as Morocco), and to analyze the potential impacts on cropping pattern, irrigation water demand,
welfare, and water agency revenues for each alternative strategic policy.
Methodology and Data
Agricultural Sector Model of Egypt (ASME) (Siam) and Agricultural Sector Model of
Morocco (ASMM) (Doukkali) are used to conduct parallel research on the subject. Both are
static partial equilibrium (PE) models in which social welfare, in the form of consumer and
producer surplus from agricultural based commodities, is maximized subject to various resource,
technical, and policy constraints. In order to achieve the maximized welfare, equilibrium demand
and supply is required, i.e. the demand and supply balance of the agricultural products will be the
key equations to solve for activity levels.
Water is a limited input in both models. The supply of irrigation water is assumed to be
fixed and does not be fluctuating over time. The reality, of course, is that there is some
fluctuation from one year to another. We also realize that irrigation policy will affect not only
welfare in the agricultural sector, but the economy as a whole. Water policy in agricultural sector
also affects other sectors of the economy, such as commercial, industrial and municipal
residential consumption, and protection of the ecosystem. The agricultural sector models used
for this research only encompass that sector and thus ignore water related benefits and costs in
other sectors.
The Positive Mathematical Programming Method (PMP) approach, as suggested by
Howitt (1995), has been employed to calibrate the models. In conventional mathematical
programming, arbitrary constraints are added to avoid too specialized solutions and calibrate the
model to the observed situation. However, PMP allows calibration of any linear or non-linear