Study On Risk Allocation Of Spongy City Project Under The Model Of Public-Private Partnership

With the development of urbanization,huge changes have taken place in the underlying surface,and the natural "spongy body" has been replaced by hardened road surface,which leads to the appearance of urban waterlogging.Therefore,the Central Government proposed the sponge city construction to improve the urban water environment.That requires large amount of investment,so that the Central Government encourages the sponge city construction by means of the Public-Private Partnership(PPP).PPP model can effectively relieve the financial pressure of the local governments.The smooth implementation of the PPP sponge city projects,it is crucial to share the project risks reasonably and properly.However,there is a lack of domestic research in this area.Therefore,it is very important to carry out relevant research on the risk allocation of the PPP sponge city projects.This paper takes the PPP sponge city project as the research object.Firstly,this paper reviews the research status of PPP project risk allocation and the application of PPP mode in rainwater management,and summarizes the characteristics,connotation and principle of risk allocation of PPP mode through reading the relevant literature.Meanwhile,the applicability of PPP model in sponge city construction was analyzed.Secondly,it is analyzed that the main parties of the sponge city project under the PPP model are public and social capitals from the perspective of PPP project contract.Then,through field research and theoretical research,35 risk factors faced by the PPP sponge city projects are summarized,evaluated and ranked by importance.Thirdly,on the basis of analyzing the risk allocation provisions of the PPP project contract guidelines,this paper identifies the deficiencies in the contract guide.At the same time,this study constructed a risk-allocation model,which combines preliminary sharing with reallocation.The preliminary allocation based on questionnaire survey and the re-sharing based on the modified AHP-Shapely value model.The preliminary allocation of the model can be used to determine whether a certain risk is borne by a single entity or by multiple parties.When use the modified AHP--Shapely value model to allocation the risks shared by multiple parties,three risk allocation factors are selected as the first-level indicators according to the risk allocation principle,then they are refined into 11 secondary indicators.By using Analytic Hierarchy Process(AHP)to calculate the index weight and revise the shapely value,this paper concludes that the concrete share proportion of each party.Finally,this paper takes the PPP sponge city project in Qingshan District,Wuhan as an empirical case.The risk factors in the PPP project were identified in a more comprehensive way,and then the model established in the paper was adopted to allocate the risks.This paper takes the sharing risks caused by changes in market prices and results in increased operating costs as an example,and the shares of governmental departments and social capital by AHP--Shapely value model are 34.69% and 65.31%,respectively.Then,the risk allocation results are compared with the PPP project contract guidelines and project contracts.The results show that the calculated results are basically consistent with the results of the contract guidelines and other regulations,thus verifying the rationality of the sharing model.This study have theoretical guidance significance and practical reference for the management and control of risk allocation in the PPP sponge city projects.