Pakistan has one of the largest contiguous irrigation systems in the world called the Indus Basin Irrigation System (IBIS). The IBIS includes 3 major reservoirs, 19 barrages, 2 head works, 12 link canals, 45 irrigation canals, over 100,000 water courses, and millions of farm channels with a total length of over 500,000 km. It provides irrigation to over 22 million hectares of cultivated land, sourcing water from the Indus River and its tributaries as well as groundwater and rainfall. Surface water makes up the largest portion at around 104 MAF annually. Groundwater contributes another 41 MAF and rainfall provides around 9 MAF. Together this irrigation system provides around 69 MAF