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A comment on Pre-Inca canal system uses hillsides as sponges to store water.

Re:Pre-Inca canal system uses hillsides as sponges to store ... by KaiserPro on Monday January 06, 2020 @04:54PM (#21973811)
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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Re:Pre-Inca canal system uses hillsides as sponges to store ... by dredds on Monday January 06, 2020 @07:35PM (#21975323)
Australian example - "For more than a decade, two farmers have shown that parched landscapes can be revived. And finally Canberra [is] listening."

https://www.youtube.com/watch?v=-4OBcRHX1Bc

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Re:Pre-Inca canal system uses hillsides as sponges to store ... by KaiserPro on Tuesday January 07, 2020 @08:08AM (#21979558)
Ahh smashing, Its interesting to note that the aussie version involves leaky weirs.

I suspect thats because the rain pattern in the indian example is different.

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Re:Pre-Inca canal system uses hillsides as sponges to store ... by CameronNemo on Monday January 06, 2020 @06:14PM (#21974612)
Dams also interfere with fish migration and reproduction. Even small ones are not exempt from that without careful workarounds.
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Re:Pre-Inca canal system uses hillsides as sponges to store ... by KaiserPro on Tuesday January 07, 2020 @04:51AM (#21978477)
The term I was looking for is "Johads"

https://www.notechmagazine.com/2015/06/water-johads-a-low-te...

They expressly do not dam a stream, they collect runoff. You put them in low lying areas that normally form puddles in monsoon.

The idea is to prevent runoff, just like the ones in peru.

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Re:Pre-Inca canal system uses hillsides as sponges to store ... by macewindu on Monday January 06, 2020 @07:31PM (#21975299)
Are there migrating fish in the area of Central India that OP talked about?
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Re:Pre-Inca canal system uses hillsides as sponges to store ... by CameronNemo on Monday January 06, 2020 @08:12PM (#21975666)
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.
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Re:Pre-Inca canal system uses hillsides as sponges to store ... by soperj on Monday January 06, 2020 @11:28PM (#21976835)
You'd be surprised. They used to go as far inland as idaho.
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