Tile drainage is a subsurface water control method that routes excess water into tubing for removal. It is used in agriculture and other settings where deposits of water beneath the surface can create a problem. Every site drains differently and may have various accompanying concerns, and a tile drainage system usually needs to be custom designed for a specific location. This can require input from a soil scientist as well as other consultants who can help develop the system.
The earliest tile drainage systems date back to Ancient Greece, Rome, and China, where people used drainage tubes made from the same clay used in tile production. They punched holes in the tubes to provide inlets for subsurface water and laid them under fields. The tubes met up at culverts to release the water into lakes, rivers, streams, and reservoirs, lowering the water table and allowing crops to thrive.
Excessive subsurface water can create a number of problems for crops. Roots have trouble growing through boggy, muddy ground and are more prone to infection with fungi and other microorganisms. Plants may fail to thrive and could be weak and subject to disease. Locations with large deposits of subsurface water, like former wetlands, can be unsuitable for crops because of the height of the water table. This makes tile drainage necessary to promote healthy deposits of soil in the fields.
Designers of tile drainage systems usually run soil tests to determine where the water table lies and what kind of soil is currently present in a given area. They can then develop an appropriate network of drainage tubes to collect and redistribute the water. One important consideration is the inadvertent release of water onto neighboring land, which can lead to disputes, as farmers may not appreciate having excess water dumped on their crops. Water pollution can also be an issue, as the tile drainage system may contain pesticides, herbicides, and other chemicals applied to the surface crop.
Farmers may need to install filtration to prevent clogs in their drainage systems. They can test the outlets periodically to determine if the water contains any harmful chemicals or microorganisms and to confirm that the groundwater is still draining appropriately. System checks can also include testing the soil to confirm that the moisture level is stable, finding potential issues like unusual concentrations of salts and chemicals that may arise as a consequence of the drainage system. If problems develop, the farmer can adjust the tile drainage system to compensate.