Managing Scarce Water Resources in Agriculture in West Asia and North Africa - Restorative Redevelopment of Devastated Ecocultural Landscapes - page 453

a) Increasing the productivity per unit of water consumed and or depleted;
through:
Changing crop varieties to new crop varieties that can provide increased
yields for each unit of water consumed, or the same yields with fewer
units of water consumed.
Crop substitution by switching from high- to less-water-consuming
crops, or switching to crops with higher economic or physical produc-
tivity per unit of water consumed.
Deficit, supplemental, or precision irrigation . With sufficient water
control, higher productivity can be achieved using irrigation strategies
that increase the returns per unit of water consumed.
Improved water management to provide better timing of supplies to
reduce stress at critical crop growth stages leading to increased yields
or by increasing water supply reliability so that farmers invest more in
other agricultural inputs leading to higher output per unit of water.
Optimizing non-water inputs . In association with irrigation strategies
that increase the yield per unit of water consumed, agronomic practices
such as land preparation and fertilization can increase the return per
unit of water.
Policy reform and public awareness . Policies related to water use and
valuation should be geared towards controlling water use, reducing
water demand, safe use and disposal of water, and encouraging the col-
lective approach in using and managing water by users. These policies
must be balanced, workable, and feasible, otherwise they will be dif-
ficult to implement and/or enforced.
b) Reducing nonbeneficial depletion; by:
Reducing evaporation from water applied to irrigated fields through
specific irrigation technologies such as drip irrigation, or agronomic
practices such as mulching, or changing crop planting dates to match
periods of less-evaporative demand.
Reducing evaporation from fallow land, decreasing the area of free
water surfaces, decreasing non- or less-beneficial vegetation, and con-
trolling weeds.
Reducing water flows to sinks—by interventions that reduce irrecover-
able deep percolation and surface runoff.
Minimizing salinization of return flows—by minimizing flows through
saline soils or through saline groundwater to reduce pollution caused by
the movement of salts into recoverable irrigation return flows.
Shunting polluted water to sinks—to avoid the need to dilute with fresh-
water, saline, or otherwise polluted water should be shunted directly to
sinks.
Reusing return flow.
c) Reallocating water among uses:
Reallocating water from lower- to higher-value uses . Reallocation will
generally not result in any direct water savings, but it can dramatically
increase the economic productivity of water. Because downstream