Wed May 4 18:08:57 EDT 2011
principles. So I am *not* talking about using these drains, or saying
they would be moving water where you want it.
I'm saying that if you were to design a system of drains based on
keyline principles, *then* you could intercept water higher up on your
land and move it slowly (reducing erosion and increasing infiltration)
to keyline-appropriate places for ponds, swales, etc..
Combining this with already mentioned subsoil ripping and rotational
grazing and/or other organic-matter-increasing strategies would be a
comprehensive long-term strategy for drought *and* flooding mitigation
as well as soil improvement, etc. etc.
> John, are you saying it is best to build a pond on TOP of the ridge,
Not on top of the top of your top ridge - not much water catchment area
up there! On the broad areas of lower ridges (or lower down sloping
ridges), yes, with water directed there via drains laid out according
to keyline principles. Drains laid out that way will typically lead
water from the concentration points in the gullies out to the ridges.
Whether or not you'll have a good pond site there depends on your
particular topography, of course.
When I say 'drain', I mean a gentle (1:100 or less) keyline type of
water channel. Working definition: a swale is a drain on contour; a
drain is a swale ever so slightly off contour. A drain is a surface
channel running along the same lines as the subsoil ripper channels
already described in someone else's post would.
>> ...but what's underneath your clay?>>
> For the most part
> I believe limestone based horizontal layers. Some are quite visible
> on deeply
> carved hills alongside good size creek. On interior hills there are
> areas of protruding rocks near tops that appear to have more granite
> structure. Lots of small,coarse rock visible on surface.
If you have lots of rock close to the surface your subsoil ripping
options would be limited in those areas; likewise pond building, unless
you move lots and lots of clay from your clayey areas to build up dams.
Drains and swales to capture, slow and redirect runoff would still be
an option, combined with the wet-footed plantings and grazing and so on
to increase infiltration and/or transpiration.
One of the more clever keyline strategies that would go along with your
grazing is this: map out your keyline drain routes for leading water
out from the concentration points to the drier areas. Then put your
grazing fences along the lower edge of where the drains would be dug
(but don't bother to dig). Put the grazers inside; as such critters
do, they will tend to walk the fence line a lot and will pound out a
drain channel for you as they graze & add organic matter.
> To some extent I have done this
> by grassing in some water ways, adding woody debris, and placing
> water bars along trails coming down the hills to divert, and break
> force of water that was eroding those trails.
All good stuff. Your water bars can divert water into keyline-pattern
drains and spread it out...
I'm mostly talking about surface channels here because I have no idea
if there's anyone in your area with a keyline ripper or reasonable
facsimile; the genuine Yeomans units are very expensive and there
aren't very many in the US, at least not in the West coast states.
Anyone know how Frank might locate owners/operators of a Yeomans or
similar subsoil ripper?
John Schinnerer, MA
- Eco-Living -
Cultural & Ecological Designing
Food - Shelter - Community
john at eco-living.net
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