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Walsh, C. J., Fletcher, T. D., & Ladson, A. R. (2005). Stream restoration in urban catchments through redesigning stormwater systems: looking to the catchment to save the stream. Journal of the North American Benthological Society. 24(3), 690-705. Fletcher, T.D., Walsh, C.J., Bos, D., Nemes, V., RossRakesh, S., Prosser, T., Hatt, B. & Birch, R. (2011) Restoration of stormwater retention capacity at the allotment-scale through a novel economic instrumentWater Science and Technology,64.2,494–502. Burns, M.J., Fletcher, T.D., Duncan, H.P., Hatt, B.E., Ladson, A.R. & Walsh, C.J. (2014) The performance of rainwater tanks for stormwater retention and water supply at the household scale: an empirical study. Hydrological Processes, DOI: 10.1002/hyp.10142.
Abstract: Restoration of streams degraded by urbanization has usually been attempted by enhancement of instream habitat or riparian zones. Such restoration approaches are unlikely to substantially improve instream ecological condition because they do not match the scale of the degrading process. Recent studies of urban impacts on streams in Melbourne, Australia, on water chemistry, algal biomass and assemblage composition of diatoms and invertebrates, suggested that the primary degrading process to streams in many urban areas is effective imperviousness (EI), the proportion of a catchment covered by impervious surfaces directly connected to the stream by stormwater drainage pipes. The direct connection of impervious surfaces to streams means that even small rainfall events can produce sufficient surface runoff to cause frequent disturbance through regular delivery of water and pollutants; where impervious surfaces are not directly connected to streams, small rainfall events are intercepted and infiltrated. We, therefore, identified use of alternative drainage methods, which maintain a near-natural frequency of surface runoff from the catchment, as the best approach to stream restoration in urban catchments and then used models of relationships between 14 ecological indicators and EI to determine restoration objectives. Ecological condition, as indicated by concentrations of water-quality variables, algal biomass, and several measures of diatom and macroinvertebrate assemblage composition, declined with increasing EI until a threshold was reached (EI = 0.01–0.14), beyond which no further degradation was observed. We showed, in a sample catchment, that it is possible to redesign the drainage system to reduce EI to a level at which the models predict detectable improvement in most ecological indicators. Distributed, low-impact design measures are required that intercept rainfall from small events and then facilitate its infiltration, evaporation, transpiration, or storage for later in-house use.(Full Text) Abstract: Urbanisation results in changes to runoff behaviour which, if not addressed, inevitably degrade receiving waters. To date, most stormwater management has focussed on the streetscape and public open space. Given that much of the catchment imperviousness is located on private land, we developed and tested a novel economic instrument (a uniform price auction) for encouraging allotment-scale stormwater retention. We evaluated bids using an integrated environmental benefit index (EBI), based on the ability of the proposed works to reduce runoff frequency, pollutant loads and to reduce potable water demand. The uniform price auction resulted in 1.4 ha of impervious areas being effectively ‘disconnected’ from the stormwater system. The EBI provided an objective and transparent method of comparing bids, which varied in the type of works proposed (e.g. rainwater tank, rain-garden), the cost and the resulting environmental benefit. Whilst the pilot auction was a success, the public subsidy of works undertaken was around 85%, meaning that property owners a relatively small private benefit in the works. Future auction rounds will be revised to (i) test an EBI which is more focussed on the protection of streams (assessing changes to runoff frequency, baseflow volumes and water quality) and (ii) provide an auction process which is simpler to understand, and provides greater practical support for landholders who wish to undertake works. Abstract: Urban stormwater run-off degrades the ecological condition of streams. The use of rainwater tanks to supplement water supply can reduce the frequency and volume of urban stormwater run-off that is otherwise conveyed directly to streams via conventional stormwater drainage systems. Few studies, however, have examined the use of tanks in the context of managing flow regimes for stream protection, with most focussed uniquely on their water conservation benefits. We used measured tank water level data to assess the performance of 12 domestic rainwater tanks against the dual criteria of their ability to (i) reduce potable mains water usage and (ii) retain run-off from rainfall events and thus reduce the volume and frequency of stormwater run-off. We found that five households relied almost entirely on tank water. Three of the tanks achieved stormwater retention performance approaching that of the same area of pre-developed land, although nine did not – a consequence of limited demand and small tank capacity. Our results suggest that tank water usage can result in substantial reductions in mains water use, if regular and sufficiently large domestic demands are connected to tanks. In many cases, such demands will also result in the best stormwater retention performance. Our results highlight an opportunity to design tank systems to achieve multiple objectives. Application of similar analyses in different locations will help to optimize tanks for simultaneous water supply and stormwater retention purposes.
