4. RESULTS

4.1 Desalination

Baja California Sur (BCS) depends on the availability of water for its development, and freshwater is very scarce due to the dry climatic conditions (Flores, 1998; Hernández, 1998; IRSC and SDSU, 2002). Most of the water found in BCS comes from aquifers that are recharged during the rainy season (Flores, 1998; López, 1998; IRSC and SDSU, 2002). However, BCS has the least amount of rainfall in the entire country, with an average of 180 mm of rain per year. Hurricanes and tropical storms (chubascos) bring large amounts of rain, sometimes up to 20% of the yearly rainfall, thus they represent the main source of water for aquifers to recharge (Flores, 1998).

A major challenge for the government is solving the problem of supplying water to the population. Population growth has led to an overexploitation of the aquifers in Cabo San Lucas and La Paz (López, 1998). Using the different growth scenarios for Loreto, Steinitz et al. (2005) show that pumping water out of the aquifer results in saline intrusion. How long it takes for this intrusion to take place varies with the different recharge and pumping rates. The study also shows that with the current population and a recharge rate of 2 Mm³/year, the wells used by the Loreto people will show signs of saline intrusion by 2025.

Although alternative water resources (i.e. sea water and brackish water) are becoming more accessible, the majority of the hotels obtain their water through municipal services, and only a very small percentage obtain their own water either from their own aquifer or desalinization plants (SEMARNAT-CNA, 2003). In Mexico there are 171 desalination plants with a total production capacity of 67,487 m3/d (781.1 L/s) and Baja California Sur is the second state with most plants. Fifty-three percent of these plants are used for tourism purposes and have a production capacity of 26,942 m3/d (311.81 L/s); 35% are owned by municipalities with a production capacity of 18,403 m3/d (213 L/s); and 12% are used for industrial purposes (Table I) (Fuentes-Díaz and Ramírez- González, 2003).