Jordan is among the most water-scarce nations on earth. At 97 cubic meters of water per person per year, it is considered to face "absolute water scarcity" according to the Falkenmark Classification. Scarce resources to begin with have been aggravated by the massive influx of Syrian refugees into Jordan, many of whom face issues of access to clean water due to living in informal settlements (see "Immigrants and Refugees" below). Jordan shares both of its two main surface water resources, the Jordan and Yarmouk rivers, with neighbouring countries, adding complexity to water allocation decisions. Water from Disi aquifer and ten major dams historically played a large role in providing Jordan's need for fresh water. The Jawa Dam in northeastern Jordan, which dates back to the fourth millennium BC, is the world's oldest dam. The Dead Sea is receding at an alarming rate. Multiple canals and pipelines were proposed to reduce its recession, which had begun causing sinkholes. The Red Sea–Dead Sea Water Conveyance project, carried out by Jordan, will provide water to the country and to Israel and Palestine, while the brine will be carried to the Dead Sea to help stabilise its levels. The first phase of the project is scheduled to begin in 2019 and to be completed in 2021.