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When carrying out the inter-basin water diversion project, we must face problems such as the long river routing distance and complex hydro-meteorological conditions along the main channel. Under the condition of the unchangeable standard of the designed rainstorm, the changes of the underlying surface could inflect the designed flood. As a result, the drainage channel is not as consistent as the designed condition, therefore the flood discharge condition in the upper and lower sub-reaches changes, and the actual flow capacity of the hydraulic structure is reduced compared with the designed conditions. The above-mentioned situations could cause risk event of the rising of designed flood level in the left bank and will cause local flood risk, and also cause corresponding economic losses and social impacts. In this study, for the first time, the fishbone-diagram method is applied to identify the local flood risk factors of the inter-basin water diversion project. By using this method, the changes of characteristic values of watershed above cross section, villages, factories or other buildings at the outlet location of the drainage structures etc. are identified as the local flood risk factors, and there are mainly eight types of local flood risk factors which can be taken into consideration when selecting engineering and non-engineering measures to reduce or eliminate the risk factors. PACS: J0101

After the water diversion project has been put into operation for many years, due to the long distance, complex hydro-meteorological conditions, and rapid development of social economy, the underlying surface conditions of corresponding natural basins in the design units of water diversion project have changed to some extent compared with the beginning of the project design, especially the underlying surface situation of rivers in the northern region has changed greatly. Based on ArcGIS to extract basin characteristic values of the design unit of water diversion project, such as basin area, river length and slope, this paper analyzes the changes of current basin characteristic values of design unit compared with the design period. For the design unit with significant changes in the basin characteristics, the original design flood calculation method is used to calculate the flood of the same design rainstorm under current conditions, and the impacts of changing basin underlying surface on design floods are analyzed. PACS: J0101

Since the 19th National Congress of the Communist Party of China, the high-quality development of China’s economy has put forward higher requirements for scientific and technological support of water safety guarantee. The flood control conditions of the design unit of water transfer project have changed to a certain extent compared with the initial design stage, especially the underlying surface of rivers and engineering conditions in the northern region have changed greatly, which has seriously affected the conveyance safety of water transfer project and the supply guarantee of water receiving area. Therefore, it is necessary to evaluate the change degree of flood control conditions in the design unit of water transfer project, and point out the weak links of flood control, so as to guide the flood control safety construction of the left bank area. In this paper, from the aspects of the change of underlying surface conditions, the actual flood discharge conditions of upstream and downstream, and the actual discharge capacity of buildings, the change of actual flood discharge conditions of water transfer project design unit compared with the original flood control design conditions is comprehensively considered. According to the principle of relatively independent, quantifiable and easy to obtain between indexes, the evaluation index system of flood control design condition change is established, On the basis of determining the classification standard for the quantitative and qualitative indexes, the entropy weight and fuzzy mathematics comprehensive evaluation model are used to evaluate the change degree of the current flood discharge conditions and the original flood control design conditions of each design unit of the water transfer project. For the units with large changes in flood control design conditions in the evaluation results, corresponding measures to eliminate risk factors and risk control will be taken. Finally, taking the flood control risk evaluation of a management office in a large-scale water transfer project as an example, this paper evaluates the change degree of the current flood discharge conditions and the original flood control design conditions of 16 three-level units in the management office. The results show that there are 6 three-level units with changes in the original flood control design conditions, including 4 great changes and 2 significant changes. The application example shows that the entropy weight and fuzzy mathematics comprehensive evaluation model can accurately reflect the change degree of each three-level design unit in the management office, and play a certain technical support role in the study of the performance change law in the life cycle of water transfer project and the theory of water transfer project and service environment evaluation. PACS: J0101

The design and development of Flood Forecasting and Regulation System (FFRS) is an important part of non-structural measures for flood mitigation, and Browser/Server (B/S) system based on WEB technology is one of the main directions of the system development. The framework of FFRS based on B/S system is introduced in this paper, which includes four levels, i.e. the database level, application support platform level, the application level and the user level. The framework can provide several functions, such as flood situation analysis, flood forecasting, flood regulation and system management, which has been used for the FFRS development of Poyanghu Lake Basin in China as technical support for decision making of local flood control. Currently, the system covers almost 102 flood forecast points and 37 reservoirs, for which flood forecasts and regulations are accessible online. This work would also be demonstration for other locations.

A point clouds filtering algorithm is presented based on Grid Partition using Dynamic Quad Tress and Moving Least Squares. First, points are partitioned reasonably and corresponding Dynamic Quad Trees indices are established. Second, points in grids are utilized to fit a DEM reference plane using moving least squares technology. Finally, ground points are separated from those non-ground ones if they are positioned above the reference plane and have a distance to the plane exceeding threshold value. Experiments show that this filtering algorithm is of high precision and identify ground points effectively without losing detailed topography information.