Along the roads in the Northern Negev, we pass areas where some trees are gathered. We use these places for picnic or rest places. We speak about "Liman".

A liman is a man-made low-lying water reservoir dammed by dikes that trap runoff water.

Trees planted in the liman depression survive on the gathered water and excess runoff flows through special channels to the wadi slope. Limans are built in the Negev areas where annual precipitation ranges between 50 to 300 mm. The term comes from the Greek word "limen", meaning a port or flooded area. It is also found in Hebrew sources.

These groves are placed in the beds of low-order Negev wadis (dry river valley, streambed that is dry most of the year, except in the event of heavy rains).

Limans are constructed in the wadi bed by positioning an earth dam plumb to the water-flow direction. Some of the flashflood water surging down the wadi is captured by the dam, serving to irrigate the trees planted in the wadi bed above the dam. The surplus runoff continues to flow down the wadi grade through an overflow.

Trees planted in limans include eucalyptus, tamarisk, acacia, mesquite (prosopis), pistachio, carob and date palm.

Various methods were developed by the KKL-JNF to collect runoff water. Structures, such as contour earth terraces, stone terraces in valleys and limans built from earth dams, were introduced into the area. These techniques capture the majority of watershed deposit, which then infiltrates the ground. The runoff collecting areas are, in effect, man-made landscape patches, whose moisture can be utilized to increase vegetative total weight of organism in a designated unit of area and variation in life forms. They can therefore serve to rehabilitate a desertified ecology.

By planting trees in sites enriched with harvested water, the region’s ecology is improved by the creation of a savanna-like landscape.