Understanding Acre-Feet to US Dry Gallons Conversion
An acre-foot measures the water needed to flood one acre one foot deep, the workhorse unit of US reservoir and irrigation accounting. The US dry gallon is a dry-measure unit of about 4.405 liters, one-eighth of a US bushel, used historically for grains and fruit. This conversion translates hydrological storage volumes into a traditional dry-goods gallon scale.
Conversion Formula
To convert Acre-Feet to US Dry Gallons, multiply by this factor:
Step-by-Step Example
Convert 25 Acre-Feet to US Dry Gallons.
How to Convert Acre-Feet to US Dry Gallons
Turn reservoir or irrigation volumes into US dry gallons in three quick steps.
- Start with acre-feet: Note the volume to convert, such as 25 acre-feet.
- Multiply by 280026: This is the count of US dry gallons in one acre-foot.
- Read the result: 25 × 280026 = 7,000,650 US dry gallons.
- Check the reverse: Multiply by 0.000003571097 to convert dry gallons back to acre-feet.
Acre-Feet to US Dry Gallons conversion table
| Acre-Feet (acre-foot) | US Dry Gallons (gal-dry) |
|---|---|
| 0 | 0 |
| 1 | 280026 |
| 2 | 560051.9 |
| 3 | 840077.9 |
| 4 | 1120104 |
| 5 | 1400130 |
| 6 | 1680156 |
| 7 | 1960182 |
| 8 | 2240208 |
| 9 | 2520234 |
| 10 | 2800260 |
| 15 | 4200390 |
| 20 | 5600519 |
| 25 | 7000649 |
| 30 | 8400779 |
| 40 | 11201040 |
| 50 | 14001300 |
| 60 | 16801560 |
| 70 | 19601820 |
| 80 | 22402080 |
| 90 | 25202340 |
| 100 | 28002600 |
| 150 | 42003900 |
| 200 | 56005190 |
| 250 | 70006490 |
| 300 | 84007790 |
| 400 | 112010400 |
| 500 | 140013000 |
| 600 | 168015600 |
| 700 | 196018200 |
| 800 | 224020800 |
| 900 | 252023400 |
| 1000 | 280026000 |
| 2000 | 560051900 |
| 3000 | 840077900 |
| 4000 | 1120104000 |
| 5000 | 1400130000 |
| 10000 | 2800260000 |
| 25000 | 7000649000 |
| 50000 | 14001300000 |
| 100000 | 28002600000 |
| 250000 | 70006490000 |
| 500000 | 140013000000 |
| 1000000 | 280026000000 |
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.
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.
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 the US Dry Gallon?
The US dry gallon (gal-dry) is a unit of volume used in the United States for measuring dry commodities such as grains, berries, and other agricultural produce. It is larger than the more familiar US liquid gallon.
Definition
The US dry gallon is defined as one-eighth of a US bushel, which equals 268.8025 cubic inches:
Exactly, 1 US dry gallon = 4.40488377086 liters. This is about 16.4% larger than the US liquid gallon (3.785411784 L) but slightly smaller than the imperial gallon (4.54609 L).
Origin and History
The dry gallon derives from the Winchester bushel, an English measure standardized in the late 17th century and defined as a cylinder 18.5 inches in diameter and 8 inches deep. The United States retained this bushel after independence, and the dry gallon is simply one-eighth of it. Dry measures existed because heaped commodities settle and compact differently than liquids, so a separate volume standard was practical for trade.
Law and Notable Facts
The US dry gallon is a legal US customary unit but is rarely used directly; dry commodities are more often traded in quarts, pecks, or bushels. It is not an SI unit. The UK abolished separate dry measures in 1824 when it adopted the imperial system, so the dry gallon is specifically an American measure.
Real-World Examples and Conversions
- 1 US dry gallon = 4.40488 L ≈ 268.8 cubic inches.
- 8 US dry gallons make 1 US bushel; 2 dry gallons make 1 peck.
- A US dry gallon holds about 4.6546 US dry quarts.
- 1 US dry gallon is roughly 1.164 US liquid gallons.
Frequently Asked Questions
How many US dry gallons are in an acre-foot?
An acre-foot contains 280026 US dry gallons, because one acre-foot is about 1,233 cubic meters and a US dry gallon is roughly 4.405 liters.
What is the formula to convert acre-feet to US dry gallons?
Multiply acre-feet by 280026. For instance, 2 acre-feet equals 2 × 280026 = 560,052 US dry gallons.
How do I reverse the conversion?
Multiply US dry gallons by 0.000003571097 to get acre-feet, so 1,000,000 dry gallons is about 3.571 acre-feet.
How does a US dry gallon differ from a liquid gallon?
The US dry gallon (about 4.405 L) is larger than the US liquid gallon (about 3.785 L) and is reserved for dry commodities such as grain.
Where is the acre-foot to dry gallon conversion useful?
It helps agricultural planners express irrigation water reserves in the dry-measure gallons familiar from crop and produce handling.