Urban development can be defined as growing population, higher population density and physical sprawl of an urban area. The physical development of urban growth demolishes the natural areas and natural resources. Water resources are the one of the example of that they are affected by Urban development. Water resources are affected by urban development which river or stream carries the pollutants. In this process pollutants gather by water runoff and mix with ground and underground water. The joining point of streams with water runoff is the important zone to intervention to water pollution. This zone is named riparian buffer zone; and riparian buffer zone is transition zone of river or stream between lands. Researches show that riparian buffer zones obstruct contamination, sediments, erosion therefore we can name the riparian buffer zones as a filter zones of rivers; besides riparian buffer zones provide to create habitat for species, improve water quality and create migration paths to species. Researches about riparian zones have shown that two main subjects were emphasized in order to protect water resources. First one is vegetation of buffer zone; and latter is expansion of buffer zones in order to hinder the negative effects of human activities such as agriculture, urbanization, industrial production. Aquatic systems are so sensitive areas that the quality of system can not be measured by just expanse and/or vegetation.