Controlled urban sprawl in Auckland, New Zealand and its impacts on the natural environment and housing affordability

Abstract

Auckland experienced phenomenal expansion since 1841. This study assesses the pace of urban sprawl and its control over the natural environment and housing affordability. After the urban built-up area was mapped, its change over time was detected, and correlated with population. From 1842 to 2014 built-up area in Auckland grew from 48 ha to 50,531 ha. The pace of growth was 151 ha/year during 1842–1945 but jumped to 989 ha per annum during 1975–2001. It dropped to only 249 ha per annum in this century. This unchecked sprawl is a direct response to population growth and facilitated by improved transportation. Since the late 1990s urban built-up areas experienced a subdued expansion despite continued population growth. This curtailed sprawl is attributed to the contentious planning regulations implemented to curtail sprawl. Consequently, population density rose to 28 persons/ha, the highest since a century ago. Urban growth has reduced biomass and green fields with mean vegetation index dropped from 129.5 to 118.7 during 2002–2014 with a smaller standard deviation, suggesting the landscape is increasingly homogenized. House prices rose slowly when the growth potential decreased slowly and vice versa (r = − 0.925) while the number of vacant sections suitable for single dwellings declined. Thus, controlled urban sprawl is largely responsible for the skyrocketed price of sections and declined housing affordability.