Mexico City is struggling with problems related to social inequality, mobility and the environment. Because the city is built on a former lake and is positioned in a valley, the effect of climate change will strongly increase the environmental problems of smog, water quality, water safety and urban heat islands. In the current situation, drinking water is extracted from surrounding nature areas and wells (both legal and illegal). The existing sewer cannot handle peak rainfalls in summer, causing streets and homes to be flooded. In contrast, the dry periods in the city are often very hot and the air quality is poor. Mexico City has a subsidence of 30 cm each year, because of growing water extraction.
The problems related to water, air quality and urban heat islands can partly be solved by increasing the capacity of rain water buffering and infiltration within the city, combined with a strategy to green the city. Doctores could be developed into an example district for sustainability, in which experiments can be done to test this new approach.
Both new and existing courtyards are suitable for collecting rainwater from the roofs. The rainwater has good quality because it has not touched the streets yet. Water can be collected in a collective rain barrel and can be used to water the gardens or to wash cars. Because of the collective character of the gardens, the quality of the water can be well controlled. Better infiltration of water within the streets will avoid further drying of the soil. A specially designed concrete tile with perforations of different diameters ensures that the street can be well used for traffic and all kinds of program and at the same time enables infiltration. A variety of trees and plants is grown in the perforations. With the tile, the degree of greening can be determined for each street, residential streets will be greener than streets with a major infrastructural function. At prominent places within Doctores filter parks are made, in which water can be buffered. The quality of the water is improved by helophyte filters, which decrease the pressure on filter installations just outside the city. The filter water parks are important public spaces and are combined with a swimming area, water playground or ecological park. The collective gardens, green streets and filter parks are well connected and function as one flexible system for water, ecology and public program.