in 2004. In function of this increase of demand for water in the region, the number of perforateed tubular wells in the region passed of 1.000 wells in the end of decade 70 for about 6.000 in year 2004, being about 70% these wells currently in activity. As in the majority of the crsticas areas of the world, in the region of Irece it does not have great superficial water sources, of form that the underground water is the most important source of supplying for the agricultural and animal and complementary use for the human and industrial use. Beyond the farming activities and fast demographic growth in the region, the occurrence of drawn out dry periods, irregularity and me the space distribution of precipitations, with annual average between 500 and 600 mm/ano, has extended the demand for underground water, with consequent increase of the number of perforateed wells and degradation of the fretico level of the water-bearing one throughout last the 20 years. The water-bearing crstico of the region of Irece is water-bearing a free associate to the neoproterozicas carbonticas rocks. Of the Group It joins in the state of the Bahia (Bambui Group in Minas Gerais), whose morphology was sculptured by successive cycles of aplainamentos, resulting a plateau dissecado with average altitude around 800m.
The water-bearing one presents piezomtrica surface following the regional topography and underground flow in direction to the gutters of the rivers Green, Alligator and its main tributaries. The estimate of values and conditions of recharge of water-bearing crsticos has been a challenge for the hidrogelogos of some parts of the world, especially in regions where it has great variation in the space and secular distribution of precipitations. In general way, the values of the recharge and discharge have been monitored from use of chemical, isotpicos tracers, physical measures of the values of liquid discharges in springs, freticos levels (NF) from monitoramento of wells and regional precipitations.