{'fraction_non_alphanumeric': 0.018777292576419215, 'fraction_numerical': 0.00960698689956332, 'mean_word_length': 4.889460154241645, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Estimation of Future Land Use Change in 109 Water Systems of Japan

In recent years, changes in river flow have occurred in various places due to the effects of climate change, affecting local and regional water resource estimates. A possible factor affecting water resource estimates is our social situation itself, such as the development of a declining birthrate and more-elderly society, which is changing dramatically. For this reason, studies on prediction and evaluation of such changes in river flow and water resource amount, as well as changes in our social situation, have become more important. However, most studies still focus only on aspects of natural change, such as climate change; therefore not many studies focus on changes in the activities of human beings and society, and the accompanying changes in land use. Changes in land use have a great impact on changes in river flow and water resource amount, because the amount of underground penetration of rainfall etc. differs for each type of land use. Therefore, by fully considering the future land use as well as the current situation, more accurate evaluation of future water resources becomes possible. The previous research have not included a comprehensive evaluation of watersheds throughout Japan for estimating future land use, and they have not covered a long-term estimation period to fully consider climate change either. For this reason, it has been difficult to compare and evaluate future land use changes in each watershed. In this study, in order to contribute to the analysis of changes in river flow and water resource amount in the future, land use for the period 2015-2100 (in 5-year intervals) was estimated by a tertiary mesh procedure for all of the 109 water systems of Japan. In addition, in consideration of anthropogenic changes, by evaluating four scenarios with different birth rates and death rates, we estimated the change of land use due to differences in future population numbers. As a result, it was found that the artificial land use of the 109 water systems of Japan decreased to the same level as in 1976. Our results clarified Japan’s future water resource situation given a high rate of decrease in artificial land use. Little difference was found among the evaluated scenarios.