Rice fields in the Katingan tidal lowlands are inundated due to spring tides and extreme rainfall. Excessive inundation in the rice fields causes crop failure. Therefore, the study was conducted to analyze the use of water gates in the secondary canals for controlling the inundation. The unsteady flow simulation boundary conditions are the upstream discharge with a return period of 5 and 25 years and measured tidal. The water flow is controlled by closing the sluice gates at the water level elevation of +3.50 m, and flap gates close during high tide and rainfall. This research shows that controlling the water flow by gates decreases the water level and inundation area. Under rainfall with a return period of 5 years, the inundation area decreased by 79.03 %, and the maximum water level decreased by 0.14 m. In the rainfall with a return period of 25 years, the inundation area decreased by 75.31%, and the maximum water level decreased by 0.11 m. The water gates’ operation incompletely decreases the inundation and water level beneath rice crops’ threshold inundation depth and duration. Therefore, there is a need for additional water control to optimize the decrease of inundation in the rice fields.

中文翻译：

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极端降雨对潮汐低地影响导致的水闸水力性能分析：以中加里曼丹卡廷安稻田地区为例

卡廷根潮汐低地的稻田因春潮和极端降雨而被淹没。稻田过度洪水导致农作物歉收。因此，本次研究对二级渠道水闸的防洪利用进行了分析。非定常流模拟边界条件为5年和25年重现期的上游流量和实测潮汐。水位高程+3.50m时关闭闸门控制水流，涨潮和降雨时翻板闸门关闭。这项研究表明，通过闸门控制水流会降低水位和淹没面积。 5年一遇降雨下，淹没面积减少79.03%，最高水位下降0.14m。 25年一遇的降雨，淹没面积减少75.31%，最高水位下降0.11m。水闸的运行不完全地降低了水稻作物的淹没深度和持续时间以下的洪水和水位。因此，需要进行额外的水控制，以优化稻田洪水的减少。