Optimising subsurface well design for coastal desalination water harvesting

Subsurface techniques which make use of a natural sand filter are often a preferred means of extracting saline water in coastal environments, and beach-well systems (both vertical wells and radial lateral wells) have been successfully used with minimum pre-treatment for large desalination plants in Israel, Malta, Saudi Arabia and numerous islands. Through a case study, this paper details the limitations of standard vertical wells in coastal aquifers and provides the general design considerations for radial lateral wells with reference to international best-practice. A feasibility assessment for a proposed desalination source site on the Central Coast of New South Wales in eastern Australia is described. Further work, including intensive monitoring and 3D numerical flow modelling, is in progress for the purpose of detailed design.