Skip to Content.
Sympa Menu

permaculture - Re: [permaculture] drainage

permaculture@lists.ibiblio.org

Subject: permaculture

List archive

Chronological Thread  
  • From: "John D'hondt" <dhondt@eircom.net>
  • To: "permaculture" <permaculture@lists.ibiblio.org>
  • Subject: Re: [permaculture] drainage
  • Date: Thu, 5 Jan 2012 20:46:41 -0000


Hi Ute,

I know we have been in contact before but I can't remember on what list that was exactly.
You are right, I am all in favour of using trees for drainage. However sometimes willows can have the oposite effect of what you desire. We have a deep root cellar here, perfectly dry as long as the drain pipe we put in the bottom of it keeps clear and every year we have to remove willow roots from that pipe. Some 2 inch in diameter and grown since the year before. Don't take the roots away and that cellar fills with water to the top. So I am a bit doubtful about hydraulic conductivity of willow roots :(

A special problem for us is that we have a fairly decent mountain (for Ireland) above us and a lot of the rain falling on that mountain is going to come our way. A problem agravated by State Forestry who are extremely bad neighbours. Before planting trees they bring a 20 ton excavator in making ridges and gullies that end at the fence line. Where the land is steep water from those gullies does not stop at the fence but rather proceeds at some speed.
Planting willows on our side of the fence definitely slows that down a bit.

But something else that might be worth mentioning is that underground water veins break to the surface in many unwanted places when it gets very wet. There are sometimes fountains (a few inches high) coming straight through the tarmac of the road when it gets very wet and that of course also happens in the middle of fields. It is impossible to stop water that comes from a few hundred meters higher up, there is fair pressure behind it and if you try you might create a bigger swamp.

We have most of the trees you mention including Salix sachalinensis. Worth mentioning is Alnus rubra, the seedlings of which will take when plunked in a heap of loose boulders without any soil as long as it remains moist. Grows fast and strong.

In West Cork this seems to be our wettest year in 25 years. Is that the same for you?
john

I'm in Ireland, like John, and have problems with drainage, given the high
amounts of rainfall. I have planted a lot of willow and many other tree species,
for all sorts of reasons, including wind shelter, fodder, firewood, bee food
etc. and also drainage.

It is important to remember that trees not only evapotranspirate (and they do a
little of that also during dormancy as they keep up their life functions) but
their deep roots also change the soils' basic physical and hydraulic properties:
they reduce soil water retention, increase hydraulic conductivity, and loosen
the soil structure, in comparison to grassland cover.

I think what Steve may have meant when he said to keep them at a constant growth
stage by coppicing is to keep them at their maximum annual growth rate. A tree's
growth rate is higher when they are younger and levels off as they mature.
However, for the purpose of maximum evapotranspiration it may be more beneficial
to have a large tree with a lot of leaf surface rather than a small and fast
growing one? I don't know.

re willow species: I have planted dozens of different willow
species/hybrids/cultivars on our land and I have found that here, in the West of
Ireland, the one which puts out leaves the earliest (c. late January) and holds
on to them for the longest time (into November/December) is Salix sachalinensis
'Sekka' (Japanese Dragon willow). It also grows very quickly and produces large
amounts of biomass. Due to the very long growing period it should be a prime
candidate for drawing water. Unfortunately it does not strike easily from
cuttings like most other Salix sp.. It has to strike roots in water and then
needs to be planted out (rather than just cutting a branch and sticking it into
the ground). Let me know if you want cuttings John or anyone else in Ireland.
I'd be happy to cut and post some cuttings for the cost of postage.

Eight years ago I planted a 200 m hedge along a drain on a field on fen peat
soil. The drain borders my neighbour's land, sloping down from a drumlin. Our
field is on level ground. As the drain is no longer accessible by machinery from
either side I decided to go for 'pumping' species rather than having to manually
clear the drain. The trees also shade out the
drain, preventing grass growth from clogging it up. Did a bit of research and
came up with the following list for our situation (also wanted something I could
lopp for our goats). All these are suited for wet sites and are considered
'pumping' species:
Alnus glutinosa (Common alder)
Alnus incana (Grey alder)
Betula pubescens
Fraxinus excelsior (Ash)
Prunus padus (Bird cherry)
Rhamnus frangula (alder buckthorn)
Salix sp. (willows)
Sambucus nigra (Black elderberry)
Sorbaria sorbifolia (False Spiraea)
Viburnum opulus (Guelder Rose)
I planted a mix of these and they are doing well. Between taking up a lot of
water during the growing season, improving drainage, and keeping the existing
drain clear the field has definitely improved (also aided by a three-row mixed
tree & shrub hedge on the other side of the field). It used to have water lying
right at the surface for long periods. Now that's a transient phenomenon for
brief periods after heavy winter rains only.
Sorbaria is quite slow-growing here but it finally seems to kick in now (7-8
years on). Alnus glutinosa is fantastic, very fast growing. It can also be
coppiced for firewood. Sambucus is great of course for its berries. One of my
favourite willows for this situation is one I got from westwaleswillows.co.uk
(great supplier and great info on their webpage by the way): Salix nigricans. It
creates nice dense bushy growth, great habitat. I also threw some Elaeagnus into
the mix as I found they do well on that type of ground.


Other 'pumping' species for wet ground that I came across but did
not plant include:
Acer pseudoplatanus
Aeculus hippocastanum
Betula nigra
Populus alba 'Nivea'
Populus canadensis 'Robusta'
Populus canescens
Populus nigra 'Italica'
Ulmus carpinifolia 'Wredei'
Ulmus hollandica 'Lobel'
Ulmus leavis

Of course there will be more/others for other climates and other continents.
This is a list for NW-Europe.

Hope this helps all those who don't struggle to keep water *on* their land but
rather to get rid of it ;-)

Ute





Wednesday, January 4, 2012, 7:07:52 PM, you wrote:


JDh> Only that willows don't do leaves here in winter when you would need them
JDh> most. They do help while growing.
JDh> john





G'day, I wonder how big an effect willows will have on lowering the water
table and whether your land supports many trees that can evapotransirate
water out of the ground. Keeping these water loving trees in a constant
growth cycle by coppicing may help with drainage over the growing period
and the leaf drop will add to SOM.
_______________________________________________

_______________________________________________
permaculture mailing list
permaculture@lists.ibiblio.org
Subscribe, unsubscribe, change your user configuration or find out more about this list here:
http://lists.ibiblio.org/mailman/listinfo/permaculture
Garden Hand Tool Sourcelist and Biointensive Gardening Guide
http://www.ibiblio.org/ecolandtech/documents/gardening-hand-tools.faq
permaculture forums http://www.permies.com/permaculture-forums
Google command to search the message archives:
site: lists.ibiblio.org/pipermail/permaculture [searchstring]
Make a donation toward list maintenance:
https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=N8YGXK5XLTPAU










Archive powered by MHonArc 2.6.24.

Top of Page