Type-2 Fuzzy Analysis Method For Hydrological Simulation And Water Resources Allocation

The rapid growth of population and the accelerating of industrialization have caused an increasing demand of water resources.The contradiction between supply and demand of water resources become more and more severe,inducing a number of ecological environment problems.In that case,how to abstract the water resources system characteristics into mathematical model and how to express the uncertianties and their interactions are crucial for water resources management.Therefore,based on water resources system analysis,type-2 fuzzy sets theory would be used to express the double fuzzy information and a number of type-2 fuzzy methods would be developed:(1)a type-2 fuzzy simulation method(TFSM).Through coupling type-2 fuzzy analysis technique with the semi-distributed land use based runoff processes(SLURP)model,TFSM can handle fuzzy sets with uncertain membership function related to hydrological modelling parameters and reveal the effects of such uncertain parameters on the hydrological processes.The TFSM would be applied to hydrological simulation for the Kaidu River Watershed.The goodness-of-fit of the performance of the hydrological model would been assessed and the effects of uncertain parameters would been revealed.(2)a type-2 fuzzy variance analysis method(TFVA).TFVA Combines the techniques of TFSM and analysis of variance.It can not only tackle the process of runoff generation,but also quantitatively evaluate the individual and interactive effects of multiple uncertain parameters expressed as type-2 fuzzy sets in the hydrological modeling system.The TFVA would been applied for assessment of parameter uncertainty in the Kaidu River Watershed and the inner-relationship among the uncertain parameters can be specified to enhance the model's applicability.(3)a type-2 fuzzy probability collection method(TFPC).TFPC can not only tackle uncertainties expressed as type-2 fuzzy random parameters,but also improve computation efficiency through using Sobol sensitivity indices based on the orthogonality of basis functions.TFPC would be applied to rainfull-snowmelt simulation for Kaidu River Watershed.Parameter effects on river runoff in different seasons would be identified.(4)a type-2 fuzzy interval programming(T2FIP)method.T2 FIP is based on an integration of type-2 fuzzy approach,fuzzy flexible programming and interval-parameter programming.It can effectively tackle uncertainties expressed as type-2 fuzzy intervals,avoiding loss of value information.T2 FIP would be applied to conjunctive use of surface water and groundwater in the Zhangweinan River Basin.Scenarios associated with different groundwater utilization ratios would be examined to help generate the optimal conjunctive water use pattern.The results would be helpful for relieving the ecological environment problems which is induced by groundwater overdraft.(5)a type-2 fuzzy-probabilistic programming(T2FP)method.T2 FP integrates the techniques of enhanced Karnik-Mendel algorithm,interval parameter programming and chance-constrained programming into a general framework.It can not only tackle uncertainties expressed as type-2 fuzzy sets in both the objective function and constraints but also address complexity with characteristic of randomness and two-layer fuzziness(i.e.,type-2 fuzzy random variables).A real case in the Zhangweinan River Basin would be used to demonstrate the feasibility of the proposed approach.Solutions under different constraint violation levels would been generated by solving a serious of submodels.Results would be helpful for resolving conflicts among system benefit and water supply security.(6)a type-2 fuzzy random factorial analysis method(T2FA).Through introducing Taguchi design into T2 FP,T2FA can not only disclose the relationship between system benefit and system reliability based on the probability of violating constraints,but also evaluate parameter effects and their interactions on modeling outputs.T2 FP would be applied to planning conjunctive water management in Zhangweinan River Basin.Parameters related to economic and environmental factors(e.g.,water conveyance efficiency and water delivery cost)would been investigated to disclose the relationship between the parameter uncertainty and modeling outputs(i.e.,system benefit,total crop area,surface water allocation and groundwater allocation).The rsults would be helpful for adjustment of agricultural planting structure.Through introducing type-2 fuzzy parameters,type-2 fuzzy interval numbers and type-2 fuzzy random varibales to reflect uncertianties in water resources systems,a number of type-2 fuzzy method would be poposed to discolse the effect of parameter s with multiple uncertainties and their interactions on model outpts.It is significant for exploring the complexity of hydrological processes.The model for conjunctive use of surface water and groundwater would be proposed based on type-2 fuzzy programming method to disclose the relationship among water resources management,social and economic development and environmental protection.Risk loss due to water shortage and system benefit because of groundwater utilization would be ananlyzed to relief the imbalance among limited water resources,food production,groundwater exploitation and environmetal protection.It can help to improve water resources utilization efficient and build water resources security system.