The Prospects for Rain are Looking Up
I hate seeing things go to waste. I am a dumpster diver from way back, regularly pick up aluminum cans and other recyclables while walking with my dogs, and am always looking for ways to drive down our household energy use. It is no surprise then that I am also an enthusiast for rainwater harvest, both personally and professionally.
I recently had a chance to share my experiences and perspectives as a panelist on a webinar, “Stormwater Capture Drivers, Impediments, and Future Visions”. This event, recorded on February 3rd, 2021, was the first of a series of four webinars planned to help implement the U.S. EPA’s National Water Reuse Action Plan issued last year.
Each of the nine experts who participated in the two-hour dialogue came at the question with a slightly different perspective. Some, like Professor Dick Luthy (Stanford) who is one of the co-founders of ReNUWIt, brought a research and systems approach to the conversation, while others like fellow Minnesotan Mark Doneux, Administrator of the Capital Region Watershed District in St. Paul, brought his experience implementing large-scale rainwater capture and re-use projects. Roughly half of the panelists came from water-rich regions where amelioration of stormwater impacts is the primary driver where the other half were based in water-stressed regions where new water sources is key to survival. I was invited in part because of my leadership role with the Water Environment Federation as well as my expertise in distributed water assets more generally.
To start things off, moderator Molly Mayo asked me what drives my interest in rainwater capture, something near and dear to my heart. My interest starts pretty simply: why would I want to spend perfectly good money and burn fossil fuels to pump water up from the ground or across the city when I can capture water from the downspouts on my house? That in and of itself is justification enough for me, especially given that my life has been spent in temperate parts of the U.S. where rainwater harvest is a realistic year-round water supply option. But I am an enthusiast for other reasons as well. When we capture rain we solve other problems:
- Capturing rain prevents erosion, flash floods, sewer overflows, and polluted runoff. In urban and built environments we have eliminated much of the natural infrastructure – the soil and plants – that can absorb rainwater and ameliorate its effects. Even lawns – the prominent landscape feature of suburban neighborhoods and office parks – are a poor substitute for natural infrastructure when it comes to slowing and absorbing precipitation. In lieu of natural infrastructure, capturing rainwater in buckets, barrels, and cisterns softens that blow.
- Capturing rain reduces reliance on groundwater withdrawals. When groundwater is pumped out faster than it can be replenished, an unfortunately common predicament, it can reduce base flow in rivers and streams, allow saltwater intrusion in coastal areas, trigger subsidence that puts buildings and infrastructure at risk, and force communities to drill deeper wells.
- With local water harvest we reduce energy use. Water is heavy, and if we capture it close to where it will be used, we cut back on pumping demands. This is especially true in the case of deep wells where the water has to be lifted farther. We also cut back on the energy embedded in the water infrastructure itself. More compact infrastructure means a lower embedded energy footprint.
- With rainwater we eliminate many contaminants. Deep groundwater often contains arsenic, radium, and other naturally occurring toxic chemicals. To illustrate this point, I look no further than Waukesha, Wisconsin, a community that over-taxed its naturally occurring springs to the point where the remaining water was deep underground and contaminated with dissolved radium. Rather than look to water re-use and localized rainwater harvest, the city built a 20-mile pipeline to Lake Michigan for its new water supply. I cringe to think of the expense and energy dependence that community members will bear for decades to come because of that decision.
- In agricultural regions, rainwater allows residents to bypass pesticides, herbicides, fertilizers, and livestock fecal contaminants that often seep into groundwater and contaminate rural wells.
- And there are unexpected bonuses to using rain rather than municipal water. Landscape managers who can use recovered rain for irrigation will tell you that the plants are healthier without the chlorine residuals found in city water. Ice hockey players report that rainwater ice is harder and faster than ice made from city water with its additives.
I don’t mean for my enthusiasm to imply a that on-site rain capture is a panacea to our water woes. Of course there are nuances and complications that need to be considered, especially when aiming to use on-site harvest as a potable water supply. That’s another blog for another day. But let us recognize that harvesting rain is an integral part of the three-fold challenge of reducing stormwater impacts, finding new water supplies, and reducing water’s energy footprint.
As Mark Doneux said in closing out the webinar, “Rainwater harvest needs to become mainstream … I think this is like recycling was 20 years ago. Like recycling, it needs to become an everyday practice.” I couldn’t agree more. At home, even the simple step of putting a bucket under the downspout to collect water for plants or wash water is a start. And for those who plan, design, build, permit, or work in larger buildings, you have big opportunities and big responsibilities to help us get it right. After all, rain is an opportunity we don’t want to waste.