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.