Missing the link: urban stormwater quality and resident behaviour

Abstract

Conventional urban drainage systems are designed to reinforce human dominance over the biophysical environment resulting in contaminated surface runoff being discharged into urban waterways. It is widely recognized that poor stormwater quality is one of the main contributing factors to the deterioration of urban rivers. The result is that bluegreen corridors of urban open spaces are compromised by the cumulative impacts of pollution that alter productive ecosystem services and are no longer able to support biodiversity. The problem is partly caused by conventional stormwater infrastructure, which is designed to remove runoff as quickly and efficiently as possible. Yet the condition of an urban waterway cannot be understood simply as a cause and effect relationship, but emerges from interactions between people, drainage and ecological systems. This study aimed to understand the linkage between biophysical and social systems in an urban setting in Cape Town, South Africa. Surface water flowing into roadside catchpits was analysed using multiple water quality parameters. Surveys, interviews and observations explored how local residents understand their impacts on the quality of an urban river. The results show that runoff is highly variable and some environmental conditions, such as rainfall, antecedent dry days and season, are the primary drivers of water quality. However, residents have a poor understanding of the linkages between what they do on the land and impacts on urban rivers. The findings suggest that the predominant focus on technological solutions and flood prevention do not persuade citizens to account for actions that result in deterioration of waterway conditions. Drainage infrastructure fails to connect citizens with their downstream impacts on environmental systems and services. The implication is that most residents ‘miss the link’ – between their actions on land, their impacts on runoff and river water quality, and, in turn, their ability to influence societal patterns and processes.

Keywords: stormwater drainage, social-ecological systems, environmental impacts, human behaviour, urban ecology