Much of the new technology is often referred to as “green infrastructure”, and can be a more subtle way of collecting rainwater from the roofs of houses or pavements, and having it filter through porous concrete or grassy fields into reservoirs for later use.
However, to make a dent, it will require more government investment, technological advances and overcoming political obstacles, they said.
To learn more, The Washington Post spoke with Andrew Fisher, a professor of hydrogeology at the University of California at Santa Cruz, and David Feldman, the director of the water institute at the University of California Irvine.
The conversation has been edited for length and clarity.
What is stormwater technology?
Fisherman: It’s kind of two pieces. In general, stormwater management is, first and foremost, about mitigating the hazards, avoiding the nuisance, avoiding the floods and avoiding the damage. [that comes with storm rain].
But we know that stormwater is also potentially a resource. So, another arm of stormwater management is figuring out what to do with some of that water. How can we retain it? How can we save it until we can use it later?
Why hasn’t it already solved California’s droughts?
Fisherman: When climate changes, the statistics change. Most of the stormwater infrastructure was built 20, 30, 40 years ago, and a lot of it was built based on old data. So [drainage pipes] which were designed for 10 year events, 20 year events, 30 year events are too small. Much of our infrastructure that was built decades ago is undersized.
Feldman: California plans to do a huge amount of work with stormwater capture and harvesting, but the actual implementation of these projects will take time. In many cases, it can take years.
Land must be acquired, things must be built, assessment studies must be undertaken, and probably most importantly, the public in the areas where this water is harvested must be brought on board.
How is stormwater technology adapting to solve droughts?
Feldman: Stormwater harvesting is an extremely old technology. You could go back to ancient Israel, for example, or other parts of the Middle East, where basic rainwater harvesting techniques were widely used.
So what’s the new wrinkle? I would say it’s this notion of green infrastructure — where you don’t use a lot of concrete and build storage reservoirs and dams. Instead, you come up with more convenient, more sensible ways to use the natural environment such as parks, wetlands, wetlands or ponds to intermittently store water.
But unless you’re really looking for it, the technology can be hard to discern. You see parks that have wetlands that sort of double as habitat for various forms of wildlife and are replenished by [and store] rain
You’ll also notice that neighborhoods increasingly have less impervious surfaces. Impervious surfaces are replaced by grass and open fields and porous pavement to allow the water to regenerate groundwater basins for example. You also see on tanks to store water, things like that.
Fisherman: Twenty years ago, 30, 40 years ago, stormwater was really just thought of mainly as a nuisance. But because of the drought, and because of the increased demand for groundwater, I would say that a big change is happening.
One of these areas is to visualize the subsurface, and understand better where our water is, and where there is space for storage. We have to use underground storage because you just can’t store enough stormwater on the surface.
Will stormwater technology end California’s droughts?
Fisherman: I would say no. Drought is very variable. [And] California’s climate swings between very wet and very dry conditions. Collecting storm water doesn’t change any of those things. But what stormwater technology can do is be part of a solution.
Feldman: Storm water harvesting [is] piece of a complex puzzle. It will not solve all our problems, but it can solve a considerable part of our problems.
We may not want to use rainwater for drinking. However, that water can be treated to varying degrees of reuse, at least for, for example, watering plants or watering landscaping.
