The phenomenon of flood in its current state in our country is caused more by the effects of interrupting the balance of natural ecosystems in the country than by the occurrence of low-probability precipitation. In the form that we can observe today, the occurrence of ordinary rainfall in most watersheds of the country causes flood.
According to available statistics, in parts of the world, especially in Asia and the Pacific, flood damage accounts for the highest proportion of damages caused by natural disasters. Despite the fact that no comparative statistics on flood and earthquake damage in our country have been published so far, Iran is nevertheless considered a flood-prone country, having arid and semi-arid climatic conditions. The province of Hamedan is among the flood-prone areas of Iran due to natural and human factors contributing to the occurrence of flood. The occurrence of historic floods such as floods in 1987 and 1992 in this province illustrates this fact.
Flood factors fall into two categories: natural factors including climatic conditions (repeated rainfall, snow melting, high temperatures ...), land features (slope, soil texture, etc.) and poor vegetation, and human factors. In Hamadan province, the above factors have in mutual cooperation caused conditions favorable to flood which are mentioned in this study.