Find the peak daily crop-water demand for a field — the figure you size an irrigation system to. Pick a location and crop; the tool pulls 10 years from two weather sources, lets you compare and choose them, fit and edit the crop coefficient, and returns the peak-period demand in mm/day plus the design flow. Export a PDF for the design team.
1 · Location
Search a place or click the map. 10 years of daily weather are used.
2 · Crop & coefficient
Pick a crop for a starting Kc curve, choose the season months, then edit any Kc value to match your field. Works in both hemispheres.
Crop
Irrigation season — click months in growing order (wrapping across the new year is fine for southern-hemisphere fields):
3 · Design settings
Net = crop demand (Kc × ET₀). Gross = net ÷ efficiency. Choose a more conservative basis for drought-sensitive crops or tight windows.
Peak daily demand
Weather data — explore & choose sources
Two independent 10-year records. Compare them, drop one if it looks off, and exclude unusual years — everything downstream updates.
Year-to-year variability — how the peak changes between years, and which years to useRaw monthly table (per source)
Design flow rate
What the system must deliver to meet the peak.
Daily crop-water demand through the year
Mean daily ETc per month (Kc × ET₀). The peak month sets the design figure.
