Urbanization and the Geoenvironment - Sustainable Practices in Geoenvironmental Engineering - page 242

CFCs can be replaced with other gases. Reforestation and increases in forest growth
will increase carbon dioxide sink capacity. Sustainable energy generation and low-energy
consuming practices for transportation, heating, and so on must be practiced, although
they are not without political implications. Green buildings for houses and commercial
use to reduce energy use are now being constructed. Eco-building codes and architecture
will need to be developed and improved. Santa Monica, California, for example, replaced
city building electricity with geothermal electricity in 1999, and Austin, Texas, offers a
GreenChoice option for consumers that includes renewable electricity from wind, solar, or
biogas (Portney, 2003).
Biodiesel is gaining popularity as a renewable fuel. It is made from the oil of various
crops including palm, mustard, rapeseed (canola), sunlower, and soybeans (Weeks,
2005). Rapeseed, which produces the highest yield, is the most common source in Europe,
whereas soybean is the most common in the United States. Waste frying oil can also be
used. All emissions (with the exception of NO x ) are reduced when biodiesel is burned in
comparison to petroleum diesel. Spills are of less impact since biodiesel degrades faster in
the environment. In addition, wastewater and solid waste generation rates are lower.
7.4.4 Minimizing Impact on Biodiversity
The encroachment of cities into natural landscape areas has a detrimental impact on biodi-
versity. To mitigate this impact, one needs to have access to a base inventory of the natural
places and biodiversity existing within the target areas so as develop a basis for determina-
tion of the nature and extent of potential impacts. This base inventory also forms the basis
for planning for urban expansion that is sensitive to the need to (a) prevent introduction
of invasive species, (b) protect endangered species, and/or (c) protect the natural habitats.
Cities such as San Francisco, California, are looking at ways to understand biodiversity,
protect, and restore the natural ecosystems, protect sensitive plants and animals through
education, purchasing green spaces, developing pest management programs, and enforc-
ing environmental regulations (Portney, 2003).
7.4.5 Altering Transportation
Although some might argue otherwise, there is a consensus that automobiles have facil-
itated transport and contributed to economic progress. However, there are many envi-
ronmental and sustainability issues related to transportation that need to be addressed.
The method of delivery of urban transportation needs (buses, cars, trucks, etc.) require
modiication if ozone production is to be reduced. Cities should be planned in an opti-
mal manner to minimize transportation requirements. Bicycles and walking should be
facilitated instead. Walking is a completely sustainable transportation mode. Copenhagen
was one of the earliest cities to promote pedestrian streets (Vega, 1999). Numerous cities
within Europe are promoting pedestrian areas and others such as Amsterdam are promot-
ing cycling. Public transportation will also need to be improved. Electric cars are another
alternative as no emissions are produced.
7.4.6 Brownfield Redevelopment
New policies are being developed in various countries to reduce greenield consumption.
In the United Kingdom, regulations require that 60% of all housing must be on brownields