Public aesthetic preferences and efficient water use in urban parks

Abstract

Local governments in Melbourne are rethinking the design of parks with the aim of increasing water efficiency. In changing park design to achieve this objective, community landscape aesthetic expectations need also to be considered if these changes are to be socially acceptable. Using a psychophysical approach of landscape assessment, this thesis examines the relationship between public perceptions of park environments in Melbourne and water consumption. The thesis first develops a perceptual classification of a sample of landscapes found in Melbourne's urban park system. Secondly, it investigates the meanings, perceptions and aesthetic and general preferences the public associate with these park landscapes. Thirdly, it estimates the relative water-use of landscape plantings associated with these park landscapes. Finally, it develops a systematic approach to balancing the public aesthetic expectations and water-use in urban parks.

Landscape visual assessment methods, including multiple photo-sorting, Web-based surveys and verbal rating scale techniques were used in studying public perceptions and preferences for the various park environments. Hierarchical clustering, multidimensional scaling, optimal scaling and factor analysis were the main statistical techniques employed in analysing the data. In developing a perceptual classification, 11 perceptual landscape types and associated meanings were identified.

Three dimensions underlying participants' similarity judgements of park landscapes were revealed. These dimensions are related to (a) vegetation type (i.e., native/indigenous vs. exotic) and degree of perceived naturalness, (b) vegetation density and spatial organisation and (c) presence of water. Web-based landscape assessment surveys were conducted to gather aesthetic and general preferences, affective and other evaluative responses fit a set of stimuli landscape selected with respect to the 11 perceptual landscape categories. No subgroup differences in relation to age, gender, educational level, environmental background and residential experience were found. However, in examining individual preferences, two subgroups were identified. Subjects associated with the first preference group rated densely forested, natural looking landscapes that are dominated by native/indigenous vegetation highest in preference with "interesting" and "exciting" being the main affective qualities associated with these preferences. In contrast, subjects associated with the second preference group rated more formal, picturesque style landscapes dominated by lush exotic types of vegetation highest in preference with "pleasant" and "relaxing" being the main affective qualities associated with these preferences.

Three dimensions underlying subjects' preference ratings of park landscapes were revealed and were identical to the dimensions obtained from MDS analysis of similarity judgements gathered from the photo sorting exercise. This finding implies that, in the context of urban parks, landscape aesthetic values may be more strongly associated with factors external (i.e., landscape) rather than internal (i.e., affect or cognition) to the observer. The two affective dimensions of pleasure and arousal were found to be influential in affecting and predicting people's preferences.

Finally, in order to evaluate landscape water-use/needs a hybrid methodology that relies on expert evaluations was developed. By plotting preference ratings against landscape water-use data four categories including "critical aesthetics" (i.e., high water-use/low preference), "undesirable aesthetics" (i.e., low water-use/low preference), "unsustainable aesthetics" (i.e., high water-use/ high preference) and "sustainable aesthetics" (i.e., low water-use/high preference) were identified. These results show that a great amount of water saving can be achieved by modifying those landscape environments that fall under the first two categories. Developing trade-off planning strategies can also help achieve sustainable aesthetics with respect to water resources conservation. The results of this research can inform decision-making about park planning and design with the aim of satisfying the dual-objective of water-use efficiency and meeting public aesthetic preferences.