Urban growth boundaries delineation coupling ecological constraints with a growth-driven model for the main urban area of Chongqing, China

Abstract

As an effective tool for achieving urban “smart growth”, urban growth boundaries (UGBs) have received broad attention and application worldwide. In this study, the main urban area of Chongqing is used as a study area to explore the methods of UGBs delineation in mountainous cities. First, starting from the perspectives of basic farmland protection, ecological security, disaster prevention and safety, and topographic limitation, nine constraint factors were selected to comprehensively delineate a rigid, inviolable UGB. Second, in the context of urban growth demand and construction suitability, 22 human activity and natural condition factors that affect changes in urban land use were selected to construct a Markov-future land use simulation (FLUS) model for predicting land use changes occurring by 2020, thereby delineating an elastic UGB in 2020. The following results were obtained. The future land use simulation results based on the Markov-FLUS model were comparatively favorable, with the mean kappa coefficient reaching 0.8455. To ensure the sustainable development of the main urban area of Chongqing Municipality, the area protected by the rigid UGB should be mainly distributed in the “four mountains and two rivers” conservation area for a longer time, with an area of up to 3654.97 km2, accounting for 66.86% of the total main urban area. In 2020, the area of the elastic UGB for the main urban area of Chongqing is recommended to be 971.44 km2, accounting for 17.78% of the total main urban area. In this way, urban growth management strategies that are mainly based on a rigid UGB and complemented by an elastic UGB can be promoted in the planning and management of mountainous cities.