[thinkingtoilet]

My question is are there downstream effects? The planting techniques are fascinating but the water that they are capturing surely was going some where, right? However little the stream may be, how do they do this without messing up people who are downstream?

[tim333]

It doesn't necessarily work like that. Vegitation can cause more rain rather than just taking water from elsewhere. A striking example is the Loess plateau, in China which went from dessert to green. Article mentioning it:

https://www.theguardian.com/environment/2021/mar/20/our-bigg...

[pwthornton]

I have to imagine a lot of it evaporated because it wasn't being captured, and then others became runoff that may have gone out to sea if it had been raining too hard.

[fnordpiglet]

They discuss this in the video, and if you watched it you’ll notice that they’re doing these projects along a major river near the ocean. They only capture 15% or so of what is today run off into the river. Rivers ultimately flow into the ocean. There is no one really downstream depending on that small percent of runoff.

[thinkingtoilet]

I did watch the video but must have missed the 15% number. Thanks.

[fnordpiglet]

Np I’d also notice the placement along the river and the river proximity to the ocean. They specifically call out not over harvesting the water. I’m pretty impressed as an engineer how well thought out the program is.

[micromacrofoot]

hard to imagine a downstream effect that's worse than becoming part of the sahara

[anonporridge]

I think the concern is downstream effects negative to areas and people far away.

Like how the Sahara feeds the Amazon rainforest. https://www.nasa.gov/centers-and-facilities/goddard/nasa-sat...

i.e. greening your land might lead to browning mine.

[micromacrofoot]

ah right, but they're not looking to reduce the sahara, but stop it... so in theory they're avoiding any new downstream effects? though I guess it's possible that some necessary process results in the sahara's growth? that's not my understanding though, part of the reason it grows is due to surrounding areas becoming more susceptible to desertification through agriculture