Sunday, March 17, 2013

Perfect Storm of Desertification

Too much bare ground is turning to desert. Allan has some surprising solutions - using herd of animals. Which reminds me to follow up on a solution presented to the Dutch public in 2010.

Disappointed that the Naga Foundation in Holland hasn't really got off the ground in doing proof of concept of the Peter Westerveld contour trenching project. Peter Westerveld  had a good idea, but his talk at TEDx Amsterdam never really followed through. Naga started a campaign before doing the proof of concept in the region. They tell me that things are happening, but I don't see any recent reportages from the region.

Sander de Haas, a civil engineer in Amsterdam writes in a Linkedin discussion:

I’ve met Peter Westerveld in Kenya in 2005 and visited one of his contour trenching projects.  Peter is a highly motivated person and has been constructing so called Sand Storage Dams for years. Sand storage dams are a proven technology that has been applied successfully in many countries. He has improved the water availability with these sand storage dams in many places. 

The contour trenches are a ‘newer’ technique and are less well understood. We have had some discussions in the field with Peter because we were interested to understand the hydrological processes behind the contour trenches. If, and how, water is retained by these contour trenches is (in my opinion) not clear. If the groundwater level is deep (>5 m), which is the case in most of these dry places, the water will flow into these trenches and percolate downward (only vertically) towards the deep groundwater table. The water will therefore be lost for the local vegetation. It will add to the deeper groundwater, but that isn’t the purpose of the trenches. 

I think these trenches can only work under certain specific local conditions. For example if there is a shallow layer with low permeability somewhere below the surface, so the water can’t percolate down vertically. Under these specific conditions a perched water table might occur, of which the local vegetation can benefit. 

We have tried to discuss these issues with Peter and suggested to research the local soil conditions (augering) and install piezometers to measure the results of the contour trenches, but (sadly) Peter wasn’t interested in this research. 

A few years later (I think around 2008) TU Delft started a research project together with Royal Haskoning and WCT (Peter Westerveld’s Foundation) on contour trenches in Vietnam. The only results I have seen from this project confirmed my ‘fears’ that the water only flows down vertically towards the deep groundwater and is ‘lost’ for the vegetation. 

So to conclude, it would be a very promising technique, if it works. The pictures I have seen so far don’t convince me: everything in Africa turns green after a few rain showers. It would be interesting to compare two areas throughout the seasons: one with contour trenches, and one without. I’m not against any new techniques (on the contrary!), but it would be a pity if much labour and money will be spend on a technique that will only work under certain conditions. 

Sieger Burger • Good that you started the conversation again Jonathan! 

I don't think that this technique is "dead", it might be that Peter Westerveld and his Naga foundation are not pushing for it, but it's absolutely used on a lot of locations: 

- Jordan, see the work that is done there on greening the desert:

- Saudi Arabia, the Al Baydha project, 

- a very interesting recent article on soil moisture, that soil doesn't behave as we thought it behaved:

I think that the main thing to get the most out of the contour trench is to combine the contour trenches always with other things like mulching and vegetation, to improve soil life, which will increase the capacity of the soil to retain the water (soil, water and vegetation are totally interrelated and can't survive without each other)

Update: after posting a question on LinkedIn, there was the following reaction:

Paul Martijn • Paul Martijn from the Naga Foundation reacted today (18th March) 

You are right Sieger. The technique isn't dead - it is alive and kicking. 

Last year Naga Foundation executed the Meshanani Project in Kenya, approx. 240 km south of Nairobi. It's about the ecological restoration of 5 sq km at a key location for the local Masai community by stopping erosion, stimulating vegetation growth and creating water access for the local communities, their cattle and wildlife.
Naga realized already several successful re-greening projects in the area and is now preparing to demonstrate its Climate Engineered Ecosystem Rehabilitation approach in a very large-scale project: the hydrological corridor from the Indian Ocean at the latitude of Malindi and Mombasa towards the Kilimanjaro hinterland.

Together with local partners Kenya Wildlife Service and the CBO of Masai Communities, Naga will restore a vast area of evergreen land that stretches 20.000 km2 (1/2 the size of The Netherlands). The climate engineering method will recover the rainwater infiltration capacity of the soil and restore the sub-surface water reservoirs at twelve strategic locations. Those locations cover only a total of 266 km2. The result will be a patchwork of evergreen area's which will create a cooling effect and more evapotranspiration, that leads when left to mother nature, to more, and more regular rainfall in the entire area and connect to 20.000 km2 greening - providing once again a rich ecological corridor for people, livestock, and wildlife. With the most likely possibility of bringing back the snow on the Kilimanjaro. And creating numerous social, economic and environmental benefits to the country, its population and its visitors.

For more information check Naga's new website (still under construction) and watch the videos (soon they will be all subtitled). Here an explanation of Peter Westerveld in English

Lessons Learned:

Jonathan: Having watched the videos, the stories from Naga are still very fragmented. They don't explain the context, and we're not given much of a clue as what all this is going to cost. Why is this the best way forward and why not a hybrid solution. These nagging questions may explain the low scores of the videos on the YouTube channel (low 100's). Because the videos are not tagged, no-one knows they are there. Still a lot of work to do then, not just on the ground but online as well.

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