Self-cleaning beach gallery design for seawater desalination plants

Surface water intakes are a major capital cost for seawater desalination facilities, and their performance can greatly impact the operation of the entire system. Alternative intakes, based on the riverbank filtration concept, are increasingly being implemented because they are less expensive than conventional intakes and can also provide natural filtering of feedwater prior to the entry of water into the treatment plant. The basic concept is to use vertical or horizontal wells or galleries located near the seawater source to produce feed water, while taking advantage of the natural sand filtration provided by the beach sands and other sediments. Although conceptually simple, the successful design of beach gallery intakes must consider a variety of sedimentological and hydrogeological factors. Production rates are dependent upon both the hydraulic conductivity of the beach sediments and the length of the flow path from the seawater source to the gallery. Beach galleries constructed inland above the high ti...