Engineering Aspects of Land Drainage

Many of the engineering aspects of land drainage are applicable both to problems in humid areas and to those in arid regions. Surface ditches and subsurface drains either singly or in combination may be required for an adequate water disposal system. This chapter discusses open ditches that refer to large collection ditches or other channels which serve as outlets for tile drains or smaller field ditches. As distinguished from field ditches, open ditches generally drain large areas and involve several property owners. Open ditches are used as collectors of water from tile-drained farms because they can carry the quantities resulting from the surface and subsurface drainage of large land areas. The drainage type terrace is becoming an increasingly important drainage and water management tool throughout the Humid area of the United States. The drainage coefficient as a criterion for determining tile size is generally selected without regard to soil permeability, deep seepage, etc.