应对人口流失的景观设计改进方法:以美国宾夕法尼亚州约翰斯敦的城市更新为例

DESIGN FOR THE DEPOPULATING LANDSCAPE: A RETROFIT APPROACH TO URBAN REGENERATION IN JOHNSTOWN, PENNSYLVANIA, USA

在过去50年里,世界范围内有370座大城市的人口缩减了至少10%。宾夕法尼亚州约翰斯敦的收缩速度位居全美第三,人口减少使这座深受去工业化影响的城市面临严重衰退,社会乱象频发,居民生活质量下降。本项目提出了一个针对收缩型城市的城市设计框架,即将永久性功能布局于高开发潜力区域,临时性功能则安排在衰退区域,待未来城市恢复活力后,开发活动也将随之兴起。项目通过利用地理信息系统建立的加权叠加模型评估约翰斯敦不同区域的衰退威胁等级,从中选出4个场地为其分别制定策略,为空置/废弃物业赋予新功能以回应居民的期望和需求,从而形成为各场地量身定制的总体规划。相较于投入高、见效快的开发激励措施,这种规划方法更注重培育经济基础的多样性,以期为城市创造新的长期经济增长点,并引发生活方式变革,同时也为推动收缩型城市的社会公平与公正提供了一种路径,丰富了城市更新规划中社会维度的内容。

Over the last 50 years, 370 large cities worldwide have severely depopulated, or shrunk, by at least 10%. Johnstown, Pennsylvania, is the third fastest U.S. shrinking city. Primarily a victim of deindustrialization, Johnstown faces severe decline issues related to depopulation, including social disorder and lowered quality of life. This project develops a framework for urban design for shrinking cities, integrating permanent functions into high development potential areas but temporary functions into declining areas. This approach allows for future development to occur through time as the city recovers. Using a GIS-based weighted overlay model to assess the threat level of decline, 4 sites were identified and strategies for each were developed. Master plans to retrofit new functions integrating residents’ desire and demands into vacant/abandoned properties were then generated for each site. Rather than chasing hefty attempted quick-hitting developmental incentives, this approach will bring new long-term economic engines and lifestyles to the city due to a diversity in the economic base;it also pays attention to the social dimension of urban regeneration by providing a structured way to promoting social justice and equity in shrinking cities.