This diversion dam was built much earlier than the Great Marib Dam. Located approximately 300 metres east of the Great Dam in the centre of the Dhanah valley, a German archaeological expedition in 1988-98 determined it predates the Great Dam by 1,000 to 2,000 years. It was 55 metres long and 30 metres wide, built with stones as large as 2 metres cemented with lead. The engineering used the natural features of the two Balaq mountains to manage sediment accumulation.
Diversion Dam
Ancient dam predating the Great Marib Dam by millennia