INVESTIGATING URBAN GROWTH BOUNDARY AS MECHANISM TO PLAN FOR SUSTAINABLE URBAN DEVELOPMENT

Urban encroachment into the peri-urban areas has blurred the borders between urban and rural areas. Thus, the urban growth boundary (UGB) has been used to encourage the sustainable development of cities and improve long-term planning efficiency. Studying the understanding of the UGB concept in ensuring sustainable development in Malaysia would be beneficial. This study aimed to investigate the perception and understanding of the UGB concept and function to achieve sustainable urban development. An online survey was conducted involving 82 experts, which comprised planners from PLANMalaysia and academicians in the field of urban planning. Results indicated that the perception of the UGB score was significantly greater by 1.16 than the normal score of 3, which indicated that the experts agreed that UGB could improve the urban development. The findings also indicated that the existing planning policy and inclusion of UGB had protected agricultural and natural land; however, stricter and tighter borderless development should be conducted.

Urban-Rural Surface Temperature Deviation and Intra-Urban Variations Contained by an Urban Growth Boundary

The urban heat island (UHI) concept describes heat trapping that elevates urban temperatures relative to rural temperatures, at least in temperate/humid regions. In drylands, urban irrigation can instead produce an urban cool island (UCI) effect. However, the UHI/UCI characterization suffers from uncertainty in choosing representative urban/rural endmembers, an artificial dichotomy between UHIs and UCIs, and lack of consistent terminology for other patterns of thermal variation at nested scales. We use the case of a historically well-enforced urban growth boundary (UGB) around Portland (Oregon, USA): to explore the representativeness of the surface temperature UHI (SUHI) as derived from Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature data, to test common assumptions of characteristically “warm” or “cool” land covers (LCs), and to name other common urban thermal features of interest. We find that the UGB contains heat as well as sprawl, inducing a sharp surface temperature contrast across the urban/rural boundary. The contrast ranges widely depending on the end-members chosen, across a spectrum from positive (SUHI) to negative (SUCI) values. We propose a new, inclusive “urban thermal deviation” (UTD) term to span the spectrum of possible UHI-zero-UCI conditions. We also distinguish at finer scales “microthermal extremes” (MTEs), discrete areas tending in the same thermal direction as their LC or surroundings but to extreme (hot or cold) values, and microthermal anomalies (MTAs), that run counter to thermal expectations or tendencies for their LC or surroundings. The distinction is important because MTEs suggest a need for moderation in the local thermal landscape, whereas MTAs may suggest solutions.