Paddy Bund Water & What Your Field Holds
Stores irrigation
Enter your field area and the ponding depth to get the volume of water held in your bunded rice field — in m³ and litres for irrigation planning and rainwater capture.
Paddy ponding
Next: holding 50 mm across 0.4 ha needs 202 m³ (202,343 L) of standing water; size your channel and refill rate to keep that layer through the season.
This is the standing volume only — it ignores seepage, percolation and evapotranspiration losses, which can need several times this volume over a crop. Strong bunds reduce refill needs.
Paddy bund water — key facts
- Volume
- area × ponding depth
- 1 mm over 1 m²
- = 1 litre
- 1 mm over 1 ha
- = 10 m³ (10,000 L)
- Typical depth
- ≈ 20–50 mm
- Holds
- irrigation + rainwater
- Bund job
- stops water draining away
- Excludes
- seepage & percolation losses
- Privacy
- Runs in your browser; nothing uploaded
A levelled, bunded field is a shallow reservoir
Rice grows in standing water, and the low earthen bund around a levelled paddy is what keeps that water in place. Trap a thin layer over the soil and the field becomes a shallow reservoir: the water it holds is simply the area times the depth of the ponded layer. Get that number and you know how much each irrigation adds, how much a rain shower contributes, and how full the bund can run before it overflows.
This tool computes the water volume in m³ and litres held at your chosen ponding depth over your field area. Use it to plan irrigation top-ups, size a pump or tank to reflood the plot, and judge how much rainfall your bunds can capture. Pair it with the Crop Evapotranspiration and Irrigation Water tools to turn the stored volume into a full season water plan.
Measure what it holds
The exact water stored at a chosen depth.
Plan each top-up
Know the volume each irrigation adds.
Capture the rain
See the rainwater your bunds can hold.
Size pump and tank
Work out what's needed to reflood the plot.
Frequently Asked Questions
What is a paddy bund?+
A bund is the low earthen embankment built around a rice plot to hold water. Bunded, levelled fields trap a thin ponded layer over the soil — the standing water that rice grows in. The bund stops the water draining away so the field stays flooded between irrigations and after rain.
How is the water volume in a paddy calculated?+
Volume = area × ponding depth. A field of 1,000 m² ponded to 50 mm (0.05 m) holds 1,000 × 0.05 = 50 m³, which is 50,000 litres. The tool takes your area and the depth of standing water and returns the stored volume in both m³ and litres.
What ponding depth should rice be kept at?+
Transplanted rice is commonly kept at a shallow 20–50 mm of standing water through most of the season, deepened a little at panicle initiation and drained near maturity. Alternate wetting and drying (AWD) lets the depth fall below the surface between floods to save water. Enter the depth you actually maintain.
How does ponding depth relate to litres per square metre?+
One millimetre of water over one square metre is exactly one litre. So 50 mm of standing water means 50 litres on every square metre, or 500 m³ over a hectare. That direct link is what makes the area × depth calculation so simple to reason about.
Why does the water stored matter for irrigation planning?+
Knowing the volume a field holds at a given depth tells you how much water each irrigation event adds, how much a rain shower contributes, and how big a tank or pump set you need to reflood the plot. It turns a vague 'top it up' into a measured amount you can plan and budget.
Can I use this to plan rainwater capture?+
Yes — the bund that holds irrigation water also captures rainfall. The volume held at your maximum safe depth (just below the bund top) is the rainwater the field can store before it overflows. The tool gives that storage so you can size bund height to catch more rain and irrigate less.
Does this include seepage and percolation losses?+
No — this is the standing volume held at the depth you enter, not the daily water use. Puddled fields lose water to seepage and percolation as well as evaporation and transpiration, so the actual water you must supply over a season is much larger. Pair this with an evapotranspiration or irrigation-water tool for total use.
What area units can I use?+
Enter the area in the units the tool offers and the depth in millimetres; it converts internally so the result is consistent. As a check, 1 hectare = 10,000 m², 1 acre ≈ 4,047 m², and a millimetre over a hectare is 10 m³ (10,000 litres).
Is this only for rice?+
The same area × depth volume applies to any ponded or flooded plot — fish ponds, lined tanks, basin-irrigated fields or recharge pits. Rice paddies are the most common bunded case, but enter any area and standing-water depth to get the volume held.