Water Sensitive Cities Research Articles

The urban water metabolism of Cape Town: Towards becoming a water sensitive city

To improve its resilience to increasing climatic uncertainty, the City of Cape Town (the City) aims to become a water sensitive city by 2040. To undertake this challenge, a means to measure progress is needed that quantifies the urban water systems at a scale that enables a whole-of-system approach to water management. Using an urban water metabolism framework, we (1) provide a first city-scale quantification of the urban water cycle integrating its natural and anthropogenic flows, and (2) assess alternative water sources (indicated in the New Water Programme) and whether they support the City towards becoming water sensitive. We employ a spatially explicit method with particular consideration to apply this analysis to other African or Global South cities. At the time of study, centralised potable water demand by the City amounted to 325 gigalitres per annum, 99% of which was supplied externally from surface storage, and the remaining ~1% internally from groundwater storage (Atlantis aquifer). Within the City’s boundary, runoff, wastewater effluent and groundwater represent significant internal resources which could, in theory, improve supply efficiency and internalisation as well as hydrological performance. For the practical use of alternative resources throughout the urban landscape, spatially explicit insight is required regarding the seasonality of runoff, local groundwater storage capacity and the quality of water as it is conveyed through the complex urban landscape. We suggest further research to develop metrics of urban water resilience and equity, both of which are important in a Global South context.
 Significance:
 
 This research provides the initial groundwork of quantifying the magnitude of the urban water cycle of the City of Cape Town at an annual timescale, in relation to becoming a water sensitive city. The urban water metabolism framework used in this study provides important insight to assess whole-of-system urban water dynamics and to benchmark progress towards becoming water sensitive. By quantifying the magnitude of flows into and out of the urban system, this research sheds light on the opportunities to improve circularity in the urban water cycle. The spatial approach adopted here provides a platform to interrogate the urban landscape and its role in the urban water cycle. By using data products that are available via national data sets or remote sensing, this approach can be applied to other African or Global South where data is characteristically scarce. Further work is required to establish metrics that can adequately describe urban water resilience and equity.

Assessment and simulation of water transfer for the megacity Istanbul

ABSTRACT The population of Istanbul increased from three to fifteen million from 1970 to 2018. The city, which has no perennial fresh water resources within its metropolitan boundaries, has long imported water from other basins. In this study, the performance of a reservoir system fed by surface runoff and inter-basin water transfer is investigated and applied. Simulations are run for water demand estimates and with Gamma-distributed realizations of monthly precipitation, based on 105-year temperature and precipitation data. The research shows that after 2060, existing and transferred water alone will not be sufficient to meet demand and it is expected that the megacity Istanbul will be on a path towards water crisis after this date, if not before. It is concluded that it is vital to adopt a more diversified water supply and demand management portfolio with extensive Integrated Water Resources Management (IWRM) measures for “Water Sensitive Cities”. Strategies for reliable system operation that take foreseeable environmental problems into account are proposed.

Best Management Practices for the Transition to a Water-Sensitive City in the South of Portugal

The uncertainty that arises from future environmental and climatic challenges requires new approaches towards urban water management in Mediterranean cities. In this work, an urban water cycle (UWC) strategy based on the best management practices (BMPs) of water-sensitive urban design (WSUD) is proposed for the transition of a coastal city in the south of Portugal into a water-sensitive city (WSC), in line with the Municipal Strategy for Climate Change Adaptation of Loulé (EMAAC of Loulé). The city’s watershed was identified using the ArcMap Hydrology toolset with geospatial data provided by Loulé’s Municipal Council Operational Unit for Adaptation to Climate Change and Circular Economy (UOACEC). A broad characterisation of the study area was conducted, identifying existing resources to further develop a SWOT (strengths, weaknesses, opportunities, threats) analysis. The Hydrology toolset outputs, precipitation events records, and survey results were used to identify flood-prone areas. The opportunities and threats identified were further used to develop the transition strategy, which is focused on critical areas identified and supported by BMPs, including source control, attenuation, treatment and infiltration measures, permeable pavements, rainwater harvesting systems, and bioretention basins. The approach is designed to increase the city’s resilience to climate extremes, as well as community engagement towards UWC management.

