Imperial College London

DR ANA MIJIC

Faculty of EngineeringDepartment of Civil and Environmental Engineering

Reader in Water Systems Integration
 
 
 
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Contact

 

+44 (0)20 7594 3796ana.mijic Website

 
 
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Assistant

 

Miss Judith Barritt +44 (0)20 7594 5967

 
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Location

 

310BSkempton BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

113 results found

Mijic A, Liu L, OKeeffe J, Dobson B, Chun KPet al., 2024, A meta-model of socio-hydrological phenomena for sustainable water management, Nature Sustainability, Vol: 7, Pages: 7-14, ISSN: 2398-9629

Overemphasizing technological solutions in water management without considering the broader systems perspective can result in unintended consequences. For example, infrastructure interventions for drought adaptation may inadvertently increase flood risk, illustrating a socio-hydrological phenomenon. Here we propose a systems meta-model that reveals the complex mechanisms and feedback loops underlying the critical human–water interactions. We show that the unintended outcomes of water management decisions result from the lack of integration and coordination of the feedback loops. The insights highlight the importance of considering environmental capacity in water management, as well as the necessity for integrated assessment and coordinated solutions for long-term sustainability.

Journal article

Mijic A, 2023, Unlocking benefits of crop switching in India, nature water, Vol: 1, Pages: 833-834, ISSN: 2731-6084

Crop switching optimization within the context of the Indo-Gangetic Plain provides compelling evidence that this approach yields significant benefits in terms of increasing calorie production and profits for farmers whilst minimizing water and energy use.

Journal article

Fan PY, Chun KP, Tan ML, Mah DN-Y, Mijic A, Strickert G, Yetemen Oet al., 2023, The spatial configuration of local climate zones reveals effects on wayfinding in human walking, PLoS One, Vol: 18, ISSN: 1932-6203

The importance of easy wayfinding in complex urban settings has been recognized in spatial planning. Empirical measurement and explicit representation of wayfinding, however, have been limited in deciding spatial configurations. Our study proposed and tested an approach to improving wayfinding by incorporating spatial analysis of urban forms in the Guangdong-Hong Kong-Macau Great Bay Area in China. Wayfinding was measured by an indicator of intelligibility using spatial design network analysis. Urban spatial configurations were quantified using landscape metrics to describe the spatial layouts of local climate zones (LCZs) as standardized urban forms. The statistical analysis demonstrated the significant associations between urban spatial configurations and wayfinding. These findings suggested, to improve wayfinding, 1) dispersing LCZ 1 (compact high-rise) and LCZ 2 (compact mid-rise) and 2) agglomerating LCZ 3 (compact low-rise), LCZ 5 (open mid-rise), LCZ 6 (open low-rise), and LCZ 9 (sparsely built). To our knowledge, this study is the first to incorporate the LCZ classification system into the wayfinding field, clearly providing empirically-supported solutions for dispersing and agglomerating spatial configurations. Our findings also provide insights for human-centered spatial planning by spatial co-development at local, urban, and regional levels.

Journal article

Liu L, Dobson B, Mijic A, 2023, Water quality management at a critical checkpoint by coordinated multi-catchment urban-rural load allocation, JOURNAL OF ENVIRONMENTAL MANAGEMENT, Vol: 340, ISSN: 0301-4797

Journal article

Fan PY, Chun KP, Mijic A, Tan ML, Zhai W, Yetemen Oet al., 2023, Identifying the Impacts of Land-Use Spatial Patterns on Street-Network Accessibility Using Geospatial Methods, GEOGRAPHICAL ANALYSIS, ISSN: 0016-7363

Journal article

Kirkpatrick L, Adjiman C, ApSimon H, Berry A, de Nazelle A, Mijic A, Myers R, Woodward G, Workman Met al., 2023, Systems thinking for the transition to zero pollution, Systems thinking for the transition to zero pollution, www.imperial.ac.uk/grantham, Publisher: Grantham Institute, 40

Systems approaches are vital for coordinating decision-making in the face of complex issues because they provide the whole picture view needed to avoid negative unintended consequences and to generate genuine benefits. This paper explains how systems thinking can be used to address environmental pollution and support decision-makers in finding solutions.

