Evaluation of the change in urban land use within the context of strategic spatial planning: İstanbul Riva case

As a complex spatial process, urban growth is an important social and economic phenomenon in developing countries. Land use change and urban growth are primary factors of the global environmental change for many cities which are among indispensable results of economic and social development. Majority of the land use changes resulting from the interactions between political, economic, social, environmental, cultural and other factors have adverse impacts on the natural environment due to their effects especially on surface temperature, climate change, surface flow and habitat diversity. Socio-cultural and ecological environment factors are effective on and change the shaping of urban landscape areas and the elements that make up the landscape. It is important to establish a protection-use balance for places with regard to a socio-cultural and ecological framework for the development of sustainable urban areas. Hence, it is of significant importance to prefer a planned urban growth. In this scope, the aim of the study was to reveal the changes in the land uses from the past to the present at the Riva Neighbourhood of the Beykoz District in Istanbul Province which has significant natural, cultural, ecological and strategic importance; to identify urban growth scenarios and the factors affecting urban growth in addition to developing suggestions within the strategic spatial planning framework. For this purpose, the urban land uses at the Riva Neighbourhood for the years 2005, 2006, 2014 and 2017 were classified under 4 classes via CBS according to CORINE Land Use Classification System as settlement areas, agricultural areas, forest areas and other natural areas thus revealing the changes in land use during the years 2005-2017. A total of 3 different urban growth scenarios were developed for the year 2050 as uncontrolled growth scenario (Scenario 1), partial controlled growth scenario (Scenario 2) and controlled growth scenario (Scenario 3). SLEUTH Model was used for estimating the urban growth and land use changes at the study area for the year 2050. Land uses for the years 2005-2017 along with the scenarios were used for obtaining the possible urban growth and land use change simulations via SLEUTH Model. The possible changes in urban land use were identified in the simulations after which comparisons were made in accordance with predetermined indicators. Moreover, the current climate data were compared with the year 2050 climate simulations thus making climate assessments for Riva. The changes during the 12 year period encompassing the years 2005-2017 in Riva were presented spatially and proportionally after which paired comparisons were used for assessment. In general, it was set forth that the increase in urban areas resulting from urbanization due to increasing population takes place primarily in forest areas spreading out over the other areas as well. Urban land uses were put forth spatially and proportionally on the basis of scenarios in accordance with the three scenarios developed for the year 2050 after which paired comparisons were made with the current situation thus evaluating land use changes. It was observed in all three scenarios developed for the year 2050 that there will be a significant increase in settlement areas coupled with a significant decrease in agriculture, forest and other natural areas. It was also observed as a result of comparisons based on indicators that the forest and other natural areas in the study area may decrease over time leading to habitat loss as well as loss of agricultural quality land. However, it is considered that the controlled growth scenario (Scenario 3) that can be put into effect by taking into consideration the sustainable use of natural resources in line with laws, regulations and administrative legislations will be the most effective scenario. In addition, data for the years 1995-2018 were compared with the climate simulations for the year 2050 and climate assessments were conducted for the study area. It was predicted when the impact of climate change on temperature changes in the study area was examined that there will be an increase compared with the current situation coupled with a decrease in the amount of rainfall. It was revealed that it is necessary to take the necessary precaution for the study area due to the impacts of urbanization on climate and urban ecosystem. In conclusion, suggestions were developed for the preservation and sustainment of the natural-cultural and ecological characteristics of Riva within the framework of strategic spatial planning.