Land drainage allows water to flow freely from land. There are a number of different forms of land drainage, ranging from natural drainage found in many regions of the world to artificial drainage installed specifically to deal with drainage issues or to address land use concerns. Land drainage is an important part of the water cycle, and it can have a variety of implications.
People often refer to drainage when they are discussing land which is being used by humans. Land drainage is usually critical for human use, because well-drained land is necessary for construction. If land is soggy, structures may not stay stable, and poor drainage can also contribute to problems with septic systems and accessibility. For example, a walkway which continually puddles in the winter months would be an accessibility problem. Poor drainage may also lead to problems with gardening and agricultural use.
Some land drainage options which can be used to improve drainage include the installation of trenches and French drains to gather water and route it to another area. On the more extreme end of things, pumping can be used to lift water out of an area of low-lying land. Parts of the Netherlands, for example, rely on pumping to make usable land because people have settled on reclaimed land which was once swampy or partially under water.
Drainage is a common issue addressed when a site is inspected prior to prospective development. Some signs that drainage could be a problem include low-lying ground, standing water, or signs that standing water is sometimes present, such as algae stains. For example, someone inspecting a home site might note that the site is lower than the road, which would suggest that water probably streams off the road and into the land during the rainy season. People may also be required to conduct soil percolation tests to learn more about the drainage and per4colation conditions on a set piece of land.
Humans have come up with a variety of ways to compensate for poor drainage. At times, this becomes problematic. Human settlements in low lying areas, for example, are prone to flooding in serious storms. As a result, a variety of measures must be used to prevent flooding, such as levees, and when these measures fail, the results can be devastating and costly. The practice of reclaiming marshy land has also become controversial for environmental reasons, as people express concern about the integrity of the natural environment.