Here's just one example, from Singapore:
Singapore's Marina Barrage.
The Marina Barrage and Reservoir, which opened in 2008, is at the heart of Singapore's two-billion-dollar campaign to improve drainage infrastructure, reduce the size of flood-prone areas, and enhance the quality of city life. It has nine operable crest gates, a series of enormous pumps, and a ten-thousand-hectare catchment area that is roughly one-seventh the size of the country. The system not only protects low-lying urban neighborhoods from flooding during heavy rains; it also eliminates the tidal influence of the surrounding seawater, creating a rainfed supply of freshwater that currently meets ten percent of Singapore's demand. More over, by stabilizing water levels in the Marina basin the barriers have produced better conditions for water sports. The Marina's public areas, which include a sculpture garden, a water-play space, a green roof with dramatic skyline vistas, and the Sustainable Singapore Gallery, bolster the city's tourist economy as well.
That's a brilliant way to address two climate impacts -- large precipitation events and rising sea levels -- at once. Singapore has also elevated all access points to its underground subway a least a meter above high-water flood levels. It's also building desalination plants and systems to reuse waste water. It's also burying its power lines.
Engineers at the Dutch firm Arcadis recently proposed a large new sea barrier for north of New York City's Verrazano-Narrows Bridge. The price tag: $6.5 billion. And that's just one small piece of the puzzle. All this stuff is prudent, but it's expensive.