Acre-Feet (acre-foot) to Kannor (kanna) conversion

What is the Acre-Foot?

The acre-foot is a unit of volume equal to the amount of water needed to cover one acre of land to a depth of one foot. It is the standard measure used for large-scale water resources in the United States, including reservoirs, irrigation supplies, and municipal water rights.

Definition

One acre-foot is defined as the volume of a prism with a base area of one acre (43,560 square feet) and a height of one foot, giving exactly 43,560 cubic feet.

$$1\ \text{acre-foot} = 1.23348 \times 10⁶\ \text{l}$$

Because the US survey foot and the international foot differ slightly, the acre-foot is fixed by its exact defining relation of 43,560 cubic feet, which equals about 1,233.48 cubic metres or 1,233,482 litres; the NIST Guide to the SI tabulates the acre-foot as 1.233 489 × 10³ m³.

Origin and History

The acre-foot arose in the American West during the late 19th and early 20th centuries, as irrigation districts and water agencies needed a practical unit for measuring large volumes of stored and delivered water. It combines the acre, an old English unit of land area, with the foot of depth, making it intuitive for engineers estimating how much water a given area of reservoir or flooded field holds.

Law and Notable Facts

The acre-foot remains the legal and administrative unit for water rights, reservoir capacity, and interstate water compacts throughout the western United States. A commonly cited rule of thumb is that one acre-foot supplies roughly one to two typical American households for a year, which is why it is used to describe how many homes a reservoir can serve.

Real-World Examples and Conversions

• A single acre-foot equals about 325,851 US gallons of water.
• Lake Mead, the largest reservoir in the US, has a capacity of roughly 28.9 million acre-feet when full.
• An Olympic swimming pool holds about 2,500 cubic metres, or roughly 2 acre-feet.
• In metric terms, 1 acre-foot is approximately 1,233 cubic metres (1.23348 million litres).

What is Kannor?

Kannor is the plural of kanna, an old Swedish unit of volume used for both liquids and dry goods before Sweden adopted the metric system. It was one of the most common everyday measures in Sweden for centuries, especially for spirits and other liquids.

Definition of Kanna

Following the Swedish measurement regulations of 1665, one kanna was standardized at approximately 2.617 litres.

$$1 \text{ kanna} \approx 2.617 \text{ L} = 2617 \text{ mL}$$

The kanna was part of a coherent system of Swedish volume units. Its subdivisions and multiples included:

• 1 kanna = 2 stop
• 1 kanna = 8 kvarter
• 1 kanna = 32 jungfrur
• 1 kanna = 1/48 tunna (barrel)

Origin and Formation

The kanna originated as a practical measure tied to common containers used for storing and transporting goods. Sweden brought its many local measures under a single national standard with the ordinances of 1665, which fixed the kanna at about 2.617 litres. The unit was used throughout Sweden (and Finland, then part of the Swedish realm) for trade in liquids such as beer, milk, and spirits, as well as for some dry goods.

Historical Significance and Usage

For more than two centuries the kanna was a mainstay of Swedish commerce and daily life. Merchants, brewers, and farmers measured and sold goods by the kanna and its subdivisions. The unit was gradually phased out as Sweden transitioned to the metric system, which became mandatory in 1889. After that, litres replaced kannor in everyday and legal use.

Conversions

Using the 1665 value of 2.617 litres:

• 1 kanna ≈ 2.617 litres
• 1 kanna ≈ 0.691 US gallons
• 1 kanna ≈ 0.576 Imperial gallons
• 100 kannor ≈ 261.7 litres

To convert a volume in kannor to litres:

$$\text{Volume in Liters} = \text{Volume in Kannor} \times 2.617$$

Laws and Associated Figures

The kanna was defined by Swedish royal measurement ordinances rather than by any single individual. Its standardization in 1665 and its eventual replacement by the metric system in 1889 reflect Sweden's long effort to bring consistency to weights and measures.