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Volume 25 (2012)
- Issue 6 Pages 351-
- Issue 5 Pages 271-
- Issue 4 Pages 201-
- Issue 3 Pages 139-
- Issue 2 Pages 71-
- Issue 1 Pages 20-
Volume 25, Issue 4
Displaying 1-3 of 3 articles from this issue
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Original research article
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Tatsuhiko UCHIDA, Ryuichi HAMABE, Shoji FUKUOKA2012 Volume 25 Issue 4 Pages 201-213
Published: July 05, 2012
Released on J-STAGE: July 17, 2012
JOURNAL FREE ACCESSIn lowland areas, the Rokkaku River and the Ushizu River have many drainage pump stations, which are necessary for flood damage mitigation. They should provide optimal control of drainage pumps without increasing the severe risk of levee breaches. This study was undertaken to clarify the influence of discharge from drainage pump stations on flood flow. An unsteady 2D flow model with observed data of water surface profiles was developed to compute the flood flow in the Rokkaku River and the Ushizu River, as affected by pump station discharge, large tidal level change of the Ariake Sea, and resistance of reeds in the flood plain. The adequacy of the model is discussed through model applications to 2009 flood in the Rokkaku River and the Ushizu River and comparisons between computed and observed data. We investigated impacts of discharge from drainage pump stations on the flood flow in the Rokkaku River and the Ushizu River at the 2009 flood using the unsteady 2D numerical model.View full abstractDownload PDF (4300K) -
Yu IIJIMA, Atsushi HIGUCHI, Akihiko KONDOH, Yasunori KUROSAKIArticle type: Original research article
2012 Volume 25 Issue 4 Pages 214-225
Published: July 05, 2012
Released on J-STAGE: July 17, 2012
JOURNAL FREE ACCESSLong-term variation in pan evaporation and its origins in Sri Lanka were investigated using trend analyses of several observations. Time series data related to pan evaporation show decreasing trends during 1951-1973 and during 1974-1993 over most climatic zones. In 1974-1993, the decreasing trend was attributed to solar dimming with increasing cloud amounts in view of the following evidence: (1) outgoing long-wave radiation decreased around Sri Lanka; (2) pan evaporation decreased, although it is in a wet climatic zone; (3) sunshine duration decreased; and (4) the radiative term in the Penman equation has a large portion in potential evaporation because of typical circumstances over Sri Lanka.View full abstractDownload PDF (877K) -
Takemi NAGASAKA, Yousuke NAKAMURA, Katsuhide YOSHIKAWA2012 Volume 25 Issue 4 Pages 226-242
Published: July 05, 2012
Released on J-STAGE: July 17, 2012
JOURNAL FREE ACCESSMaintenance and management of levee systems in Japan are based on the design flood level, assuming that a design flood might occur. Based on the design flood, the safety of certain zones of a river is regarded as stochastically uniform between the left and right banks and between the upper and lower streams. However, assumptions often differ from reality. River safety often entails differences between upper and lower streams, for instance.
Maintaining and managing such a levee system requires hydraulic analysis of damage to the levee system and additional analysis of the destruction that would result from such damage.
In this study, we analyzed damage-related properties of a river by estimating the damage from levee system collapse. Comparisons with foreign examples and from a damage-based viewpoint supported a basic discussion of the direction of the management of river levee systems. The discussion was focused on the Tone River which is the largest river in Japan and analyzed quantitatively. This approach is also applicable to analysis of other river basins.View full abstractDownload PDF (1725K)
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