Calculation and Analysis of the Influence Characteristics of Inland River Flood on the Flood Storage Volume of the Longsai Lake Flood Storage and Detention Area.

The effective flood storage volume of flood storage and detention area is the real capability of occupying flood, which is a fundamental basis when formulating and optimizing real-time the flood dispatching plan in flood storage and detention area. The dispatch of inland river flood will occupy the flood storage volume of lakes, polders and swales in the flood storage and detention area, reducing the effective flood storage volume. This paper selects the flood storage and detention area of Longsai Lake, Hanbei River as an example, calculates and analyzes the flood storage volume and its variation characteristics of lakes, polders and swales occupied by the inland river flood dispatching at different frequencies as well as the change rule of the effective flood storage volume after dispatching inland river flood and its influence. The results show that: ➀ When there are lakes, polders and swales in a flood storage and detention area, the flood storage volume of lakes occupied by the dispatching of inland river flood is significantly greater than those of polders and swales, and the greater the inland river flood, the greater the difference in flood storage volume occupied between lakes versus polders and swales. When the 5-year to 50-year occurrence flood happens in the inland river of the Longsai Lake flood storage and detention area, the flood storage volume occupied by lakes are 97.9%~98.1% in all dispatching volume. ➁ The reduction of the effective flood storage volume in flood storage and detention area caused by inland river flood dispatching changes with the frequency of inland river flood. The greater the flood in the inland river, the more significant the reduction of effective flood storage volume in flood storage and detention area. When the 50-year occurrence flood happens in the inland river of the Longsai Lake flood storage and detention area, the effective flood storage volume decreases by about 13.5%, and when the 5-year occurrence flood happens, the effective flood storage volume decreases by 7.81%. ➂ When the inland river flood occurs and is likely to encounter the flood of the mainstream, the reduction of effective flood storage volume will influence the flood dispatching plan obviously, and the effective flood storage volume of the flood storage and detention area shall be calculated and determined in real time according to the incoming flow, and the dispatching plan shall be optimized or adjusted, the personnel and property shall be transferred in advance. [ABSTRACT FROM AUTHOR]