Jawa dam is featured an originally 9m high and 1m wide stone wall, supported by a 50m wide earth rampart.In which country was this earliest known dam?

The earliest known dam is the Jawa Dam in Jordan,100 kilometres (62 mi) northeast of the capital 

The Jawa Dam is actually several gravity dams that are part of one reservoir system. They are located in Jordan and date back to approximately3,000 B.C. To store water for the dry season, the Jawaites built canals from the Rajil River to fill reservoirs formed by building a series of dams. The reservoirs also trapped surface runoff. Even though the dams are so ancient, they are very complex and well designed. One feature that I find fascinating is that they placed rock fill material behind the upstream wall which protected the wall from breach by water pressures. This design was a safety feature that was lost and only reinvented in modern times.

1. The Jawa Dam is the remains of an ancient masonry gravity dam on Wadi Rajil at Jawa in Mafraq Governorate, Jordan,58 kilometres (36 mi) north of Azraq. 
2. Jawa Dam in Jordan, the oldest known dam in the world.

Thanks Mr. Alex & Prof. zeidan and Mr. Galal Hussein for sharing the Information i was not aware about this.

thanks to Mr Alex

The Jawa Dam is the remains of an ancient masonry gravity dam on Wadi Rajil at Jawa in Mafraq Governorate, Jordan,58 kilometres (36 mi) north of Azraq. It is the oldest known dam in the world, dating back to3000 BC. The dam was part of a water supply system that included other smaller dams, channels and deflectors across the wadi to support the short lived local town of Jawa. Therefore, the term Jawa Dams is sometimes used to describe the dams around Jawa. The Jawa Dam, though, is the largest of the dams and withheld the largest reservoir.