Journal of Japan Society of Civil Engineers, Ser. G (Environmental Research)
Online ISSN : 2185-6648
ISSN-L : 2185-6648
Volume 77, Issue 2
Displaying 1-4 of 4 articles from this issue
Paper (In Japanese)
  • Ippei KAMEDA, Nagahisa HIRAYAMA
    2021Volume 77Issue 2 Pages 22-30
    Published: 2021
    Released on J-STAGE: May 20, 2021
    JOURNAL FREE ACCESS

     The objective of this study is to develop a structural equation modeling that can describe the process of cultivating ownership among the municipal officials who are in charge of disaster waste management. In this study, the questionnaire survey on recognitions of municipal officials relevant to disaster waste management was carried out. Potential factors related ownership of municipal officials in disaster waste management were examined using structural equation modeling. As a result, three structural equation models were revealed; disaster waste management planning, operation and management of temporary sites, and disaster debris flow. It was indicated that the acquisition of the knowledge on disaster waste management might not always result in the development of ownership. And the increase of concern on disaster debris management by acquisition of the knowledge should cultivate the ownership. In addition, it was pointed out that the knowledge of damage presumption and regional characteristics is as important for increasing the concern on disaster debris management as that of disaster debris operations.

    Download PDF (567K)
  • Yoshihisa SUGIMURA, Tomoko KOBAYASHI, Yugo MITO, Satoru YOSHIHARA, Tom ...
    2021Volume 77Issue 2 Pages 31-48
    Published: 2021
    Released on J-STAGE: May 20, 2021
    JOURNAL FREE ACCESS

     A blue carbon offset system and a system in which a part of the entrance fee and donations from companies and others are used as financial mechanisms for environmental activities at Hakata Port were established. However, the blue carbon offsetting system is not sufficiently appealing to the ESG management of companies because it is difficult to convincingly explain the effects of the system since it is not placed under the framework of the Paris Agreement and the amount of credit generated and sold is small. It is difficult to motivate companies to donate as there is no incentive for donors. In this paper, we present solutions to these problems and the future prospect of expanding the system to evaluate the co-benefits of seagrass meadows to enable the implementation of environment conservation and creation projects on a self-financing basis.

    Download PDF (2670K)
  • Shingo ADACHI, Yasuhiro ARAI, Akira KOIZUMI, Shinsuke TAKAHASHI, Motoa ...
    2021Volume 77Issue 2 Pages 49-59
    Published: 2021
    Released on J-STAGE: May 20, 2021
    JOURNAL FREE ACCESS

     As the ageing of pipe networks progresses, a quick response to a pipe burst is gaining importance. Online monitoring methods have been proposed to detect a burst, but these methods tend to fail or take too long to detect a gradually developing burst. This study proposes a monitoring method to detect both step-shaped and gradually developing bursts earlier by combining multiple flow prediction models with various prediction horizons. A prediction model with a shorter horizon contributes to detect a step-shaped burst earlier based on a smaller prediction error. On the other hand, another model with a longer horizon is expected to detect a gradually developing bursts earlier since its prediction is more robust compared with the former. The proposed method is composed to take the advantage of each model and complement each other. In a case study, the proposed method was evaluated by applying to a set of synthetic data based on an open dataset of actual flow readings. The set of synthetic data was generated by adding actual flow readings and a sigmoid shaped burst flow with various combinations of size, rate of development, and datetime of a simulated burst. It was found that the proposed method shortened the time by 1‒2 hours to detect gradually developing bursts compared with a method with a single flow prediction model in the case study area of this study. The proposed method is expected to contribute to prevent secondary accidents and expansion of supply suspension by the saving the time to detect.

    Download PDF (891K)
  • Ryusei HASHIMOTO, Shinobu KAZAMA, Takashi HASHIMOTO, Kumiko OGUMA, Sat ...
    2021Volume 77Issue 2 Pages 60-71
    Published: 2021
    Released on J-STAGE: June 20, 2021
    JOURNAL FREE ACCESS

     This study aimed to assess the relationship between land use indicators and the levels of water pollution in Japanese rives and water quality improvement by extension of sewerage in river basins. A total of 101 river basins were categorized into four groups based on their three types of land uses, namely forest, farmland and built environments. Nationwide, the largest number of river basins were categorized into Group 3, which is characterized by high forest and farmland coverages. This group of rivers have not experienced serious pollution, while water pollution had been serious in the river basins that belong to high area coverages by built environments. Nonetheless, there were differences in the levels of water pollution even among the river basins belonging to the same groups; namely, the river basins having high population densities and high basin areas per base flows were more prone to water pollution than others. As opposed to the river basins having high development areas, which is the sum of the built environments and farmlands, the river basins having high forest areas were more found to be easier and faster in extending sewerage coverage and thus more effective in improving water quality in rivers by extension of sewerage systems.

    Download PDF (1758K)
feedback
Top