Report

Puchol-Salort P, Boskovic S, Dobson B, Krivtsov V, Rico-Carranza E, van Reeuwijk M, Whyte J, Mijic Aet al., 2023, Integrated Urban Planning Decision-Making Process Towards Water Neutral Solutions

<jats:p>Urban water security levels will be threatened during the next few years due to new development pressures combined with the climate emergency and increasing population growth in cities. In the UK, London&amp;#8217;s planning authorities have a target of more than half a million households for the next 10 years. This new housing will increase the current impacts on urban consumer demand, flood risk, and river water quality indicators. In our previous work, we developed a new concept for urban Water Neutrality (WN) inside an integrated urban planning sustainability framework called CityPlan to deal with water stress and urban complexity issues. This framework integrates the UK&amp;#8217;s planning application process with systemic design solutions and evaluation, all being spatially represented in a GIS platform. With the new digital era, there is a constantly increasing number of spatial datasets that are openly available from different sources, but most of them are disaggregated and difficult to understand by key urban stakeholders such as Local Planning Authorities, housing developers, and water companies. Moreover, there are several Multi-Criteria Decision Support Tools (MCDST) that address water management challenges in the literature; but there is still little evidence of one that evaluates the impacts and opportunities to allocate water neutral urban developments.In this work, we expand the CityPlan framework and present an innovative fully data-driven approach to test WN indicators at different urban scales. WaNetDST integrates GIS spatial data with a series of rules for development impact and offset opportunity based on the current properties of the urban land. This integration is linked to a new scoring system from expert advice that maps strategic areas for water neutral interventions and links the most impactful zones with others more prone to be intervened. The tool connects different urban scales with a series of case study areas: f

Other

Mijic A, Liu L, Dobson B, 2023, Water Systems Integrated Modelling framework (WSIMOD): A Python package for simulating human-impacted water quality and quantity

<jats:p>The water cycle is highly interconnected; water fluxes in one part depend on physical and human processes throughout. For example, rivers are a water supply, a receiver of wastewater, and an aggregate of many hydrological, biological, and chemical processes. Thus, simulations of the water cycle that have highly constrained boundaries may miss key interactions that create unanticipated impacts or unexpected opportunities. Integrated environmental models aim to resolve the issue of boundary conditions, however they have some key limitations, and we find a significant need for a parsimonious, self-contained suite that is accessible and easy to setup. With this in mind, we have developed the WSIMOD &amp;#8211; a Python package that allows for the representation of the water system&amp;#8217;s demands and impacts of multiple sectors and actors&amp;#8217; decisions within a single tool, which is considered beneficial to increasing a shared understanding of system performance and for more collaborative and coherent decisions on integrated water resources, water quality and flood management. The WSIMOD is a self-contained software package that includes modelled representations of key physical and infrastructure elements of the water cycle (urban and rural), with each type of modelled element generically described as a component. Components are written in such a way that any component can interact with any other component. This enables a flexible representation of a water system that is needed to accommodate the wide variety of different built/natural infrastructure configurations and scales. We will showcase how the WSIMOD tool has been developed and successfully tested through a range of applications in the UK, including integrated analysis of urban water systems, catchment water management and urban water neutrality. &amp;#160;</jats:p>

Other

Peng F, Liu L, Gao Y, Krivtsov V, Dobson B, Mijic Aet al., 2023, Evaluating the impact of urban wetlands as nature-based solutions at the catchment scale

