- Introduction
Urbanization can be defined as a multidimensional process characterized by the increasing concentration of populations in urban centers, leading to significant shifts in socio-economic structures, land use patterns, and cultural dynamics. This process often involves the transformation of rural landscapes into urbanized environments, driven by factors such as industrialization, economic opportunities, and migration patterns.
In most urban places, water stress has grown to be a serious issue. The improvement of water resources is crucial for human livelihood, industrial sector expansion, and environmental sustainability. Human life depends on water. Urbanization, pollution, and climate change all have an impact on the amount and quality of surface and groundwater, which in turn affects water availability. One of the primary factors influencing the supply and usage of water in metropolitan areas is urbanization. Water quality is significantly impacted by urbanization since it converts natural landscapes into constructed ones. This process creates new pollution sources and modifies hydrological cycles.
- Urbanization and its effect on water quality
2.1. Runoff transformation
The dynamics of surface runoff and the process of runoff generation are greatly impacted by the existence of urban areas. Roads, walkways, and buildings are examples of the impermeable surfaces that are frequently seen in urban environments. When it rains, these surfaces increase surface runoff because they stop water from penetrating the ground. Rainwater runoff rises as natural landscapes are replaced by impermeable surfaces. Pollutants including oils, heavy metals, and sediments can enter aquatic bodies directly through this runoff.
2.2 Altered hydrology
Natural water flow patterns are altered by urbanization. While less infiltration has an impact on groundwater recharge, increased floods can destroy banks and stir up contaminants. Local ecosystems and flow patterns are impacted by urbanization’s alteration of the natural hydrology. Urbanization-related increases in impervious cover change the way water naturally cycles. The most noticeable consequences of increased imperviousness are changes in the size and form of urban streams, followed by a decline in water quality. Alterations in the aquatic environment associated with these hydrological changes greatly compromise the normal functioning of waterways (Mercy Kintu, 2019)
2.3 Temperature changes
By increasing the water temperature in adjacent rivers and lakes, urban heat islands can harm aquatic ecosystems and cause issues like algal blooms. Trees and green areas, which can cool the atmosphere through shade and evapotranspiration, are frequently removed as part of urbanization. Natural cooling is reduced when there is less greenery. Urbanization changes land cover from vegetation to impervious surfaces, which can modify local microclimates and increase overall temperatures (Toby N Carlson, 2000).
2.4 Loss of green spaces
Stormwater management and pollution filtering are aided by vegetation. Water quality deteriorates as a result of the loss of these natural filtration systems brought on by urban development. Natural ecosystems are being destroyed for development as cities grow, endangering biodiversity and causing the extinction of plants and animals. The loss of vegetation reduces this carbon sequestration capacity, contributing to higher atmospheric CO2 levels (Vijaykumar Bejagam, 2024).
2.5 Pollution
Water bodies may be directly contaminated by waste from industries, sewage treatment facilities, and other industrial establishments. Road salt, fertilizers, and pesticides are examples of urban activities that contribute to disperse pollution that enters waterways by runoff. Kathmandu Valley primarily faces health challenges, compound effects of Air and Water pollution (Peng Jian Dong, 2024).
2.6 Pathogen contamination
Sewage leaks, pet waste, and trash can all contribute to the spread of germs, viruses, and other pathogens into adjacent water bodies through urban runoff. Public health issues may arise as a result of this contamination, rendering the water unfit for drinking and recreation.
- Conclusion
Urbanization poses significant challenges to water quality by increasing pollution, altering hydrological patterns, and disrupting natural filtration systems. Impervious surfaces, industrial activities, and increased runoff contribute to higher levels of pollutants like chemicals, heavy metals, pathogens, and nutrients in water bodies. These changes can result in harmful environmental impacts, such as eutrophication, sedimentation, and loss of aquatic habitats. To mitigate these effects, sustainable urban planning and management practices such as green infrastructure, improved wastewater treatment, and stormwater control measures are essential for protecting and enhancing water quality in rapidly urbanizing regions.
References
Mercy Kintu, A. S. (2019, june ). A Literature review of impacts of urbanization on water resource management: A case study in South Africa. International journal of scientifice research publications, 9(6). doi:10.29322/IJSRP.9.06.2019.p9051
Peng Jian Dong, T. K. (2024, August 29). Impact of Urbanization on Public Health in Kathmandu Valley, Nepal- A Review. Juniper Online Journal of Public Health. Retrieved 2024, from https://juniperpublishers.com/jojph/
Toby N Carlson, S. T. (2000, july ). The impact of land use — land cover changes due to urbanization on surface microclimate and hydrology: a satellite perspective. Global and Planetary Change(1-2), 49-65. Retrieved from https://doi.org/10.1016/S0921-8181(00)00021-7
Vijaykumar Bejagam, A. S. (2024, March 15). Projected decline in the strength of vegetation carbon sequestration under climate change in India. Science of The Total Environment. Retrieved from https://doi.org/10.1016/j.scitotenv.2024.170166
