| Flood disaster,is one of the world’s most severe natural disasters and seriously affects the safety of people’s lives.With the deepening of the study flood,flood forecasting as an important non-structural measures of flood control,can effectively help people to flood prevention,to reduce flood damage.This paper takes Tangma Reservoir as the research object,combines the characteristics of small and medium-sized reservoir basins in the hilly area,and analyzes the rain and water conditions based on many years of historical data.Considering the stagnation of the upstream small reservoirs,a model for predicting the flow of small and medium sized reservoirs based on API model and SCE-UA algorithm is constructed,and the model is validated using the observed data.Different production flow and confluence schemes were formulated and the effects of different production and confluence schemes on the design water level of Tangma Reservoir were analyzed and compared.The main conclusions and research results obtained are:(1)Judging from the total amount of rainfall for many years,the annual rainfall generally shows an upward trend,inter-annual rainfall changes greatly,and the rainfall is distributed unevenly during the year.The rainfall in the Tangma Reservoir basin is mainly concentrated in the period from May to August,water utilization rate is not high;annual rainfall is mainly concentrated in the rainfall interval of 700-900mm and 900-1100mm.Rainfall is mainly caused by light rain and moderate rain,there has been no torrential rain in 50 years;the relationship between rainfall and rain days is generally presented.As for the rising trend,the rainfall in most years will increase with the increase of the rainy days,and the rains and rains will be scattered in different years.The correlation between the annual rainfall and rain days will be poor;the return period will be 10 and 20.In the design of annual rainfall,the results of the multi-year method and the super-quantitative method can be considered.When the return period is large,the multi-year method and the super-quantitative method do not apply to the Tangma Reservoir.(2)Considering the influence of the upstream small reservoirs on regional production flow,an output prediction program for flood forecasting of the Tangma Reservoir based on the API model and the SCE-UA algorithm was constructed.In the 48 floods of the Tangma Reservoir,the number of qualified sites was 35.The qualification rate is 73%,and the runoff forecast program is B.In the 48 floods,small reservoirs played a role in impounding and impounding,and the total storage capacity accounted for 77.3%of the total storage flow of small reservoirs.The storage function of small reservoirs had a greater impact on the catchment flow of the Tangma Reservoir.(3)Through the analysis of the effect of different production and confluence schemes on the design water level,it was found that the production flow parameters have less impact on the design water level and the sensitivity is not high.The convergence parameters have a greater impact on the design water level and have higher sensitivity;for two parameters of production flow(Cp,Ci),the sensitivity of Cp is lower than that of Ci.For the two sink parameters(n,K),K is more sensitive to peak flooding flow and highest water level in storage than n.For the runoff plan,when the Cp value becomes larger,the net rainfall produced by the basin will decrease,the flow of storage will decrease,the peak flow rate of storage will also decrease,and the maximum water level will also decrease;when the value of Ci increases,The net rainfall produced by the basin is reduced,the flow of storage is reduced,the flow of flood peaks into the reservoir is also reduced,and the maximum water level is also falling.For the convergence scheme,the changes in n and K have a significant effect on the shape of the inbound flow curve.As the value of n becomes larger,the graph becomes taller and thinner,the peak flow rate of the flood peak becomes larger,and the appearance time of the flood peak is delayed.However,the maximum water level appears to be smaller and then larger;the value of K increases.The curve became chunky,the peak flow rate was delayed,the flood peak flow became smaller,and the entire inbound traffic flow became flatter.Different production flow and confluence schemes were formulated and the effects of different production and confluence schemes on the design water level of Tangma Reservoir were analyzed and compared.This paper takes Tangma Reservoir as the research object,and provides the scientific basis for the production forecast,flood disaster prevention and reservoir operation of Tangma Reservoir through the study of this paper.According to the analysis of the production flow model and the influence of production and sink flow parameters on reservoir design water level in this paper.The research results can provide certain reference for the flood forecasting construction of small and medium-sized reservoirs in the Jiangsu Province,especially the small and medium-sized reservoirs in the hilly areas,the reservoir’s flood regulation calculations,and reservoir regulation. |
