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For more general design patterns for water management, see Brad Landcaster's book series, "Rainwater Harvesting for Drylands and Beyond". In the pictures in th

by hosh 3y ago

For more general design patterns for water management, see Brad Landcaster's book series, "Rainwater Harvesting for Drylands and Beyond". In the pictures in the article, the roads form berms, and the fields are basins. It doesn't just have to be roads -- walkways threading through a smaller scale can act as berms as well. The two volume book contains many other water harvesting structures. As a note, Andrew Millison has a youtube video about a river system that was developed in India over the course of centuries -- deliberately engineering a delta, with flood channels. They basically did what beavers have been doing in North America (slowing down and spreading out water) for ... longer than we humans have been around. These ideas are not new. They have been around for a long time. It's not that we found new ways to progress, but rather, rediscovering old methods that had been dropped in our rush for modernity.

hinkley 3y ago
I don't know where he got the idea, but I've also seen videos by Mark Shepard where he uses roads as spillways. Instead of running water retention parallel to access, he will run it perpendicular. I was never quite clear how he prevents the overflow from exiting the property at maximum speed. If your water retention system reaches capacity, by definition you cannot hold onto it, but water flowing at speed is also an erosion risk. It can lead to earthworks failures, which are about as bad as landslides.
- hosh 3y ago
  If he slowed down the water so that it has a chance to pecolate, it might help. But that only expands the capacity, and there may be days when that overflows. I think Lancaster talks about the perpendicular flow, and also talks about ways to mitigate that with curves (as well as discussion about erosion patterns when water exits a structure too quickly, which in turn reshapes the terrain, sometimes going into degenerative erosion patterns). On-contour swales (or trenches) are good examples, especially when there are multiple tiers with overflow to increase the distance the water has to travel as it snakes back and forth across the contour and descends down a slope. There are multiple chances to slow down water and let it try to infiltrate. In his latest edition, Landcaster talks about gambesons (retaining walls), which he used to advocate. But because of long-term erosion patterns, those can fail pretty quickly.
  - hinkley 3y ago
    He's in Wisconsin. He's not thinking about dry season farming. On the other hand, if you are thinking about dry season farming, the government is already 150 years ahead of you and may fine you for attempting to hold onto more water than what can safely percolate in a day or two.
    - hosh 3y ago
      That depends on the scale and the state. I doubt the government cared that much 150 years ago; it was more about claims on surface and ground water. These days, past a certain scale, you’d work with an engineer to plan it out and get the permits.

by hosh 3y ago

hinkley 3y ago

I don't know where he got the idea, but I've also seen videos by Mark Shepard where he uses roads as spillways. Instead of running water retention parallel to access, he will run it perpendicular. I was never quite clear how he prevents the overflow from exiting the property at maximum speed. If your water retention system reaches capacity, by definition you cannot hold onto it, but water flowing at speed is also an erosion risk. It can lead to earthworks failures, which are about as bad as landslides.

hosh 3y ago
If he slowed down the water so that it has a chance to pecolate, it might help. But that only expands the capacity, and there may be days when that overflows. I think Lancaster talks about the perpendicular flow, and also talks about ways to mitigate that with curves (as well as discussion about erosion patterns when water exits a structure too quickly, which in turn reshapes the terrain, sometimes going into degenerative erosion patterns). On-contour swales (or trenches) are good examples, especially when there are multiple tiers with overflow to increase the distance the water has to travel as it snakes back and forth across the contour and descends down a slope. There are multiple chances to slow down water and let it try to infiltrate. In his latest edition, Landcaster talks about gambesons (retaining walls), which he used to advocate. But because of long-term erosion patterns, those can fail pretty quickly.
- hinkley 3y ago
  He's in Wisconsin. He's not thinking about dry season farming. On the other hand, if you are thinking about dry season farming, the government is already 150 years ahead of you and may fine you for attempting to hold onto more water than what can safely percolate in a day or two.
  - hosh 3y ago
    That depends on the scale and the state. I doubt the government cared that much 150 years ago; it was more about claims on surface and ground water. These days, past a certain scale, you’d work with an engineer to plan it out and get the permits.