The main dune and beach at Aberlady Sands
Looking across the estuary of the Peffer Burn towards Aberlady at high tide
Significance: a coastal nature reserve with extensive beach, dune and salt marsh systems backed by raised shorelines
Aberlady Bay is a much-loved local nature reserve with a wide range of coastal habitats and landforms. The extensive beach shows a range of classic constructional forms, with berms and swales. On dry, windy days sand is moved shoreward towards the extensive dune system. Towards the estuary of the Peffer Burn, the sediment becomes finer and mud flats and salt marshes appear. The advancing tide moves rapidly across these low-angle beaches to cover the edge of the salt marsh. At spring tides there is inundation not only of the salt marshes and also of the linear hollows or slacks between the dune ridges.
Extensive older raised shorelines occur around Luffness, with marine clays, silts and fine sands that accumulated as the last ice sheet retreated. Raised beach deposits are widespread near Aberlady village. The highest former sea level at 9 m is associated with the main post glacial transgression, and therefore equivalent to the main post glacial raised beach in the Forth estuary. The lower shore line consists of shelly gravel overlying a rock platform - it has been dated at less than 4000 BP. Associated with the sea level at 6-7 m was a raised spit, which then projected southwards across the mouth of the Peffer Burn.
Recognising these raised beaches is made difficult by the later accumulation of dune sands. Sections displayed during the construction of the sewer outfall pipe in 1968 enabled the geomorphological history of the area to be determined. Changes in sea level during the last 5,500 years have left a number of fossil shorelines, sand banks and cockle beds, mainly in the southern part of the complex, indicating an advancing coastline hinged at Jophies Neuk gradually building north westwards by spit and dune formation. Shallowing of the channel into Aberlady from the 18th century onwards contributed to the decline of the port for Haddington. The rapid evolution of the spit projecting south westwards across the sand flats represents the current phase of development, with low salt marsh areas being developed on the landward side.