Managing Scarce Water Resources in Agriculture in West Asia and North Africa - Restorative Redevelopment of Devastated Ecocultural Landscapes - page 466

• Macrocatchment systems are characterized by having runoff water col-

lected from a relatively large catchment. Often, the catchment is a natural
range, steppe land, or mountainous area. Catchments for these systems are
mostly located outside the farm boundaries where farmers have no control
over them. Generally, runoff productivity per area is much lower than for
microcatchments. Water is often stored in surface or subsurface reservoirs
but may also be stored in the soil profile for direct use by crops.

There are several water harvesting (WH) systems, used in WANA. Small farm
reservoirs are especially popular in providing water for irrigation and for livestock.
This is a macrocatchment WH system that is low in cost and can be very efficient.
Harvested water in rainfed areas may be used for supplemental irrigation. Harvesting
rainwater for supplemental irrigation is popular in Turkey, Syria, and Tunisia. The
research work showed great potential in improving water-use efficiency in the pro-
duction of winter and summer crops such as wheat and vegetables. However, prob-
lems include slitting, evaporation, seepage, and management. Social issues include
water rights, farmer capacity, and land ownership. Upstream-downstream balance
and efficiency of water collection and use are among the most important issues. A
cistern is another WH system that has served human consumption and agriculture
for centuries and is still widely used in many areas like northern Egypt.
Jessour is a traditional system in Tunisia and still supporting figs and olives.
Preserving the systems and improving their agricultural return are subjects for sev-
eral research projects currently implemented. Another macrocatchment WH system
is the water spreading bunds that are constructed to help spread the water from a
stream that passes through the farm to various parts of the farm. They are usually
used for field crops. Among the widely used microcatchment WH systems are the
contour ridges, usually used for shrubs and field crops. They are formed along the
contour by maintaining good catchment surface conditions for runoff and down-
stream fertile cultivated areas. They are suitable for mechanized agricultural prac-
tices but require high precision in layout and implementation. A Negarim WH system
is small rectangle or diamond-shaped basins surrounded by small earth bunds. Part
of the area is used as a catchment where the lower part receives runoff water and
contains the crop. Negarim is used for growing trees or bushes.
Runoff strips WH is a technique that is applied on gentle slopes and used to sup-
port field crops, where production is usually risky or has low yield level. The farm
is divided into strips along the contour. One strip is used as a catchment and the one
downstream is a cropped one. The same cropped strips are cultivated every year.
Semicircular bunds WH is constructed by forming a bund along the perimeter of
semicircles, thus creating a basin behind the bund. The radius of the basin ranges
from 2.0 to 5.0 meters used for bushes or trees and sometimes for field crops. It can
be constructed manually or (now) by machines. Mechanizing the construction made
it possible to implement it on very large scale in steppe areas. They are suitable for
rangeland development and fodder production.
In the Syrian badia , a special implement mounted on a tractor (vallerani) was used
to construct semicircular bunds mechanically. The implement was able to provide
over 40 ha of bunds per day, creating over 5,000 bunds of varying size and spacing.