The economic growth has fueled income disparity for the 3.86 million residents who live in the Monterrey Metro area (MMA).

Monterrey's rapid urbanization was driven in part by the development of assembly plants (‘‘maquiladoras’’) and expanded significantly with the 1994 signing of the North American Free Trade Agreement (NAFTA).

Monterrey has an elevation of 1,740 feet (530 m) above sea level and is located in a wide basin about 40 miles (64 km) across, surrounded to the north, west, and south by mountains.

[1] Monterrey's annual rainfall averages 584 mm (23 inches), with most of this total falling between June and October during the Atlantic hurricane season.

The watershed therefore ranks amongst the poorest regions in regards to per capita water availability with countries such as Syria, Israel, and Saudi Arabia.

Per capita water use estimates, including domestic, commercial, municipal, and industrial supplies, approach 290 liters per day per inhabitant for MAM.

[2] The José López Portillo ‘Cerro Prieto’, reservoir (ordinary storage capacity 393 mm3) was built in the early 1980s in the adjacent Rio San Fernando watershed to supply the domestic and industrial water demands of Monterrey Metro Area (MAM), and was the first case of inter-basin transfer of freshwater to cope with shortages in Mexico's northeast.

[1] According to data gathered by researchers at the Autonomous University of Nuevo León in Mexico, a medium annual precipitation of 538 mm/year within the Buenos Aires wellfield's catchment area is sufficient to recharge the aquifer while allowing for a discharge of around 1,600 L/s (400 gal.)

While this does occur, the wellfields are quickly and completely recharged back to artesian conditions by hurricanes that have passed through in recent decades.

[8] Water from the Río Bravo including the San Juan sub-basin are used as follows: 78% for agriculture, 12% for urban-public supply, 8% for industry, and 2% for Livestock.

Despite high coverage and efficiency rates, the city continues investing in expanding its capacity and improving its operations.

[2] The fast pace of economic growth for the Monterrey Metro Area (MMA) has placed an increasing toll on water quality as industry (ex.

Electronics) has discharged untreated industrial effluents and population has grown at a faster rate than the rest of Mexico.

Consequently, availability of clean water resources has been impaired by contamination from industrial and residential sources along the Rio San Juan.

Adding to the problem, a municipal wastewater treatment plant (WWTP) operated by SADM in Montemorelos, 45 miles southeast of Monterrey, is unable to make the capital investment required to expand unit operations and processes and therefore cannot meet the current needs of a growing community resulting in a heavily overloaded plant producing effluent that does not meet discharge standards of 30 mg/L BOD and Total suspended solids (TSS).

[10] Evaporation and droughts have played a significant role in Monterrey's ongoing struggle to acquire adequate quantities of water.

[2] An article from a 1999 issue of the publication, Borderlines, does a good job of describing why there is conflict between the states of Nuevo León and Tamaulipas.

Until the construction of the El Cuchillo project, the reservoir created by the Marte R. Gómez Dam, known in the U.S. as Sugar Lake, had provided a relatively clean source of drinking water to Reynosa, Tamaulipas and irrigation water to the 26th Irrigation District, which surrounds Sugar Lake.

Approximately 300 fishing families who earned their living from Sugar Lake lost their livelihoods, as have some local merchants and motel owners.

[11] In response to the contamination of the San Juan River, the government of Nuevo León initiated a sanitation program in 1994 entitled Plan Monterrey IV, which included the construction of three large wastewater treatment plants and the discharge of municipal effluents and treated water to other Rio San Juan tributaries.

SADM is an autonomous public utility under the government of the state of Nuevo León and is the acting water authority in throughout the MMA.