Challenges of Water Sensitive Cities in Mexico: The Case of the Metropolitan Area of Guadalajara

Mexico is currently facing important water management challenges. Cities in the country are facing water scarcity and at the same time they struggle with floods during the raining season. The water sensitive urban design (WSUD) approach has proved to be helpful around the world in tackling urban water challenges such as floods or water scarcity. The WSUD approach highlights the role of both the water cycle and the water utilities systems, when transitioning towards a water sensitive stage. Therefore, the objective of this research is to demonstrate the relevance for cities of a WSUD approach by analyzing the current situation of the water cycle and the water utility in the Metropolitan Area of Guadalajara (MAG). This research proposes a case study approach. Within our case of study, we focused on the water cycle and the water utilities system (Sistema Intermunicipal de los Servicios de Agua Potable y Alcantarillado (SIAPA)) and ask two questions: (1) What are the causes of water scarcity and flooding in the MAG? and (2) What are the proposals to solve these problems under a WSUD approach? By answering these questions, we identified that the water management in the MAG corresponds to a single purpose infrastructure. This type of water management is common in developing cities and does not contribute to solve the problems of water scarcity and floods. The water supply policy is based only on the construction of large dams disregarding the storage and use of rainwater, and reuse of greywater, and water-conservation devices. In order to transition towards a water sensitive stage, changes in the water policy need to take place and a WSUD approach that includes multi-purpose infrastructure, should be considered.

When urban stormwater meets high groundwater

New land releases in the Perth Region on Western Australia’s Swan Coastal Plain are increasingly constrained by seasonally high groundwater (within 4m of the land surface). The measurement, modelling, and management of the effects of urbanisation in these high groundwater environments remains a challenging problem. To address this problem, the Cooperative Research Centre for Water Sensitive Cities (CRWSC) funded the “Knowledge-based water sensitive city solutions for groundwater impacted developments” Integrated Research Project, IRP5. In 2019, this project convened an Expert Panel to assess best-practice, and make recommendations to land development, engineering consulting, regulatory and advisory stakeholders. The Expert Panel explored strategies for groundwater risk assessment and provided technical guidance for measuring, modelling and predicting changes in groundwater as urbanisation progresses. It also obtained extensive input from stakeholders on the need to reduce the costs and risks of urban development in sites with high groundwater. In this paper, we argue that, by integrating technical best-practice groundwater assessments with design innovations and reforms to governance, urban development on high groundwater sites on the Swan Coastal Plain can minimise the current reliance on large volumes of sand fill. Although challenging, shifting to a low-fill development paradigm would represent a triple-bottom-line “win” for developers, homeowners and the environment.

The water-sensitive city meets biodiversity: habitat services of rain water management measures in highly urbanized landscapes

The water-sensitive city meets biodiversity: habitat services of rain water management measures in highly urbanized landscapes

Flood-reduction scenario based on land use in Kedurus river basin using SWAT hydrology model

The rapid growth population phenomenon has causes excessive land demand for residential and economic activity. Moreover, the rapid urbanization also increases the contribution of land constrains. Land conversion from conservation to cultivation uses affects the surface runoff volume that leads to flooding. According to these problems, it is necessary to take steps to control flood in Kedurus Watershed. One of the proper urban development concept is the Water Sensitive City (WSC). The protection against flood in WSC can be accomplished with the land use arrangement that can reduces the surface runoff. The aim of this research is to determine the proper land use scenario to reduce floods in Kedurus Watershed. In order to reach this aim, the writer uses sensitivity analysis to identify the proper land use scenario to be applied in the watershed and SWAT to select the best scenario. The efforts to reduce flood through the land use scenario (scenario 2) could reduce the flood volume by 44,320.32 m3 or 8.11% of the total volume of flood in the area. The average reduction of flood volume in each sub basins is 12,92% and the highest number of reduction is 65,67% (sub basin 22).

Deconstructing water sensitivity: experiences from global cities

Cities around the world today are facing common issues of rapid urbanization, varying climatic conditions, and challenging economies, which are known to impact the environment and quality of life. In response, multiple concepts have emerged related to water management practices over the past few decades. One such recently discussed concept is of Water Sensitive Cities, which envisions a place that judiciously uses its existing resources, building resilience for tomorrow by simultaneously ensuring community participation for sustainability. Synonymous with this notion, there exist other overlapping concepts such as Water Sensitive Urban Design, Low Impact Development, Best Management Practices, Green Infrastructure, and the like. This research intends to deconstruct these concepts and their practices through a review of 120 case studies located across different agro-climatic and water-stressed regions globally. These cases were analyzed for their inclination to three thematic components: society, water sensitive urbanism, and technologies. The evidence suggests that there is not a single water sensitive city in the world today. This paper discusses the Utopian nature of this notion and identifies relevant pathways to explore to reach the destined vision of Water Sensitive Cities.

