Evaluating the strategy of decentralized urban land-use planning in a developing region

Abstract

This study emphasizes the utility of decentralized urban planning in a developing region. The multi criteria evaluation (MCE) method was applied to produce suitability surfaces for agriculture, environmental protection and urbanization. The SLEUTH urban growth model was calibrated using two of the suitability maps: agriculture and environmental protection whereas the urbanization suitability layer was used for evaluating the results. These layers were used as weighted excluded inputs under two scenarios of agricultural land protection (AP) and environmental protection (EP). In this way ranges of resistance values against urbanization were provided for the SLEUTH model calibration. Hence, the model was forced to allocate urban clusters in locations with a minimum negative impact on farmlands and natural areas. The MCE-informed SLEUTH calibration assisted in performing decentralized urban growth allocation. Predicted under both scenarios (up to 2040) in the Gorgan township area, Iran; the major urban cores with large sizes were strictly constrained from further sprawl, instead, small scale and decentralized urban centers were established and started their own growth cycles. While substantial increase in the amount of impervious surface was allowed to occur, no meaningful negative impact was brought about on the land suitability of targeted land-uses. For both scenarios, the connectivity and compactness of urban patches were also investigated. The EP storyline yielded urban patches with more connectivity, while the AP scenario was more successful in retaining higher suitability values. The decentralized strategy can serve as a planning paradigm, which simultaneously considers several environmental parameters.