Win a copy of Permaculture Design Companion this week in the Permaculture Design forum!
  • 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

Question about swales and earthworks etc.

 
Posts: 175
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I have a section on my property sort of a triangle if you will  that I want to do a food forest in  about 65ft across the bottom and 135 ft down the sides.    over that 135 ft there is a drop of maybe 6-8 ft.

I was assuming no real need for major swales etc but now I am wondering if I should?    is there a rule of thumb for what slope starts requiring swales, terracing etc?

thanks
 
Posts: 104
Location: Zone 6 - Missouri
6
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I don't know if there's a good rule for that or not, but the thing I'm going by on my property is based on runoff.  I go out while it's raining and try to see how much water is leaving the land.  If it looks like enough so that it would make a difference (especially if you're in a drier climate or your rainfall comes in spurts with droughts between), then I'd say it's probably a good idea.  If you go out in a good rainstorm and it looks like it's all soaking in, then they may not provide a lot of value.

If you're in an arid place, I think I'd just go for the swales no matter what.  But, if it doesn't look like you're losing much to runoff then maybe it's not so big a deal.  That's the process I'm using anyway, I guess time will tell whether it's good or not...

If you don't want to go with swales, another option I'm looking into that should help with water penetration is keyline plowing (basically a deep subsoil cut on contour).  According to the keyline folks, if you do that three or four years in a row and add compost tea and deep rooted plants to the knife cuts in the soil, you can build aerobic topsoil at a rate of several inches a year.  Haven't tried it myself yet though.
 
gardener
Posts: 856
Location: South Puget Sound, Salish Sea, Cascadia, North America
15
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Ditto - mulch can store a lot (I haven't run into a good formula for inches of rain held by inches of mulch but I bet it is out there somewhere - maybe 1/2 inch of rain in a good mulch).  It depends on how quickly your soil percolates, and how fast your rain falls.  If you have a clay soil and get 2-3 inches in a rainfall event, than I'd say swales are a good thing.  I have lots of light rain, and a silt loam so I don't worry about it except if I am managing impervious surface sources of water.
 
Posts: 225
Location: Adelaide, South Australia (Mediterranean climate)
1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Swales could help with infiltration into hydrophobic soil, usually found in arid areas, even if it is sandy.  Basins around tree plantings or soil imprinting would probably achieve the same thing on flat land - getting sufficient water in one spot in order to get infiltration.  Geoff Lawton's greening the desert is a good example of swales on relatively flat dryland (see youtube videos).

Knowing your specific rainfall/climate/soil type would help in answering the question.
 
Tim Canton
Posts: 175
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Thanks guys,

I get just under 50 inches a year rainfall  with it being relatively even spread out over the year.  Feb the wettest  aug/sept drier but it still rains some.      I live in N.carolina mts    so I have the pretty typical somewhat clayey soil but its not that impervious clay they have someplaces.  It drains well.  I dont ever have sitting water even in flat spots.  (maybe due to rocks creating opening for drainage below the soil?)

 
Paul Cereghino
gardener
Posts: 856
Location: South Puget Sound, Salish Sea, Cascadia, North America
15
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Since you can get the hurricane dumps, it might be nice to cultivate a few wet spots to capture water when it really dumps.  I have enjoyed having hight and low spots in the food forest just to have the variety of moisture levels (vertical edge?) for different kinds of plant.

So its not just about water capture at the site scale, but also variable soil moisture at the patch scale.
 
Posts: 52
Location: north Georgia
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
You could even determine runoff when it is not raining by looking for exposed earth and signs of erosion or bits of vegetation carried down the slope by the water. 

I hate to have water run off my land and, in the middle of summer in north Georgia my rainwater harvesting storage tanks occasionally run dry.  So I have installed several contour ditches to enable water infiltration, which reduces irrigation needs - you can see some 'photos at www.nutrac.info.
 
Tim Canton
Posts: 175
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Paul,  we only really get rain from gulf coast hurricanes here and usually the tail ends of it......i should have obviously mentioned this but the north long side of the triangle is bordered by a very small creek/ mt run off........so i do have that whole side of constantly moist edge.    I am planning on paw paws and elderberries for alot of that edge, maybe some persimmons as well

nutrac thanks for the site....what are thoose pics under?
 
Hugh Hawk
Posts: 225
Location: Adelaide, South Australia (Mediterranean climate)
1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Plenty of water, good drainage, sounds about perfect organick.  If you had sandy soil then I would guess it to be low in nutrients, but I think the clay should hold onto most of the good stuff.  Do things grow well for you in this area?
 
Tim Canton
Posts: 175
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
right now its just grass/ "weeds" but they grow well yes....I never water anything at my house but the garden and its all green.    the other side of the triangle is a driveway that acts as run off so I may dig a few entry points to direct that water back over the land......  I guess I am wondering if the work is worth the gain  or if tight planting heavy mulching etc would leave me about the same result.......I mean the swales could never really hurt if done right i guess.
 
Hugh Hawk
Posts: 225
Location: Adelaide, South Australia (Mediterranean climate)
1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Do you have any pictures Organick?

I'd dig a small swale to test with and see if it fills up in a moderate rainfall event.  If it does then perhaps there is a benefit to them.
 
I want my playground back. Here, I'll give you this tiny ad for it:
Rocket Oven plan download
https://permies.com/t/rocket-oven-plans
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
Boost this thread!