megalitres

The megalitre (ML) is a metric unit of volume equal to one million litres, or 1,000 cubic metres. It is commonly used in water resources and civil engineering to describe large quantities of water, such as reservoir storage, municipal supplies, and irrigation allocations. In practical terms, 1 ML = 1,000 m³ = 1,000,000 L. The unit is convenient for reporting capacity figures and annual water use across large projects.

Flow rates are also expressed in megalitres per day (ML/d) or megalitres per year, depending on the context and the precision required. In this system, larger volumes are tiered as kilolitres (1,000 L), megalitres (1,000,000 L), and gigalitres (1,000 ML).

Usage and conventions vary by region, but the megalitre is standard in many Commonwealth countries and in international water-management literature. The abbreviation ML is widely recognized, and the spelling megalitre is common in British and Australian English, while litre remains the unit for volume and is used consistently with ML in the same contexts.