Proceeding of Annual Conference
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Showing 1-50 articles out of 131 articles from the selected issue
  • Zhipin Ai, Naota Hanasaki
    Pages 10-
    Published: 2019
    Released: December 07, 2019
    CONFERENCE PROCEEDINGS FREE ACCESS

    Bioenergy and bioenergy with carbon capture and storage (BECCS) technologies can achieve zero or even negative CO2 emissions, hence have been considered as one of the essential technologies in achieving the 2-degree climate target. With ambitious climate policy, the demand for bioenergy would be up to 200-300 EJ per year based on recent predictions. At this level, a large volume of biomass is needed to generate energy. In order to enhance the simulation performance in bioenergy crop yield, we modified the algorithm and adjusted parameters of a state-of-the-art global hydrological model termed H08. Overall, overestimation or underestimation seen in the original H08 have been largely suppressed in this enhanced H08, which performs much better in simulating yield of Miscanthus and Switchgrass. Results also showed that irrigation significantly increased the yield for both Miscanthus and Switchgrass especially under dry climate condition.

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  • Julien Eric Stanislas Boulange, Naota Hanasaki
    Pages 12-
    Published: 2019
    Released: December 07, 2019
    CONFERENCE PROCEEDINGS FREE ACCESS

    The global hydrological H08 model and a new generation of routing model, CaMa-Flood, were successfully coupled to represent the effect of dams on river discharge and hence inundation dynamics. While, at the end of the 21st century, change in flood frequency highly depends on geographical factors, implementing dams reduced flood frequency for the majority of locations. In addition, implementing dams also reduced maximum flooded areas in major basins, up to 39%, compared to the same scenario with no dam.

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  • Naota Hanasaki, Sayaka Yoshikawa, Shinjiro Kanae
    Pages 14-
    Published: 2019
    Released: December 07, 2019
    CONFERENCE PROCEEDINGS FREE ACCESS

    Water scarcity indicators have been used for global water resources assessments, as there is no adequate physical quantity to indicate water scarcity. The most widely used indicators are the Withdrawal to Availability (WTA) and the Availability per capita (APC). WTA is the ratio of annual water withdrawal to annual water resources, and empirically, a region is judged under water scarcity when it exceeds 0.2 and 0.4. APC is the annual volume of water resources per person, and a region is judged so when it falls below 1700 m3/year/person and 1000 m3/year/person. Both are widely accepted, but the concrete basis for these thresholds has never been presented. Here, we conducted a series of global simulations using the latest global water resource model H08, and investigated what kind of water resources state the WTA and APC thresholds represent. This contribution is a summary of recent publication in Water Resources Research in 2018.

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  • Orie Sasaki, Koji Fujita, Yukiko Hirabayashi, Shinjiro Kanae
    Pages 16-
    Published: 2019
    Released: December 07, 2019
    CONFERENCE PROCEEDINGS FREE ACCESS
  • Chihiro Hiraoka, Shigenobu Tanaka, Kenji Tanaka
    Pages 18-
    Published: 2019
    Released: December 07, 2019
    CONFERENCE PROCEEDINGS FREE ACCESS

    Water use in Central Asia highly depends on meltwater of glaciers. In order to know the meltwater’s seasonal availability, seasonal change of glacial water/heat balance should be clarified. This research aims to demonstrate SWE’s behavior on a land-surface process model SiBUC, which requires 7 meteorological factors for input data, using observed data and re-analysis data JRA55 as the input data. Since the sensor failed to observe snowfall, snowfall amount was reproduced by using observed snow depth and estimated density. SWE calculation was done in two ways; by using observed data (with reproduced precipitation), and by replacing each factor with JRA55, which aims to see the discrepancy between JRA55 and observed data and how it leads to the error in SWE. The result showed that the accuracy of short wave and long wave radiation particularly in the snowmelt season is crucial to the correct demonstration of SWE.

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  • Mori Masanori, Shimadera Hikari, Matsuo Tomohito, Kondo Akira, Koga Yu ...
    Pages 38-
    Published: 2019
    Released: December 07, 2019
    CONFERENCE PROCEEDINGS FREE ACCESS

    Since the latter half of the 1990s, nutrient salt in Harima-nada in Seto Inland Sea has been decreasing, a possible cause of which is the reduction of nutrient supply from flowing rivers. In order to seek countermeasures of the problem, it is necessary to calculate the nutrient inflow load from the rivers and estimate the nutrient concentration in the sea based on the inflow load to the sea. In this study, we constructed hydrological and water quality models and analyzed total nitrogen dynamics in the Kako river, which has the largest catchment area among the inflowing rivers, during rainfall and normal stage of water. Total nitrogen sources included point sources and rainfall-runoff driven nonpoint sources. The models well reproduced total nitrogen loads during both of rainfall and normal stage of water. In the future, we will expand the calculation area to basins of other rivers flowing into Harima-nada.

