Tuesday, 23 July 2013

How to reverse desertification

Last month Nikita and I visited Tamera in the far South of Portugal -  a parched landscape of rolling hills, rolling fields once dedicated to intensive wheat production, then intensive grazing, now exhausted and denuded.  In their wisdom the Government with EU funding has introduced mono-culture eucylptus and pine plantations, which will exacerbate the water crisis in this area, increasing fire risk and bring virtually no sustainable economic opportunities to local communities.  

We came to see an alternative land-use option.  To learn how you can turn this into an area of perpetual productivity and an oasis for biodiversity.

It looks like this - for mile upon mile (this photo taken on the adjacent watershed / valley to Tamera, so it shows how it would have looked like before the project began.
Annual rainfall here: about 600mm - about half the amount of Northern Portugal or the UK


We arrive mid-afternoon and are immediately shown around by Cristophe a graduate of forestry from Germany; he is passionate about their project and completely familiar with each aspect of its design and implementation which makes for a brilliant walk-through and presentation.  And the best thing was learning about it all as we walked the land and learned physically what we were hearing.  Being there makes such a difference.



So their plan is simple: establish dams across the valley in as many places as you can. This means getting diggers down there and increasing the depth of the valley a bit and using all this material to form the dam.  This one shown above is their newest lake - only a year old - filled by just the winter and spring rains.  In the foreground you can see a solar pump that moves some of this water uphill further for vegetable production.




Move a few meters to the left and this is what you see. The road sits on the top of the damn. The water on the left of the picture is part of the next dam further down.  Cristophe explained that the dams hold the water, plenty of it infiltrates into the ground, but once it is saturated it slowly spreads to the surrounding land.  

Without these dams all this water would have run through the valley and away to the sea.  The parched earth would remain dry.


Cristophe explaining the design of one of their older lakes, this one five years old I think..

Incredibly detailed planning went into the underwater design as well - shallow areas for reeds for fish breeding and other wildlife, a deep section in the middle to increase overall volume and to maintain some cold water sections, some "shelves" or terraces for various other biodiversity benefits.  

At ground level they have planted thousands of trees. At first there are fruit, nut and other deciduous species, close to the water, followed by a terrace about 3 or 4 meters wide, then another band of trees, then another area of veg production.  

This photo shows the stages of tree plantations, only five years on. There's a new veg bed on the terrace between them which does need some irrigation during the long dry months, but the trees benefit from the increased water available in the water table. 

Think back to the first picture - arid, brown, dry and denuded landscape. THis looks (and feels) more like France or Southern England. It is much cooler with all the shade and water around, and they say that the lakes create increased breeze down the valley as well.  

Nice to see that some beds were dedicated to seed production only.
I haven't seen this kind of thing before - vegetables all allowed to go to seed
and get on with securing their reproduction


7 years on, trees now well established creating their own micro-climate,
all possible because of the water that is now retained for longer time by the dams. 



Finally - a reminder of how this land looked before they started here.  I walked up here the day after our tour and couldn't help seeing all the little valleys and creeks that could be dammed up to create zones of regeneration and biodiversity.  

And then imagine what it could transform in some really arid countries where people suffer constant food insecurity, droughts, floods.  Here is a design alternative that could solve all those problems. 

Tamera is about much more than this.  For more info see their website here







5 comments:

LeePsycho said...
This comment has been removed by the author.
LeePsycho said...

I have never been a believer in dam projects, always believed they were akin to a blocked blood vein in the human body, but these small dams slowing the water through this valley seems to make sense because it is consumed by the surrounding area creating or reestablishing a diverse ego system.

Jamie Bull said...

That looks really great. I'd just be a little interested in the effects further down the valley. Did you get a chance to ask about that? I mean it's no Three Gorges but still, there must be some knock effect.

RESET Blanche said...

Fantastic Magnus, thanks so much for the information. Presumably this is damming/intercepting rain water rather than a river/waterway? Great project.

magnus wolfe murray said...

Jamie, interesting thought / question re down stream impact. Didn't ask and doubt they have much way of measuring to be honest. But seriously doubt there are any negative impacts, as the whole landscape is now absorbing more water; downstream the rivers will be fed by the remaining valleys and taking all this fresh water to the sea. So eventually reducing overall fresh water available to the land / people. Also, as compared to downstream impact of pumped irrigation from deep wells (as in parts of Spain etc) this is seriously better in just about every way. Time for one in Troporiz?