| As the growth of the national economy, the contradiction between supplyand demand of water resources become more and more prominent in Lvliangcity nowadays, take no account of new flood control project, On the premise ofmeet the reservoir’s flood control safety, raising the flood limit levelappropriately and increasing the reservoir’s utilizable capacity is one of theeffective ways to solve the water shortages in Lvliang city. This paper aroundthe relevant issues of flood limit level, and start the research from the aspects ofre-checking design flood, flood season division, ascertaining the design flood,determining flood limit level, analyzing the availability of rainfall forecast andthe risk of reservoir. The main research contents are as follows.(1)Shanxi Province formulated the new <Shanxi Province hydrologycalculation handbook> in2011, this paper adopts the new method to re-checkthe design flood of Taiping Reservoir, the results show that the calculating resultof the new method is5%~10%lower than old one, and the result provides thepossibility for raising the flood limit level.(2) The flood season of Taiping Reservoir has never been divided, thescheduling pattern is single flood limit level during the all flood season. Thiswill lead to the reservoir in an over flood control standard condition at most time,and a large number of utilizable capacity are waste. Therefore, this paper fromthe two aspects of qualitative and quantitative, uses hydrological geneticanalysis method, mathematical statistics method, Fisher optimal partitionmethod and the fractal theory method to divide the flood season, thensummarizes the advantages and disadvantages of various methods, finallydetermines results as follows: pre-flood season is from June1st to June30th, major flood season is from July1st to August31th and fol-flood season is fromSeptember1st to September30th.(3) On the basis of the flood season divison, this paper expounds thevarious of the sampling methods, and summarizes their advantages anddisadvantages, then combined with the actual situation of Taiping Reservoir,adopted the annual maximum series in each season to choose the sample, anddiscussed flood control standard between the annual and each season, putforward the suitable method to calculate the flood control standard of eachseason., That is the flood control standard of each season is three times as it in ayear. Then the seasonal design flood can be calculated out.(4)Using the seasonal design flood to determine the flood limit level, theflood limit level in pre-flood season and major flood season keep the original121.2m, and putting emphasis on the regulating calculation of fol-flood season,finally, the flood limit level of fol-flood season can be raised to122.8m. Andthen putting forward the scheduling criteria of Taiping Reservoir.(5)By analyzing the accuracy of rain forecast and actual measurementprecipitation, we can obtain that no rain, light rain and moderate rain forecastare available, and according to the pre-store and pre-discharge method, we cancalculate out the upper limit value of dynamic flood limit level is123.5m.(6) Calculating the risk of raising the flood limit level and omitting therainfall forecast, flood season division can be described as an event, which is thehighest flood level in each flood season overpass the original flood level.According to the describe, we can establish the calculation model and adopt thenumerical approximation method to calculate the risk of raising flood limit levelup to122.8m. The result is0.0041%, less than0.33%, which is the checkstandard of Taiping Reservoir. The risk of omitting the rainfall forecast can beexpressed as the flood frequency which Taiping reservoir can resist. Bycalculation, when encounter no rain, light rain, moderate rain, the risk ofomitting rain forecast are0.002277%,0.004871%and0.003841%respectively, less than0.33%, which is the check standard of Taiping Reservoir. |
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