<jats:p>During COP14 in 2022, Ramsar Convention commended 25 cities around the world for their efforts to protect urban wetlands. With the development of cities and the increase in land demand, the trend is to reduce the number of open blue spaces. Yet when preserved and sustainably used, urban nature-based solutions in the form of constructed wetlands could provide water management benefits including water quality regulation and flood mitigation. However, these water management benefits have rarely been evaluated at a catchment scale, and the mechanisms behind them are not fully understood, both of which hinder effective integrated constructed wetlands planning. We aim to explore the impact of wetland changes on water quality and quantity at the catchment scale. This study firstly evaluates the benefits by analysing the monitoring water quantity and quality datasets before and after the wetland construction in Enfield catchment, London. To understand the mechanisms behind the benefits, we build a Water Systems Integration Modelling framework (WSIMOD) to simulate the catchment-scale water cycle. This model is validated against monitoring river flow and water quality data. The constructed wetlands are then conceptualised and integrated into the WSIMOD, and their interactions with the catchment water cycle are simulated. Scenarios are constructed to analyse the impacts of different configurations and sizes of the constructed wetlands on the catchment water cycle. The results show that urban wetlands play a role in flood detention and water quality purification of watershed water resources at the catchment scale. Scattered small wetlands can more effectively reduce the impact of a flood under the same total wetland area. The results provide useful insights into the planning of constructed wetlands for maximising the water management benefits at a catchment scale. Future studies could focus on representing the interaction between the quantity and quality of water

Other

Liu L, Dobson B, Mijic A, 2023, Optimisation of Urban-Rural Nature-Based Solutions for Integrated Catchment Water Management

<jats:p>Nature-based solutions (NBS) have co-benefits for water availability, water quality, and flood management. However, searching for optimal integrated urban-rural NBS planning to maximise co-benefits at a catchment scale is still limited by fragmented evaluation. This study develops an integrated urban-rural NBS planning optimisation framework based on the CatchWat-SD model, which is developed to simulate a multi-catchment integrated water cycle in the Norfolk region, UK. Three rural (runoff attenuation features, regenerative farming, floodplain) and two urban (urban green space, constructed wastewater wetlands) NBS interventions are integrated into the model at a range of implementation scales. A many-objective optimization problem with seven water management objectives to account for flow, quality and cost indicators is formulated, and the NSGAII algorithm is adopted to search for optimal NBS portfolios. Results show that rural NBS have more significant impacts across the catchment, which increase with the scale of implementation. Integrated urban-rural NBS planning can improve water availability, water quality, and flood management simultaneously, though trade-offs exist between different objectives. Runoff attenuation features and floodplains provide the greatest benefits for water availability. Regenerative farming is most effective for water quality and flood management, though it decreases water availability by up to 15% because it retains more water in the soil. Phosphorus levels are best reduced by expansion of urban green space to decrease loading on combined sewer systems, though this trades off against water availability, flood, nitrogen and suspended solids. The proposed framework enables spatial prioritisation of NBS, which may ultimately guide multi-stakeholder decision-making, bridging the urban-rural divide in catchment water management.&amp;#160;</jats:p>

Other

Boskovic S, Puchol-Salort P, Mijic A, Maksimovic Cet al., 2023, Systemic design approach for climate change adaptation and enhancement of public health and wellbeing

<jats:p>Climate change-related phenomena are putting an enormous strain on cities&amp;#8217; infrastructure, human livelihoods, public health and citizens well-being. This, together with the increase in urban growth and urbanization, results in an expansion of urban hazards - including water scarcity, disease transmission and consequent social issues.To address this complexity in an urban design context we introduce a Systemic Design (SyD) framework for Multifunctional Nature-based Solutions (NBS) to rethink and contribute to the planet&amp;#8217;s health and people&amp;#8217;s quality of life. The SyD approach focuses on context knowledge creation (environmental, climatic, social&amp;#8230;) that includes perspectives from the point of view of multiple stakeholders, maps its key features, and analyses alternatives for exploiting different design options. Exploratory or suitability modelling supports all these steps.The examples here presented are part of the multidisciplinary project euPOLIS focused on climate change adaptation and on enhancement of public health and citizen&amp;#8217;s well-being through the implementation of nature-based solutions (NBS). Although diversity of the size and the scale of presented case studies, the systematic baseline analysis have revealed that there are several shared conditions, such as an immediate need for improvement of existing green spaces, mitigation of direct and indirect UHI effect and refinement of maintenance systems.A mapping of the local features, and variety of specific spatial and social conditions in public spaces studied in euPOLIS&amp;#8217;s Cities (Belgrade, Gladsaxe, Lodz and Pireas) gives synthetic prospects to better understand the potential effectiveness of Blue-Green Infrastructure (BGI) solutions (design options) in relation to their wider ecosystem and citizens&amp;#8217; concerns.&amp;#160; This leads to a systematic assessment of possible future scenarios of differ