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  • Tomijiro Kubota, Moono Shin, Sanyun i, Tatsuhiro Nishikiori
    Pages 40-
    Published: 2019
    Released: December 07, 2019
    CONFERENCE PROCEEDINGS FREE ACCESS
  • Haruya Tanakamaru, Nobuto Tatebayashi, Akio Tada
    Pages 42-
    Published: 2019
    Released: December 07, 2019
    CONFERENCE PROCEEDINGS FREE ACCESS

    In this study, we examined flood mitigation effect by water release from irrigation ponds in Awaji district, Hyogo prefecture and proposed a method for selecting irrigation ponds with large flood mitigation effect. Firstly, we assumed that the water release is introduced in renovated irrigation ponds and estimated spillway width which can drain design flood safely in 1,902 irrigation ponds. Secondly, we conducted flood runoff analysis by the 10-year probability rainfall in all irrigation ponds and examined flood mitigation effect by the decrease of pond outflow in percentage terms for water release of 10% and 30% of total storage. Thirdly, we showed that the pond with large retention in mm (the space in pond by water release divided by catchment area) shows large reduction rate of peak discharge. Therefore, the retention is useful as an index of large flood mitigation effect by water release.

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  • Jean Margaret R. Mercado, Akira Kawamura, Hideo Amaguchi
    Pages 44-
    Published: 2019
    Released: December 07, 2019
    CONFERENCE PROCEEDINGS FREE ACCESS

    Integrated flood risk management (IFRM) implementation in Metro Manila is a challenging task to heavy reliance on traditional structural measures and because of the “barriers” that may hamper IFRM. This study presents for the first time The application for the Interpretive Structural Modeling (ISM) method to barrier analysis related to IFRM. This method is a systematic approach that analyzes the other The ISM model clearly showed that the barriers on the governance aspect are the most influential barriers that may dictate the movement of all other barriers.The ISM model produced in this study shows the interconnections of each barrier that can aid the decision makers and practitioners in Metro Manila, Philippines.

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  • Keigo Noda, Akiko Iida, Satoshi Watanabe, Kazutoshi Osawa
    Pages 46-
    Published: 2019
    Released: December 07, 2019
    CONFERENCE PROCEEDINGS FREE ACCESS

    Land resources are essential for humans to survive, and different methods of land- resource use

    depend largely on the local natural context and society. Here we propose a method to assess landresource

    use in terms of efficiency and sustainability for three historical types of land-resource use in

    the Babeldaob Island, Republic of Palau: self-supply, resource development and nature conservation.

    Our proposed index of land-use efficiency makes comparisons possible among the types of landresource

    use, considering both the natural and social conditions; land-use efficiency increased in the

    order of self-supply, nature conservation and resource development. At the same time, sustainability

    of land-resource use corresponded to population growth; when the population density was less or

    more than 15 capitakm−2, self-supply and nature conservation were the most sustainable,

    respectively.

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  • Chris Leong Leong, Yoshiyuki Yokoo
    Pages 48-
    Published: 2019
    Released: December 07, 2019
    CONFERENCE PROCEEDINGS FREE ACCESS

    This study explores the potential use of a disaggregated flow duration curve (FDC) to estimate runoff in island catchments under humid conditions. The study disaggregates the FDC into three sections (top, middle and low) and attempts to estimate runoff in each section independently using simple hydrologic models. The results show the Curve Number method and the mean monthly flow (MMF) are able to make proper runoff estimations in the top and middle components respectively. For the low flow section, in perennial catchments the MMF or a process based Tank model is able to make proper estimations but not in ephemeral catchments. The ephemeral catchments low flows are estimated using the precipitation index. The study shows that in island catchments, climate is possibly the main control of the hydrologic nature.

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  • Aulia Febianda Anwar Tinumbang, Kazuaki Yorozu, Yasuto Tachikawa, Yuta ...
    Pages 100-
    Published: 2019
    Released: December 07, 2019
    CONFERENCE PROCEEDINGS FREE ACCESS

    In this study, the characteristics of runoff generated by land surface models SiBUC and MRI-SiB were examined from river discharge view point. From the analysis result by using NHRCM 5km output data, it was found that the amount of runoff in SiBUC was higher compared to MRI-SiB. In MRI-SiB, the base runoff was more dominant than surface runoff, while in SiBUC was the opposite. The generated runoff from both model was given to a flow routing model 1K-FRM to conduct river discharge simulation. The 10-years-mean monthly river discharge analysis showed the different of discharge volume and timing of peak discharge from both models, which was due to different runoff amount and their characteristics.

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  • Kazuaki Yorozu, Saeto Kojima, Yasuto Tachikawa, Tomohiro Tanaka, Yutak ...
    Pages 102-
    Published: 2019
    Released: December 07, 2019
    CONFERENCE PROCEEDINGS FREE ACCESS

    To enhance the accuracy of runoff estimation by GCMs (General Circulation Models), effects of land surface parameters on runoff estimation were investigated by using MRI-AGCM3.2H. In this study, two experiments were conducted. One was simulation with default saturated hydraulic conductivity, the other one was simulation with low value saturated hydraulic conductivity. As a result of setting low saturated hydraulic conductivity, surface runoff was increasing and subsurface runoff was decreasing. In some area, the magnitude of increasing surface runoff exceeded that of decreasing subsurface runoff and vice versa.

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