The world water legislation has a common challenge: distribute fresh water resources in a fair, efficient and sustainable way. Traditionally, agriculture, industry, mining and municipalities have competed for these limited resources.

Mathematical models of global climate can reproduce many aspects of the physical climate system. General Circulation Models (GCMs) simulate physical processes in the atmosphere, ocean, cryosphere, and on land surface. Predictive scenarios on climate change will be applied to selected GCM models and their output will be used on the PRMS hydrologic simulations.

Water balance is known as the balance of water entering the system and the water that leaves within a specified time, but to understand it better we need to understand: what is a watershed? Unterstood as a whole, a unity, as a system, as the space bounded by the union of all the headers that form the main river through the territory drained by a single natural drainage system.

A monitoring system is a platform where level and quality records that describe groundwater resources are generated, made available and evaluated. These records are consistent, representative and long lasting. Managing the aquifer to local or regional level is required in order to have environmental managers with easy access for comprehensive, representative and reliable information.