In the battle against desertification and the restoration of semi-arid land, a water bund (also known as “earth smiles” or “rainbow barriers”) is one of the most effective tools. They prevent erosion, retain rainwater and – through groundwater recharge – increase soil moisture, thereby helping crops to grow and reducing the risk of flooding. This step-by-step guide empowers local communities in these areas to construct and maintain bunds effectively.

Managing Water Spills: The Role of a Water Bund

There are a number of different ways to design a bund. The wall height and floor area can be varied according to site requirements. A lower wall may be preferable to reduce the potential load on the walls and make tank inspections easier. However, low walls are at greater risk of breaching due to spigot flow – a jet of leaking liquid passing over the wall before reaching the ground below. To combat this, a bund may be designed with a higher wall height and larger floor area to increase the distance between the tank and the base. In addition to visual inspections, a bund’s integrity can be assessed using hydrostatic testing and/or by filling it with water. Once the test has been completed, a period should be allowed for the water to drain so that any loss of capacity can be identified and rectified. Regular maintenance is important for internal and external uncovered bunds as they are open to the elements and will fill with rainwater. This can mask leaks, leading to chemicals/oil leaching out of the bund and contaminating the surrounding environment.