Gerash is a small city in Fars, a province in the south-west of Iran (Coordinates: 27°39′35″N, 54°08′15″E). The urban area is about 6 km² (2.3 sq mi), with an elevation of 912 m (2,992.1 ft) above sea level. The city is densely populated, with urban density of 5,300 people per km² (13,726.9 per sq mi).
Gerash has been mentioned in written history since the 10th century AD. Although based on the archaeological evidences, the people originally maintained a sparsely populated rural life in the fields around the present-day Gerash, over time they migrated to an urban life at the foot of a hill or a small mountain, locally known as “Kalat”. The city soldiers watched over town from the higher levels of the mountain, while the ruler of Gerash had traditionally lived at the mountain peak.
This traditional lifestyle continued until the 20th century when soldiers of Reza Shah, the autocratic king of Iran, attacked the city and the rulers’ compound was bombarded using fighter aircrafts.
People of Gerash speak Gerashi (Achomi), a dialect of Persian. As of 2011, the population of the county is estimated to be at around 47,000 people (30000 people in city and 17000 people in rural areas). Gerashi people adhere to Shi’a branch of Islam. Since the early 19th century, many have immigrated to the southern Persian Gulf countries, working mostly in the retail industry.
Berka is a traditional reservoir of drinking water in Iranian antiquity, and can be found in various locations in Gerash.
To withstand the pressure the water exerts on the containers of the storage tank, the storage itself was built below the ground level. An important aspect is their resistance to earthquakes. Gerash lies in a region that has been struck with earthquakes. However, since berkas are subterranean structures capped barely above ground level, they inherently possess stable structures