Better Urban Drainage for Liveable Cities - creating blue green infrastructure through science translation, collaboration and multi-stakeholder governance

The paper describes drainage management as a wicked problem, where one agency’s solutions to their objectives created problems for another; with competing storm water design objectives and a splintered approach to the spending of government monies for flood prevention, water quality, and the liveability of the City. At the strategic level, the issue was addressed through integrated water policy. The paper identifies how science and policy translation were used to achieve a radically different and sustainable strategic direction for the City. The City has taken advantage of an opportunity to re-envision assets from grey to blue-green in the regeneration of the drainage system; achieved through multi-stakeholder engagement, collaboration, and policy development as part of its transition towards a water sensitive city.

Water Sensitive Cities Index: A diagnostic tool to assess water sensitivity and guide management actions

Cities are wrestling with the practical challenges of transitioning urban water services to become water sensitive; capable of enhancing liveability, sustainability, resilience and productivity in the face of climate change, rapid urbanisation, degraded ecosystems and ageing infrastructure. Indicators can be valuable for guiding actions for improvement, but there is not yet an established index that measures the full suite of attributes that constitute water sensitive performance. This paper therefore presents the Water Sensitive Cities (WSC) Index, a new benchmarking and diagnostic tool to assess the water sensitivity of a municipal or metropolitan city, set aspirational targets and inform management responses to improve water sensitive practices. Its 34 indicators are organised into seven goals: ensure good water sensitive governance, increase community capital, achieve equity of essential services, improve productivity and resource efficiency, improve ecological health, ensure quality urban spaces, and promote adaptive infrastructure. The WSC Index design is a quantitative framework based on qualitative rating descriptions and a participatory assessment methodology, enabling local contextual interpretations of the indicators while maintaining a robust universal framework for city comparison and benchmarking. The paper demonstrates its application on three illustrative cases. Rapid uptake of the WSC Index in Australia highlights its value in helping stakeholders develop collective commitment and evidence-based priorities for action to accelerate their city's water sensitive transition. Early testing in cities in Asia, the Pacific and South Africa has also showed the potential of the WSC Index internationally.

WITHDRAWN: Water Sensitive Cities Index: A diagnostic tool to assess water sensitivity and guide management actions

The Publisher regrets that this article is an accidental duplication of a published article, http://dx.doi.org/10.1016/j.watres.2020.116411. The duplicate article has therefore been withdrawn.The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal

Design Thinking Methodology to Achieve Household Engagement in Urban Water Sustainability in the City of Huelva (Andalusia)

To advance to water sensitive cities (WSC) it will be necessary to achieve the commitment of the citizens, involving them in this transition. Citizen participation is considered essential, and one of the possible approaches to achieve this is through Design Thinking (DT), a human-centered methodology that allows creating a framework to develop the hydrosocial contract. The Suez group proposed the challenge of collecting initiatives to achieve more efficient use of urban water in homes, by conducting a pilot in one of its investee companies, Aguas de Huelva. Our research proposal, selected by the Suez group, to achieve greater engagement of households regarding efficient water use, was to develop a web-based prototype applying DT methodologies, which would allow us to generate new messages and meanings regarding water, producing an innovation of meaning that would enable tracking the progress of the results. This article describes the approved framework to carry out the pilot experience in the homes of the city of Huelva in Andalusia, Spain.

