Evaluation of Irrigation Network Performance in Terusan Tengah Swamp Irrigation Area Due To High Tidal Water Level and Extreme Rainfall Condition

The Terusan Tengah Swamp Irrigation Area, located in Kapuas Regency, Central Kalimantan Province, experiences inundation during extreme rainfall events and high tides. This study aims to evaluate the performance of the irrigation network within the Terusan Tengah Swamp Irrigation Area in discharging excess water from agricultural lands under conditions of extreme rainfall and high tidal water levels. The data utilized in this study include designed water level data, which were derived from analysis using observational data from October 2024 to September 2025. Furthermore, the study also incorporates design rainfall data for return periods of 5 years. The evaluation of the irrigation network’s performance was conducted through flow simulations using HEC-RAS software. The simulations were performed under two distinct channel condition scenarios: one employing the existing channel geometry and another utilizing a normalized channel geometry. The result shows that normalization scenario can decreased inundation area and depth, but still can not significantly decreased the duration of inundation.