Other

Rico Carranza E, Mijic A, Whyte J, 2023, Co-Creating Digital Twins for Planning of Water Resources and Housing Development

<jats:p>The potential to deliver better, more efficient and sustainable cities has motivated recent research on Digital Twins (DTs) that seek to support planning decisions by displaying analytical evidence to inform collaborative design actions. Prior research identifies different types of DT tools and gives recommendations for their use, but it has not been grounded in engaged research that co-designs DTs with planning users from the context description and problem formulation stage. We report on a research project to co-create DTs with local government planners to visualize interactions between water resources and housing development. We describe co-creating two different DTs starting from the context and problem for water management and assess the steps against these three categories. While engaging with the field we built on prior studies to identify a set of categories relevant to co-creating and assessing DTs: context, governance, spatial and technical definition.&amp;#160; By recording the steps of the DT design process, and contrasting the results with the theoretical proposals, we develop a three-step framework for the co-creation of DTs. This step-by-step framework, illustrated by examples, provides a contribution to the literature on the co-design of DT, and we conclude by discussing implications for practitioners and areas for further research.&amp;#160;&amp;#160;</jats:p>

Other

Zhang Z, Dobson B, Moustakis Y, Meili N, Mijic A, Butler A, Athanasios Pet al., 2023, Assessing the co-benefits of urban greening coupled with rainwater harvesting management under current and future climates across USA cities, Environmental Research Letters, Vol: 18, Pages: 1-11, ISSN: 1748-9326

Globally, urban areas face multiple challenges owing to climate change. Urban greening (UG) is an excellent option for mitigating flood risk and excess urban heat. Rainwater harvesting (RWH) systems can cope with plant irrigation needs and urban water management. In this study, we investigated how UG and RWH work together to mitigate environmental risks. By incorporating a new RWH module into the urban ecohydrological model Urban Tethys-Chloris (UT&C), we tested different uses of intervention approaches for 28 cities in the USA, spanning a variety of climates, population densities, and urban landscapes. UT&C was forced by the latest generation convection-permitting climate model simulations of the current (2001–2011) and end-of-century (RCP8.5) climate. Our results showed that neither UG nor RWH, through the irrigation of vegetation, could significantly contribute to mitigating the expected strong increase in 2 m urban canyon temperatures under a high-emission scenario. RWH alone can sufficiently offset the intensifying surface flood risk, effectively enhance water saving, and support UG to sustain a strong urban carbon sink, especially in dry regions. However, in these regions, RWH cannot fully fulfill plant water needs, and additional measures to meet irrigation demand are required to maximize carbon sequestration by urban vegetation.

Journal article

Liu L, Dobson B, Mijic A, 2023, Optimisation of urban-rural nature-based solutions for integrated catchment water management, JOURNAL OF ENVIRONMENTAL MANAGEMENT, Vol: 329, ISSN: 0301-4797

Journal article

Tan Z, Berry A, Charalambides M, Mijic A, Pearse W, Porter A, Ryan M, Shorten R, Stettler M, Tetley T, Wright S, Masen Met al., 2023, Tyre wear particles are toxic for us and the environment

This briefing paper discusses the current knowledge on the effects of tyre wear particles on our health and environment, highlights the need for an ambitious research agenda to build further understanding of the impacts on people and nature and develop solutions, and includes recommendations for policymakers.

Report

Muhandes S, Dobson B, Mijic A, 2023, A method for adjusting design storm peakedness to reduce bias in hydraulic simulations, Proceedings of the Institution of Civil Engineers - Water Management, Vol: 176, Pages: 1-13, ISSN: 1741-7589

In the UK, decision makers use hydraulic model outputs to inform funding, connection consent, adoption of new drainage networks and planning application decisions. Current practice requires the application of design storms to calculate sewer catchment performance metrics such as flood volume, discharge rate and flood count. With flooding incidents occurring more frequently than their designs specify, hydraulic modelling outputs required by practice are questionable. The main focus of this paper is the peakedness factor (ratio of maximum to average rainfall intensity) of design storms, adjudging that this is a key contributor to model bias. Hydraulic models of two UK sewer catchments were simulated under historical storms, design storms and design storms with modified peakedness to test bias in modelling outputs and the effectiveness of peakedness modification in reducing bias. Sustainable drainage systems (Suds) were implemented at catchment scale and the betterment achieved in the modelling outputs was tested. The proposed design storm modification reduced the bias that occurs when driving hydraulic models using design storms in comparison with historical storms. It is concluded that Suds benefits are underestimated when using design rainfall because the synthetic rainfall shape prevents infiltration. Thus, Suds interventions cannot accurately be evaluated by design storms, modified or otherwise.

