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Peru is reviving a pre-Incan technology for water

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Re: Peru is reviving a pre-Incan technology for water

#31

Post by hinkley »

KaiserPro wrote: post #19

tldr: Diverting streams to go into different places increases the dwell time of the water by 45 days. when you have a rigid dry season, keeping the streams running for an extra 45 days is absolutely fucking huge. The clever part is that over the years the locals have managed to find the best place to divert water so it goes into springs that feed streams. its a similar idea to a Johad, https://en.wikipedia.org/wiki/J…

Especially if you already use plants adapted to a dry season.

There's a huge difference between surviving 50 days without rain and being able to survive 90 days without rain.

Re: Peru is reviving a pre-Incan technology for water

#32

Post by wolverine876 »

For a more scientific, technical discussion, see this paper, linked in the article:

https://www.nature.com/articles/s41893-019-0307-1

Available here:

http://mural.maynoothuniversity.ie/13800/1/SG_geog_potential...

(Thanks abdullahkhalids for finding the latter link; I'm just posting it here for more visibility.)

Re: Peru is reviving a pre-Incan technology for water

#33

Post by foxhop »

I'm not sure why it's only happening in Peru, we should be doing this work world wide. I have similar water capturing techniques at my house where I redirect road runoff into a gentle stream and allow it to infiltrate my landscape, watering Maple, Apple, Plums trees, hydrating the landscape to reduce effects of multi-month droughts:

Reference: https://www.youtube.com/watch?v=lAQS4CN_4OY

Re: Peru is reviving a pre-Incan technology for water

#34

Post by kjkjadksj »

foxhop wrote: post #33

I'm not sure why it's only happening in Peru, we should be doing this work world wide. I have similar water capturing techniques at my house where I redirect road runoff into a gentle stream and allow it to infiltrate my landscape, watering Maple, Apple, Plums trees, hydrating the landscape to reduce effects of multi-month droughts: Reference: https://www.youtube.com/watch?v=lAQS4CN_4OY

Road runoff is usually pretty polluted in cities and some places have laws against capturing rainwater to protect downstream resources.

Re: Peru is reviving a pre-Incan technology for water

#35

Post by hinkley »

dpierce9 wrote: post #8
koheripbal wrote: post #3

TLDRV They divert the rainy season water to natural aquifers and hope it reappears down river in the dry season. The small scale of the effort currently makes me a little skeptical that it's achieving anything. Underground water is impossible to measure. What might be more effective and certainly more measurable would be to build a dam/reservoir.

Article woo aside, underground water is not impossible to measure. Min well depth (or depth of dry wells) is a straightforward way to measure the aquifer level for a small area. It doesn’t tell you much but it tells you something. Combine with your neighbors taking the same measurement over time and you have a good data set. That is before you get to things like ‘geology’ which are known factors shaping underground w…

I learned that it's fairly routine in wetland restoration work to sink shallow 'wells' (stand pipes) a couple feet down to measure water table levels over the course of a year or so. Wetlands - and in particular the plants that are adapted to them - can be permanent or seasonal, and can change over a 20 foot distance, so knowing which you have and where can be the difference between a failed or successful restoration.

Re: Peru is reviving a pre-Incan technology for water

#36

Post by hinkley »

ralfn wrote: post #5
koheripbal wrote: post #3

TLDRV They divert the rainy season water to natural aquifers and hope it reappears down river in the dry season. The small scale of the effort currently makes me a little skeptical that it's achieving anything. Underground water is impossible to measure. What might be more effective and certainly more measurable would be to build a dam/reservoir.

Thank you so much. The article is just too polluted with pseudo intellectual nonsense, but water management is a very underappreciated discipline of engineering. Although it seems impossible to measure how much water is stored in the deep soil, it is often possible to notice if it runs out. We had that last summer in the Netherlands. I suppose knowing we reached zero, and knowing the influx (mm rain, and the flow of…

I don't know what I was watching but someone mentioned and then drew a diagram showing that a well may be at a certain depth, to comfortably reach water, but the water level will drop as soon as you start pumping because the water has to move horizontally through the rock, and so you will get a gradient between 'water level' in the aquifer and water level at your well, and the faster you pump the higher the slope.