Transforming Built Environments: Towards Carbon Neutral and Blue-Green Cities

In the 21st century, the creation of built environments that are carbon neutral and water sensitive is critical for addressing sustainable urban development challenges. Both require transformative change: Decarbonisation to mitigate greenhouse gas emissions and incorporation of green-blue water sensitive solutions to adapt to climate change impacts. Transition pathways in both arenas involve combinations of new technology, innovative urban design, enabling policies and regulations, new processes for planning and managing urban development, and demand-side changes in consumer attitudes and practices for urban living related to energy and water use. In this paper, we present new knowledge, concepts and frameworks developed for application in Australia, as well as internationally, through research by the national Cooperative Research Centres for Low Carbon Living (CRCLCL) and Water Sensitive Cities (CRCWSC) between 2012 and 2020. These findings and outputs illustrate common features of the research strategies and initiatives that were central to the activities of the CRCs, and highlight promising directions for collaborative interdisciplinary and transdisciplinary research that drives urban sustainability transformations towards carbon neutral and blue-green cities.

Scenarios analysis using water-sensitive urban design principles: a case study of the Cape Flats Aquifer in South Africa

A feasibility assessment was undertaken on the application of water-sensitive urban design (WSUD) for the Cape Flats Aquifer in Cape Town, South Africa, at the local scale. The study contributes towards the planning of water-sensitive cities in the future. A three-dimensional steady-state groundwater flow model was applied to the Cape Flats Aquifer to predict WSUD scenarios by incorporating managed aquifer recharge (MAR). Analysis of the scenarios of varying recharge estimates and groundwater abstraction rates, predicted using the model, indicated that the water-table distribution and outflows from identified groundwater balance components show direct proportionality to the varying recharge scenarios. A notable increase in these outflows was observed when the recharge rate was increased by 50%. Varying groundwater abstraction scenarios indicated that with increasing abstraction rates, water levels and outflows from groundwater balance components also decreased accordingly. A notable decline in water levels and outflows was established at an abstraction rate of 2.5 and 5 L/s, respectively. Similar to the previous regional studies in the area, the results from the predicted scenarios show that there is a potential for applying WSUD, particularly MAR, at site-specific scale within the Cape Flats Aquifer. However, shallow groundwater levels during wet seasons limit the opportunities for application of WSUD in the area. This finding would provide an important reference to the ongoing debate on the Cape Town water crisis and similar environmental conditions where WSUD is considered.

China's sponge city development for urban water resilience and sustainability: A policy discussion

China recently introduced a national policy initiative called sponge city development as a holistic, ecosystem-based approach integrated with urban planning and development to address storm-induced pluvial flooding as well as other urban water and environmental issues. The initiative, while following the U.S. low impact development with a concept also similar to the U.K. sustainable drainage systems and Australian water sensitive cities, is subject to a major design issue in practice with infrastructure projects of similar types adopted unanimously across regions despite spatially diverse and heterogeneous hydrological and biophysical conditions. The ecosystem services framework as applied to the urban setting, particularly its holistic consideration of ecosystem structure and management intervention in relation to services or benefits delivery, can and should guide the planning, design, development, and evaluation of relevant projects or nature-based practices for carrying out the policy initiative, a perspective of practical value with foreseeable transformative impact that has received little recognition in China's current green urban movement toward water resilience and sustainability.

Towards a water-sensitive city: level of regional damage to floods in Makassar City (case study: Manggala District)

Makassar City is a large city that is facing climate change, population growth and rapid urbanization. This has an impact on increasing land market and demand for servicing facilities and infrastructure. Those impacts can decrease environmental quality, such as environmental degradation and natural disasters. One problem that often occurs every year is the problem of flooding. One of the districts in Makassar City that experienced a flood was Manggala District. This is the background of the researchers to provide an overview of the level of flood vulnerability based on flood vulnerability variables. The variables used in determining the level of flood vulnerability are land cover, rainfall, drainage density, and slope. The objectives of this study are to (1) identify flood vulnerabilities in Manggala District, and (2) identify steps towards Water Sensitive City in its handling solutions from the perspective of urban water management. This study uses a quantitative analysis method with an overlay analysis approach to analyze the vulnerability of flood disasters.

