ABSTRACT
During theAztec period, excess water was the problem rather than the lack of it. Tenochtitlan City (the ancient name of Mexico City) was designed to manage floods by controlling the water level in lakes and canals (used
also as a means of communication) through a complex set of sluices. In 1942, when the City was made up of 2 million people, water had to be imported from the Lerma River, located in a basin 100 km from and 300 m above Mexico City level, and in 1951 from the subsoil of this same basin. In 1975 the population reached 7 million, and surface water had to be imported from the Cutzamala region, 130 km away and 1,100 m below Mexico City’s level. At the present time, Mexico City, uses 85.7 m3/s of water (Figure 2), 48% of which is supplied through the network system, 19% directly pumped from local aquifer by farmers and industries and the rest, 9%, corresponding to treated wastewater that is being reused. First use water (78 m3/s) comes from (Jimenez, in press-a):
• 1,965 wells that are pumping 57 m3/s from the local aquifer
• local rivers located in the southern part (1 m3/s) • the Lerma region (5 m3/s) • the Cutzamala region (15 m3/s)
Supplied water is for municipal use (74%), fresh water irrigation (16%), self-supplied industries (2%) and for non drinking water reuse (1%).Agriculture takes place in 40,000 ha of the Valley. Reuse is performed to refill recreational lakes, parks and green area irrigation, car washing, environmental restoration, fountains and for industrial uses. Water service is provided through the network to 89% of the population, and so there are 2.3 million people receiving water through water tanks at a high price and with a lower quality. Due to leaks, 40% of the water distributed to the population (62 m3/s) is lost; therefore the actual per capita supply is 153 L/d instead of 255 L/d.
