Methodologies for abstraction from coastal aquifers for supplying desalination plants in the south-east of Spain

Supplying seawater to desalination plants using boreholes or drains can be less expensive than direct water intakes, since the silt density index (SDI) tends to be much lower. This approach is dependent on the presence of coastal aquifers with good hydraulic connection to the sea. Moreover, conventional boreholes are not suitable for pumping water on a long-term basis, since seawater is very aggressive. Hence, this type of abstraction requires the application of special technologies, from borehole location to borehole lining and special operations. These include the selection of the most appropriate drilling method, which depends on the lithology to be penetrated and its structure. This study focuses on Horizontal Directional Drilling (HDD), which encompasses very advanced technology. Various examples of work done in south-eastern Spain are described, along with the keys to their success.