ABSTRACT
This chapter focuses on urban hydrological cycle and how it is highly modified by urban metabolism and pollution. Urban vegetation plays a key role in such hydrological changes. The ecological and environmental impacts of urban water can be modified by creating sustainable urban drainage systems using green and blue infrastructure. Urban areas have a dual hydrological system: the people-modified natural drainage system, including canals and river diversions, and the artificial water supply and wastewater disposal system. Rainfall volumes and intensity, especially thunderstorm development, are affected by the presence of urban areas. Urbanization also greatly affects groundwater quality, with many incidents of contamination of aquifers from which public water supplies are withdrawn. All pathways of concentrated water flow in urban areas are part of the urban drainage system and contribute to the urban drainage density. Urban streams have often been buried, turned into sewers, or completely culverted.
