The 36 km of coast between Number One Rock and Geltwood Reef contains perhaps the most energetic beach in South Australia, and one of the highest energy in Australia. The beach faces directly into the prevailing high southwest swell and winds, which are expressed in the continuous 400 to 500 m wide high energy surf. The surf is dominated by large rips spaced approximately every 500 m, and the beach backed by a active transverse dunes extending up to 1 km inland and reaching heights of 40 m (Figure 4.9). The 4WD tracks follow the back of the beach from Number One Rocks to Oil Rig Square. There are beach access points at Number One Rock, in lee of Whale Rock, then every few kilometres until a major 2WD access and camping area at Oil Rig Square. The tracks from Southend extend down to Geltwood Reef, with the beach providing the only access between Oil Rig and Geltwood. This is however a very hazardous section to drive owing to the soft sand, steep beach and high waves. Number One Rock is a calcarenite reef extending 1 km seaward and capped by some low rocks. If forms a prominent cuspate foreland in its lee which separates the two beaches. The south beach (50) is 1.7 km long terminating at Little Rock a low calcarenite beachrock outcrop, with two prominent reefs lying off the beach. It receives waves averaging 1.6 m and usually has 3 to 4 reef controlled rips flowing out through the 300 m wide surf zone. read more

Beach Length: 1.7km