Overview
This article is part of a series of articles about Sustainable Water Management in Arid Regions of Africa. Proper water management facilitates rural development and is the first stap of a roadmap towards realizing a region rich in biodiversity, with a sustainable, prosperous economy.
Summary
Digging trenches can increase vegetation, even in the African desert. This proven concept is cheap, scalable and very effective, even for regions with annual rainfall of less than 100 mm.
Problem
Arid regions tend to form a hydrophobic soil, which hinders surface water from seeping into the soil, especially after heavy rainfall. As a result, terrestrial runoff create superficial streams of water, that rapidly evolve into fast-flowing rivers, causing both loss of precious water and soil erosion.
Solution: Contour Trenching Method
Digging trenches stops terrestrial runoff. For the trenches to be effective, they can be just 1 to over 3 feet deep.
Trenches capture rainwater, so rainwater has time to slowly seep into the soil, thereby raising groundwater levels.
At the same time, soil erosion is prevented, preserving the top layer of soil (which contains most of the nutrients) for vegetation.
In addition, trenches create a better microclimate for plant growth.
In time, a robust ecosystem can be developed with potential for agriculture / polyculture. This could include multiple crops, such as annuals, perennials (incl. bulbs), shrubs and even trees.
On flat land a pattern of straight trenches (each of limited length) is applied.
For hilly areas parallel C-shaped trenches are used, about 4 meter in diameter.
For mountaineous areas continuous trenches are used (perpendicular to the slope of the hill).
The contour trenching technique was invented by the Peter Westerveld (The Netherlands). The contour trenching method is being promoted by non-profit organization Naga Foundation.
Ambitions are to use contour trenching to combat desert formation and even to regreen existing deserts in Africa.
Videos
Contour trenching in Africa
contour trenching on a large scale in Israel and Australia.
Continuous contour trenching in practice in Asia
All articles about Water Management for Reforestation and Agriculture in Africa
Contour Trenching – Peter Westerveld
This article is part of a series of articles about Sustainable Water Management in Arid Regions of Africa. Proper water management facilitates rural development and is the first stap of a roadmap towards realizing a region rich in biodiversity, with a sustainable, prosperous economy.
Sustainable Water Management – Agriculture Africa: WaterBoxx – Pieter Hoff
The Waterboxx is one of the options for sustainable watermanagement in Africa. Read here more about this device.
Sustainable Water Management – Agriculture Africa: Water Pyramid – Martijn Nitzsche
The water pyramid (or waterpyramid) basically consists of a large, pyramid shaped balloon with slight overpressure inside. The water pyramid is made of transparant material which lets sunlight energy through.
Sustainable Water management – Agriculture in Africa
Water shortage threatens drinking water supply and food production in tropical and subtropical Africa. This article describes three solutions, developed by Dutch social entrepreneurs, to combat lack of water.
