In contradiction to the main Vaal System, the main Orange System or ORP is used to mainly supply water for irrigation purposes (approximately 60% of demand), with a small portion (only 2.5%) of the demand comprising of urban/industrial & mining requirements. Irrigation demands are in general obtained by the quota for the given area times theallocated irrigation area. There is very little observed measured irrigation abstraction data available and the actual true irrigation use will differ from that obtained from the allocated area and quota. Although this data is, as in the case for the Vaal System, also updated on an annual basis as part of the operational analysis, it is not to the same confidence level as that of the Vaal, due to the large irrigation component. Return flows from urban/industrial requirements is almost negligible and those from irrigation amounts to 207 million m3/a, or 13% of the gross irrigation requirement.