Reservoir re-housed, historical artifacts moved or rare environments relocated. Examples include the temples of Abu Simbel (which were moved before the construction of the Aswan Dam to create Lake Nasser from the Nile in Egypt), the relocation of the village of Capel Celyn during the construction of Llyn Celyn, and the relocation of Borgo San Pietro of Petrella Salto during the construction of Lake Salto. Construction of a reservoir in a valley will usually need the river to be diverted during part of the build, often through a temporary tunnel or by-pass channel. In hilly regions, reservoirs are often constructed by
Abu Simbel temples ancient human civilization were under threat from the rising waters of the Nile that were about to result from the construction of the Aswan High Dam. One scheme to save the temples was based on an idea by William MacQuitty to build a clear fresh water dam around the temples, with the water inside kept at the same height as the Nile. There were to be underwater viewing chambers. In 1962 the idea was made into a proposal by architects Jane Drew and Maxwell Fry and civil engineer Ove Arup. They considered that raising the temples ignored the effect of