Abstract
Urban centers act as magnets for population growth, drawing people from surrounding rural and semi-urban areas in search of employment, education, healthcare, and better living conditions. This rapid urbanization significantly increases the demand for land to accommodate housing, industry, transportation networks, and public infrastructure. As cities expand, natural landscapes—such as forests, grasslands, wetlands, agricultural lands, and floodplains—are increasingly transformed into urbanized areas. Also building cities often changes the way rivers, streams and underground water move. This happens because people take much water change the path of rivers and take over land. This affects the amount and quality of water. More people living in cities also puts a lot of pressure on how cities deal with waste and dirty water. In large cities, there are no adequate wastewater treatment facilities or proper waste disposal systems. Consequently, untreated waste from households, factories, and landfills ends up in rivers, lakes, ponds, and wetlands. This pollution degrades water quality, destroys aquatic habitats, reduces oxygen levels in the water, and endangers fish, birds, and other aquatic animals. Invasive species and many nutrients speed up this damage and cause long-term problems for the environment.
Wetlands are essential for sustainable cities, as they act as natural water filters. They use chemical and biological processes to purify water: removing pollutants, absorbing nutrients such as nitrogen and phosphorus, capturing heavy metals, and breaking down pollutants. This purification improves the quality of water before it reaches rivers, lakes, or groundwater; later, the clean water can be used in lakes, ponds, or artificial reservoirs. These areas promote urban biodiversity, restore water quality, and provide water for agriculture. In addition, wetlands help prevent urban flooding by storing rainwater, regulating local climate, and providing habitat for many plants, birds, fish, and insects. Therefore, protecting and restoring wetlands is not only essential for protecting wildlife, but also for enabling communities to adapt to climate change, ensure water security, and grow in an environmentally sustainable manner.