Sustainable Water Management - Sustainable Practices in Geoenvironmental Engineering - page 79

world, although water quality is in general good, water use is increasing. Many cities
lose up to 40% of their water through leaking sewer and distribution systems (United
Nations Economic Commission for Europe, 1998; Bertram et al., 2002). In developing
countries, water is both scarce and unhealthy due to rapid urbanization. Water manage-
ment practices must be improved to reduce scarcities and impacts on ecosystems. Factors
affecting leakage include system age, main type and pressure, soil type, climate and
topography, and local value of water. A program by the water regulator in England and
Wales reduced water leakage from 29% to 22% between 1992/1993 and 2000/2001.
Water can also be used as geothermal energy. The sites are mainly in volcanic and seis-
mic regions. Countries such as Iceland, Spain, France, Hungary, Japan, Mexico, Russia, and
the United States (in the states of California and Hawaii) are exploiting this form of energy
(Chamley, 2003). Iceland uses this form of energy for domestic heating, greenhouse culti-
vation, and electricity production. Exploitation can be from the steam of geysers or very
hot liquids of 100°C or more. Cooled water can then be reinjected for reheating and reuse.
Geothermal systems can also be utilized where groundwater at a depth of 100 m is about
15°C. This is warm enough to heat buildings in the winter using a heat pump principle.
There are some hurdles that need to be overcome in exploiting geothermal energy. These
include (a) transportation of warm water over long distances without major loss of heat,
and (b) induced earthquakes. The advantages in the use of geothermal energy include
(a) negligible amounts of contamination produced, (b) little or negligible production of
greenhouse gases, and (c) almost no waste production.
As water serves many purposes, these demands can be highly competitive. Agriculture
is an intensive user and thus water use must be more eficient per crop grown. Since eco-
systems can be depleted for human water use, public awareness of these links is necessary
if conservation and sustainability goals are to be achieved. In parallel with WSSD (2002),
the WaterDome , which was organized by the African Water Task Force (AWTF) highlighted
the importance of water and sustainable development—an imperative that was not really
addressed in the Summit in Rio in 1992. They addressed the link of poverty with lack of
water and sanitation, and the importance of hydroelectric dams as a means of electricity
generation.
3.3 Water Quality Characterization and Management
3.3.1 Classes of Contaminants Characterizing Chemical Stressors
Organic contaminants in water will deplete oxygen required for ish and other water
organisms. These contaminants generally originate from the discharge of domestic and
industrial wastewaters into water bodies. Increases in population density near these water
bodies generally result in corresponding increases in the levels of organic matter in the
water. High levels of biological oxygen demand (BOD) or chemical oxygen demand (COD)
deplete the oxygen in the water through microbial degradation of the organic matter. This
depletion of oxygen can lead to severe effects on aquatic biota. Color, taste, and odor of the
drinking water may also be affected.
Farming and agricultural activities have added contaminant sources such as insecti-
cides, pesticides, fungicides, and fertilizers. It has been estimated that 38% of the agricul-
tural land cultivated in the world has been damaged by agricultural practices by aspects