Impact of regulating rubber dams on the accompanied flood risk during

Existing risk analysis methods have neither the simulation of physical processes nor the discussion of risk randomness. Taking the Interconnected River System Network (IRSN) as an example, the associated risk analysis model of IRSN under random hydrological conditions was established based on the hydraulic model and the correlation of flood peaks. The flooding process in the upper reaches of the Yi and Shu River System is simulated by 1 200 sets of hydrological conditions. Aiming at the problem of flood peak superposition caused by rubber dams, this paper provides risk control suggestions for rubber dam operation and dispatch under different flood return periods. Our results showed that the risk of water level is extremely high (risk probability> 0.8) and the risk of flow rate is lower than 0.3 at the site of the rubber dam under the conditions of the 50-year flood return period and the hundred-year flood return period. When the rubber dam is increased by about 25% of the designed dam height, the risk of water level increases by approximately 70% in front of the dam in the Yi and Shu Rivers, and the risk of flow rate is reduced by about 50% at the dam site of the Shu River. If the dam is collapsed to release water before the flood season, the superposition of man-made flood peaks will cause an extremely high risk in the middle and lower reaches of the Shu River. By dividing the comprehensive flood risk safety area of water level and flood rate, it is suggested that the rubber dams be adjusted to less than 50% of the designed dam height before flood season in the Yi and Shu Rivers, and the depth and velocity the of Shu River be controlled within 12 m and 2.23 m/s respectively, so as to reduce the risk of water level and flow rate to low risk (< 0.4) in the 50-year flood return period. Moreover, to effectively reduce flood control pressure of the Yi and Shu River System in a hundred-year flood return period, it is necessary to adjust the rubber dams to below 25% of the designed dam height or to slowly collapse the dam before the flood season.