With a little help from what's called the Internet of Things, engineers are transforming cities from passive conduits for water into dynamic systems that store and manage it like the tissues of desert animals. By using the Internet to connect real-world sensors and control mechanisms to cloud-based control systems that can pull in streams from any other data source, including weather reports, these efforts enable conservation and money-saving measures that would have been impossible without this virtual nervous system.
Marcus Quigley, principal water engineer at the infrastructure engineering firm Geosyntec, has been tackling this problem using hardware from Internet of Things company ioBridge, whose Internet-connected sensors have been used in everything from location-aware home automation to tide gauges that tweet.
It may sound like a trivial problem, but the EPA estimates that the U.S. has $13 billion invested in wastewater infrastructure alone. More importantly, the majority of America's largest cities--more than 700 in all--dump millions of gallons of raw sewage into our waterways every time it rains, because their sewer and stormwater systems were designed a century ago.
These overwhelmed cities include New York City, Detroit, Boston, Portland, St. Louis, Chicago, Seattle, Philadelphia, Washington, D.C., San Francisco, many other cities, mostly in the Rust Belt and New England. With the notable exception of Los Angeles, almost every major urban center in the U.S. is in need of a way to soak up rainstorms rather than dump them straight down the drain in a desperate attempt to prevent flooding.
That's where "high performance" infrastructure--infrastructure that can react to its environment like a living thing--comes in.
"The conventional way to build a city is you build what you want, and then you get rid of water as quickly as possible," says Quigley. Historically, that's meant massive projects to redirect all the water sluicing down impermeable streets and concrete and into the Moria-like recesses of a city's sewer system. Green infrastructure tries to control runoff on-site, rather than sending it below, through the use of "bioretention cells" and rain gardens, which absorb and filter the water into collections of plants and artificial wetlands.
High-performance green infrastructure takes things a step further, by anticipating demand for water storage and preparing a system accordingly. For example, in seven projects deployed in St. Louis and one in New Bern, North Carolina, Geosyntec integrated a building's rainwater catchment system with software that uses weather predictions from the Internet to know when a basin should be partly emptied to accommodate incoming stormwater.
Many more projects of this kind are on the way, including installations in Washington, D.C. and New York City.
"Instead of trying to use what I consider sub-optimal passive systems to control these ... components of the urban environment, what we're doing is making decisions in real time to achieve specific environmental goals," says Quigley.
Dynamic control of a rainwater catchment allows these basins to be used to their maximum without fear that they'll be overwhelmed by weather events. Giving building planners the assurance that they'll always have access to a free water supply means they can actually use it. And putting these on enough buildings could go a long way to solving the problem of combined sewer and stormwater systems being overwhelmed when it rains.
It's early days for these kinds of systems, and managing runoff is just one of the applications they could be put to use.
"The big picture is that we are able to take any piece of information that is Internet-accessible, any feed, and integrate it into the logic of how we operate these components of our city," says Quigley.
Geosyntec's cloud-based infrastructure is just as important as the physical infrastructure it puts into place on-site. Led by software developer Alex Bedig, the company has created a general-purpose platform for handling all the relevant inputs, sending instructions to valves and other control points, and never, ever failing in an emergency.
Taken together, these physical and virtual systems are explicitly biomimetic, says Quigley.
"The intent of an active system is to take the built environment and have it perform as if it were natural. We're fundamentally saying that passive systems are unable to do that in an optimal way. In many cases they are unable to do it at all."
It's a story we've heard in the energy industry for years--hence the notion that a dynamically managed "smart grid" is not only helpful, but absolutely essential for integrating our power-generating infrastructure with the natural world through renewables. The smart grid extends all the way down to the level of the individual through demand management for energy conservation, but these principles have yet to show up on the same scale in the management of physical resources like water.
Humanity has a sorry habit of neglecting its waste stream, whether its the 99% of precious rare earth elements we fail to recycle or the complete absence of curbside composting from most American cities. The handy thing about water is that, through evaporation, it recycles itself. Now all we have to do is make the best use of it we can while it's coursing through our cities.