Journal article

Fan PY, Chun KP, Mijic A, Tan ML, Yetemen Oet al., 2022, Integrating the Budyko framework with the emerging hot spot analysis in local land use planning for regulating surface evapotranspiration ratio, JOURNAL OF ENVIRONMENTAL MANAGEMENT, Vol: 316, ISSN: 0301-4797

Journal article

Dobson B, Barry S, Maes-Prior R, Mijic A, Woodward G, Pearse WDet al., 2022, Predicting catchment suitability for biodiversity at national scales, WATER RESEARCH, Vol: 221, ISSN: 0043-1354

Journal article

Puchol-Salort P, Boskovic S, Dobson B, van Reeuwijk M, Mijic Aet al., 2022, Water neutrality framework for systemic design of new urban developments, Water Research, Vol: 219, Pages: 1-13, ISSN: 0043-1354

The climate emergency and population growth threaten urban water security in cities worldwide. Growth, urbanisation, and changes to way of life have increased housing demand, requiring cities such as London to increase their housing stock by more than 15% over the next 10 years. These new urban developments will increase water demand, urban flood risk, and river water pollution levels; therefore, an integrated systems-based approach to development and water management is needed. Water Neutrality (WN) has emerged as a concept to frame the concerns about escalating water stresses in cities. We frame WN as a planning process for new urban developments that aims to minimise impacts on urban water security and offset any remaining stresses by retrofitting existing housing stock. In this work, we present a novel systemic design framework for future urban planning called CityPlan-Water, which guides how WN might be achieved to tackle current and future water pressures at a city scale. CityPlan-Water integrates spatial data with an integrated urban water management model, enabling urban design at a systems level and systematic assessment of future scenarios. We define a Water Neutrality Index that captures how successful a given urban planning scenario is in achieving WN and how multiple interventions could be combined at a city scale to improve WN. Results from CityPlan-Water suggest that it will be necessary to retrofit almost the same number of existing homes with WN design options to completely offset the impact imposed by proposed new developments. Combining options such as water efficient appliances, water reuse systems, and social awareness campaigns can offset the impact of new development on water demand by 70%, while to neutralise potential flood risk and water pollution at a city scale, interventions such as rainwater harvesting and Blue Green Infrastructure need to be added both in new urban developments and 432,000 existing London households. We see CityPlan-Wa

Journal article

Zhang Z, Paschalis A, Mijic A, Meili N, Manoli G, Van Reeuwijk M, Fatichi Set al., 2022, A mechanistic assessment of urban heat island intensities and drivers across climates, Urban Climate, Vol: 44, Pages: 1-18, ISSN: 2212-0955

The urban heat island effect (UHI) has been widely observed globally, causing climate,health, and energy impacts in cities. The UHI intensities have been found to largelydepend on background climate and the properties of the urban fabric. Yet, a completemechanistic understanding of how UHIs develop at a global scale is still missing. Usingan urban ecohydrological and land-surface model (urban Tethys-Chloris) incombination with multi-source remote sensing data, we performed simulations for 49large urban clusters across the Northern Hemisphere in 2009-2019 and analysed howsurface and canopy air UHIs (SUHI and CUHI, respectively) develop during day andnight. Biophysical drivers triggering the development of SUHIs and CUHIs have similardependencies on background climate, but with different magnitudes. In humid regionsdaytime UHIs can be largely explained by the urban-rural difference inevapotranspiration, whereas heat convection and conduction are important in aridareas. Plant irrigation can largely promote daytime urban evapotranspiration only inarid and semi-arid climates. During night, heat conduction from the urban fabric to theenvironment creates large UHIs mostly in warm arid regions. Overall, this studypresents a mechanistic quantification of how UHIs develop worldwide and proposesviable solutions for sustainable climate-sensitive mitigation strategies.

