As tunneling technology continues to advance, this article says that transportation tunnels get all the press but water tunnels are also becoming much more numerous and common.

Most of the attention in other cities may go to the multibillion-dollar transportation tunnel projects, like the Second Avenue Subway in New York City or the Gateway tunnel between New York and New Jersey. But the sheer number of water tunnels being built or planned exceeds the sexier transportation tunnels. “There are more water tunnels than transportation tunnels,” says Mike Schultz, technical strategy leader for the geotechnical-structural group at CDM Smith.

Egger at Black & Veatch estimates there are about 200 miles of water tunneling in various stages of planning and design in North America, 50 miles of which directly involve Black & Veatch. Jacobs alone is involved in the development of  more 150 miles of water, wastewater and CSO tunnels around the world.

Technology has reduced the price of tunnels enough so that mid-size cities like Fort Wayne and Alexandria, Va., can use a tunnel option to handle their excess water. Technology also has made tunneling a viable option in some cities with soft ground, such as Houston, which couldn’t have considered building tunnels just a decade ago.

Full disclosure: This is the business I am in and I have a business relationship with one of the firms above. Well, not the tunneling business specifically but the water management business. I would much rather see water managed using green infrastructure and ecosystem-based solutions as much as possible, but a backbone of hard infrastructure certainly has its place in urban areas.