development in an attempt to identify and quantify the impacts of this development
on surrounding water or downstream water (Rodriguez et al. 2013). However, the
dynamics of urban development strategies vary throughout the world. In developing
countries, urban growth takes place along large-scale areas which include entire
cities built in very short time periods such as new projects to develop cities in China.
Contrarily, urban growth in developed countries is often locally scaled, with construction of single house estates or individual buildings in a spatial vicinity with the
help of modern monitoring technologies that offer perspective regarding the surrounding environment (Blocken et al. 2013). In spite of that, having a comprehensive metrics for evaluating urban expansion is rather tricky; however, several studies
tackling this issue have considered several approaches such as population density,
growth rate, spatial geometry, total impervious areas, accessibility, and aesthetics
(Bowyer 2015).
Urban landscape has a noticeable influence on hydrological and meteorological
processes. Urban expansion increases artificial drainage systems that alter significantly the amount and route of runoff generated from certain vicinity (Dams et al.
2013). The increase in particulate matter and artificial thermal characteristics from
urban areas affects the rainfall pattern and may lead to convective summer thunderstorms and downwind precipitation (Jin and Shepherd 2005). Moreover, sewage
treatment facilities and sewerage conveyance system discharge huge quantities of
pollutants into the water bodies that alter the natural composition of water and
change the dynamic of the aquatic ecosystem (Leung and Jiao 2006).
The implications of urban expansion on water quality have been the focus of
several researches, in order to find out some mitigation strategies to reduce the risk of
water quality of rivers and streams. Effluents from point sources and runoff from
non-point sources increase the pollution load in rivers with diverse contaminants
including heavy metals, major nutrients, and organic matter. Recently, efforts have
shifted to address more urgent and crucial issues such as synthetic chemicals, nano
pollutants in rivers, and the fate and transport of pollutants in general (McGrane
2016). In developed countries, steps are being taken to treat storm water and runoff
as a renewable resource. Sustainable management strategies are being implemented
to make use of this resource and at the same time reduce its dire effects on river
water, which would help to restore and enhance river water quality (Blocken et al.
2013). In Canada, urban ponds are being used increasingly to retain storm water
runoff to protect water systems and reduce downstream flooding. This has become a
prominent feature in many parts of Canada including Ontario and Toronto, which
has about 500 ponds within its realm. Moreover, samples taken from some of these
ponds indicated that they could improve water quality downstream by retaining
pollutants; also the in-pond vegetation can help in reducing nutrient content (Drake
et al. 2016).
Agricultural practices like excessive use of fertilizers to obtain high product yield,
use of herbicides and pesticides, and impractical irrigation practices also lead to
surface water contamination. These applications increase the flux of sediment,
nutrients, pathogens, and various chemical compounds, which alter the composition
of river water and affect the aquatic ecosystem.
2 Landscape Perspective to River Pollution: A Case Study of Bentong River,. . .
21
on surrounding water or downstream water (Rodriguez et al. 2013). However, the
dynamics of urban development strategies vary throughout the world. In developing
countries, urban growth takes place along large-scale areas which include entire
cities built in very short time periods such as new projects to develop cities in China.
Contrarily, urban growth in developed countries is often locally scaled, with construction of single house estates or individual buildings in a spatial vicinity with the
help of modern monitoring technologies that offer perspective regarding the surrounding environment (Blocken et al. 2013). In spite of that, having a comprehensive metrics for evaluating urban expansion is rather tricky; however, several studies
tackling this issue have considered several approaches such as population density,
growth rate, spatial geometry, total impervious areas, accessibility, and aesthetics
(Bowyer 2015).
Urban landscape has a noticeable influence on hydrological and meteorological
processes. Urban expansion increases artificial drainage systems that alter significantly the amount and route of runoff generated from certain vicinity (Dams et al.
2013). The increase in particulate matter and artificial thermal characteristics from
urban areas affects the rainfall pattern and may lead to convective summer thunderstorms and downwind precipitation (Jin and Shepherd 2005). Moreover, sewage
treatment facilities and sewerage conveyance system discharge huge quantities of
pollutants into the water bodies that alter the natural composition of water and
change the dynamic of the aquatic ecosystem (Leung and Jiao 2006).
The implications of urban expansion on water quality have been the focus of
several researches, in order to find out some mitigation strategies to reduce the risk of
water quality of rivers and streams. Effluents from point sources and runoff from
non-point sources increase the pollution load in rivers with diverse contaminants
including heavy metals, major nutrients, and organic matter. Recently, efforts have
shifted to address more urgent and crucial issues such as synthetic chemicals, nano
pollutants in rivers, and the fate and transport of pollutants in general (McGrane
2016). In developed countries, steps are being taken to treat storm water and runoff
as a renewable resource. Sustainable management strategies are being implemented
to make use of this resource and at the same time reduce its dire effects on river
water, which would help to restore and enhance river water quality (Blocken et al.
2013). In Canada, urban ponds are being used increasingly to retain storm water
runoff to protect water systems and reduce downstream flooding. This has become a
prominent feature in many parts of Canada including Ontario and Toronto, which
has about 500 ponds within its realm. Moreover, samples taken from some of these
ponds indicated that they could improve water quality downstream by retaining
pollutants; also the in-pond vegetation can help in reducing nutrient content (Drake
et al. 2016).
Agricultural practices like excessive use of fertilizers to obtain high product yield,
use of herbicides and pesticides, and impractical irrigation practices also lead to
surface water contamination. These applications increase the flux of sediment,
nutrients, pathogens, and various chemical compounds, which alter the composition
of river water and affect the aquatic ecosystem.
2 Landscape Perspective to River Pollution: A Case Study of Bentong River,. . .
21