Submitted to: Encyclopedia of Soils in the Environment
Publication Type: Review Article
Publication Acceptance Date: June 12, 2004
Publication Date: October 27, 2004
Citation: Fausey, N.R. 2004. Drainage, surface and subsurface. In: Encyclopedia of Soils in the Environment. Rosenzweig, C., Powlson, D.S., Scow, K.M., Singer, M.J., Sparks, D.L., Hatfield, J., editors. Oxford, UK: Elsevier Ltd. p. 409-413. Technical Abstract: Soil drainage is a natural process by which water moves across, through, and out of the soil as a result of the force of gravity. Drainage is a component of theglobal hydrologic cycle; and streams and rivers are the naturally developed drainage conduits through which some of the water arrives at the land surface as precipitation is transported across the landscape and eventually to the oceans. this natural process also provides the water that supports seeps, springs, stream baseflow, and aquifer recharge. As water leaves the soil, air moves into the space previously occupied by the water; this process is called aeration. Adequate soil aeration is vital for maintaining healthy plant roots and the many beneficial organisms that live in the soil and require oxygen for respiration. As the proportion of water and air in the soil changes as a result of drainage, the ability of the soil to provide support and traction for animals and vehicles (traffic- ability) is altered as the strength of the soil changes with water content. The natural drainage of the soil may limit human use of the resource. Poor drainage has social and economic impacts. The drainage of the soil can be accelerated by the use of surface and subsurface drain age practices. Surface drainage diverts excess water from the soil surface directly to streams, thereby redu cing the amount of water that will move into and possibly through the soil. Subsurface drainage, pro vided by ditches and drainpipes, collects and diverts water from within the soil directly to streams.