• Post Reply Bookmark Topic Watch Topic
  • New Topic
permaculture forums growies critters building homesteading energy monies kitchen purity ungarbage community wilderness fiber arts art permaculture artisans regional education experiences global resources the cider press projects digital market permies.com private forums all forums
this forum made possible by our volunteer staff, including ...
master stewards:
  • Nicole Alderman
  • r ranson
  • Anne Miller
  • paul wheaton
stewards:
  • Jocelyn Campbell
  • Mike Jay Haasl
  • Burra Maluca
garden masters:
  • James Freyr
  • Joylynn Hardesty
  • Steve Thorn
  • Greg Martin
gardeners:
  • Carla Burke
  • Dave Burton
  • Pearl Sutton

Swales - How Often and What Is Too Steep?

 
Posts: 225
Location: S.E. Michigan - Zone 6a
12
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I have an area that drops about 15' in elevation. Some areas are more gradual, doing this over 50'-60' and others are much steeper. This slope is south facing and runs about 600'. My question is how frequently would you cut in swales? Every 2' in elevation drop? Every 4'? And at what point does it become too steep? I want to plant this hill side into fruit & nut trees
 
Posts: 48
Location: Oregon - Willamette Valley
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
As they say.... It Depends.

- how much rainfall do you get
- how large are you planning to make the swales, (width & depth)
- is this an open field, or are you working around any existing trees
 
Jerry Ward
Posts: 225
Location: S.E. Michigan - Zone 6a
12
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
It looks like I get about 32" of rain a year.

I don't know how big or deep to make the swales, but I'm starting to suspect I need to terrace due to the grade of the slope.

There are only a couple of trees I want to save (large black walnuts), otherwise there is a bunch of brush growing.
 
pollinator
Posts: 1528
Location: zone 7
18
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Careful about changing the ground level near the trees. Too much added on top or taken away can damage or kill the trees.

 
Jerry Ward
Posts: 225
Location: S.E. Michigan - Zone 6a
12
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
What slope is considered too steep for swales and needs terraces instead?
 
Matt Saager
Posts: 48
Location: Oregon - Willamette Valley
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Jerry,
I am still not clear how steep of a slope you have.

Can you describe:
- slope, elevation change per foot
- length and width of the slope
 
pollinator
Posts: 1877
Location: La Palma (Canary island) Zone 11
61
purity forest garden tiny house wofati bike solar
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I think only photos cn be clear enouogh!

Jordan Lowery wrote:Careful about changing the ground level near the trees. Too much added on top or taken away can damage or kill the trees.



If you take away, you damage roots.
If you bury part of the trunk, some trees (most?) will hate it.

But why should they die of having more earth to expand, if this does not affect the trunk?
Do you have a direct experience or a sure source about this?
 
Posts: 3375
Location: Kansas Zone 6a
37
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Agree with the "it depends" answer.

There is a ratio between
the amount of rainfall you need to harvest (not only yearly total, but single storm or rainy week average). This is the amount you get
the size of the swale, both height and width. This is the amount you can store per swale.
so then you adjust the distance between the swales so they fill in a nice rain but don't get washed out in a big one.

You also have to figure on how fast your soil percolates as to how fast the swales will drain and soak in.

And what you want to grow on these swales--if they are larger than your swale-to-swale distance you could create a full canopy and that probably isn't your goal.
 
Jerry Ward
Posts: 225
Location: S.E. Michigan - Zone 6a
12
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I have a topo map someplace and I'm trying to find it. The slope is steep enough that it would be very dangerous to try and drive a tractor side-wise and in many places I don't think you could. I'm guessing but I would say the drop in elevation is something like 10-15 feet over 50', maybe in the 30 deg range with some small areas about 45 degrees. This area runs for 600' or so and is south facing.

Matt Saager wrote:Jerry,
I am still not clear how steep of a slope you have.

Can you describe:
- slope, elevation change per foot
- length and width of the slope

 
R Scott
Posts: 3375
Location: Kansas Zone 6a
37
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
You would be surprised what kind of slopes you can drive a tractor on if you can pucker tight enough. But if you can't drive a tractor sideways, that is a pretty good indicator you are really should be terracing instead of swaling. Even if you build them as swales they will be spaced like terraces.
 
Posts: 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

Xisca Nicolas wrote:I think only photos cn be clear enouogh!

Jordan Lowery wrote:Careful about changing the ground level near the trees. Too much added on top or taken away can damage or kill the trees.



If you take away, you damage roots.
If you bury part of the trunk, some trees (most?) will hate it.

But why should they die of having more earth to expand, if this does not affect the trunk?
Do you have a direct experience or a sure source about this?



Adding soil on top of a tree's root system results in extra weight and soil compaction, leading to root damage, leading to tree decline and possible tree death. I don't have a specific source, but as a landscape architect with years of experience dealing with arborists this is a well-known fact. You have to stay out of what is known as the tree protection zone.

I'd also add to the starter of this thread - you may already know this - that black walnut releases "toxins" into the soil that many other plants cannot tolerate. It's a competition mechanism. Just be sure the plants you want to add are either Juglans tolerant or far enough away from their roots to not be bothered by it.
 
Do you want ants? Because that's how you get ants. And a tiny ads:
Dave Burton's Boot Adventures at Wheaton Labs and Basecamp
https://permies.com/t/119676/permaculture-projects/Dave-Burton-Boot-Adventures-Wheaton
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
Boost this thread!