Online ISSN : 1349-2853
Print ISSN : 0915-1389
Volume 30 , Issue 6
Showing 1-10 articles out of 10 articles from the selected issue
Original research article
    2017 Volume 30 Issue 6 Pages 356-372
    Published: November 05, 2017
    Released: January 13, 2018

     Flood damage from heavy rainfall is increasing recently, as Typhoon No. 12 in 2011 and the Kinu River flooding in 2015 demonstrate. Moreover, rainfall and flood discharge are expected to increase because of climate change. We specifically examined the Probable Maximum Precipitation (PMP) and Probable Maximum Flood (PMF) depending on rainfall durations and basin areas through atmospheric conditional change for upstream areas of the Yattajima, Tone River Basin. We proposed an index correlated with rainfall using the WRF model, and evaluated its maximum value using long-term data to estimate PMP and PMF.

     Results show the following: (1) Moisture fluxes show high correlation with 12-hr to 72-hr rainfall, for the upstream basin of Yattajima, and for its sub-basins through WRF model calculation in the area, which suggests that they can be used as suitable parameters to estimate PMP. (2) Estimation methods of PMP were shown by maximum moisture flux for the past 100 years and by climate model outputs for RCP8.5 scenario. (3) Temporal and areal distributions of PMP depend on the type of typhoon and/or front. (4) PMFs were evaluated using a run-off model for heavy rainfall patterns in current and climate change conditions.

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  • Takuya MATSUURA, Taichi TEBAKARI, Ryuhei KITA, Toshiaki MIZOGUCHI
    2017 Volume 30 Issue 6 Pages 373-385
    Published: November 05, 2017
    Released: January 13, 2018

     Long-term and regular monitoring of the groundwater environment is usually is extremely important to manage groundwater appropriately. Monthly regular groundwater observations and analyses had been conducted during the five years of April 2011 - March 2016 to clarify medium-term and long term and seasonal change in discharge and water quality of flowing wells in the Kurobe River alluvial fan.

     Results show that both of pH and electric conductivity of all flowing wells were almost constant through the five years. Groundwater temperatures and flowing discharges of all flowing wells exhibited seasonal changes. Dissolved ions of flowing wells at the edge of fan increased as they left the Kurobe River. Moreover, the characters of dissolved ions of flowing wells between the edge and the top of fan differed greatlty.

     Future observations must be made for appropriate groundwater environment management in the Kurobe River alluvial fan. However, this study revealed some water quality items that show changes even for short periods of 2–3 months. This fact can facilitate planning and save labor related to observations.

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  • Satoshi WATANABE, Masaomi KIMURA, Yukinaga NISHIHARA, Mie GOMYO, Keigo ...
    2017 Volume 30 Issue 6 Pages 386-394
    Published: November 05, 2017
    Released: January 13, 2018

     The report presents results of an investigation of long-term effects of flooding by typhoon No. 9 2009 in Sayo, Hyogo. The long-term influence of flooding in mountainous region of Japan has not been studied well. The effects of flooding on local society, economy, and living conditions were investigated using statistical analysis of social indices and a questionnaire survey. Results indicate that flooding effects are substantially lower than effects of other phenomena such as depopulation and population aging.

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