Effect of Extreme Floods on the Archaeological Sites of Persepolis and Naghsh-e-Rostam, Iran

UNESCO has designated the archaeological sites of Persepolis and Naghsh-e-Rostam as cultural world heritage sites. These sites are located at 55 km northeast of Shiraz, in southern Iran. Persepolis consists of three parts: the Platform, the Southern Barzan, and the Northern Barzan. The Sivand River, which flows near these archaeological sites, is historically known as a severe flood river. This study investigates the possible inundation of the Persepolis and Naghsh-e-Rostam regions under extreme floods of the Sivand River. The 10,000-year return period flood and peak flow of probable maximum flood are estimated to be $\mathrm{2,717}\hspace{0.17em}\text{and}\hspace{0.17em}\mathrm{7,862}\hspace{0.17em}{\text{m}}^3/\text{s}$, respectively, at a station near these sites. The Hydrologic Engineering Center River Analysis System (HEC-RAS) model was then used to simulate the potential inundated downstream area with the estimated flow rate of a 10,000-year return period flood and the probable maximum flood. The model showed no risks of inundation by 10,000-year return period flood, but the probable maximum flood can potentially submerge the Southern Barzan and some parts of the Platform. The archaeological sites must be protected from any damage during the time span of human life; therefore, it is recommended that all of the archaeological sites be studied for extreme floods as a routine procedure.