Monetary valuation of urban underground space: A critical issue for the decision-making of urban underground space development

•Service replacement cost method (SRCM) is established to access the UUS value.•Urban services provided by UUS is summarized.•A relative magnitude of the UUS value is obtained through case study. Urban underground space (UUS) has attracted more and more attention worldwide, but its value, external value particularly, is often ignored or underestimated, which will influence or even change the trade-offs in the decision-making processes of UUS development. This paper employed service replacement cost method (SRCM) to access the value of urban underground space. Since the precise estimate of the value of urban underground space is almost an impossible task, this paper can only provide a crude approximation, in other words, a relative magnitude of the value of urban underground space. The case study of Changzhou City in China manifested that urban underground space provided an important portion of urban economy, which reached up to, but not be limited to, 1.8% of its GDP. This paper should aid in giving urban underground space more weight in urban decision-making process.