     
Brown, H.L., Bos, D., Walsh, C.J., Fletcher, T.D. & Rossrakesh, S. (2015) More than money: how multiple factors influence householder participation in at-source stormwater management. Journal of Environmental Planning and Management. Nemes, V., La Nauze, A., Walsh, C.J., Fletcher, T.D., Bos, D., Rossrakesh, S. & Stoneham, G. (2014) Saving a creek one bid at a time: a uniform price auction for urban stormwater retention. Urban Water Journal. Walsh, C.W., Fletcher, T.D., Bos, D.G. & Imburger, S.J. (2015) Restoring a stream through retention of urban stormwater runoff: a catchment-scale experiment in a social–ecological system. Freshwater Science, 34(3).
Abstract: Urban stormwater run-off is a threat to stream ecosystems. New approaches to stormwater management aim to protect urban streams from such impacts, by retaining, treating and using stormwater at its source. As up to ∼50% of runoff from urban surfaces comes from private property, fostering stormwater retention requires effective householder engagement. We evaluated householder participation in the Little Stringybark Creek project, a stormwater retrofit programme aimed at waterway protection, using qualitative enquiry through formal and informal interviews to identify factors that influenced participation. Participation was governed by multiple factors, with financial incentives and personal co-benefits of tanks primary motivators, while process complexity and distrust were primary barriers. Results suggest an approach combining education to encourage review of subjective norms and attitudes, with incentives to mitigate behavioural controls can transform public behaviour towards sustainable stormwater management. Abstract: Urban stormwater runoff degrades waterway health. We describe a market-based approach to identify the most efficient investments to reduce urban stormwater impacts at minimum cost. The framework involves the joint consideration of public and private supply of environmental services across scales; a metric to compare the benefits of interventions across and within scales; an environmental procurement auction to reveal and minimise the cost of private interventions; and an endogenous reserve price to select the optimal portfolio of investments. The paper discusses the economic and environmental rationale for the proposed approach, along with the results of Stormwater Tender, a field trial in Melbourne, Australia. To conceptualize the optimal portfolio of investments we draw the aggregate supply curve and the production possibility frontier (PPF) using data from the field trial. We find considerable heterogeneity in both the private and public cost of providing environmental benefits, highlighting the need to consider interventions across a range of scales. We also find that existing theory is limited in its ability to predict bidders' behaviour. Despite this, it is evident that using the PPF to select projects considerably improves the cost effectiveness of the investment. We therefore conclude that the approach is an effective way of maximising the benefits of policy interventions to reduce the impacts of stormwater on urban waterways. Abstract: Restoration of ecological structure and function of urban streams probably requires catchment-scale modification of drainage infrastructure, but such catchment-scale restoration attempts and their assessment are rare. They require stream ecologists to embrace the interdisciplinary challenges of studying the social–ecological systems that are urban catchments. We designed and monitored a catchment-scale experiment that involved the retrofit of urban stormwater infrastructure throughout an urban catchment to restore more natural hydrology, water quality, and consequently, ecological condition in the receiving stream. We worked with government authorities and the catchment community (residents and property owners) over several years to fund and implement 289 stormwater retention systems. The length of the project allowed adaptation of the experimental design to expand the project’s breadth and of retention-system design to match community needs and catchment context. Planning provisions are particularly important for such an experiment to ensure that the effect of dispersed experimental treatments is not countered by creation of new connected impervious areas elsewhere in the catchment. Catchment-scale experiments can help to transform policy and practice, but their success requires substantial effort and time to build trust among the numerous, diverse stakeholders of human-dominated urban ecosystems. Researchers need to be prepared to adopt an adaptive approach to the implementation of such experiments and to play the lead role in seeking funds for the implementation of the on-ground works necessary to underpin the experiment.(Full Text)
     