Journal article

O'Keeffe J, Pluchinotta I, De Stercke S, Hinson C, Puchol-Salort P, Mijic A, Zimmermann N, Collins AMet al., 2022, Evaluating natural capital performance of urban development through system dynamics: A case study from London., Science of the Total Environment, Vol: 824, Pages: 1-12, ISSN: 0048-9697

Natural capital plays a central role in urban functioning, reducing flooding, mitigating urban heat island effects, reducing air pollution, and improving urban biodiversity through provision of habitat space. There is also evidence on the role played by blue and green space in improving physical and mental health, reducing the burden on the health care service. Yet from an urban planning and development view, natural capital may be considered a nice to have, but not essential element of urban design; taking up valuable space which could otherwise be used for traditional built environment uses. While urban natural capital is largely recognised as a positive element, its benefits are difficult to measure both in space and time, making its inclusion in urban (re)development difficult to justify. Here, using a London case study and information provided by key stakeholders, we present a system dynamics (SD) modelling framework to assess the natural capital performance of development and aid design evaluation. A headline indicator: Natural Space Performance, is used to evaluate the capacity of natural space to provide ecosystem services, providing a semi-quantitative measure of system wide impacts of change within a combined natural, built and social system. We demonstrate the capacity of the model to explore how combined or individual changes in development design can affect natural capital and the provision of ecosystem services, for example, biodiversity or flood risk. By evaluating natural capital and ecosystem services over time, greater justification for their inclusion in planning and development can be derived, providing support for increased blue and green space within cities, improving urban sustainability and enhancing quality of life. Furthermore, the application of a SD approach captures key interactions between variables over time, showing system evolution while highlighting intervention opportunities.

Journal article

Hinson C, O'Keeffe J, Mijic A, Bryden J, Van Grootveld J, Collins AMet al., 2022, Using natural capital and ecosystem services to facilitate participatory environmental decision making: Results from a systematic map, PEOPLE AND NATURE, Vol: 4, Pages: 652-668

Journal article

CIWEM, 2022, River water quality and storm overflows A systems approach to maximising improvement

his report presents the findings of research involving stakeholder engagement, systems mapping and policy and regulatory analysis around the issue of sewage pollution from storm overflows.It considers the challenges in their widest context, understanding where certain action should be driven by significant actors in the system and factors which combine to create the current situation, but can be considerably enhanced though action in a range of other complementary areas. The report’s focus is on England, but the principles discussed apply to greater or lesser extents to the devolved nations of the UK, as well as internationally.

Report

Dobson B, Barry S, Maes-Prior R, Mijic A, Woodward G, Pearse WDet al., 2022, Predicting catchment suitability for biodiversity at national scales

<jats:title>Abstract</jats:title><jats:p>Biomonitoring of water quality and catchment management are often disconnected, due to mismatching scales. Great effort and money is spent each year on routine reach-scale surveying across many sites, particularly in the UK, and typically with a focus on pre-defined indicators of organic pollution to compare observed vs expected subsets of common macroinvertebrate indicator species. Threatened species are often ignored due to their rarity as are many invasive species, which are seen as undesirable even though they are increasingly common in freshwaters, especially in urban ecosystems. However, these taxa are monitored separately for reasons related to biodiversity concerns rather than for gauging water quality. Repurposing such monitoring data could therefore provide important new biomonitoring tools that can help catchment managers to directly link the water quality that they aim to control with the biodiversity that they are trying to protect. Here we used the England Non-Native and Rare/Protected species records that track these two groups of species as a proof-of-concept for linking catchment scale management of freshwater ecosystems and biodiversity to a range of potential drivers across England. We used national land use (Centre for Ecology and Hydrology land cover map) and water quality indicator (Environment Agency water quality data archive) datasets to predict the presence or absence of 48 focal threatened or invasive species of concern routinely sampled by the English Environment Agency at catchment scale, with a median accuracy of 0.81 area under the receiver operating characteristic curve. A variety of water quality indicators and land-use types were useful in predictions, highlighting that future biomonitoring schemes could use such complementary measures to capture a wider spectrum of drivers and responses. In particular, the percentage of a catchment covered by freshwater was the single most

