Water Resources in Syria July 23, 2019 Rain is the main water resource in Syria, affecting the availability of all other water resources. The average annual rainwater resource is estimated at 46 billion cubic metres (BCM). Tags: Alyarmouk - Desalination - Euphrates - Groundwater - rainwater - Rainwater Harvesting - S - Surface Water - Syria - Tigris - treated wastewater - Wastewater - Water Resources