A 5,100-year-old dam, capable of flood control and irrigation（灌溉）, has been identified as China's earliest （know ） water engineering project. The Xiongjialing Dam is part of the Qujialing relics site in Jingmen, China's Hubei Province.
The dam was initially built around 5,100 years ago on a branch of the Qingmudang River. The （exist） dam measures 2 meters in height, 13 meters in width and 180meters in length. It has a water storage area to the east, equal to the size of three West Lakes, and 8.5-hectare irrigation area to the west, with the （late） found to have been an expanse of prehistory rice field. A flood way at the northern side of the water storage area allowed for discharge （排放） of extra water during flood seasons. The dam （construct） with local earth, which was mixed with plant roots （ increase） the structure's toughness.
The design of the water project suggests that prehistoric （ancestor） in the area had learned to control water use rather than （simple） defending against floods and droughts. The Qujialing relics site is famous for witnessing the first-ever discovery carbonized rice along the midstream of the Yangtze River. Researchers say the dam further illustrates that, in the Neolithic Age, the area had a mature rice-growing agriculture. That's this relies heavily on irrigation.