I guess there are some ways to work out permeability and volume based on how the levels at one well are affected by activity at the next well.

Re: Peru is reviving a pre-Incan technology for water

#37

Post by kjkjadksj »

KaiserPro wrote: post #19

tldr: Diverting streams to go into different places increases the dwell time of the water by 45 days. when you have a rigid dry season, keeping the streams running for an extra 45 days is absolutely fucking huge. The clever part is that over the years the locals have managed to find the best place to divert water so it goes into springs that feed streams. its a similar idea to a Johad, https://en.wikipedia.org/wiki/J…

The biggest issue with the west was that it was in a historic wet period 100 years ago when water rights laws were solidified with different groundwater levels. Its a drought only relative to this time, historically in Southern california it is usually dry like this. The issue with runoff water in LA and other cities is that its super polluted. You don’t even want to swim in the ocean after a rain. If you wanted to be smart about it you would have to treat it, but it rains in earnest so few times that building that infrastructure would be too costly if its only going to be used when it deluges 6 times a year.

What the city has been doing instead is honestly a better long term move imo. They treat sewage and turn it into grey water, which is used to water public grass spaces like parks and is starting to be used as well as recharge local aquifers since the state says the ground is the best filter for grey water.

Re: Peru is reviving a pre-Incan technology for water

#38

Post by hinkley »

wolverine876 wrote: post #30
ralfn wrote: post #5

Earlier quoted context omitted.

Thank you so much. The article is just too polluted with pseudo intellectual nonsense, but water management is a very underappreciated discipline of engineering. Although it seems impossible to measure how much water is stored in the deep soil, it is often possible to notice if it runs out. We had that last summer in the Netherlands. I suppose knowing we reached zero, and knowing the influx (mm rain, and the flow of…

> The article is just too polluted with pseudo intellectual nonsense Always an ironic comment!

Projection ain't just a river in Egypt.

Wait... that doesn't sound right.

Re: Peru is reviving a pre-Incan technology for water

#39

Post by kjkjadksj »

JuettnerDistrib wrote: post #22
KaiserPro wrote: post #19

tldr: Diverting streams to go into different places increases the dwell time of the water by 45 days. when you have a rigid dry season, keeping the streams running for an extra 45 days is absolutely fucking huge. The clever part is that over the years the locals have managed to find the best place to divert water so it goes into springs that feed streams. its a similar idea to a Johad, https://en.wikipedia.org/wiki/J…

> In LA, everything is done to make sure the water yeets into the sea as quick as possible. The infrastructure bill may change that [0]: "Also, the money could fund stormwater capture and reuse projects, like the ones that filter rainwater into underground aquifers rather than let it flow into the ocean." Anyone know how likely this actually is? [0] https://laist.com/news/climate-environment/socal-could-get-b...

Unlikely since it rains so few times the cost to benefit ratio is terrible. Instead the city has been treating wastewater and using that constant source of greywater to irrigate public parks and recharge aquifers.

Re: Peru is reviving a pre-Incan technology for water

#40

Post by frankfrankfrank »

Water retention needs to be made a bigger issue globally. Others eluded to the fact that what is effectively the draining of the water cycle in CA is a main cause of CA's water/fire problems, but that is also the problem in places like central Europe where the straightening of the rivers during industrialization (19th C.) is and has essentially been "draining the swamp" of the central European water cycle.

It's something I have had the hardest time getting people to understand. The various straightened rivers all throughout Europe that have far less retention capacity than in the past, are essentially drainage canals that are sucking the whole of the central European region dry of water, which will only compound problems.

There are a couple things going on that are fooling people into an illusion that everything being fine, but it is happening and it is causing the low rainfalls, the low snow packs, and the low cloud cover that increases temperatures that are all perceived as/blamed on global warming.

If Europeans don't stop the draining of the continent, the problems and heat will only accelerate. Just alone in order to prevent the necessity of using climate control systems that devour energy should be enough of an argument to try to restore the cloud cover and rainfalls that could lower temperatures to what they were like before the rivers were straightened and evaporation also caused more winds and breezes.

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