1. Drainage Systems
Surface
Subsurface

4. Surface Drainage
Surface drainage systems involve forming soil into shallow beds or deeper drains that can remove excess rainfall.
They are used mainly on flat to gently sloping land.
The slope of the drain must not be too shallow or else water can't be cleared adequately.
A slope that is too steep will result in undesirable scouring of the soil or erosion.

5. Examples of surface drainage
Shallow open ditches:
Deep open ditches
Bedding or humps and hollows

12. Subsurface drainage
Subsurface drainage systems have none of the disadvantages mentioned for surface drains; there is no loss of land, maintenance requirements are comparatively low, there is no safety risk to animals, people and machines and access for workers and machines is unrestricted.
Subsurface drainage can be achieved by using field tiles, plastic pipes (Nova-Flo), mole ploughing and subsoiling systems.

13. Subsurface drainage Field Tiles Mole drains Subsoiling
Plastic/Nova-flo
Clay pipes
Mole drains
Subsoiling

14. A mole and tile drain in situ

15. Installation of a mole drain being pulled through the backfill in a tile drain to allow easy interchange of water from the mole to the tile drain.

18. Subsoiling