Studies of sediment hazards and associated countermeasures in Venezuela

这项联合研究旨在从泥沙动力学的角度分析1999年的泥沙灾害，并为泥沙灾害的防治提供可靠的工具，并进行了四个分专题的研究。1.委内瑞拉北部加勒比海沿岸地区强降水特征。2.1999-灾后泥沙径流特征模拟。3.泥沙灾害的历史面貌；4.泥沙灾害的防治对策。研究结果总结如下：1.研究成果。分析了与暴雨相关的时间和空间尺度上的气象相互作用。在此基础上，提出了一种从众多事件中区分异常降水的方法。改进了预报泥沙径流的一维和二维数学方法，并将它们应用于1999年的灾害，并用自灾害以来收集的泥沙径流数据进行了检验。这些肯定是描绘危险地图的强大工具。泥沙灾害历史方面的研究结果表明，除了适当的结构对策外，常规的教育表现、危险地图和相关的土地利用对于减少泥沙灾害也是重要的。提出了数学工具来确定碎片控制结构的位置、类型和大小。

This joint research was conducted to analyze 1999-sediment disaster from a viewpoint sediment dynamics as well as to propose reliable tools for countermeasures against sediment hazards, and four sub-topics were studied. 1. Characteristics of heavy rainfall in Caribbean Sea coastal region of north Venezuela. 2. Simulation of 1999-sediment runoffs and sediment runoff characteristics after the disaster. 3. Historical aspects of sediment disasters and 4. Countermeasures of sediment hazards. The results are summarized as follows.1. Meteorological interactions between temporal and spatial scales associated with the heavy rainfall are analyzed. Based on the results, a method is proposed to distinguish an abnormal rainfall from numerous events.2. 1-D and 2-D mathematical methods for predicting sediment runoff are refined by applying them to 1999-disasters and tested using sediment runoff data which have been collected since the disaster. These are assured to be powerful tools in delineating hazard maps.3. The results obtained from the study on historical aspects of sediment disaster suggest that usual education performances, hazard maps and associated land uses are of importance to reduce sediment hazards in addition to proper structural countermeasures.4. Mathematical tools are proposed to specify the location, type and size of debris control structure.