Simulating City Expansion Using a CA Urban Growth Model, Through a Case Study of Nairobi, Kenya

The acceleration of urbanization and industrialization has augmented the development of existing urban centers and hastened urban expansion. Especially in developing countries like Kenya. Recently, Cellular Automata has witnessed significant technological advancements as many CA-based urban models have been developed. These CA-based dynamic spatial urban models provide an improved ability to forecast and assess future urban growth and to create planning scenarios. In this research, we have sought to understand how marginally closer functional towns affect each other growth through time using SLEUTH, a cellular automation urban growth model. The existing data from 1986 to 2015 was used as input and calibration and prediction done to simulate the next 35 years and different indices of expansion employed to expound these changes. Classification results showed that the urban area had expanded from 39.62 km2 in 1986 to 367.02 km2 in 2015 with most urban growth in the North-east and the west of the Nairobi CBD. The prediction poised the city urban fringes to continue growing at a rate of 5.01% between 2015 and 2020, and slower rate of 2.51% between 2040 and 2050. The urban growth is much determined by breeding from existing urban patches along the road networks with a very small spontaneous growth. This infer that most expansion is determined by existing urban patches