Water Journal : Water Journal May 2014
MAY 2014 WATER 41 Feature Article Typical urban stormwater harvesting schemes include all or some combination of the components shown in Figure 1. DEVELOPMENT OF STORMWATER HARVESTING PRACTICE The robust engineering basis for the planning, design, construction, operation and maintenance of urban stormwater harvesting is yet to be developed. This is because it is a relatively new engineering concept, despite being used in some form or another in various places around the world for centuries. In the absence of the established design basis for stormwater harvesting -- designers of these schemes frequently resort to the approaches borrowed from more traditional disciplines such as municipal drainage and water-sensitive urban design (WSUD) -- a number of leading Australian stormwater professionals have commented on the issue. For example, Hatt, Deletic and Fletcher wrote in their article 'Integrated Treatment and Recycling of Stormwater: A Review of Australian Practice' (Journal of Environmental Management): "Existing stormwater recycling practice is far ahead of research in that there are no technologies designed speci cally for stormwater recycling. Instead, technologies designed for general stormwater pollution control are frequently utilised, which do not guarantee the necessary reliability of treatment. Performance modeling for evaluation purposes also needs further research, so that industry can objectively assess alternative approaches." However, as the practice of stormwater harvesting is continued and more projects are commissioned in the years to come, the design paradigm for stormwater harvesting should be further developed and validated. STORMWATER HARVESTING GUIDELINES One of the major barriers to the wider uptake of SWH, particularly by local government, is the absence of comprehensive SWH guidelines. Such guidelines would allow the stakeholders in schemes (councils, regulators, consultants, contractors and other groups) to have a uniform reference document outlining current best practice including legislative framework, design/functionality, construction, operation and maintenance. Once developed, this document, could offer comprehensive guidelines for implementation of stormwater harvesting schemes in Australia as part of an IWCM approach, based on current legislation, best available engineering science and practical lessons learnt during planning, design, construction and operation of existing SWH schemes. SWH guidelines will provide a clear path for implementation of best practice stormwater management related to SWH and use in Australia, contributing to: • Better management of stormwater (balancing the harvesting to maximum aquatic and terrestrial bene ts); • Improved water quantity and quality management; • Reduced local ooding; • Maximising the sustainable utilisation of stormwater as a resource; • Greater uptake of stormwater harvesting; • Improved green space in urban areas, contributing to liveability; • Improved allocation and harvesting of stormwater and integration with water-sensitive urban design; • Better landscapes and parkland managed with available stormwater; • Informed strategic directions and policies for stormwater management and integrated water management. By providing the knowledge and con dence to implement sustainable, well-designed SWH projects the Guidelines will set the benchmark for best practice SWH and provide the know-how to achieve it, overcoming many concerns and lack of knowledge currently associated with stormwater harvesting. The development of SWH guidelines is a complex and multidisciplinary project, requiring good coordination, adequate resources, extensive stakeholder consultation and suf cient time. The resulting document should be based on four main components (see Figure 2): 1. Current regulation and legislation 2. Best engineering practice 3. Consideration of operation and maintenance issues 4. Case studies and practical examples. A more detailed owchart on topics and structure of the guidelines is presented in Figure 3. PERFORMANCE ASSESSMENT FOR STORMWATER TREATMENT DEVICES Selecting the right treatment train to meet the water quality objectives is essential for the successful and sustainable operation of SWH systems. Figure 2. Major components of stormwater harvesting guidelines development.
Water Journal April 2014
Water Journal June 2014