Many of us surely have been to a waterpark in our lives, with fond memories of leaping (or being pushed) down a serpentine slide, ultimately splashing into a big pool of cool water. But how many of us have been to a stormwater park? You may have indeed been to one, but you may not have noticed. As urban ecology and sustainable development become the norm in cities like Seattle, neighborhood stormwater parks are sure to inundate the landscape (quite literally).
More often than not, cities spring up near steady, abundant water supplies. Ironically, those same cities have long taken that water for granted thanks to the wonderfully consistent and reliable hydrologic cycle. In urban landscapes where pavement rules, excess water is a nuisance and potentially hazardous. So, the goals of water management in the city are to provide drinking water and to quickly get rid of stormwater. In fact, in the water management sense, stormwater is a subset of wastewater (redefining wastewater is a whole different story).
However, population increases and climate change threaten the sustainability of many urban water supplies, and cities now must reconsider that which has been a given for decades: how will we meet our future water needs?
Consider the life of a water droplet as it enters the city:
The water droplet makes a long journey as rain or snowmelt and finds its way into the city. Sometimes this droplet ends up infiltration into the groundwater or evaporating right back into the atmosphere, but if it is lucky, the droplet will be used to meet humans’ basic needs, such as an icy glass of water, a hot shower, or as irrigation for a pea patch plot. Regardless if that droplet is used or wasted, it eventually finds its way into the city’s wastewater system, receives proper treatment, and is sent off to the nearest river or ocean outside the city limits. One and done. In and out.
It doesn’t have to be that way, and city’s are beginning to recognize this illogic. Engineers and developers are splashing around a paradigm shift in urban water management: Instead of looking for new outside water sources, why not look inwards and turn the urban landscape into a water source?
Think about it. We have all of this area (rooftops, roads) designed to carry away water as quickly and efficiently as possible. But what if we designed cities to retain the water and save it for use? Just as cities and developers seek creative solutions to sustainability through green infrastructure, they should also look to incorporate this concept of “blue” infrastructure, or at least blend the two.
Take stormwater parks, for example. Not only do they provide a much-needed green space in urban areas, they also act as a flood control, a carbon sink, and can even get rid of some of those nasty organic chemicals coming out of our tailpipes. And did I mention they are easy on the eyes and probably good for the soul? In Qunli New Town, China, the city revitalized a dying wetland and turned it into a National Urban Wetland (and won the ASLA Award for Excellence in 2012). Some cities, such as Los Angeles, are even looking into ways to reuse treated effluent (affectionately known as sewage) for drinking water (it’s not nearly as bad as it sounds).
It is time to acknowledge stormwater and wastewater as resources, not engineering inconveniences. Closing the urban hydrologic loop requires an intensive investment, but the reward of a local water supply is too good to pass up. Heck, I’ll drink to that!