What is Irrigation Water Requirement?
Irrigation Water Requirement (IWR) is the amount of water that must be supplied through irrigation to meet crop water demand after accounting for effective rainfall.
Formula Used
IWR (mm) = ETc − Effective Rainfall
Water Volume (m³) = IWR (mm) × Area (ha) × 10
Where:
• ETc = Crop evapotranspiration (mm)
• Effective rainfall = Useful rainfall (mm)
• 1 mm water over 1 ha = 10 m³
Enter Field Data
Field Notes:
• ETc = ET0 × Kc
• Effective rainfall excludes runoff & deep percolation
• Used in canal scheduling & micro-irrigation design
• ETc = ET0 × Kc
• Effective rainfall excludes runoff & deep percolation
• Used in canal scheduling & micro-irrigation design
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