Author(s): Yuko Ishida; Misaki Kitamura; Kento Okunishi; Kenji Sawai; Masanori Sera; Yoshiya Ogawa; Masato Maegawa; Ryo Hirako; Yukisada Kitamura
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Keywords: Green infrastructure; Integrated watershed management; Biodiversity; Land conservation
Abstract: Once, the Ogura-Ike Pond (area 794 ha, the maximum water depth 1.1 m) located in the southern part of Kyoto Prefecture had a flood control function by being connected to the Uji River with braided channel, and various organisms of the Yodo River Basin inhabited. After being diked in 1941, living things disappeared from the pond, and the pond lost its flood control function. Recently, heavy rainfall happens more frequently than expected in various area in Japan. Flood disaster risk is increasing in the three rivers (Katsura, Uji and Kizu River) junction area including the former Ogura-Ike Pond Basin in the Yodo River Basin, so in addition to the current river improvement plan, the Yodo River Basin requires new flood control measures. We considered plans to confirm the effect on both flood control measures and environmental conservation measures from the results of analyses using iRIC as two-dimensional flood flow analysis software, to see if the current Ogura-Ike drained land was restored as a pond. As results of flood analysis using iRIC Nays2DFlood (ver.5.0), water of the Uji River flooded from various places, spreading widely in particular around low-altitude Ogura-Ike reclaimed areas. These results showed the possibility of reserving water in the Ogura-Ike Pond and preventing flooding from other places by setting surrounding levee around the pond and an overflow levee at a specific location in the Uji River. It was shown that the restored pond can also be utilized as evacuation site of aquatic organisms during flooding.
Year: 2018