Evidence and consequences of the flood in Iran from prehistory to the present

During periods of climate change, catastrophic floods have occurred, mainly due to extreme rainfalls, leading to widespread damages and heavy economic losses, the spread of epidemics, and the mortality of many people. Psychological research related to current global warming also indicates the appearance or exacerbation of mental disorders after the occurrence of this natural event. In this study, the socio-economic and health consequences of floods have been studied, and also, using paleoclimate, archeological, and historical researches, some severe and extensive flood events from prehistory to the present have been presented. Finding reports of flood events from historical documents and discovering evidence of floods among the cultural layers of ancient sites, along with paleoclimate and paleo-flood studies, can yield more accurate results from past climatic and environmental conditions. In the studies of environmental sedimentology of some ancient sites of Iran, evidence of catastrophic floods belonging to the mid-fourth millennium B.C. has been found and some have been reported in the historical books of the Islamic period. These events coincide with periods of climate change called medieval warming and the Little Ice Age and occurred mostly in Iran due to extreme rainfalls and flooding of rivers and seasonal streams.

In this study, first, the devastating social, economic, and health consequences of floods are explained. Then, archaeological evidence is examined, some of which are the result of field research. Finally, historical documents and reports that mention the occurrence of great and influential floods from the early Islamic period to the present are presented.

Floods kill more than 2,000 people each year and affect 75,000,000 of the world's population. The reason is the geographical distribution of alluvial fans and shorelines that have long been attractive for human habitation. The occurrence of floods, due to the extreme rainfalls related to climate change, mainly overlapped with drought periods. One of the most important archeological evidence of floods dates back to the fourth millennium B.C. According to the high-resolution paleoclimate research of Lake Neor in Ardabil, from about 4200 to 3000 B.C., there was a very dry period with increasing dust. During this period, at least two periods of severe drought occurred, 3600-3700 B.C. and 3150-3250 B.C., which are shown by the paleoclimate research of Soreq Cave in the west of Jerusalem. Archaeological evidence of floods in the middle and late fourth millennium B.C. as a result of environmental sedimentology and archaeological excavations in the sites of Mafin Abad Islamshahr, Meymanat Abad Robat Karim and Qara Tepe of Qomroud in North Central Iran, as well as in the sites of Shuruppak, Kish and Ur in Iraq have been identified. The flood of 628 A.D., which occurred due to the flooding of the Tigris and Euphrates rivers in Mesopotamia, was probably one of the main reasons for the fall of the Sassanid dynasty. Blazeri, the historian of the Islamic period, attributes the occurrence of this great flood to the end of the reign of Khosrow Parviz. This event has led to the death of many people, the destruction of crops, famine, displacement, and the spread of plague.

Therefore, it can be said that if flood prevention and control in Iran are not managed efficiently and effectively, extreme rainfalls related to current climate change (global warming) can cause serious damages and irreparable losses.