**2. Purposes of River Relocation**

Ancient civilisations, such as the Egyptians and Mesopotamians, modified watercourses for consumptive purposes from the Neolithic period [24]. However, the earliest true river relocation that we have found is the ninth century diversion of the Opak River for the construction of the Loro Jonggrang temple within the Prambanan Temple compound in Indonesia [25]. There were almost certainly earlier channel relocations than this. Modern river relocation is carried out for a wide variety of purposes, and following are some examples.


**Figure 2.** Examples of river relocation channels. (**a**) River relocation for the construction of the Shasta Dam on the Sacramento River (1943) (Photo: California State University); (**b**) the temporary relocation of the Coeur d'Alene River, Idaho, to allow the clean-up of contaminated tailings; (**c**) permanent river diversion of the Goulburn River for coal mining in NSW, Australia (Photo: Cathy Toby).