Journal article

Boskovic S, Puchol-Salort P, Krivtsov V, Mijic Aet al., 2022, Systemic Design Approach: A Framework for a resilient urban transition

<jats:p>&amp;lt;p&amp;gt;Cities are open living systems, which rely on the confluence of multiple layers of infrastructure and corresponding services. The interaction among these components is made even more complex by the demands of businesses and governments, together with constraints arising from ecological and environmental considerations. Climate change-related phenomena are putting an enormous strain on cities&amp;amp;#8217; infrastructure, basic services, human livelihoods, public health and well-being. In many parts of the world concerns mount in regard to the scarcity of resources and growing risk of natural disasters (heat waves, urban flooding, droughts).&amp;amp;#160; The converse also holds true, cities are major contributors to climate change through greenhouse gas emissions, notwithstanding other sources of pollution. This, together with the increase in urban growth and urbanization, results in an expansion of urban hazards - including water pollution, disease spread and issues with food security. Despite these pressing issues, we are witnessing an almost paradoxical mismatch between the needs of future cities and the practices currently used in numerous urban projects. A wholesale re-thinking of existing urban design methods at systems level (Systemic Design), is therefore not only necessary, but also provides significant opportunities to explore critical aspects of Blue-Green Infrastructure (BGI) and systematic assessment of possible future scenarios of different scales (local, urban, regional&amp;amp;#8230;). Nature-based solutions (NBS) are at the very core of the conception and development of BGI and provide a range of ecosystem services including alleviation of flood risk, mitigation of climatic effects, increase in biodiversity and amenity values, improvements in water quality, and further, rather more intangible benefits related to the residents&amp;amp;#8217; health and wellbeing.&amp;lt;/p&amp;gt;&am

Journal article

Zhang Z, Paschalis A, Mijic A, Dobson B, Butler Aet al., 2022, Assessing co-benefits of urban greening coupled with rainwater harvesting management under current and future climates across USA cities

<jats:p>&amp;lt;p&amp;gt;Globally, urban areas will face multiple water-related challenges in the near future. The main challenges are intensified droughts leading to water scarcity, increased flood risk due to extreme rainfall intensification, increased total water demand due to an increasing urban population, amplified urban heat island intensities due to urban sprawl, and reduction in urban carbon sink due to plant water stress. Urban greening is an excellent option for mitigating flood risk and excess urban heat. Meanwhile, rainwater harvesting (RWH) systems can cope with water supply needs and urban water management. In this study, we investigated how urban greening and RWH can work together to mitigate the aforementioned risks. We evaluate the joined-up management approach under climate projections for 30 cities in the USA spanning a variety of climates, population densities and urban landscapes. By incorporating a new RWH module in the urban ecohydrological model UT&amp;amp;C and flexible operational rules of reusing harvested water for domestic use and urban green space irrigation, we tested 4 intervention approaches: control, RWH installation, urban greening supported by RWH, and urban greening supported by traditional irrigation (i.e., supplying via mains water). Each intervention approach was evaluated using our adapted version of UT&amp;amp;C and forced by the last generation convection-permitting model simulations of current (2001-2011) and end-of-century (RCP8.5) climate from Weather Research and Forecasting (WRF). The volume of RWH is assumed to be 2000L per household for all cities. Results showed that neither urban greening nor RWH could contribute significantly to reducing the expected increase in canyon temperature, because of the strong change in background climate (i.e., increases in average atmospheric temperature). However, RWH alone can sufficiently reduce the intensifying surface flood risk and effectively enhance water

Conference paper

Mijic A, Liu L, O'Keeffe J, Dobson B, Chun KPet al., 2022, Solving water management paradoxes requires a systems meta-model

