Land Suitability Evaluation Based Multi-Scenario Simulation And Forecast Of Urban Expansion

Exploring the laws of urban expansion,coordinating the contradictions between urban development and ecological protection,and predicting the trend of urban expansion are of great significance for the formulation of urban planning.Taking the main urban area of Hefei as the study area,we first established the urban land suitability zoning based on the minimum cumulative resistance difference.With the urban extent of the study area in 2000,2005,2010,2015,and 2018,the urban expansion process of Hefei's main urban area was then analyzed from the perspectives of expansion scale,expansion form,and expansion mode.Finally,three types of urban expansion scenarios were designed,and the multi-scenario urban expansion forecast based on the SLEUTH model from 2015 to 2040 was performed.The main results and conclusions obtained are as follows:(1)Based on the minimum cumulative resistance model,the urban land suitability zone was divided.By selecting the source of expansion,establishing the resistance surface,and calculating the minimum cumulative resistance difference,the four levels of urban land suitability zoning,namely ecological stuiable,low ecoligcally suitable,construction suitable,and low construction suitable regions were obtained.Their areas are 1172 km~2,1443 km~2,1107 km~2,and 2675 km~2,respectively.(2)The urban expansion process of Hefei's main urban area was analyzed from the perspectives of urban expansion scale,expansion form,and expansion mode.The expansion speeds of the four-time periods were 16 km~2/year,37 km~2/year,54 km~2/year,and 64 km~2/year,respectively,showing an increasing trend.The highest peaks of the expansion intensity appeared at 7.5 km,10 km,12.5 km,and 17.5 km away from the urban center,respectively.The urban boundaries accelerated to expand outward,morein the southwest but less in the northwest and southeast.The expansion intensity in the east increased after 2015.From 2000 to 2018,the edge model was the main mode of urban expansion,with the largest expansion area.The difference between the expansion area of the infilling and outlying mode and that of the edge mode gradually decreased.(3)Based on historical development scenario and urban planning development scenario,the free urban expansion and the expansion under planning constraints were predicted.The historical development scenario results in the largest expansion area.The expansion of the main urban area in the form of"spreading the pancake"and the strip-shaped expansion along the road encroached on a large number of high-quality cultivated land and ecological land.This shows that the SLEUTH model without effective constraints will produce unreasonable prediction results.The urban planning development scenario greatly limited the scale of urban expansion and protected cultivated land and ecological land.The policy-oriented forecast results also accurately reveal the hotspots of urban development.(4)Based on the land suitability development scenario,the integration of the minimum cumulative resistance model and the SLEUTH model was realized,and a reasonable urban expansion space was predicted.Compared with the historical development scenario and urban planning development scenario,the urban expansion area,and cultivated land occupation area of this scenario are both at a medium level.In the forecast results,ecological land and cultivated land are fully proected and the needs of urban development are also considered.The main urban area and surrounding towns have a clear expansion direction and reflect the same urban development hotspots as the urban planning development scenario.This thesis has 41 figures,16 tables,and 181 references.