Relationships between flood detention and utilization of water and soil resources at small and medium circled embankments in Lake Poyang

摘要

Lake Poyang is the largest freshwater lake in China with a catchment area of 162,000km~2 and its flood prevention will cause a great influence to the regional economic development and social stability. There are 564 circled embankments in the lake, which protect agricultural field of 4180.7 km~2 and populations of 7.227 million. these embankments take active actions to economic production and social stability. But some negative effects of these embankments have come out these years, such as they occupy too much width of the lake for flood drainage so that they have produced negative influence to lake flood discharge. Based upon the actual circumstances of Lake Poyang and elementary theory of flood hydraulics, this paper analyzes influences and contributions of embankment flood detention to descend lake flood water level, and discusses the embankment utilization forms of "flood detention during flood period and utilizing water and soil resources during low water period". The criterions for flood detention with embankments, the flood detention frequency and the sequence of embankments putting into flood detention have been pointed out. Moreover, the utilization forms of water and soil resource in the circled dykes, which coordinate with the requirements of flood detention, have also been studied in this paper.