High performance geocomposites, such as Salt Barrier, are the preferred choice for the salt barrier capillary break layer. This is because the cuspated core maintains an open void with its high compressive strength and excellent support to the geotextile surfaces under the action of soil pressure and its performance is further enhanced when unperforated, where the lower side of the cuspated core provides a practically impermeable barrier to the rising saline moisture.
In deserts and arid regions, the groundwater is often saline and the water table can be relatively close to the surface. The capillary rise above the water table brings dissolved salts near to the surface of the ground. This results in severe problems for vegetation and the foundations of building structures.
Landscaping within modern developments in arid regions is particularly at risk. Most vegetation is intolerant of even slightly saline water (3-6 g/litre). Saline moisture must be prevented from reaching the root system of the vegetation. Similarly, it is important that irrigation water has minimal salt content to minimise the risk of salination of the soil (<0.5 g/litre no risk; 0.5-2g/litre moderate risk). For vegetation to survive, it is essential that there is a barrier between the saline ground and the clean ground and that this barrier also provides good drainage.
An effective barrier is to provide a capillary break layer between saline ground and clean ground. The capillary break layer creates a void across which capillary rise of saline moisture is prevented. It is essential that the capillary break layer is installed above the highest level of the water table so that the void is never totally saturated by ground water and that the capillary break has high in-plane flow capacity so as to remove sub-surface and irrigation water that enters through the clean ground above