Why we dig bunds

Bunds (or as we like to call them: "earth smiles") are semi-circular shaped pits that capture rainwater.

They are dug in our project areas in Africa in order to capture rainwater that will otherwise get washed away over the dry, barren soil. By digging bunds, we can regreen large areas in a very short amount of time, benefiting biodiversity, nature, people and – eventually our climate. Learn all about bunds!

Dry soil drought

Why we capture rainwater

Global warming and persistent droughts cause land degradation in many African areas. The top layer of the soil becomes hard, which prevents rainwater from infiltrating into the soil. This rainwater will flow to lower areas, and wash away the upper layer of fertile soil. Our digging of semi-circular bunds opens up this hard top layer, and retains the rainwater.

Regrowing vegetation: how it works

By capturing rainwater with the help of bunds, it has more time to enter the soil. The water balance is restored, and more water is available for the seeds present in the soil. These seeds now get the chance to sprout, which means: regreening! Sometimes we give the regreening process a little push, by sowing extra seeds within the bunds. This way the area can be restored even better!


Watch this timelapse to see how fast the regreening process goes!

Bunds Pembamoto Tanzania

How bunds regreen an area

Not only inside the bunds vegetation has grown back, the area surrounding the bunds also gets increasingly greener. Here’s a quick explanation of how this works: 

– Bunds prevent rainwater from washing away: this leaves more time for water to sink into the soil, within the bund but also in the surrounding area. This gives seeds located outside the bunds also the chance to sprout.

– The vegetation becomes so large and extensive that it starts to spread and grow outside of the bunds, further increasing water infiltration outside the bunds;

– The seeds of the vegetation inside the bunds spread out and start growing outside the bunds where they lead to even more regreening!

And look at the great result!

Why semi-circular bunds?

The semi-circular shape of the bunds is an optimal balance between the amount of water captured and the labor requirements. Bunds are usually 2.5 meters long and 5 meters wide, which is about the size of an adult elephant! 

Bunds are dug on slopes, with the ‘closed’ side of the bunds directing downhills. This way they can capture the water running downhills. The bunds do not only capture the rainwater, they also make sure that the water running downhills in between the bunds is slowed down. Now the water also has a chance to enter the soil in between the bunds.

Water bunds landscape restoration Justdiggit Cooling effect vegetation

The benefits of regreening

Regreening degraded areas has many benefits. Bringing back vegetation prevents soil erosion, improves the quality of the soil and the water availability and it cools down the planet by storing carbon. Vegetation does not only promote cooling of the earth globally, it also helps to cool down the environment locally. The shadow and transpiration of vegetation helps to cool down the soil. The impact of vegetation on the micro-climate can be clearly seen in this picture of a water bund. 

Here you can see the temperature difference between the vegetation inside the bund and the surrounding bare soil. The soil within the bund is much cooler than outside the bund due to the increased vegetation!

Buy your own bund!

Do you already know our Regreening platform? By buying bunds on this platform you ensure regreening and directly support an African farmer who digs the bunds. For this, you first create an account, after which you choose the number of bunds that you want to have dug.