| Floods disaster frequently occurs, and annual floods control is really challengingproblem in China. On the other hand, the increasingly lack of water resources is a seriousproblem we are facing now. Exploiting floods resources and realizing benefits and floodscontrol are important research fields in hydrology science under the condition of guaranteeingthe safety of floods control. In this dissertation, as for some problems in flood forecast andreservoir regulation, the research had been done based on the special research topic dynamiccontrol on limit water level in flood season using theories of fuzzy optimizing theory,maximum entropy theory, entropy-weighted multi-objective decision making method, geneticalgorithm etc. And the research focused on evaporation calculation, fuzzy description ofcatchraent impoundage, fuzzy similarity calibration method, nolinear watershed concentrationmodel and error distribution maximum entropy model and risk computation of dynamiccontrol reservoir water level in flood season when the flood forecast and precipitation forecastare taken into consideration. The research mainly includes:(1) As for some existing problems in simplified graded-evaporation calculation anddescription of catchment impoundage, in the dissertation, taking Dahuofang Runoff Model foran example, the function of membership grade was used to fuzzily describe the evaporationand impoundage. It can solve parameter sensitivity resulted from original graded-evaporationcalculation and get a reasonable evaporation result. And according to the characteristics ofunderlaying surface of catchments and that of runoff, the variation of impoundage was takeninto consideration in runoff model. Furthermore, given the factors of the similarity prior toprecipitation, a fuzzy similarity calibration method of flood forecast model parameters wasestablished, which was given from physical mechanism of error production. After themodification of model parameters, the runoff forecast results was calibrated.(2) As for the treatment on nolinear problem in instantaneous unit hydrograph (IUH), themain nolinear factors including period precipitation intensity and its spatial distribution wereinvestigated. And a new watershed concentration model named time variable instantaneousunit hydrograph (TVIUH) was put forward. And as for the multi-objective decision-making(MODM) problem that requiring flood peak discharge, time to peak and deterministiccoefficient meet the requirements simultaneously, two objective evaluation functions: fuzzycombination objective function and entropy-weighted MODM method were suggested todetermined the parameters of the model. In application of Guanyinge-Shengwo cascadereservoir, the results show that the model parameters of interval flood concentration andchannel progression model should be calibrated simultaneously, so that the negative value,indention shape and their error occurred in back-analysis interval concentration process ofcasacade reservoir could be avoided reasonably. (3) As for the existing problems in describing flood forecast error using normaldistribution & logarithm normal distribution, the maximum entropy model of forecast errordistribution of total flood discharge was established. The model takes the characteristic offorecast error lying a limit domain into consideration. The limit error of different forecastscheme was determined. And comparison analysis has been done error limits resulted fromcommon error distribution functions. As for determination of upper bound of error, a primarymethod was suggested from the viewpoint of safety of flood control. And using the obtainederror distribution from suggested model, uncertainty of forecast error has been evaluated.(4) The precision of flood forecast and precipitation forecast for Huanren Reservoir andDanjiangkou Reservoir were discussed firstly in this section. Then using floods forecastregulation method and modified pre-discharge capacity constraint method, dynamic controldomains of limit water level of Huanren Reservoir and Danjiangkou Reservoir in flood seasonwere determined. Combined with precipitaton forecast and flood forecast, the upper bound ofdynamic control on limit water level of Huanren Reservoir in flood season was determined.Analysis results show that when the reservoir water supply and power generation benefitare guaranteed, using flood forecast and precipitation forecast solely and using combinationinformation of these two forecast results, Huanren Reservoir in flood season could save30.21×10~6, 60.42×10~6 and 90.63×10~6 cubic meter water resource respectively fromdischarging. As for Danjiangkou Reservoir, when using precipitation forecast results ofindividually, it could save 4.1×10~8 cubic meter water resource from discharging.(5) If the flood forecast and precipitation forecast information is used to control waterlevel of reservoir in flood season, the risk of it on flood control was analyzed in this section.Then, transmission relationship between frequency for maximum flood discharge in a yearand frequency for every flood in this year was established. And based on the risk rate ofdynamic controlling reservoir water level in flood season defined by Prof. B.D Wang andmaximum entropy model of forecast error distribution, the definition of risk rates when usingflood forecast or combination of flood forecast and precipitation forecast to control limitwater level in flood season were difined. And their corresponded calculation methods weregiven as well in this dissertation. After that, the risk of dynamic controlling limit water levelin flood season was analyzed for Huanren Reservoir and Danjiangkou Reservoir respectively.And risk rates obtained from different error distributions were compared with each other.Comparison results show the risk distribution for the same characteristic water level atdifferent control limit water level in flood season.Finally, the conclusions were drawn and further research perspectives were discussed.
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