Data-envelopment-analysis-based Interval Two-stage Stochastic Programming Method For Urban Ecosystem Planning

Ecosystem is an important carrier for socioeconomic development which can provide both resources and ecological services for human survivals.However,with the rapid development of industrialization and urbanization,the natural ecosystem has been severely damaged.It is an urgent issue for balancing the relationship between industrial development and ecological protection,as well as for rationally planning urban ecological system to realize the sustainable development of social economy.Urban ecosystem is a complex system involving social,economic,natural,environmental and other elements.Such elements are plagued with multiple uncertainties that bring great challenges to ecosystem planning.Accordingly,this study has developed a data-envelopment-analysis-based interval two-stage stochastic programming(DEA-ITSP)method for urban ecosystem planning.Through incorporating data envelopment analysis(DEA),interval-parameter programming(IPP)and two-stage stochastic programming(TSP)approaches into a framework,DEA-ITSP can effectively(i)tackle uncertain parameters expressed as discrete intervals and the random variables with known probability distribution;(ii)correct targeted decisions after random event happens,so as to minimize the loss caused by decision-making mistakes;and(iii)overcome subjectivities in decision making process and screening out the best alternative.In this study,a series of policies and objectives such as urban industrial development,land planning and environmental protection are comprehensively considered,and an ecosystem planning model based on the DEA-ITSP method is then applied to the City of Guangzhou for planning regional ecosystem,where ecological service value and land transaction mechanism were introduced to explore the impacts of pollutant emission on urban industrial development and ecological land planning under multiple uncertainties.162 scenarios(four pollutant types,three pollutant reduction levels and two land transaction modes)were considered,and urban ecological land planning and industrial development planning schemes corresponding to each scenario were obtained.The obtained results show that waste water,solid waste and SO2 are the main components of industrial pollution in Guangzhou.Wetland with strong sewage capacity is the main land buyer.Forest service value accounts for more than 65%of the total ecological service value,indicating that forest plays an important role in Guangzhou's ecosystem.Therefore,Guangzhou should strictly observe the red line of forest protection and strengthen forest management in the process of ecosystem planning.DEA analysis results show that under the optimal alternatives,ecological land will increase by[3548.22,4608.18]hectares compared to current situation(2017).Moreover,industries need to be transformed towards high-and-new-technology and low-pollutant-emission modes.The obtained results can help decision-makers and managers fully understand the contradictory relationship between urban system benefits and pollution emissions,and provides theoretical basis and support for planning urban ecosystem.