> 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.
Keyline design predates Permaculture One. It was introduced by P A Yeomans as a means of dryland farming in Australia. It's a somewhat similar concept to the Inca system described here. Basically trenches are run horizontally with a very slight slope from a 'keypoint' where water enters a topography. This slowly distributes water throughout the land, producing fertile and moist regions between the lines.
This in turn is predated by decades of contour plowing, and thousands of years of terrace farming.
In a lot of Dutch towns and cities new neighborhoods are designed to have a system of Wadi's [0] where rooftop rainwater is directed to instead of to the sewer system. These are usually dry, but fill up when it rains. They provide attractive green spaces between the buildings and road network where plants, flowers and other fauna can thrive.
Other cities, like Apeldoorn, are providing subsidies to decouple the rainwater drain from the sewer to let the water infiltrate in your own garden instead.
Calling plants and flowers "fauna" makes me think of Seymour from Little Shop of Horrors. Not sure a bunch of man eating plants between the buildings would be optimal civil engineering.
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.
If there are fish in the river at all, the biological diversity could be limited by the inability for those fish to wander beyond their side of the dam. I am not sure if there are salmonid fish there, or other fish that require swimming upstream to reproduce. I would doubt it that far inland.
If anyone ever has the chance to explore Peru and the Sacred Valley, I highly recommend it. There are some fascinating ruins apart from Macchu Picchu like Moray which they believe was a greenhouse where each steppe is a different microclimate.
Such aquifer draining structures (quanat) would result in dry climate over time, much like we see in Iran. Deep rooted plants - trees, perennial grasses - would no longer get water from the drier aquifer.
In contrast, aquifer recharging systems (amunas, swales) tens to create a wetter climate over time. In addition to the plants using water themselves, some trees also create aerosols that cause more rain. Very special trees - such as redwoods [0] - can directly capture moisture from fog, that would otherwise never fall as rain. .
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.