<jats:p>&amp;lt;p&amp;gt;Sustainable development is becoming increasingly urgent in the post-COVID recovery and climate crisis era. Despite this need, the water management scientific community is still deciding how to comprehensively represent and assess the role of humans within the hydrological cycle. An explanation may be found in numerous examples where water managers are often challenged when their decisions, policies, and interventions lead to a range of unintended consequences that cause increased pressures on the environment, which have been described by socio-hydrological paradoxes. If the paradoxes are seen as the main obstacles hindering sustainable development in the context of water management, then investigating their mechanisms and understanding logic may help us to reveal unintended system responses and define guiding principles critical for designing robust and sustainable water management plans. We analyse the socio-hydrological paradoxes from a systems perspective and assume that water management decisions and plans developed adopting a linear thinking and goals-focused approach are likely to neglect consequential effects which occur throughout the wider system. This definition enables us to rename the phenomena into water management paradoxes, which might be fundamentally related to systems&amp;amp;#8217; complexity and unexpected behaviour arising from internal feedbacks along with external driving forces that generate nonlinear outcomes which are inconsistent with the expected results or responses from inputs and actions within the system.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;To find solutions for the water management paradoxes, we hypothesise that they can be described in the context of three feedback mechanisms, which define the purpose of systems water management (SYWM) as coordination of development and water infrastructure with environmental management to improve the quality of life. We argue that the lack of

Journal article

Liu L, Dobson B, Mijic A, 2022, Coordinating systems headroom for more efficient multi-catchment water quality management at a critical checkpoint&amp;#160;

<jats:p>&amp;lt;p&amp;gt;Managing river water quality at critical checkpoints that have significant impacts on water use is important for sustainable catchment development. This requires managing the whole multi-catchment systems upstream of a critical checkpoint. Concepts of systems headroom (deficit below permit) and excess (extra above permit) have been used to distinguish sub-catchments&amp;amp;#8217; roles in pollution contribution. Based on the concepts, we propose a three-phase management approach. In the first phase, we frame the headroom and excess at temporal, spatial, and source domains and evaluate them to investigate the systems mechanisms. The evaluation is by simulating physical processes a semi-distributed integrated model (CatchWat-SD). We apply the model to 12 sub-catchments that make up the Upper Thames river basin and validate it using monitoring data. In the second phase, we incorporate the evaluated headroom and excess in loads allocation to develop a strategy that coordinates systems headroom for more efficient and realistic interventions. In the last phase, we validate the strategies by simulating the scenarios that coordinate headroom at different domains and evaluating them in water quality improvement, efficiency, temporal steadiness, spatial homogeneity, and practical feasibility. Results show that dry seasons, downstream catchments and urban sources generally have more excess. Thus, more target loads reduction is allocated to dry season, downstream catchments and urban sources in the fully coordinated scenario. The higher degree of headroom coordination a strategy achieves, the better performance this strategy generally obtains in all five metrics. This study emphasises the need to incorporate headroom in loads reduction allocation, which helps to more efficiently improve systems water quality performance with a more realistic degree of intervention. The whole procedure can be further expanded to water quality managemen

Journal article

Dobson B, Muhandes S, Borup M, Mijic Aet al., 2022, Clustering networks: reducing the complexity of urban hydrology models with graph partitioning for fast and flexible simulations

<jats:p>&amp;lt;p&amp;gt;Graph partitioning algorithms separate nodes of a graph into clusters, resulting in a smaller graph that maintains the connectivity of the original. In this study we use graph partitioning to produce reduced complexity sewer networks that can be simulated by a novel urban hydrology model. We compare a variety of algorithms, including spatial clustering, spectral clustering, heuristic methods and we propose two novel methods. We show that the reduced network that is produced can provide accurate simulations in a fraction of the time (100-1000x speed up) of typical urban hydrology models. We address some likely use cases for this approach. The first is enabling a user to pre-specify the desired size of the resultant network, and thus the fidelity and speed of simulation. The second is enabling a user to preserve desired locations that must remain in their own cluster, for example, locations with complex hydraulic structures or where monitoring data exists. The third is a case where detailed sewer network data is not available and instead the network must be simulated hundreds of times in a random sampling of network parameters, something that is only possible with the speed gains that our method allows. We envisage that this reduced complexity approach to urban hydrology will transform how we operate and manage sewer systems, enabling a far wider range of model applications than are currently possible, including optimisation and scenario analysis.&amp;lt;/p&amp;gt;</jats:p>

Journal article

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