Mental models of a water management system in a green building Anastasia Kalantzis a , Andrew Thatcher a, * , Craig Sheridan b a School of Human & Community Development, University of the Witwatersrand, WITS, 2050, South Africa b Industrial and Mining Water Research Unit (IMWaRU), School of Chemical & Metallurgical Engineering, University of the Witwatersrand, WITS, 2050, South Africa article info Article history: Received 2 March 2015 Received in revised form 17 March 2016 Accepted 14 April 2016 Available online xxx Keywords: User mental models Expert design models Constructed wetlands Water management system Green ergonomics abstract This intergroup case study compared users' mental models with an expert design model of a water management system in a green building. The system incorporates a constructed wetland component and a rainwater collection pond that together recycle water for re-use in the building and its surroundings. The sample consisted of five building occupants and the cleaner (6 users) and two experts who were involved with the design of the water management system. Users' mental model descriptions and the experts' design model were derived from in-depth interviews combined with self-constructed (and verified) diagrams. Findings from the study suggest that there is considerable variability in the user mental models that could impact the efficient functioning of the water management system. Recom- mendations for improvements are discussed. © 2016 Elsevier Ltd and The Ergonomics Society. All rights reserved. 1. Introduction There is growing evidence from several scientific disciplines that human activities have resulted in severe degradation to mul- tiple ecosystem services which now threaten human wellbeing in many parts of the world (Intergovernmental Panel on Climate Change, 2014). The most publicized impacts are referred to as climate change or global warming. Millions of people are now threatened by changing weather systems and the places we choose, or are forced, to live exacerbate the impacts of these natural phe- nomena. That these changes are due to anthropogenic causes is now beyond scientific dispute, indeed any residual dispute is mainly in the policy and not in the scientific arena (Fisher et al., 2013). One of the responses to climate change from the ergo- nomics community is green ergonomics. Green ergonomics focuses on the bi-directional relationships between natural and human systems in order to enable the wellbeing and effectiveness of hu- man and natural systems (Thatcher, 2013). One of the aims of green ergonomics is to design low resource intensity systems that reduce the negative impact on the environment and where humans can benefit from these systems (Thatcher, 2013). South Africa is a water scarce country with an annual average rainfall of approximately 495 mm (United Nations Environment Program, 2010) and climate modelling suggesting that it is only likely to get drier (Intergovernmental Panel on Climate Change, 2014). Additionally, Johannesburg, the economic hub of the country, is already a net importer of water and the region is currently under considerable water stress. Due to a combination of increasing population, increased provision of access to potable water and sanitation ser- vices, together with large industrial and agricultural demand, water allocation currently sits in excess of 98% of available resources (United Nations Environment Program, 2010). Municipal misman- agement of water delivery networks and sewage treatment plants combined with a significant threat to water resources from the uncontrolled decant of acid mine drainage (Name and Sheridan, 2014) in the Witwatersrand region (also the centre of population mass, containing approximately 12.5 million inhabitants) places significant additional stress upon this already highly constrained resource. The water management system examined in this study is considered an environmentally-friendly system as it attempts to reduce resource consumption intensity, particularly when the constructed wetland (i.e. waste-water recycling) and rainwater collection components are taken into account. Unfortunately there is a great deal of inconsistency in the literature on the meaning of the term ‘mental model’ which has been applied in various fields (and even within the same field) to mean different things (Staggers and Norcio, 1993; Revell and Stanton, 2012; Richardson and Ball, 2009; Wilson and Rutherford, * Corresponding author. E-mail address: Andrew.Thatcher@wits.ac.za (A. Thatcher). Contents lists available at ScienceDirect Applied Ergonomics journal homepage: www.elsevier.com/locate/apergo http://dx.doi.org/10.1016/j.apergo.2016.04.007 0003-6870/© 2016 Elsevier Ltd and The Ergonomics Society. All rights reserved. Applied Ergonomics xxx (2016) 1e12 Please cite this article in press as: Kalantzis, A., et al., Mental models of a water management system in a green building, Applied Ergonomics (2016), http://dx.doi.org/10.1016/j.apergo.2016.04.007