Frameworks for urban water sustainability

AbstractIntegrated water management, sustainable water management, water sensitive cities, and other formulations are often presented as the latest in a series of paradigms of water management. This implies a unified approach, while urban water debates reflect a wide diversity of political, social, and technical viewpoints. Five distinct but overlapping frameworks for urban water sustainability are evident in research, policy and practice, reflecting wider environmental theory, politics, and discourse. Sustainable development is based on meeting the needs for water and sanitation of the urban poor. Ecological modernization focuses on policies to improve water efficiency and treatment through technological innovation and individual behavior change. Socio‐technical framings aim to understand how change in water systems occurs across physical and institutional scales and addresses the co‐evolution of infrastructures, cultures, and everyday practices. Urban political ecology analyses water infrastructure in terms of relationships of power, pointing to the unequal distribution of costs and benefits of urban water management for the environment and citizens. Radical ecology addresses the relationship between human culture and non‐human nature, proposing fundamental reorganization of society to solve ecological and hydrological crises. Characterizing alternate frameworks of urban water sustainability provides clarity on the underlying assumptions, methods, and politics across a diversity of approaches. Frameworks may be deployed strategically to deliver policy impact, or may reflect deeply held political or epistemological standpoints. Understanding different conceptions of urban water sustainability provides the basis for more constructive dialogue and debate about water and its role in sustainable cites.This article is categorized under: Engineering Water > Planning Water Human Water > Water Governance Water and Life > Conservation, Management, and Awareness

Urban water management and climate change adaptation: A self-assessment study by seven midsize cities in the North Sea Region

Cities are experiencing the impacts of climate change through water-related disasters, while the sustainable management of water resources remains crucial for urban climate resilience. Accordingly, frameworks that integrate urban water management with climate change adaptation become increasingly relevant. The Water Sensitive Cities (WSC) framework is built on three pillars that address cities’ role as communities and networks, water catchments, and providers of ecosystem services. A major element of the framework is the WSC index, which can be applied to assess cities by using multiple indicators under each pillar. With the objectives of adjusting and testing the WSC index in the context of the North Sea Region through a transdisciplinary knowledge co-production process, this paper presents the results from a self-assessment conducted by seven midsize cities. Insights gained from the comparison of self-assessment results are twofold. Firstly, the cities need to value the benefits of ecosystem services for climate change adaptation, and integrate climate change into other sectors. Secondly, the cities differ regarding the priority of climate change, and even the cities that aspire to be frontrunners have weaknesses. The application of the self-assessment process also creates an exchange and mutual learning platform for cities, and increases their awareness on climate resilience.

Future city - challenges and opportunities for water-sensitive sustainable cities, in India

Rapid urbanization, depleted resources, imbalance in urban hydrologic cycle, tremendous pressure on ecological functions, unhygienic and unhealthy environment is the scenario in almost all Indian cities. Water resources in the urban areas are fast depleting while the demand for the same is fast growing. Now more than ever before, water resources face threats from climate change, population growth, aging infrastructure, declining revenues, and a variety of other localized challenges. The challenge is to find ecologically sustainable, socially justified, economically viable, culturally transferable, and technological and managerial innovations which are appropriate to meet the needs of the future generations i.e. sustainable urban development. What is sustainable development? Detail study of sustainable development goals especially related to water, various recent trends of city development at major parts of world, from water perspective like Water-sensitive city, Water-wise city. Water-centric sustainable community can prove to be an ideal model of city development that will be truly sustainable with full focus on ecological balance so that social and economical sustainability also can be achieved.

Modelling a ‘business case’ for blue-green infrastructure: lessons from the Water Sensitive Cities Toolkit

AbstractStormwater management through Blue-Green Infrastructure (BGI) delivers multiple benefits across urban environments. However, current integrated modelling tools fail to provide a simplified way of assessing these benefits. In this study, we reflected upon the development of an interdisciplinary BGI planning-support tool, known as the Water Sensitive Cities Toolkit (the WSC Toolkit) and offer guidance for effective tool development going forward. Based on interdisciplinary research, the WSC Toolkit incorporates a suite of independent sub-modules but can be connected together to provide integrated assessment, allowing evidence-based quantification of multiple benefits associated with BGI, e.g., stormwater treatment and harvesting, stream hydrology, erosion, minor flooding, urban microclimate, etc. Distinguished from other larger complex models, the WSC Toolkit was characterised by its simplicity, modularity and extensibility, providing scenario-based integrated assessment of these benefits. Through case studies, we demonstrated how the WSC Toolkit can be used to support improved decision-making towards maximising the benefits of BGI. We also showed how it can act as a platform for practical application of latest research outcomes and meanwhile encouraging interdisciplinary collaboration. We reflect upon five key lessons that could guide future researchers in developing effective integrated assessment tools, particularly within highly interdisciplinary fields such as BGI.