Negarim

• It is important to point out that it is not possible to grow trees where the biophysical conditions do not allow it (such as too shallow soils).
• Maintenance is required to repair damaged bunds; the site should be inspected after each heavy rainfall and any breakages must be repaired.
• Negarim interventions are usually done by hand because it is hard to mechanize the process once trees are already present.
• Soil type: Knowing the soil texture is fundamental to understanding and to designing successful micro catchment systems. Micro catchments on clay soils with medium to fine texture are the best to generate sufficient runoff, hence not subject to erosion.
• Soils that should be avoided: those that present cracks on drying, such as those , containing a high proportion of clay. very sandy soils or soils with poor structure should also be avoided.
• Adding mulch and organic matter: Adding these features in the basin area significantly increases the success in retaining water and improves soil fertility. However, if mulching is too expensive, it should be combined with grass strips or tree strips.

Material required:

• Line level or water tube to define the contour line
• Tape measure
• String or thin rope
• Peg
• Hoe (not strictly necessary)
• Shovel

Steps of Implementation

Water runoff infiltrates at the lowest tip of each rhombus, where the trees are planted at the infiltration pit. The surface of each basin functions as a catchment area for this infiltration pit. The size of every pit can vary according to plants’ water requirements but usually micro-catchment size can vary between 10 m2 to 100 m2. This depends on the tree species that has to be planted and on how many are meant to be planted over the surface area. A 3 x 3 m spacing is the minimum required for a Negarim catchment system.

Sometimes V shaped Negarims are more efficient than those that are diamond shaped, as the excess water can flow around the tips of the bund and reach the other V shaped Negarims (a bit like the as seen with demi-lunes), but water storage capacity will be less. V shaped Negarims are particularly useful when implemented where there are a small number of trees present around homesteads.

Click here for a detailed step-by step on how to build Negarim micro-catchments.

Diamond shaped:

Seedlings in the pits:

V-shaped:

Source of images.

Species selection
Plant species that are able to endure periods of intermittently wet or dry soil will benefit most from these kinds of interventions. These plants should have deep roots and be well accustomed to   local rainfall patterns. Tree seedlings of at least 30cm height should be planted after the first rain of the season. It is recommended to plant two types of seedlings: one in the bottom of the pit and one on a step at the back of the pit. If both survive, remove the weaker one at the beginning of the second season. Some species can be planted directly.

OTHER

The technique was originally developed in the Negev desert in Israel; in fact, the word Negarim comes from “Neger”, the Hebrew word for runoff. Nonetheless, the first report of this water harvesting technique comes from the south of Tunisia. This micro-catchment system is widely spread in Israel, especially among research farms in the Negev desert where the yearly amount of rainfall reaches 100-150 mm. However, Negarim and its variations are well known, and used also, in other arid and semi-arid areas like in North- and Sub-Saharan Africa.

This intervention contributes to:

Nigeria:
A good example of Negarim technique in a citrus plantation in Nigeria can be found here.

Kenya:
An interesting example of the use of Negarim in a Mango plantation, where the V shape works better than diamond shaped Negarims, can be found here.

• Click here for a step-by-step on how to build Negarim.
• A useful guide about indigenous knowledge in dry areas (including Negarim) can be found here.