Nonthaburi
Bangkok's flood-prone suburb—1.5m elevation, sinking 1-2cm/year, sea rising 3-5mm/year, 'missing-teeth zones' fill when Chao Phraya discharges peak.
Nonthaburi trades flood risk for Bangkok proximity—and the bargain keeps getting worse. The province hugs the Chao Phraya's banks immediately north of the capital, its Pak Kret and Bang Kruai districts occupying low-lying basins that GISTDA flags annually for inundation risk. In October 2025, when the Royal Irrigation Department raised discharge from Chai Nat to 2,800 cubic meters per second, Nonthaburi's riverside zones flooded again. The "missing-teeth zones"—areas outside flood barriers—fill first.
The city sinks while the sea rises. Bangkok and its suburbs sit on soft clay averaging just 1.5 meters above sea level, subsiding 1-2 centimeters annually from historical groundwater extraction. The Gulf of Thailand rises 3-5 millimeters each year. By 2025 projections, 9.5 million rai of land could flood, causing 23.6 billion baht in damage. The World Bank warns that without adaptation, floods could eventually cost 10% of GDP—and Bangkok generates over 30% of Thailand's output.
Yet population keeps flowing here. Nonthaburi functions as Bangkok's overflow basin in two senses: absorbing residents priced out of the capital and absorbing water when drainage fails. The economics of proximity overwhelm the hydrology of vulnerability. People build where opportunity concentrates, even when the concentration sits below sea level on subsiding clay. Nonthaburi bets that flood walls will hold faster than the ocean rises.