Research And Application Of Flood Loss Estimation In Flood Detention Area

The loss caused by flood and waterlog is more than any other natural damages all over the world. In general, flood damage can be broadly classified into two categories: tangible and intangible damages. Tangible flood damage consists of two types: direct and indirect damages. In this study, flood loss is restricted to tangible damages for each of the major categories.Because of the idea of water control conversed from flood control to flood management, flood storage and detention area is playing an important role in the contemporary floodwater prevention and control. Estimation of economic loss caused by floods in a detention area is very important for mitigating flood disaster, and a flood loss model is essential for this purpose. Such a model has a wide range of application in various flood disaster mitigation aspects such as flood warning, flood insurance policy development, real-time flood mitigation measures, etc.This paper introduces an integrated model for flood loss estimation in flood storage and detention area. A case study illustrates the application of the integrated model to DaHuangPuWa detention area in Tianjin, which is the detention area of Haihe river basin. The integrated model has two major components: a numerical model of flood propagation and a flood loss estimation model.The numerical model consists of a 1-D model to simulate the movement of flood in rivers and a 2-D model applied to the detention area. The St-Venent's governing equations for flow propagation in flood propagation model are solved using finite difference schemes. In the flood propagation model, the area is divided into small grids to establish a network and the model simulates flood inundation parameters for each grid which can be used in the loss estimation model to simulate flood damage for each grid cell.The loss estimation model is formulated based on different flood inundation parameters and social and economic features. The model calculates the economic loss based on the simulated flood parameters obtained from the numerical flood propagation model. Some of the most important issues in flood loss estimation are acquisition of detailed flood parameters such as flow velocity, depth and duration. Loss rate of flood reflects the relationship between flood parameters and possible damage, which are derived based on historical flood damage information, questionnaire survey, laboratory experience, etc. In this paper, an integrated system of loss rate is established and applied to DaHuangPuWa detention area and this system has a special reference to North China.In this paper, the spatial distribution information of flood is united with which of social and economy information, and Geographical Information such as RS and GIS is used to estimate the loss of flood damage by the way of establishing the model of spatial information grid.In the loss estimation model, the system of flood loss estimation is established, and it could be applied abroad owing to its high precision and simpleness.