Geoscience Reference
In-Depth Information
in response to ever stricter emission controls
and environmental guidelines. As such, urban
sediments are likely to become less important
vectors for contaminant transfer through the
sediment cascade. The volume of sediment is
likely to remain high, however, unless controls
and guidelines for sediment quantity are intro-
duced. In contrast, in the developing world the
ever increasing rate of urbanization, coupled
with a lower level of environmental control, will
mean that sediments in urban environments
will continue to have a major impact on con-
taminant cycling and surface water quality.
In response to this, there needs to be a much
more sustainable approach to urban develop-
ment, and the consideration of sediments will
need to play a key role in this. Sustainable drain-
age systems (SuDS) are increasingly being seen
as the best way to manage surface water quality
and quantity (Charlesworth et al. 2003b). These
systems are designed to slow down the rate
of surface runoff, through the use of permeable
land surfaces (the 'porous' city). Currently, these
focus principally on the hydrological aspects
of urban environments, but potential exists for
integration of sediments into SuDS. For example,
the use of sediments as buffers for pollution
(e.g. in artificial wetlands) is currently being
pioneered in SuDS.
Climate change will also have a likely impact
upon the hydrology, and hence sediment trans-
port, of urban environments. Although numer-
ous studies on the impacts of climate change
on natural systems have been undertaken, little
consideration has been given to engineered
environments. Changes in climate may alter rain-
fall and snowmelt patterns, however, thereby
having an impact on urban drainage. Semadeni-
Davies (2004) modelled the impact of possible
future climate change on a cold region and city
and showed that frequency and volume of waste-
water flows in an urban environment would be
altered, with implications for drainage system
design and management.
