The Flood Alert Level Review for Cirarab River was conducted to assess the causes of severe flooding in Tangerang and to formulate effective mitigation strategies. The study identified key issues, including obstructed river flow due to bridge structures, inadequate embankment elevation in Gelam Jaya Village, and sedimentation and narrowing near Akong Factory in Sepatan District. These factors significantly contributed to prolonged flooding, necessitating urgent river normalization and infrastructure improvements. The study also revealed that six out of sixteen drainage gatesalong the Cirarab River embankment were non-functional, limiting the flood drainage capacity, especially in Villa Permata Tangerang. Additionally, the Sarakan Dam, located on the border of Gitung Village and Kosambi Village, remained structurally intact but had three damaged floodgates that were temporarily replaced with wooden partitions.

The evaluation covered existing water resource infrastructure, including water level monitoring posts, water pumps, drainage gates, and embankments. It was found that only one out of three water monitoring posts was integrated with an online early warning system managed by Tangerang BPBD, while the others functioned as manual Water Guessing Posts (PDA) at the Ledug River Estuary and Situ Bulakan Estuary. The study also recorded nine operational water pumps, strategically placed for lake discharge, drainage, and river estuaries. Most embankments along Gelam Jaya Village in Pasar Kemis District were in good condition, but some sections showed visible cracks requiring maintenance.

To enhance flood preparedness, flood discharge calculations were performed using three different methods: the HSS method, HEC-HMS software modeling, and AWLR data analysis. The insights gained from this study provide a comprehensive foundation for flood risk reduction, infrastructure improvement, and sustainable urban resilience planning in the Cirarab River basin. By implementing these recommendations, the local government can ensure a more effective flood response system, reducing future flood impacts on residential and industrial areas in Tangerang.

Status: 100% Completed – Ready for Implementation