RM100mil spent on JB flood mitigation, but system overwhelmed by intense rain

The city of Johor Baru has spent over RM100 million on drainage and flood mitigation since 2023, but the existing infrastructure was still unable to handle today's intense rainfall combined with high tide. Johor Housing and Local Government Committee chairman Datuk Mohd Jafni Md Shukor reported that rainfall intensity reached 60mm per hour, three times the reference rate, while the high tide hit 3.5 meters.

This combination put significant pressure on Johor Baru's drainage and flood mitigation systems. Between 1pm and 7pm, rainfall totaled about 90mm, with a significant spike between 1.30pm and 5pm. The sudden surge in rain flow overwhelmed the drainage and retention systems, causing a backwater effect that slowed drainage and raised water levels upstream.

Jafni noted that rapid development increased paved and built-up areas, reducing water infiltration and accelerating surface runoff. For 2027, RM46.8 million has been allocated for flood management, prioritized based on technical assessments of drainage, retention, and pumping capacity, flood risk, and tidal impacts. At Kampung Mohd Amin, the retention pond will be deepened, and at Jalan Danga opposite Tune Hotel, the on-site detention facility will be upgraded.

The number of pumps discharging water into the Johor Strait has increased from four to eight units. Jafni emphasized the need for cooperation between local authorities, technical agencies, and landowners to ensure measures taken at one location don't increase flooding risk elsewhere. A Johor Baru Flood Task Force will meet to examine rainfall data, tide records, inundation levels, drainage capacity, and pump operations to identify restrictions and prioritize upgrading works.