South Africa is a water-stressed, developing country facing the challenge of providing basic services, including water, to its people. Rapid urbanization has led to concerns regarding social and environmental sustainability of urban areas. Water security is becoming a major problem, with most surface water resources fully accounted for and concern about poor water quality downstream of urban areas. The potential impact of climate change is an additional challenge.
Over the centuries humankind has developed methods with which to manage water resources in urban environments. Water supply, wastewater, and stormwater systems form an extensive network and manage the flow of water throughout the urban built form. The process of the movement of water through this man-made infrastructure is known as the urban water cycle. Currently the water management discourse adopts a linear approach to water resource usage, extracting water from the natural environment, transporting it to the consumer, and ultimately discharging it into natural water ways downstream. Stormwater is rapidly removed from urban environments and discharged into natural waterways downstream.
The urban water cycle consists of three major components:
i) Potable water supply;
ii) Wastewater management; and
iii) Stormwater Management.
To address the current practices and progress towards the sustainable management of water resources an alternative approach is necessary. Water Sensitive Urban Design (WSUD) is a interdisciplinary approach to urban water management that aims to holistically consider the environmental, social and economic consequences of water management infrastructure (Wong & Eadie, 2000). The approach aims to consider the environment in conjunction with infrastructure design and management at the earliest possible stage of the decision making process (McAlister, 2007). WSUD aims to do away with conventional water management thinking and begins to consider the environment as a critical resource central to a sustainable future.
WSUD is interpreted to mean a range of things. It is often considered to be synonymous with Sustainable urban Drainage Systems (SuDS) but is not. WSUD is the holistic management of the whole water cycle while considering additional aspects such as economic, social and environmental impacts. SuDS could be considered a branch of WSUD, specifically focussing on the management of stormwater through a series of controls which aim to mimic the natural system.
The goals of WSUD
Ultimately WSUD is a planning and design approach that looks to integrate water cycle management with the built form, the aim being to minimise the impact of the built environment (QDIP, 2009). The Queensland Department of Infrastructure and Planning highlights the specific goals of the WSUD concept in the list below (QDIP, 2009:1)
- Protecting and enhancing the intrinsic values of the natural water cycle by minimizing disturbance to natural landforms, wetlands, watercourses and riparian zones;
- Protecting the quality of surface and groundwater to maintain and enhance aquatic ecosystems and enable reuse2 opportunities;
- Reducing downstream flooding and the effects of drainage on aquatic ecosystems by managing stormwater runoff and peak flows;
- Promoting more efficient use of water by reducing the demand for potable water and encouraging use of alternative water supplies;
- Minimising the generation of wastewater and ensuring it is treated to a sufficient standard to enable the effluent to be reused and/or released into receiving waters;
- Controlling soil erosion and managing sediment during the construction and operational phases of development; and
- Using stormwater to maximise the visual and recreational amenity of developments (e.g. by using it for landscaping) and to promote.
Essentially WSUD is the ‘marriage of water sensitivity and design’, and is characterized by the following key aspects:
- Water security
- Climate change
- Better co-ordination between different professionals involved with water services.
Links to relevant articles
- SWITCH Resources (SWITCH was “a five year experiment focused on some of the key sustainability challenges in urban water management” the outputs from this project include a range of reports, papers, theses and software)
- Water By Design- A web page full of WSUD resources
- WSUD – WiKi
- Learnt about the water cycle (basic)