[HN Gopher] Pre-Inca Canal System Uses Hillsides as Sponges to S...
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       Pre-Inca Canal System Uses Hillsides as Sponges to Store Water
        
       Author : bryanrasmussen
       Score  : 35 points
       Date   : 2020-01-06 21:04 UTC (1 hours ago)
        
 (HTM) web link (eos.org)
 (TXT) w3m dump (eos.org)
        
       | vanderZwan wrote:
       | > _A team of hydrologists, engineers, and social scientists is
       | hoping to strengthen the water security of Lima and other
       | Peruvian cities through analysis of a 1,400-year-old nature-based
       | system developed by pre-Inca mountain communities. The technique
       | uses a canal system that diverts water from streams to small
       | ponds or spreads it over rocky hillslopes that act as natural
       | sponges. This slows the flow of water down the mountains,
       | preserving it into the dry season._
       | 
       | Isn't that exactly what swales in permaculture practices intend
       | to do as well? Did the permaculture community copy this from
       | indigenous techniques perhaps?
       | 
       | > _Like most modern cities, Lima relies on gray infrastructure
       | like reservoirs and dams for water diversion and storage. Gray
       | infrastructure alone, however, has its drawbacks. It is often
       | expensive and challenging to implement. It also has a static
       | threshold, unable to adapt to shifting environmental conditions._
       | 
       | > _Natural (green) infrastructure can be much more dynamic and
       | cost-effective than gray infrastructure. Green infrastructure is
       | a broad category that can include planting native grasses to
       | prevent erosion and maintaining wetland health to hold and filter
       | water. Crucially, communities can use it in addition to the dams
       | and reservoirs already in place, amplifying their effectiveness
       | and providing a buffer when their threshold is exceeded._
       | 
       | This reminds me of a few articles I've seen in the last years
       | about a German city that is trying to be better at coping with
       | lots of rainfall by installing lots of green areas specifically
       | designed to hold a lot of water, while at the same time reducing
       | the heat island effect.
        
       | KaiserPro wrote:
       | The paper is far more illuminating:
       | https://agu.confex.com/agu/fm19/meetingapp.cgi/Paper/503994
       | 
       | This similar to some of the things I've heard about in central
       | india(I think) where they create half moon dams (less than
       | 2m(8ft) tall) that hold water back creating mini-lakes.
       | 
       | This serves two purposes: one it slows down water, meaning that
       | flash flooding is reduced. Two is keeps water hanging around
       | longer, meaning it makes the area less arid.
       | 
       | However it means more mosquitoes, so its not all good.
        
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       (page generated 2020-01-06 23:00 UTC)