Challenges and opportunities for implementing Water Sensitive Design in South Africa Report to the Water Research Commission by Kirsty Carden, Neil Armitage, Lloyd Fisher-Jeffes, Kevin Winter, Benjamin Mauck, Tom Sanya, Preetya Bhikha, Greg Mallett, Thokozani Kanyerere and Siyamthande Gxokwe Urban Water Management research unit, University of Cape Town: Departments of Civil Engineering, Environmental & Geographical Sciences, Architecture & Planning, and Construction Economics & Management Department of Earth Sciences, University of the Western Cape WRC Report No. 2412/1/18 ISBN 978-0-6392-0015-6 June 2018 ii Obtainable from Water Research Commission Private Bag X03 GEZINA 0031 [email protected] or download from www.wrc.org.za DISCLAIMER This report has been reviewed by the Water Research Commission (WRC) and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the WRC nor does mention of trade names or commercial products constitute endorsement or recommendation for use. Printed in the Republic of South Africa © Water Research Commission iii Preamble This report is a compilation of several research projects that were undertaken in an attempt to start ‘building a case’ for the implementation of WSD on a broad scale in South Africa – in recognition of the fact that a new approach to the management of water is required. It therefore simply provides an overview of what might (and might not) work in this regard, rather than being a prescriptive manual on WSD implementation in South Africa. In this regard it represents a ‘work in progress’, aimed at demonstrating the various research contributions and at showing that there is potential to change the way water is managed in this country. The document should be read in conjunction with WRC Report TT 588/14: “Water Sensitive Urban Design (WSUD) for South Africa: Framework and guidelines” (Armitage et al., 2014) and WRC Report TT 558/13: The South African Guidelines for Sustainable Drainage Systems (Armitage et al., 2013). iv This page was left blank deliberately v Executive summary Introduction One of the most pressing issues of concern in South Africa is the availability and quality of water, both as a natural resource critical for human development, as well as a commodity that contributes significantly to the country’s economic growth. Worldwide, evidence suggests that the philosophy of Water Sensitive Urban Design (WSUD) – an approach to urban planning and design that integrates the management of the entire urban water cycle into land use and development processes – offers a wider variety of choices in the management of scarce and often deteriorating water resources, and that it adds general economic and environmental value to cities. In the South African context, the WSUD approach can additionally be seen to transform urban areas, potentially connecting spatial divisions through the development of ‘blue-green corridors’, and ensuring greater equity in terms of the availability of a wider variety of water services – as well as through the adoption of alternative technologies and enterprise innovations that ensure water security. The importance of an approach such as this was acknowledged in WRC study K5/2071 (Armitage et al., 2014), which provided a framework and guidelines for WSUD in South Africa. However, outside of a relatively small number of professionals, there is a lack of information on the potential benefits that could result from implementing WSUD on a large scale in this country. A business case needs to be developed to show that it is a viable approach, and to encourage national / local authorities, developers and citizens to change their behaviour accordingly – specifically in a developing country such as South Africa which is committed to addressing the effects of rapid urbanisation, and achieving universal access to basic services in a manner that is resource-efficient whilst minimising environmental impact and improving affordability. It is not only urban and peri-urban environments that could benefit from such an approach; the integration of water cycle management into planning and design for the growth of communities needs to include rural settlements as well. For this reason, reference to the word ‘urban’ has been removed from the term WSUD; thus Water Sensitive Design (WSD) is envisioned as the enabler for ensuring that local authorities move closer to meeting developmental goals in all settlements where people dwell, irrespective of scale and locality. The study has explored the challenges to and opportunities for the implementation of WSD in South Africa, mainly from a technical perspective – as highlighted through detailed catchment studies. The future development of policy on WSD in South Africa will likely be informed by the various different components of the project aimed at identifying opportunities for implementing the various WSD tools and techniques in selected urban catchments – including rainwater harvesting (RWH) and stormwater harvesting (SWH); sustainable (urban) drainage systems (SuDS), Water Conservation and Water Demand Management (WCWDM), water efficient devices, greywater harvesting, and groundwater use linked to managed aquifer recharge (MAR). WSD elements have been assessed in the design / redesign of precincts of the selected catchments to demonstrate how WSD could potentially improve water quality, water quantity, biodiversity and amenity value – thus creating liveable, sustainable and resilient outcomes for urban areas. vi Background and rationale As South Africa continues to face the challenges of water scarcity and declining water quality, the relevance of WSD will increase and the need to start considering cities in a different way will become more urgent. Climate change has the potential to further complicate these challenges by decreasing the availability of water while simultaneously increasing demand. Changes in storm intensities can also result in extensive flooding in areas where stormwater systems are either inadequate in terms of safely removing runoff, or have not been properly maintained. Locally-relevant information on the individual technologies associated with WSD is generally available and well-documented; what is not so apparent in the South African context however, is the way in which the notion of water sensitivity links with urban design and planning, and how the concept of WSD can be used to transform towns and cities through policy development; institutional structures; community participation; integration of operation and maintenance processes, job creation, etc. The use of modelling tools is seen as an effective approach for developing information to illustrate the benefits and feasibility of sustainable water management interventions, and one of the most useful of these modelling approaches is the development of a water balance which performs an analysis of the inputs and outputs of water for a given catchment. Recent approaches towards achieving resilience-based water management recognise the value of water in all its competing uses. There has been growing interest in both the notion of reducing system inefficiencies, as well as in the idea of resource capture and use through sustainable water supply options such rainwater / stormwater, and the use of groundwater, greywater and treated wastewater. As an example of water system inefficiencies, the average per capita demand for potable water in South Africa is 235 ℓ/c/d, increasing to 290 ℓ/c/d in metropolitan areas – compared to the international average of 173 ℓ/c/d (McKenzie et al., 2009). There is thus significant scope to reduce unit consumption of water in this country and proactively curtail water losses. The impacts of urban domestic RWH, including the related costs, stormwater management impacts, and water demand benefits are not well established. Additionally, whilst SWH is increasingly being considered in water management planning internationally, there has been little experience in South Africa of its viability and benefits, and very few studies have considered the impacts of RWH and SWH in combination. Further attention is being focused on the strong interactions between groundwater and these other water flows, and the fact that groundwater is becoming an increasingly important resource in urban areas worldwide. The most established role of groundwater within WSD is directly or indirectly linked to various forms of MAR, which fulfils a number of WSD objectives, such as stormwater management, stormwater / wastewater reuse, and reducing demand for potable water by providing alternative sources of water that can be used for a number of ‘fit-for-purpose’ applications. Research approach The overall aim of this study was to test the WSD concept and framework that was developed as part of WRC Project K5/2071 within selected catchments and/or municipalities in South Africa. This was achieved by way of an intensive, multidisciplinary study of an urban vii catchment in Cape Town, the Liesbeek River catchment – including aspects such as: developing a total water balance; investigating the viability of water (re)use options (RWH, SWH, greywater harvesting, and water efficient devices); assessing property value capture opportunities; exploring architectural influences in WSD; and determining environmental and socio-economic externalities (for example, public knowledge related to stormwater quality, societal perceptions, and amenity value of WSD). A range of other sites in and around Cape Town