"They love dykes," says Ho Long Phi, a professor at Vietnam National University in HCMC.Mr Phi may be Saigon's best flood-control asset.
In the Netherlands dykes have been pushed out and flood plains restored to give rivers more room to flood.Third, governments must eliminate the perverse incentives their own policies produce.
A vast, cheap labour force could go to work on road improvements, rainwater reservoirs, irrigation channels, dykes and community centres.
In Pakistan authorities have breached dykes in the Indus river watershed in order to protect towns and cities.
In the 1960s, the corps crisscrossed the remnants of the grassy river with dykes, ditches and levees.The river is now in the wrong place and more akin to a series of ponds.
Tearfund points to the effectiveness of such measures as planting trees to reduce the impact of floods and landslides, building techniques to help houses withstand earthquakes, cyclone shelters, sea dykes and so on.
Peru's government had done much to prepare against the rains, building dykes, cleaning waterways and strengthening bridges.
In January a commission established by Pakistan's supreme court began to investigate allegations that landlords in Sindh had deliberately breached dykes to channel floodwaters away from their own farmlands and towards villages.
The Dutch invented the word "polder" centuries ago to describe dry land created by enclosing floodplains (or shallow waters) with dykes.
Deltares, a research institute, recommends that the Thai government emulate Room for the River by moving dykes farther back where possible, limiting floodplain development and unifying water management so that safety is no longer subservient to irrigation and electricity generation.But the Dutch approach has limits.
A series of dykes now regulate the amount of water that enters the Everglades National Park, drying up large tracts of marshland.