Bos, D.G, & Brown, H.L. (2015) Overcoming barriers to community participation in a catchment-scale experiment: building trust and changing behavior. Freshwater Science, 34(3) Burns, M.J, Wallis, E. & Matic, V. (2015) Building capacity in low-impact drainage management through research collaboration. Freshwater Science, 34(3) Prosser, T., Morison, P.J., & Coleman, R.A. (2015) Integrating stormwater management to restore a stream: perspectives from a waterway management authority. Freshwater Science, 34(3)
Abstract: Communities have an important role to play in the protection of urban streams, particularly with how stormwater runoff from their properties is managed. As part of a larger research project, we used 3 sequential approaches to engage communities in protecting their local creek by managing their properties’ stormwater runoff. We assessed their success through surveys and measurements of uptake. Our initial efforts elicited strong interest from the community, but participation rates were greatest when the application process was simplified and barriers to participation were removed. The sequential implementation of the approaches limits inference of their comparative effectiveness, but the results suggest that the iterative and adaptive nature and extended period of the process facilitated the targeting of diverse motivations and the building of community trust, which in turn led to greater community participation.(Full Text) Abstract: Municipalities often play the principal role in the management of urban stormwater runoff. Dominant approaches involve routing urban stormwater runoff directly to streams, which has negative impacts on waterway health. Alternative management approaches, such as low-impact drainage management, have the potential to protect or restore urban streams, but remain rarely used. The Yarra Ranges Council (YRC), a municipality in Melbourne, Australia, collaborated with a team of researchers to construct stormwater-harvesting schemes, infiltration systems, and other measures (e.g., low-flow filters for water-quality treatment), as part of a catchmentscale experiment on low-impact drainage management. We held a workshop to elicit views of staff across a range of departments on insights gained from the experiment. We also gathered information on the design and construction of works to support findings from the workshop. Over time, research collaboration increased the capacity of YRC in low-impact drainage management. This increased capacity was linked to the temporary assignment of one of the researchers to work in the municipality’s engineering department. The researcher increased the confidence and trust of YRC in the use of new stormwater-management technologies. This temporary assignment into YRC helped support the long-term nature of the collaboration, which built trust over time. Our results support the views of scholars that civil experimentation can improve the capacity of municipalities to implement alternative approaches to urban stormwater management, with the aim of protecting or restoring streams.(Full Text) Abstract: Urban stormwater management is complex with diverse institutional responsibilities, imperfect regulation, and limited, often unclear accountabilities. Improving practices in that context requires strong leadership, long-term commitment, and lasting interorganizational relationships founded on trust. We summarize events that steered Melbourne’s waterway management authority to support a catchment-scale experiment markedly different from management applications or research approaches it had previously attempted. We highlight challenges, lessons learned, and subsequent institutional changes to stormwater management. Project challenges included: substantial investment in a small area from an organization with dispersed regional responsibilities, gaining intra- and interorganizational commitment, ongoing catchment development that counteracted management efforts, requirement for ongoing investment under short-term funding and political cycles, and absence of short-term measurable responses in stream health. These challenges led to design innovations, new catchment planning approaches, new best practice objectives, and new government policies that collectively changed approaches to stormwater management in our region. Critical to the initiation and success of this project, and probably to other similar projects, was building institutional commitment through long-term relationships between researchers and practitioners, and risk sharing made possible by co-investment.(Full Text)
Walsh, C. J. and Fletcher, T. D. (2015).Stream experiments at the catchment scale: the challenges and rewards of collaborating with community and government to push policy boundaries. Freshwater Science, 34, 1159–1160. (Full text)    

 

For more journal papers associated with the Little Stringybark Creek project, visit the Waterways Ecosystem Researcg Group (The WERG).