Science is finally catching up with permaculture – the way to work with nature to create the most amount of resources with the least amount of work put in, and also thinking long-term and sustainable. And what could be a better suit for those guidelines than to gather rainwater and using it indoors or for irrigating vegetables?
Thanks to massive amounts of data collected by the joint project TRMM, Tropical Rainfall Measuring Mission, a collaboration between NASA and the Japan Aerospace Exploration Agency, the researchers behind the study found that almost 20 percent of the indoor needs for water could be covered by rainwater collection.
Unlike other studies of rainwater benefits to communities and livelihood, this study did not focus on how precipitation first needs to reach the groundwater level to be pumped up again, but instead the researchers looked at what it would mean if Indians collected rainwater in cheap 200-gallon tanks. These tanks could be engineered to easily be placed in more densely populated urban areas as well.
While the 20 percent coverage of the need for water indoors is fantastic, there’s even more to this equation – if used for vegetable irrigation, the collected rainwater would instead be covering the entire need for water. The research team also concluded that this would be the most beneficial use, since it would both lead to bigger water bill savings, provide healthy food, give profits from selling any excess veggies as well as give a much shorter payback period for whatever maintenance, operation and infrastructure work needed to pull it all off.
Dan Stout, research assistant in the Department of Civil Engineering at the University of Utah and one of the three study authors, explains the thoughts behind the mission: “India has severe problems getting potable water to all of its residents. We considered collecting water in a relatively small tank, and it’s amazing the effect that doing something that small and simple can have on the Indian people.”
The study was published in the June issue of the Urban Water Journal, and based its calculation on TRMM data of the rainfall over the tropics and subtropic, from 1997 to 2015. This kind of data had been very hard to come by, and according to Stout, without the TRMM database the project might have had to be cancelled altogether.
The financial return is also meaningful when considering the positive effects of harvesting rainwater in the day-to-day life in India; after a payback period of one year, the profit after using rainwater for vegetable irrigation would be between 1,548 and 3,261 rupees per year, while the total cost savings wold be between 2,605 and 4,522 rupees per year. That’s enough to pay the rent for six months for a one bedroom apartment in an average Indian city!
How’s that for simply putting all that freshwater that’s served every year from the skies to good use. And hey – why stop at India? A lot of countries have both rain and troubles getting the freshwater to cover all its needs.
Image: NASA / Hal Pierce
