| Natural water contains endogenous and exogenous chromophoric dissolved organic matter(CDOM),which is an important source of water and water environment medium.The change of its proportion structure can profoundly affect water quality and water ecological health.Shanzi Reservoir is an important water source in the upper reaches of the Minjiang River in Fujian Province.The current dispatching plan is based on ensuring the safety of the reservoir facilities and the maximum power generation.Because this scheduling scheme weakens or ignores the ecological objectives of the basin,such as the reasonable proportion of CDOM,it is impossible to achieve both the basic function of the reservoir and the regional ecological environment.In view of the current ecological environment of Shanzi Reservoir,this paper takes power generation,downstream comprehensive water demand and CDOM suitable runoff change as the economic,social and ecological targets of reservoir operation,and explores three typical hydrological years:high,low and normal flow year.The formulation method of the reservoir dispatching plan will realize the coordination of economy,society and ecology.Based on Landsat 8 remote sensing image,the correlation between water reflectance and CDOM absorption coefficient is established to extract water characteristic band and retrieve CDOM concentration in the whole Shanzai reservoir.Then,the quantitative relationship between the proportion of DOM components and the built-up runoff of support vector machine is used to estimate the optimal ecological runoff of Shanzai reservoir.Based on the runoff data of each typical hydrological year of Shanzai Reservoir,the minimum ecological flow of the river is calculated by the minimum ecological water requirement monthly and the 7Q10 method,and the suitable ecological water requirement of the river is calculated by the improved Tennant method,which is combined with the comprehensive water requirement of the lower reaches of Shanzai Reservoir as the regional water requirement objective,and the optimization model of reservoir ecological operation is constructed by coupling the power generation objective.An improved spider optimization algorithm,chaotic annealing spider optimization algorithm(CMOSSO-SA),is constructed to solve the optimization calculation problem of multi-objective reservoir operation model.This method improves the exploration and development ability of the algorithm.By comparing the performance of multi-objective particle swarm optimization(MOPSO),genetic algorithm(NSGA-II),multi-objective spider algorithm(MOSSO)and multi-objective spider improved algorithm(CMOSSO-SA)with standard test function,it shows that the CMOSSO-SA improves the convergence by 89%and the uniformity by48%.A multi-objective operation model is established based on CMOSSO-SA,a non-inferior solution of pareto optimal solution is selected according to the fuzzy membership function.The objective function values of different typical hydrological years and water level,discharge,water shortage and power generation at the beginning and end of each month are obtained.The results of the model show that the annual power generation of Shanzi Reservoir is 0.75×10~8 kw·h in extra low flow year,0.91×10~8 kw·h in normal flow year and 3.22×10~8 kw·h in extra high flow year.The discharge of Shanzi Reservoir in different hydrological years can generally meet the runoff corresponding to DOM optimal proportion.Considering the power generation and regional water demand objectives,Shanzai Reservoir is short of water 1.14×10~8 m~3 in extra low flow year,1.74×10~8 m~3 in normal flow year,the water shortage months in normal flow year mainly concentrate from December to April of the next year.Considering Shanzai Reservoir is a seasonal regulating reservoir,water storage in flood season can supply water shortage month in normal flow year to meet its water requirement.However,joint operation of cascade reservoirs need to be employed to meet the water requirement of reservoir in low flow year. |
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