Geography Reference
In-Depth Information
worth remembering that much of the land now in park use could not be developed
for houses because of the presence of steep gullies, marshy depressions, plateaus
where water could not initially be delivered, or along rivers that flooded, although
too much development has been allowed in river valleys which suffered the conse-
quences in a major flood in June 2013. However in another sense the city is a leader,
for by 2016 the city will complete a Greenway (GW
2014
) around the city, a 140 km
cycle and pedestrian pathway system encircling the city that has amenities at vari-
ous points. This will connect 55 communities and link to other parks and paths in
the city. It is billed by the city as the largest green urban pathway in the world.
The concept of connecting up as many of the green and recreational areas in a
city as possible has been taken a stage further by the creation of
ecoducts
across,
or sometimes under, major transport arteries, with Utrecht and other cities in the
Netherlands, in particular, providing many examples. Some ecoducts are designed
primarily to allow all fauna to cross from one area to another, with a construc-
tion above a road providing better sight lines and protection from predators; others
are species-specific, such as the dormouse passages over roads near Llantrisant in
South Wales. Some ecoducts are controversial as they are expensive, such as those
which cross the four lane highways in Canada's Banff park and cost up to C$ 3 mil-
lion each. Less open to criticism are the human-orientated ecoducts formed by
pedestrian bridges or bikeways over major roads or rails, to prevent them acting as
barriers to movement between different parts of urbanized areas. In a few cases the
roadways have even been covered over, so that the formerly open road, rail or canal
route is transformed into a short tunnel. One of the best examples of this can be
seen in Vienna where 2 miles of freeway from the inner city is buried, with a treed
area above that contains a series of roof vents to provide the necessary ventilation
for the road.
Another general trend in the environmental rehabilitation of towns and cities has
been the conscious decision to encourage the
rehabilitation of contaminated areas,
including water courses.
Governments have increasingly tried to direct develop-
ment on to brownfield sites
—
the old industrial or residential sites that have been
abandoned—rather than on greenfield sites on the edge of towns and cities in order
to increase urban density and decrease sprawl. Until the creation of new environ-
mental laws in most western countries from the 1970s, material hazardous to human
health was often dumped by industrial activity in rivers, ponds or nearby vacant
ground. Increasingly governments try to ensure that such activity is prohibited, with
large fines for offenders, while in many countries new mines or industrial plants
have to set aside money for clean-up operations once the activity closes. Although
there has been a great deal of progress in this area, the numbers of polluted sites in
many countries is still staggering. For example, in June 2012 a Canadian federal
government agency reported that there were 22,000 federal contaminated sites in
the country, some were properties that were a direct result of government activities,
but many others were inherited from old industrial activities that had been aban-
doned. Although a 15 year programme of rehabilitation from 2005 budgeted for
$ 3.5 billion to be spent over 15 years to resolve these problems, the 2012 report
estimated it that would take at least $ 7.7 billion to clean up these sites, showing the
