Land leveling is the process of equalizing the ground to eliminate the basin on the land, but without altering the topography see Figure 8. 8. This is often done after land leveling is done, because the topography is irregular. On the land, surface drainage system can have two different layouts, the random drainage systems and drainage systems in parallel.
Figure 26. Alignment of Land Surfaces
a. herringbone system
Consisting of lateral drainage pipes arranged in parallel and connected to the main pipe by making a certain angle, usually from both sides. The main pipe or main sub placed on the lower land or land on the slope that is great or valley.
Figure 27. Scheme of the drainage network fishbone
b. Gridiron systems
Gridiron drainage system consists of pipes lateral drainage lines are laid in parallel and connected to the main pipe vertically, usually on one side. The system is suitable for areas of land in lower altitudes with the same size of land.
Figure 28. Drainage Systems Gridion
c. Drainage systems Interception
The drainage system can accommodate the interception of seepage water that flows into the land which lies lower or at the bottom. Interception pipe is usually placed on top and wet areas are determined from observations of the initial drainage.
Figure 29. Drainage Interception System