In situ permeabilities of selected coastal marine sediments

An in situ permeameter probe was deployed off Fort Walton Beach, Florida in shallow-water coastal sandy sediment. Stations were occupied in a 600 m × 600 m area. Intrinsic permeability in sand at 17 stations varied from 0.3 to 6.1 × 10^-11 m² to subbottom depths of 50 cm. Permeability decreased with increasing subbottom depth and minimal compaction. The sediment is a well-sorted, medium quartz sand with a mean grain size of approximately 0.34-0.52 mm and with 5%-8% carbonate shells and shell fragments. The probe was tested in a slightly finer-grained sediment near the main study area and revealed permeabilities of 0.1-3.2 × 10^-11 m². The permeabilities measured are reasonable for the observed sandy and slightly finer-grained sediments.