Bangkok to Partially Open Nong Bon Water Drainage Tunnel as Rainy Season Approaches

Picture courtesy of Khaosod.

Bangkok authorities have announced plans to partially open the Nong Bon water drainage tunnel as construction nears completion. With 96% of the project finished, the tunnel is expected to play a crucial role in mitigating floods in several districts during the upcoming rainy season.

Speaking at Bangkok City Hall, Deputy Governor Wisanu Subsompon provided an update on the construction of the Nong Bon water drainage tunnel, which will channel floodwater from Nong Bon Lake into the Chao Phraya River.

Construction progress has reached 96%, but the project faced delays due to subsidence near the Klong Kled water intake structure. To resolve the issue, engineers had to re-drill sections of the tunnel.

Officials now expect construction to be completed by 2026, when the entire system will undergo final testing and cleaning, although sections of the tunnel will be operational this rainy season to help prevent flooding in key areas of Bangkok.

The tunnel has already proven effective, having been partially used in 2024 to manage floodwaters. Once fully completed it will provide long-term flood prevention for Prawet, Bang Na, and Phra Khanong districts, as well as neighbouring areas.

The project relies on Nong Bon Lake as a key water retention area, which will collect excess rainwater from surrounding canals before channelling it into the Chao Phraya River via Bang O Canal.

Authorities remain confident that the tunnel will significantly reduce flood risks and improve water management across Bangkok.

-- 2025-04-04