comprehensive perception utility for each scheme is calculated based on the regret theory. Then, non-uniform and fuzzy opinion of different decision subjects are negotiated and gathered, and negotiation intervals of the attribute weights are calculated through group negotiation gathering theory. Moreover, fuzzy complementary judgment matrixes describing an excellent degree of the diversion schemes are obtained by conducting Monte Carlo simulations. Finally, the alternative diversion schemes are sorted in terms of their priorities, and the reliability of the sorting procedure is confirmed. The multi-attribute group-decision problem in the selection of a construction diversion scheme for Jinping I Hydropower Station is effectively solved by the proposed method. The proposed method is reliable and may significantly contribute to engineering decision-making.

Diversion Scheme for Yuliang Hydro-Junction Project of Youjiang River in Construction Period

Determination of construction diversion scheme is the most important part in the hydro-junction engineering design of inland waterway, which will influence the general layout, construction time and total cost. Based on the method of combining remote-controlled self-propelled ship model test with physical model test, the velocity and flow pattern of diversion channel in the first construction period, navigation flow condition of temporary channel, the velocity and flow pattern of release sluice and the navigation flow condition during the second construction period were analyzed in this paper. The problems in the construction diversion scheme were studied, and the improve measures which could meet the requirement for navigation and diversion were proposed.