講演情報
[PS-02-46]Development of Flood Forecast Model
Integrating Local Irrigation Planning on Lombok Island, Indonesia
*Amalia Wijayanti1, Nakamura Yosuke1, Abe Shiori1, Higashiguchi Hiroshi1, Eka Nugraha Abdi2 (1. Mitsui Consultant Co., Ltd., 2. Nusa Tenggara 1 River Basin Organization)
キーワード：
Flood Forecast、RRI Model、Ancar River
This study addresses flood forecasting challenges in small island watersheds influenced by irrigation systems, using Lombok Island, Indonesia, as a case study. The Ancar watershed is selected as a representative basin with mixed urban and irrigation networks. To improve model applicability, the Rainfall–Runoff–Inundation (RRI) model was modified to incorporate local irrigation planning. The conventional time-series boundary condition format was replaced with a date-based framework using start and end timestamps, enabling direct representation of government irrigation schedules. To maintain compatibility, inputs are internally converted into elapsed simulation time, and the simulation start is automatically derived from rainfall data filenames. Application to the July 2025 flood event shows improved model performance, with RMSE reduced from 5.1 to 4.4 m³/s during peak conditions and from 4.33 to 0.39 m³/s during no-rainfall periods. The proposed approach improves both usability and forecasting accuracy.