Sustainable groundwater resources development implies use of groundwat
er as a source of water supply, on a long term basis, in an efficient
and equitable manner sustaining its quality and environmental diversit
y. An understanding of the behaviour of a groundwater system and of it
s interaction with the environment is required to formulate a sustaina
ble management plan. Mathematical models supported by field informatio
n play a key role in assessing the future behaviour of a system to str
esses and to find effective operating conditions for sustainable devel
opment and management of groundwater resources. Basic principles for s
ustainable development are stressed and a brief review of two case stu
dies is provided to illustrate how a systems approach and its computat
ional framework of mathematical models can be used in addressing the m
ain issue of water allocation satisfying some of the technical and env
ironmental constraints.