PHYSIOGRAPHY & DRAINAGE

The Shoalhaven Coast region lies within landforms classified as “the Coastal Plain” (Bowman 1971). The area lies immediately east of the major escarpment that forms the eastern boundary of the Great Divide.

Bowman notes that the escarpment is an active erosional feature that is retreating westward due to the action of rapidly flowing streams with easterly flowing courses. In the west of the proposed region drainage on the east-facing slopes is predominantly eastward while on the lower levels of the coastal area drainage may also be in northerly or southerly directions.

The boundaries of the proposed region have been largely selected on topographical and geological features. The northern extremity is defined by the course of the Minamurra River that essentially separates the intensively developed Illawarra Region to the north and the more agricultural regions of the coastal catchment of the Shoalhaven River to the south. The western boundary follows the crests of ranges parallel to the escarpment of the Great Divide, generally at an elevation of 500m or less, to a point 16 Km west of the town of Ulladulla. From there the boundary proceeds south to the coast at Flat Rock Island, 40 Km south southwest of Ulladulla. The southern termination of the Region is more or less coincident with the southern margin of the geological feature known as the Sydney Basin.