24% of the total for the whole of Scotland. North and South Uist and Lewis, in particular, have landscapes with a high percentage of fresh water and a maze and complexity of loch shapes. Harris has fewer large bodies of water but has innumerable small lochans. Loch Langavat on Lewis is long, and has several large islands in its midst, including Eilean Mòr. Although Loch Suaineabhal has only 25% of Loch Langavat's surface area, it has a mean depth of and is the most voluminous on the island. Of Loch Sgadabhagh on North Uist it has been said that "there is probably no other loch in Britain which approaches Loch Scadavay in irregularity and complexity of outline." Loch Bì is South Uist's largest loch and at long it all but cuts the island in two. Much of the western coastline of the islands is machair, a fertile low-lying dune pastureland. Lewis is comparatively flat, and largely consists of treeless moors of blanket peat. The highest eminence is Mealisval at in the south west. Most of Harris is mountainous, with large areas of exposed rock and Clisham, the archipelago's only Corbett, reaches in height. North and South Uist and Benbecula (sometimes collectively referred to as The Uists) have sandy beaches and wide cultivated areas of machair to the west and virtually uninhabited mountainous areas to the east. The highest peak here is Beinn Mhòr at . The Uists and their immediate outliers have a combined area of . This includes the Uists themselves and the islands linked to them by causeways and bridges. Barra is in extent and has a rugged interior, surrounded by machair and extensive beaches. The scenic qualities of the islands are reflected in the fact that three of Scotland's forty national scenic areas (NSAs) are located here. The national scenic areas are defined so as to identify areas of exceptional scenery and to ensure its protection from inappropriate development, and are considered to represent the type of scenic beauty "popularly associated with Scotland and for which it is renowned". The three NSA within the Outer Hebrides are: South Lewis, Harris and North Uist National Scenic Area covers the mountainous south west of Lewis, all of Harris, the Sound of Harris and the northern part of North Uist. An area of the south west coast of South Uist is designated as the South Uist Machair National Scenic Area.