Study on the ecosystem services value of urban river using contingent valuation method and bias analysis of the results

Rivers in urban area are characterized themselves by special landscape ecological function, and can provide with important ecosystem services. For this reason, this paper discusses mainly the nature and value of the services, and in order to probe into this, a case study on the comprehensive management project of Zhangjiabang Creek, Shanghai using Contingent valuation method (CVM) is conducted, where 640 Dichotomous Choice questionnaires have been sent out with 507 fed back. In the case study, the values of Willingness to Pay (WTP) and the total economic value of the ecosystem services of the urban river Zhangjiabang Creek have been surveyed. Meanwhile, relative problems of the Contingent valuation method such as design and survey techniques of the questionnaires, bias analysis, reliability and validity test of the results have also been approached. It shows that: (1) The mean value of WTP to the ecosystem services of the urban river Zhangjiabang Creek is RMB ¥107.42 per household per month (RMB ¥1289.08 per household annually), and the total economic value of the ecosystem services is RMB ¥0.634 billion every year in the forthcoming 3 years. Due to disparities of the economic level, comparatively, the results are close to the findings of overseas cases in the order of magnitude while obviously higher than that of the domestic. (2) The bid vector designed in the Dichotomous Choice CVM study has well defined the range and distribution of the respondents' WTP, which makes the statistical efficiency of the mean value of the WTP relatively higher than expected. While some biases, such as starting-point, hypothetical, strategic, payment vehicle, information and yea-saying bias are basically under control in the design and survey procedure of this study. (3)Socio-economic variables of the respondents such as income, education degree, donation experience and environmental attitude significantly influence the values of the WTP of the respondents and this is consistent with the economic theory and verifies the reliability of the CVM. However, as far as we can see in this paper, ages of the respondents have no clear relation with their WTP. (4)About 58.10 per cent of the respondents who do not live near Zhangjiabang Creek have positive WTP to the ecosystem services of the urban river Zhangjiabang Creek, and 86.17 per cent of the respondents think that the river is very important to them in life, this testifies the existence value of the urban river, with the validity of the CVM justified in the non-use value evaluation process of ecosystem services.