Japan Geoscience Union Meeting 2019

Presentation information

[E] Oral

A (Atmospheric and Hydrospheric Sciences ) » A-HW Hydrology & Water Environment

[A-HW23] Hydrology & Water Environment

Tue. May 28, 2019 3:30 PM - 5:00 PM 103 (1F)

convener:Isao Machida(Geological Survey of Japan), Dai Yamazaki(Institute of Industrial Sciences, The University of Tokyo), Takeshi Hayashi(Faculty of Education and Human Studies, Akita University), Keisuke Fukushi(Institute of Nature & Environmental Technology, Kanazawa University), Chairperson:Megumi Watanabe

4:00 PM - 4:15 PM

[AHW23-08] Representation of dams in global flood inundation simulations by coupling the global hydrological model H08 and the global hydrodynamic model CaMa-Flood

*Julien Eric Boulange1, Naota Hanasaki1 (1.National Institute for Environmental Studies)

Keywords:Global hydrology, Flood, H08 model, CaMa-Flood model

Dams and reservoirs regulate the flow of rivers, storing and releasing water to maximize its availability for human and environmental needs1. While regulating water flow is beneficial regarding human water security, it was reported to have rather dire consequences for the environment such as aquatic biota2,3. Nevertheless, currently about half of the major global river systems are affected by dams4.
Global hydrodynamic models have greatly improved in terms of accuracy and computational efficiency in reproducing flood inundation extent5. However, to this day, still few such models successfully simulated flood inundation considering the influence of dams.
In this research, the global hydrological model H086,7 is coupled to the global hydrodynamic model CaMa-Flood8 for representing dams in global flood inundation simulation. The input meteorological dataset used in this study were provided by the ISIMIP2b project9 and consisted of 4 GCMs and 4 scenarios.

The coupled model simulates river discharge and inundation globally at a daily interval, at a spatial resolution of 0.5° × 0.5°. Discharge predicted with the original CaMa-Flood model were compared to those obtained with the coupled model. The seasonal discharge in rivers heavily affected by reservoir operation were very different between the two simulations. Generally, annual minimum (maximum) 7-day discharge was significantly higher (lower) for the simulation explicitly representing dams. In addition, timings of the discharge peaks were also different between the 2 simulations. We deeply investigated the results in several selected river basins.

References:
1 Ehsani, N., Vörösmarty, C. J., Fekete, B. M. & Stakhiv, E. Z. J. Hydrol. (2017).
2 Pringle, C., Freeman, M. & Freeman, B. Regional Effects of Hydrologic Alterations on Riverine Macrobiota in the New World: Tropical–Temperate Comparisons. Vol. 50 (2000).
3 Kingsford, R. T. Austral Ecology (2000).
4 Dynesius, M. & Nilsson, C. Science (1994).
5 Teng, J. et al. Environmental Modelling & Software (2017).
6 Hanasaki, N. et al. Hydrol. Earth Syst. Sci. (2008).
7 Hanasaki, N. et al. Hydrol. Earth Syst. Sci. (2008).
8 Yamazaki, D., Kanae, S., Kim, H. & Oki, T. Water Resour. Res. (2011).
9 Frieler, K. et al. Geosci. Model Dev. Discuss. (2016).