Validation of Consumptive Use of Water (ETo) And Calculation of Discharge of Greater Thal Canal

Abstract

The Greater Thal Canal command area is situated between River Indus and Jhelum in Doaba Sind Saghar. It is a vast desert land sprawling over 0.7 million hectares. Indus Basin Irrigation System (IBIS) is one of the largest irrigation systems in the world. One of the most important issues is the loss of over 60% water during conveyance and application in the fields. Over-irrigation is a common practice due to lack of knowledge about Irrigation scheduling (when to apply and how much to apply irrigation water?). The knowledge of crop water requirement/evapotranspiration is important for devising proper irrigation scheduling. The climate of the area is arid with an average annual rainfall of 295 millimeters and evapotranspiration of 1769 mm, which is almost 6 times the rainfall. During Kharif the evapotranspiration is very high making it almost impossible to farm without irrigation facility. Provision of a regulated irrigation system is essential for successful farming in the command area. GTC is planned to command 703,858 hectares (1,739,233 acres) of extensive desert land. The Project command area will be divided in three phases. Phase l is the Greater Thal Main canal and Mankera Branch canal. These canals have been constructed and commissioned.