Agriculture Reference
In-Depth Information
2.2 CASE STUDY
The case study is located in Xochimilco, one of the 16 boroughs (delega-
ciones) in Mexico City. The entire delegación Xochimilco has an area of
approximately 12.5 × 10
7
m
2
[12,13], of which 2.5 × 107 m
2
are urbanized.
The peri-urban areas (which can be legal or illegally urbanized) cover the
additional 3.0 × 10
7
m
2
, and serve for this study (Figure 2). These peri-
urban areas have a mixed topography with plain (1.26 × 10
7
m
2
) as well
as mountainous areas (1.74 × 10
7
m
2
). Xochimilco has a high biologi-
cal and cultural value due to the wetlands and chinampas. Chinampas are
rectangular land plots (usually 10 by 100 meters) surrounded by narrow
canals used for irrigation, fishing, transportation and as a water source.
The construction of chinampas dates from pre-colonial times and they are
used for agricultural purposes [12-15]. In general, they are considered to
be biologically very diverse and agriculturally very high productive areas
[12,16,17]. Farmers cultivating crops on a chinampa are called chinampe-
ros. It was listed as a World Heritage site in 1986 and as a wetland of
international importance in 2004 [12,18].
The trends of the past four decades confi rm a dual-pressure process
in Xochimilco, referring to progressive shortages of water and expansion
of other land uses. Natural systems (water interactions, soil, vegetation,
fauna) are under pressure by the urbanization. In recent years, water has
been injected into the aquifer and is used as the main water supply source
to retard groundwater depletion of Mexico City. The effl uent of a waste-
water treatment plant, Cerro de la Estrella, is discharged to the surface
water bodies of Xochimilco to ensure that water remains [12]; if this is not
done, the surface water bodies will dry as the natural springs have been
depleted [19]. Nevertheless, there are no signs that the drying effect on
both groundwater and surface water can be countered, not to mention the
environmental pollution that takes place due to the discharge of untreated
wastewater by households living near or on the chinampas. If this trend
continues, the expected scenario for the area is that there will be a large
water defi cit in the next century [20]. The peri-urban zone has been ex-
periencing problems with services for water, wastewater and solid waste
management. This situation will be aggravated due to the unregulated ur-
banization, defi nitely.
