The River Torrens is the most significant river of the Adelaide Plains and was one of the reasons for the siting of Adelaide, South Australia. It flows 85 kilometres (53 mi) from its source in the Adelaide Hills near Mount Pleasant, across the Adelaide Plains, past the central business district and empties into Gulf St. Vincent at Henley Beach South. The upper stretches of the river and reservoirs in its watershed supply a significant part of the city's water supply. The river's long linear parks and a constructed lake in the lower stretch are iconic of the city.
The river's flora and fauna have been both deliberately and accidentally impacted since settlement. Native forests have been cleared, gravel removed for construction and many foreign species introduced. With construction of the linear parks, many species native to the river have been replanted and introduced species controlled as weeds. Since European settlement the river has been a frequently touted tourist attraction. It has also acted as the city’s primary water source, and main sewer leading to outbreaks of typhus and cholera.