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🏞️ Dam Volume Calculator — Water Storage Capacity

Calculate farm dam water storage volume in megalitres and litres. Plan water budgets for stock, irrigation and firefighting.

Quick answer: Rectangular dam: L × W × D × 0.8 (sloping sides). 50×30×3m = 3,600 m³ = 3.6 ML. Circular: π × r² × D × 0.8. 1 ML = 1 million litres = 1,000 m³.

🏞️ Calculate Dam Volume

Average length at full water level
Average width at full water level
Typical: 2-5m for farm dams
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Storage Volume (Megalitres)
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Litres
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Cubic Metres

📐 How Dam Volume Is Calculated

Rectangular: Volume = L × W × D × Shape factor (0.8 for sloping sides)
Circular: Volume = π × r² × D × 0.8
1 m³ = 1,000 litres = 0.001 ML
  1. Measure dimensions — length, width, depth at full water level
  2. Apply shape factor — 0.8 for sloping sides, 1.0 for vertical walls
  3. Calculate cubic metres — multiply dimensions
  4. Convert to megalitres — divide by 1,000

📊 Worked Example

Rectangular dam: 50m long, 30m wide, 3m average depth. Sloping sides (0.8 factor).

Volume = 50 × 30 × 3 × 0.8 = 3,600 m³
Megalitres = 3,600 ÷ 1,000 = 3.6 ML
Litres = 3.6 × 1,000,000 = 3.6 million litres

This dam can supply 100 cattle for 3.6 ML ÷ (100 × 0.08 kL/day) = 450 days, minus evaporation.

❓ Frequently Asked Questions

Rectangular: L × W × D × 0.8. Circular: π × r² × D × 0.8. 1,000 m³ = 1 ML = 1,000,000 litres.

Small dam (10×10×2m): 0.16 ML. Medium (50×30×3m): 3.6 ML. Large (100×50×4m): 16 ML. Typical farm dam: 1-10 ML.

Pace length and width. Estimate depth. Volume = L × W × D × 0.7. Rough estimate only — 20-30% error possible.

Days = Dam volume ÷ Daily use. Add evaporation: 2-5mm/day in summer. Large shallow dams lose more to evaporation than stock use.

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