Optimization of Flood Control in the Lake by Gate Opening Simultaneously

This research aims to optimize the management of Limboto Lake as a flood control measure in Gorontalo Province. Limboto Lake serves as a flood retention basin, receiving inflows from 23 rivers and discharging through a single outlet, the Tapodu Canal, which flows into the Bolango River and ultimately drains into the Bone River (Tomini Bay). Flooding in Gorontalo Province and Gorontalo City often occurs due to the absence of a regulated operation pattern for Limboto Lake. The study employs optimization techniques by simulating various scenarios of Tapodu gate operation under different design flood return periods, considering the canal's capacity of 199.00 m³/s. Given that the lake's storage capacity at an elevation of +7.00 m is 172.465 million m³, the embankment remains structurally safe for floods with a return period of up to 1,000 years. However, in the event of a Probable Maximum Flood (PMF), the embankment is expected to experience overtopping by 0.28 cm. Optimization results indicate that, without gate regulation, the outflow and maximum lake elevation reach 369.74 m³/s at +6.09 m for a 1,000-year flood and 408.80 m³/s at +6.84 m for a PMF event. In contrast, with gate regulation, these values are significantly reduced to 110.50 m³/s at +6.58 m for a 1,000-year flood and 142.00 m³/s at +7.28 m for a PMF event. Given that the Tapodu Canal's capacity is 199.00 m³/s and the lake's elevation is +7.00 m, uncontrolled outflows could lead to an overflow of the Tapodu Canal by 0.28 cm. Doi: 10.28991/HEF-2025-06-01-010 Full Text: PDF