Mexico City, Mexico

Brief History

The city was built on an island of Lake Texcoco, and the Spanish colonists dug canals and tunnels in the surrounding Valley of Mexico in the 17th century because the lack of natural drainage led to periodic flooding from mountain runoff. The lake was subsequently drained, and the city rests on heavily saturated clay, which has begun to collapse since the early 20th century due to overextraction of the groundwater. The sinking complicates runoff and wastewater management and exacerbates flooding problems in the rainy season.

Water Management

Responsibility for Greater Mexico City's water management is divided among various governments. The federal government regulates the use of water resources. The state of Mexico treats waste-water, provides bulk water, and assists municipalities in providing water and sanitation services. The 60 municipal governments in the area are in charge of sanitation and water distribution. The federal district provides water and sanitation services to the city proper. The federal government takes a particular interest because of Mexico City's economic, political, and infrastructural importance to the country and the national welfare. These [Page 537]governments have instituted a water sustainability program and a green plan, which emphasizes water conservation. Both plans call for transporting groundwater from north of the city where the groundwater table is higher, constructing a significantly expanded stormwater drainage tunnel, and investing in wastewater treatment improvements.

An aerial view of the northern part of Mexico City and the Palacio de Bellas Artes (Palace of Fine Arts) reflects the statistic that Mexico City is the largest city in Mexico and the third most populated metropolitan area in the world. It also accounts for over one-third of the country's gross domestic product. The size and age of the city have led to a number of consumption and waste management challenges. About 85 percent of the wastewater in the city is discharged, untreated, into the north to irrigate crops; this presents serious health risks.

The National Water Commission is the federal body responsible for water resources management in the country, granting of wastewater discharge permits, and the supply of bulk water to Mexico City. The combined sewer system of Greater Mexico City collects municipal wastewater, storm water, and industrial wastewater, and it consists of 7,400 miles of pipe, 68 pumping stations, and numerous open canals, tunnels, underground collectors, dams, lagoons, and regulatory tanks, and intersecting with rivers. A single storm in the rainy season can produce a full tenth of the annual precipitation, necessitating significant capacity for the stormwater drainage system in order to avoid highly damaging floods.

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