Applying the social-ecological systems framework to understand impacts of flooding in the Palmiet River catchment.

Abstract

Accelerating urbanization in African cities is impacting the ability of urban ecosystem services to provide services to contribute to the wellbeing of people. Additionally, climate change presents increased urban risks such as the increased frequency and intensity of flooding. This thereby threatens human life and built infrastructure; and challenges the resilience of communities already strained by socio-economic challenges. Ecosystem services in urban catchments are poorly understood which further adds to the lack of understanding the value of natural resources in urban catchments and subsequently how to restore and protect vital natural resources in order to ensure ecosystem services delivery. The aim of the study is to understand how impacts of flooding decrease the resilience of the communities in the Palmiet River catchment located in Durban, South Africa, through applying the social-ecological system (SES) framework. The Palmiet River catchment is a dynamic and heavily urbanized catchment in which the Palmiet River extends 26km through its headwaters at an elevation of 510m flowing through the lower informal settlement at 18m elevation. The SES framework is an interdisciplinary approach to understanding biophysical and social aspects in a relational landscape – both of which can no longer be studied in isolation. The methodology of the study uses data collected from public community engagement forums to identifyspecific issues occurring within the catchment and understanding the roles of interested and affected stakeholders. Further, aerial photography images of the Palmiet River catchment from 1981 to 2016 were used to identify the rate of urbanization and terrestrial impacts; this data was additionally supported by drone images. A SES framework was applied for sub-sections of the Palmiet River catchment in order to develop a narrative for the total river catchment to improve understanding of societal actions of urbanization that impact the functionality of the Palmiet River. The findings of the study reflect that: 1) Flood events are occurring more frequently, and more peopleare at risk as the influx of people within the catchment increases and the land use/cover changes. 2) A collaborative social system with a strong governance unit exists within the Palmiet catchment. This has facilitated conversations amongst resources users and actorsin the rehabilitation of the resource system. This could potentially serve as a springboard for identifying viable areas for ecological infrastructure investments. 3) The social system has increased resilience within the catchment – however, this may change as flood events continue to increase in intensity and frequency. 4) The Palmiet River is a dynamic social-ecological system that presents challenges as well as opportunities for sustainable and integrative catchment management. The SES framework provided a tool to evaluate the social and ecological systems through which to assess thecurrent limitations for the Palmiet River to regulate flood events. 5) It was lastly necessary to identify ways in which sustainable urban design systems and ecological infrastructure could be used as a part of catchment management strategies to rehabilitate and enhance ecosystem services. It was concluded that the ecosystem services once offered by the Palmiet River catchment have been compromised byunprecedented rates of urbanisation, particularly impacts of growing informal settlements in the lower parts of the catchment as well as industrial areas in the upper parts of the catchment.