Ancient Intervention Could Boost Dwindling Water Reserves in Coastal Peru:
Senior author Dr Wouter Buytaert, of Imperial's Department of Civil and Environmental Engineering, said: "The people of Lima live with one of the world's most unstable water situations. There's too much water in the wet seasons, and too little in the dry ones.
"The indigenous peoples of Peru knew how to get around this, so we're looking to them for answers."
Ancient Peruvian civilisations in 600 AD created systems within mountains to divert excess rainwater from source streams onto mountain slopes and through rocks.
The water would take some months to trickle through the system and resurface downstream -- just in time for the dry season.
To study this, the researchers looked at one such system in Huamantanga. They used dye tracers and hydrological monitoring to study the system from the wet to dry seasons of 2014-2015 and 2015-2016. Social scientists involved also worked with Huamantanga's local people to understand the practice and help map the landscape.
They found the water took between two weeks and eight months to re-emerge, with an average time of 45 days. From these time scales, they calculated that, if governments upscale the systems to cater to today's population size, they could reroute and delay 35 per cent of wet season water, equivalent to 99 million cubic metres per year of water through Lima's natural terrain.
This could increase the water available in the dry season by up to 33 per cent in the early months, and an average of 7.5 per cent for the remaining months. The method could essentially extend the wet season, providing more drinking water and longer crop-growing periods for local farmers.
Journal Reference:
Boris F. Ochoa-Tocachi, Juan D. Bardales, Javier Antiporta, Katya Pérez, Luis Acosta, Feng Mao, Zed Zulkafli, Junior Gil-Ríos, Oscar Angulo, Sam Grainger, Gena Gammie, Bert De Bièvre, Wouter Buytaert. Potential contributions of pre-Inca infiltration infrastructure to Andean water security. Nature Sustainability, 2019; DOI: 10.1038/s41893-019-0307-1
(Score: 2) by PartTimeZombie on Friday June 28 2019, @12:51AM (6 children)
It sounds a bit like building a reservoir when you don't have the engineering to actually build a reservoir.
Make the water flow downhill much slower so that you can make use of it later is pretty clever in my view.
(Score: 2, Funny) by Anonymous Coward on Friday June 28 2019, @02:46AM (3 children)
In SoCal they built large concrete flood channels that diverts the unneeded mountain rain to help refill the Pacific ocean.
(Score: 5, Funny) by PartTimeZombie on Friday June 28 2019, @03:03AM
That's good. I live on the other side of the Pacific and last night it was looking a bit empty.
It is a bit odd though. This morning it was full again. Maybe it rained in California?
(Score: 2) by DeathMonkey on Friday June 28 2019, @05:53PM
Ewww, gross, you want them to use domestic tap-rain?!?!
Nah....they prefer artisanal rain imported from Colorado.
(Score: 3, Interesting) by ElizabethGreene on Friday June 28 2019, @08:11PM
One of the primary causes of subsidence in California is aquifer compaction due to groundwater pumping.
Correlation is not causation, but I'm curious if there is a connection.
(Score: 1) by khallow on Friday June 28 2019, @06:10AM
It also has the virtue of reduced evaporation at the surface and greater introduction of ground water.
(Score: 0) by Anonymous Coward on Friday June 28 2019, @08:09AM
See also: https://en.wikipedia.org/wiki/Glacier_growing [wikipedia.org]
http://www.waterhistory.org/histories/qanats/ [waterhistory.org]
(Score: 0) by Anonymous Coward on Friday June 28 2019, @01:14AM
or in this case good, maybe, hopefully
(If you delay 35% of the water by months, you are causing climate change. Impact TBD.)
(Score: 0) by Anonymous Coward on Friday June 28 2019, @06:47AM
took a gazillion dollar supercomputer to figure that out, now did it?
(Score: 0) by Anonymous Coward on Friday June 28 2019, @06:48AM
"Ancient Intervention Could Boost Dwindling Water Reserves in Coastal Peru"
I know it's a headline, but the tenses all fucked up.
(Score: 0) by Anonymous Coward on Friday June 28 2019, @07:43PM
Sounds like they need a tip or two
https://www.cnn.com/2019/06/27/india/india-water-crisis-intl-hnk/index.html [cnn.com]