Surface drainage system

1) Land smoothing

• Land smothering sometimes called land forming or grading is the operation of producing a plane land surface with a uniform slope.
• This practice is usually necessary to supplement the field surface drainage or irrigation.
• Rough grading is done with a bulldozer scraper. Final smoothing is done by a flat leveler or grader.

2) Open ditch system

• An open ditch drainage system consists of a network of channels draining a given watershed.
• It consists of field ditches which collect surface water directly and employ into outlet ditches.
• The outlet ditches collect water from field ditches or tile drains and also directly from the surface and empty into mains.
• Lateral outlet ditches are spaced about 1.5 km apart.

3) Random ditch system

• This is suitable for land with regular topography and with depressions scattered over the area.
• Field ditches more than 30 cm deep should transect as many depressions as feasible.
• Surface water from ponded areas may be removed by random field ditches or surface drains.

4) Bedding system

• The bedding system of surface drainage is designed, constructed and maintained so that surface water drains laterally from crowned stripes of lands into dead furrows then into collection ditches and finally, into an outlet.