基于FLUS-UGB的县域土地利用模拟及城镇开发边界划定研究

当前城镇开发边界的制定与已有基本农田和生态保护红线存在较大的龃龉,在新的国土空间规划体系下,需要科学划定县域合理的城镇开发边界以实现国土空间的可持续开发利用。对此,本文提出了基于三线协调和FLUS-UGB的城镇增长边界划定方法,以江苏省丰县为研究案例,在对其2011—2017年土地利用进行模拟和验证的基础上预测了至2035年的多情景土地利用变化,结合耕地保护与生态控制背景,最终确定城镇增长边界。结果表明：① 2017年丰县土地利用模拟的总体精度达到94.7%,Kappa系数为0.895,模拟精度较高。② 基准情景下,城镇用地呈现“摊大饼”的空间扩张趋势。在耕地保护与生态控制背景下,城镇呈“放射式”向外有序扩张。③ 预测2035年丰县城镇用地开发边界面积为80.29 km²,2017—2035年共17年增长幅度达到69.07%。明确划分城镇开发边界能够有效避免城镇用地对永久基本农田和重要生态用地的侵占,从而实现城镇扩张、永久基本农田和重要生态用地保护三者之间的良好空间协调。

The Land Use Simulation and Delimitation of Urban Development Boundary in County Area based on FLUS-UGB

Exploring the spatial extent of urban development within acounty is helpful to clarify the spatial relationships between urban land, permanent farmland, and ecological land, which lays an important foundation for the urban sustainable development of a county. Currently, the urban growth boundaries, and the existing permanent farmland and ecological protection boundaries have great conflicts with each other in different maps. Based on the new territory land spatial planning system, it is necessary to realize the "Three-Line Coordination" during territory land planning. However, the existing models of the delimitation of UGBs are highly subjective. The determination of the weight of each factor is usually subject to artificial influence, or only considers the dominant land use type without considering the other land use types. Thus, the simulation results of small-scale land use changes greatly differ from the actual results in the surrounding area. In this paper, we presented a delimitation method of urban development boundary based on the "Three-Line Coordination" and FLUS-UGB.We selected the Feng County in Jiangsu, China, as the study area where agriculture was the main development direction. Under the scenario of permanent farmland protection and ecological control, we delimited the urban development boundaries of Feng County. Our results show that: (1) the overall accuracy of the model was 94.7%, and the kappa coefficient was 0.895, which demonstrated the high simulation accuracy of our method; (2) under the baseline scenario, the spatial pattern of urban area presented a expansion trend. Under the scenario of cultivated land protection and ecological control, the urban area expanded outwards radially outside the permanent farmland and ecological control areas with an orderly manner; (3) the predicted area of urban development in Feng County would increase to 80.29 km² in 2035 with the growth rate of 69.07%. The boundary results predicted in our study can be used to effectively avoid the occupation of permanent farmland and important ecological land regions by urban development, leading toa better spatial coordination between urban expansion, and existing permanent farmland and ecological land protection in future. Moreover, our delimitation method of the urban growth boundary simulation was based on the "Three-Line Coordination", which met the demand of permanent farmland and ecological landprotection, and thus can reflect the urban land expansion of Feng County more accurately.