Irrigation

[edit] Introduction

Irrigation is the controlled watering of land by artificial means. It is primarily used to sustain crop growth, cool livestock, suppress weeds or protect land from freezing. It can also be used as a control measure in areas where lack of consistent water supply can have a negative impact on the landscape.

Irrigation has also been used for non-agricultural purposes such as sewage disposal and dust suppression.

[edit] History

As an agricultural tool, irrigation has been used around the world for thousands of years. The earliest evidence of its existence was found in Iran; this system is believed to date from 6000 BC.

In Egypt, significant irrigation measures were built around 3000 BC to control the level of the Nile. In addition to supplying water to crops, this irrigation project also involved the construction of other complex water engineering measures.

Irrigation was used extensively in ancient civilisations in China, India, Sri Lanka, Korea and the Americas.

[edit] Types of irrigation

There are several methods of irrigation, which vary in how the water is supplied. Some of the most common types include:

• Surface irrigation (also known as gravity irrigation).
• Micro-irrigation (also referred to as localised irrigation, low volume irrigation, trickle irrigation or drip irrigation).
• Sprinkler irrigation (also referred to as overhead irrigation).
• Subirrigation (or subsurface irrigation).

There are several water sources that can be used for irrigation purposes. These include:

• Groundwater (from springs or taken from wells).
• Surface water (taken from rivers, lakes or reservoirs).
• Treated water (including wastewater, desalinated water or drainage water).
• Floodwater harvesting (referred to as spate irrigation) or fog collection.

[edit] Related articles on Designing Buildings Wiki

• Dam construction.
• Hydropower.
• Major Henry De Bude.
• Rainwater harvesting.
• Water engineering.