Chapter
4
4.1· The Water Resources System
The water resources system whose configuration is shown in Fig. 4.1 will
be used as an illustration of the application of the algorithm described in
Chapter 3. The configuration represents the energy and irrigation needs of
a hypothetical river basin [hereafter called the model for development
(MD) river basin] and is similar to the existing configuration in the Maule
River Basin, which lies in Central Chile between latitudes 35°10" S and
36°20" S [McLaughlin, 1967; Wallace, 1966].
The MD river basin lies in a semiarid region that has an annual rainfall
of about 29 in. The bulk of the rainfall (about 60%) occurs in the winter.
In the MD river basin approximately 1.5 million acres are irrigated, and
half of the irrigation waters are surface waters. Five hundred forty million
kilowatt-hours of hydroelectric energy are generated annually. Because of
projected increasing industrialization and depletion of ground-water resources, demands for hydroelectric energy and irrigation surface water will
increase. To meet the prospective demands on the surface-water resources,
new impoundments are proposed for construction at technologically feasible
sites in the river basin.
Four dams (represented by nodes 1, 4, 22, 28) are used for flow regulation. Ten unregulated streams (represented by arcs Z7i, C/2, ... , Uio) are
the physical inputs to the system. The specified schedule of increasing
energy and irrigation needs of the river basin can be met by building a
suitable combination of dams. Three possible dam sites exist (represented
by nodes 14, 21, and 27) and any of three sizes of dam may be built at
each site. A planning horizon of 50 yr has been chosen, and the problem is
106
4
4.1· The Water Resources System
The water resources system whose configuration is shown in Fig. 4.1 will
be used as an illustration of the application of the algorithm described in
Chapter 3. The configuration represents the energy and irrigation needs of
a hypothetical river basin [hereafter called the model for development
(MD) river basin] and is similar to the existing configuration in the Maule
River Basin, which lies in Central Chile between latitudes 35°10" S and
36°20" S [McLaughlin, 1967; Wallace, 1966].
The MD river basin lies in a semiarid region that has an annual rainfall
of about 29 in. The bulk of the rainfall (about 60%) occurs in the winter.
In the MD river basin approximately 1.5 million acres are irrigated, and
half of the irrigation waters are surface waters. Five hundred forty million
kilowatt-hours of hydroelectric energy are generated annually. Because of
projected increasing industrialization and depletion of ground-water resources, demands for hydroelectric energy and irrigation surface water will
increase. To meet the prospective demands on the surface-water resources,
new impoundments are proposed for construction at technologically feasible
sites in the river basin.
Four dams (represented by nodes 1, 4, 22, 28) are used for flow regulation. Ten unregulated streams (represented by arcs Z7i, C/2, ... , Uio) are
the physical inputs to the system. The specified schedule of increasing
energy and irrigation needs of the river basin can be met by building a
suitable combination of dams. Three possible dam sites exist (represented
by nodes 14, 21, and 27) and any of three sizes of dam may be built at
each site. A planning horizon of 50 yr has been chosen, and the problem is
106