|Regenerative Agriculture Technologies for the Hill Farmers of Nepal: An Information Kit (IIRR, 1992, 210 p.)|
|Natural resources and their enhancement|
Runoff diversion (Mal Tarkaure) for landslide control
Gullies and landslides pose threats to sloping farms. Gullies tear away the cultivated terraces, and landslides take away the terraces either from the bottom or the sides. The reason for gully formation and landslides is generally poor runoff management.
During the rainy season, water collected in the house yard flows down to the terraces causing rills. When not taken care of in time, the rill becomes deeper, forming a gully which can further result in landslides. This process also takes place when the runoff water is thrown to a side of the farm carelessly. To avoid such problems, well-planned runoff diversions channels should
Every household should have a small runoff diversion channel of about 2 ft wide and 1 ft deep. Generally, the main diversion is also a trail that is almost in level with the contour. The small diversion channels coming from the households joins this trail-cum-main drain. Therefore, the main drain provides access for runoff diversion for the community as a whole. The main drain can be several hundred meters long, ending in a small stream or a safe place. The effected community should be involved while making such layouts.
· Generally, the diversion channel can be constructed on hard ground. Otherwise, the channel can be paved with rocks or planted with grasses so that the concentrated flow of the run cannot scour the channel, causing erosion.
· The sides of the drain should be planted with shrubs and trees. Generally, farmers plant both thorny shrubs and fodder trees.
Maintenance measures have to be carried out each year. The channel needs to be cleaned so that the run-off water does not get blocked and cut slopes on the lower terraces. When the channel breaks or gets cut, it should be quickly fixed with rock and clay works, and shrubs and trees planted immediately. Community efforts are necessary to maintain the main drain and should be given the responsibility of carrying this out. It should be noted, however, that increase in forest cover in non-cultivated areas reduces runoff, eventually reducing maintenance needs.