Development of water footprint inventory database on Japanese goods and services distinguishing the types of water resources and the forms of water uses based on input-output analysis

Abstract

Water footprint is expected as a tool to identify critical and effective points for reducing the impact of water use through the entire life cycle of products, services, and organizations. The purpose of this study is to develop a water footprint inventory database that makes it possible to account the water intensities of all the Japanese goods and services with a differentiation for the types of water resources and the forms of water uses. An input-output analysis was applied to establish a comprehensive database covering all of the Japanese goods and services. The amount of water consumption in each sector was estimated by modeling (for agricultural goods) and determined based on the uses of input water according to the statistic reports and hearing survey results (for other sectors). The intensities of direct water input or consumption in each sector were calculated by dividing the amount of water input or consumption with the domestic production amount for each sector. Based on the input-output analysis by using Leontief’s inverse matrix, the intensities of water use and consumption from cradle to gate were estimated for all goods and services in 403 sectors of Japan. The intensities of water input and consumption in the primary sectors of industry from cradle to gate showed large values and high dependency on rain water as the sources of input water. While the water input intensities in secondary sector of industry were relatively higher than those in tertiary sector of industry, the water consumption intensities generally showed larger reduction in secondary sectors in comparison with those in tertiary sectors due to the utilization of recycling water. The results of comparing the intensities in this study with previous studies showed some differences due to the consideration of site-specific conditions in production and the temporal resolution for the calculation of consumed amount in crop production. By considering the site-specific conditions, the intensities were developed as the datasets suitable for water footprint of products, services, and organizations in Japan. While this database would be expected to be applied to the implementation of water footprint, the reflection of the effects by imported goods and services through international trade needs to be conducted in the future study for improving the preciseness and reliability of the results of water footprint.