Discuss the relationship between urbanization (land use change) and runoff (discharge). Support your answer with the some findings (e.g. Journal papers, articles, books, etc.).
Relationship between urbanization and runoff.
Urbanization can be define as the condition where towns and cities are formed and become larger as more people start to living at that area and working in central areas. Urbanize area can be identified by having more building, sky crappers and also good road systems. As in Malaysia, the most urbanize area is in Klang Valley. There will be change on the soil cover of that area into concrete and impervious land cover. It will definitely effecting the runoff water.
Subramanya in his books state that urbanization (land use change) is one of the factor that effecting runoff. Urbanization will increase the amount of impervious surface area and this will decrease the infiltration and surface retention rate. When amount of infiltration rate is low, the runoff will be increase, as a result flood could happened. From the graph(a), can be shown that the discharge is increase when there are urbanization in that area. From the graph also shown that the peak time of the discharge also increase.
The relationship of urbanization( land use change) and runoff also can be identified through rational method equation. Discharge Q is depends on C, A and i where C is coefficient of runoff, A is area and i is rainfall intensity.
Q = CiA
The value of C is depend on the surface cover at that area,as an example for lawn is 0.10 and industrial is 0.80. By this we can conclude that the value of runoff coefficient will be huge for industrial area( urbanize area) and small for lawn area. A part from that the value of runoff coefficient is also depends on the soil type and area size.
References
1- K.Subramanya, 2013 Engineering Hydrology Fourth Edition McGraw Hills (India) Private Limited.
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