Landform – Drainage
The land consists of gently to moderately undulating slopes on the eastern side, and flatter land on the western side. The elevation ranges from 215 to 278 metres ASL (Above Sea Level).
The hilly portion consists of mainly skeletal soils formed on metamorphosed sandstone of the Backstairs passage formation of the Kanmantoo group (Middle Cambrian age) in an area of pronounced metamorphism. A main feature of this area is the coarseness of the basement rocks and the resulting sandy nature of the landscape.
The lower slopes consist of pale brown sandy clays of the Pooraka formation with Loveday formation carbonate and gravel lenses. Surface drainage is from west to east into two tributaries of Gorge creek, itself of tributary of Reedy Creek which runs into the River Murray near Caloote.
The area lies in a rain shadow caused by the Central Mt Lofty Ranges, rainfall dropping by approximately 15 mm/km. The annual rainfall at Woodside is 830 mm and at Mannum it is 290 mm. At Rockleigh it is ca. 550 mm.
The growing season, when rainfall exceeds evapo-transpiration, is about seven months.
The rainfall is distinctly seasonal with some 70% falling in April to October. Summers are warm to hot and winters are cool to cold.
There is no good quality groundwater (i.e., relatively fresh), but the creeks have springs which have surface water all year which is important for wildlife in the area. However increasing salinity is becoming a problem in the creeks.
Near the eastern end of the property adjacent to the creek there is a small dam and a shallow well. In the past, water has been pumped from the dam to storage tanks on adjacent land where it is used for stock water. The dam has been left open and provides a variety of aquatic and riparian edge habitat with native rushes and sedges having been allowed to develop with the removal of stock.