We’re in our 15th year of drought on the Colorado River. As the most critical water source west of the Mississippi River, the Colorado sustains millions of acres of farmland and nearly 40 million people in seven Western states and Mexico. But since 2000, the river’s water inflows have been 73 percent of its historic average, according to the United States Bureau of Reclamation.
Drought, of course, isn’t unique to the Colorado River Basin, or even to the West. In 2007, Florida, Alabama, and Georgia grappled over a shrinking Lake Lanier. A 2011 drought ravaged the Plains and Midwest, painting nearly all of Texas crimson red on drought maps and eventually threatening navigation on the Mississippi River early the next year. This year, California has been struggling with its most critical drought in modern history with 100 percent of the state declared to be in severe, extreme, or exceptional drought.
Drought not only diminishes water supply, it also increases demand as users draw upon stored supplies to fill the widening gap between sparse local rainfall and their needs. To add insult to injury, drought affects energy production and use: Shrinking reservoirs produce less hydroelectric power while increased pumping of groundwater ramps up energy demand.
But even a “dust cloud” can have a silver lining. Sustained drought gives us both the time and necessity to implement serious, long-term efficiency measures (provided our attention span isn’t snapped by the next big snowfall).
The good news is that we have extraordinary potential to reduce water demand in every sector and the interest in achieving that potential grows with each parched day. In fact, one of the threats is not that we’ll fail to implement water efficiency policy and measures, but that in our haste, we’ll choose options that come with unintended consequences.
Let’s Not Waste the Grid
In 2011, I stood inside a pristine 30,000-cubic-foot mechanical room within a highly touted New York City apartment building. An impressive array of pipes, pumps, tanks, and gauges comprised a state-of-the-art wastewater plant that handled about 8,000 gallons of blackwater each day. The system produced highly refined recycled water which was pumped more than 300 feet to the top of the tower to flush toilets and supplement cooling tower water.
As awestruck as I was, I still wondered just how “green” this setup really was. Was it appropriate to build and maintain a space the size of a three-bedroom house to recover a few thousand gallons of water each day? Could this micro-plant truly outperform the water and wastewater grid of the City of New York?
As it turns out, no. Each 1,000 gallons of water reused by the on-site treatment plant consumed 43 kilowatt-hours of electricity—more than 10 times as much as the City of New York uses to provide equivalent water and wastewater service. In addition to the initial capital costs, the building spends nearly $100,000 per year on operation and maintenance, bringing the unit cost of recycled water to more than $30 per 1,000 gallons—about three times what equivalent city services cost.
There are sound reasons to implement off-the-grid projects, but too often, we’re merely building redundant infrastructure right on top of it instead. In some cases, these “on-top-of-the-grid” systems are upstream of existing community wastewater recycling facilities that already fully recover wastewater for reuse.
Not All Water Efficiency Is Created Equal
According to the U.S. Geological Survey, irrigation accounts for more than 60 percent of all freshwater withdrawals in the United States. Predictably, agriculture accounts for the vast majority of this, but urban landscapes remain the greatest opportunity for improved water efficiency in the built environment. A 2011 EPA-funded study found that, despite the inclusion of improved appliances and plumbing fixtures, homes built after 2000 typically use more water than their predecessors, and landscape irrigation was the culprit. Even in cities with abundant rainfall, automated sprinkler systems have become an expected amenity for new home buyers.
Since irrigation is a consumptive use—one that terminates as water vapor in the atmosphere—there’s no opportunity for reuse. Many cities are already investing in infrastructure to recover and reuse wastewater on a municipal scale, so it makes sense for building designers to put a high priority on reducing consumptive uses, such as evaporative cooling, landscape irrigation, and surface evaporation from open bodies of water.
So, Where to From Here?
Embrace the grid. Ensure you can truly outperform existing services on both infrastructure and energy before committing to on-site reclamation. As admirable as it sounds to reuse your own water, community systems typically produce broader results with fewer resources. If on-site treatment looks marginally feasible, consider the benefits of satellite plants that may serve more than one building.
Go with the flow. Passive rainwater harvesting systems—where water is directed by gravity and soil-banked for deep-rooted, climate-adapted plants—not only reduces water demand, but mitigates stormwater runoff. This approach can be implemented with minimal cost and infrastructure and should be integrated into virtually every project.
Put water to work. Alternative supplies are often undervalued, though they may be the most costly supply. Rainwater and recycled water shouldn’t be spent frivolously. Although it garners attention to put up a sign that says “this decorative water feature uses recycled water,” such supplies should be applied to their highest and best use.
Support sound water policy. It’s not enough to put up attention-grabbing, LEED-certified buildings. And catchy incentive programs will merely retrofit a small fraction of the questionable water use decisions we’ve made in the past. What we need is a sea change in the way we plan and build communities to ensure all buildings use water efficiently for their entire lifetime—the type of change that can only be accomplished by sensible development policies tailored for each community’s water supply strategy.
We are making progress, but let’s be frank, we’re not achieving our water-use vision for 2020. It’s not lack of know-how so much as it is social and economic factors that stand in our way.
When drought inflicts meaningful pain, it illustrates that our baseline demands should be much lower. Drought gives us the opportunity to rapidly accelerate our progress toward greater resiliency by changing the economics of efficiency and unifying political will. It’s an opportunity that shouldn’t be wasted.