Urbanization and Sources of Water Tundisi, 2010). This is the cost of the deterioration of the supply source. Official statistical data inform
3.2 Urbanization and Sources of Water Tundisi, 2010). This is the cost of the deterioration of the supply source. Official statistical data inform
The fast urbanization process of Brazil in the last that in Brazil, 90% of the population receives treat-
ed water in their residence. The remaining 10% uses the water supply, water treatment and wastewater
50 years produced several problems in all stages of
groundwater usually from local wells at each house treatment: supply of adequate water for the urban
or village. In the South and part of the South East, population, distribution of water and wastewater
deep wells (120-500m) pump water from the Gua- treatment. The urban development in Brazil has
rani underground reserve, a huge water resource increased the frequency of flooding, production of
(43.000 km 3 ) shared by Brazil, Paraguay, Uruguay sediments and deterioration of water quality. As
and Argentina. These are groundwaters of high the urbanization progresses, the impact increases
quality, so the cost of pumping is compensated by due to the fact that the urban infrastructure is
the small cost of water treatment.
not organized during the process: problems of The loss of the water supply services in Brazil is urban drainage, construction of roads, bridges approximately 30% in the pipelines after treatment. and channels, deforestation, are not included in However there are cities where 60% loss is common. the evaluation of urban plans (Tucci, 2006). The
This is due to the old infrastructure of the pipelines. significant impact on the maximum discharge is one
In some cases this infrastructure has more than 100 of the important consequences of the urbanization
years of age. It is also to be noted that there is no along with changes in the soil cover, increase of
information about the water quality in the pipelines floods and environmental deterioration in general.
after treatment and in the distribution process. It is in this general picture that the water supply services occur in Brazil.
3.3 Threats to Water Supply
The sources of water for public supply in Brazil
(Quantity and Quality)
from surface waters, in most cases, are located in the peri-urban regions, or groundwaters located in the
3.3.1 Competitive Uses of Water
urban area or in the rural areas. In general, the urban In Brazil 70% of the water available in the water- demand for domestic supply is usually sufficient
sheds is consumed by agricultural activities. In some from the small watersheds around the urban area.
regions (E. G. South East, South, Center West) com-
petitive uses for agriculture and industry threatens Brazil have specific discharges of 15 to 25 liters/sec/
Small watersheds (<500 km 2 ) in the South East of
the water supply for domestic use.
km 2 (Tucci, 2006). This is sufficient for the domestic
use of 200 liters/inhabitants/day. However as 3.3.2 Water Quality Degradation
urbanization develops, the water quality of surface The water quality degradation is one of the biggest and groundwaters deteriorates; therefore, it is problems of Brazil in the beginning of the 21 st Centu- necessary to use other sources of supply.
ry. The main causes of water quality degradation are: These sources can be far from the water treat-
• Deforestation. The lack of vegetation cover is a ment stations, generally located in the urban center.
cause for the deterioration and loss of quality of Therefore, this increases the need for more energy
surface and groundwaters. Deforestation also for the pumping of the water from the sources. There
impairs recharge to the aquifers.
is an additional problem that increases the cost of • Lack of wastewater treatment. In Brazil, only treatment: if the water source is well preserved with
47 % of the wastewater is treated. This produc- gallery forests, wetlands, or mosaics of vegetation,
es an enormous amount of organic matter that the cost of treatment for producing potable water is
deteriorates the water quality of surface and low. The figure is around 2 or 3 US dollars for 1.000
m 3 treated. This is the case when there is no need for • Surface drainage. The surface drainage of wa- chemical treatment. If the supply source is contam-
ters in most cases is full of solid waste residues inated, the chemical treatment (coagulants, activat-
(plastic, papers, glass, and organic matter). This
ed charcoal, and others) increases the cost to U$ 200
is another source of deterioration.
or U$ 300/1.000m 3 treated (Tundisi and Matsumura • Transport of sediment. Due to erosion in the soil