Water Sensitive Cities Research Articles

Assessing the water metabolism of coastal urban areas based on the water mass balance framework across time periods: A case study of Cape Town, South Africa

The status of water resources in many coastal cities has become increasingly fragile. In a changing climate, the amount and intensity of rainfall have continued to decline, causing some coastal regions to experience severe drought and deteriorated water supply situation. This article presents a comprehensive study of the urban water metabolism of Cape Town, South Africa. A water mass balance framework was utilized to examine the city's water system across four distinct periods. In addition, the water-energy nexus before and after the drought crisis was evaluated. The key findings include a large amount of surface runoff in the Cape Town area that was not utilized before the drought crisis, resulting in a natural loss potential of water supply that is 2.54 times greater than water used for supply systems. During the drought, per capita water consumption dropped by a substantial 25%; at the same time, the total rate of water loss experienced a substantial decrease of approximately 21%. Since the pandemic, Cape Town's water resources policy has shifted to diversifying water sources, and the use of wastewater and natural water losses will be optimized by more than 32% in 2040 to achieve a water-sensitive city. Future research should explore the temporal and spatial dynamics of urban water flows, the impact of socioeconomic factors, and the integration of water system optimization models for enhanced urban water management.

Application of Sponge City Ecological Landscape Design in Residential District

In response to the escalating challenges posed by rapid urbanization, this article conducts a comprehensive exploration of innovative models for urban water management. Through a comparative analysis, we delve into the principles, methodologies, and potential outcomes of three prominent models: the Sustainable Urban Drainage Systems (SUDS), Water-Sensitive City Model (WSUD), and Depression-Infiltration Canal System Model. Each model offers a unique perspective on addressing urban water challenges, emphasizing sustainability, adaptability, and environmental protection. The SUDS model emphasizes replicating natural ecological drainage systems to mitigate urban waterlogging, enhance water quality, and promote sustainable water management practices. Incorporating green infrastructure, natural ecological restoration, and community participation, the WSUD model integrates various aspects of water management to achieve effective utilization and recycling of water resources while enhancing urban resilience. This paper is helpful to promote a more sustainable and flexible future.

Stormwater reuse for water-sensitive city - Integrated analysis of urban hydrology for efficient alternatives of Amaravati city, India.

In the present study, Amaravati, a proposed city of Andhra Pradesh, India, is identified for stormwater reuse analysis and for various efficient options for reuse. Peak runoff from the entire catchment is determined for the management of stormwater using different models such as soil and water assessment tool (SWAT), stormwater management model, and intensity-duration-frequency curves by the log Pearson Type III method. Further, the bio-retention cell low-impact development option with 60% impervious area, 60% zero depression impervious area, bio-retention cell for 40% area for each sub-catchment, and the underground stormwater network system, for part of peak runoff reduction, remaining peak runoff is considered for reuse. The remaining peak runoff is proposed to be reused for irrigation purposes (option 1), and storage retention ponds as extended detention ponds (option 2). Also, in situ storage/percolation is recommended for unaccounted stormwater within or around each premise. The findings can help to propose, implement, and maintain various stormwater reuse measures and/or practices for any city.

Pathways toward Water Sensitive Cities: An Educational Approach through Geography Learning

The 2030 Sustainable Development Goals (SDGs) have seventeen global goals for the sustainability of human life on planet Earth. One of these goals is to ensure access to water and sanitation for all. This article aims to formulate a grand design of Geography learning as part of social studies taught in the school. The context of the research is the east coast of Aceh Province. The research method used in this paper is a systematic literature review through books, scientific journals, and reports from several community-based water development programs. The grand design is formulated within ten years with three phases, namely (1) Acceleration; (2) Evaluation, and (3) Sustainable Education. The results of this literature review are expected to contribute to the management of water resources in the coastal area of East Aceh while at the same time increasing the implementation of the Merdeka Belajar (Independence Learning) policy at every level of education that is oriented toward local natural resources.

The dynamic challenges of mainstreaming water sensitive cities in our built environment: Lessons from Australia

Stormwater has been acknowledged as a major concern in cities because of mismanagement of this resource. It has also been underestimated as a resource in climate change actions and policies. Water sensitive urban design (WSUD) is considered as an effective adaptation measure to address these issues while providing many co-benefits. This paper reports the challenges of implementing WSUD in the Australian context. Semi-structured interviews were conducted with 57 experts in Australia. The experts are involved in design, research, engineering, and planning policy in both public and private sectors. The qualitative analysis of the interviews involved thematic and content analysis through NVivo12. Analysis of the responses indicated six main challenges including financial, innovation and evaluation tools, capacity, institutional arrangements, and policy. The experts believe that a lack of standardized design and implementation can be addressed through collaborative design processes. They suggest a robust structure of approval process and establishing clarity of roles and responsibilities in all sectors. All respondents confirm the critical role of monitoring and maintenance in these projects. It is suggested that allocating recurrent funding for these ongoing activities from the beginning and setting incentives to engage communities and local councils in maintaining the projects can be helpful.

Multi-objective optimization methodology for green-gray coupled runoff control infrastructure adapting spatial heterogeneity of natural endowment and urban development

Cost-effective runoff control scheme drafting involves localization, multi-sector coordination, and configuration of multifunctional infrastructures. Numerous independent variables, parameters, weights, and objectives make runoff control optimization quantitatively arduous. This study innovatively proposed a multi-objective optimization methodology for green-gray coupled runoff control infrastructure adapting spatial heterogeneity of natural endowment and urban development. The quantitative methods of multi-objective evaluation, hydrological feature partition, and pressure-adapted multi-objective weight assignment were proposed. Remote sensing inversion of water quality, hydrological model simulation (using SWAT and SWMM software), landscape pattern index calculation, life cycle cost (LCC), life cycle assessment (LCA) on ecological impact, and NSGA-II optimization algorithm were applied. Wuhan, the most water-sensitive city in China, was studied as a case. Runoff control function (RCF), capital investment (CI), and ecological return on investment (EROI) served as optimized objectives. High, medium, and low built-up regions in Wuhan urban development planning district were extracted by topographic factors and landscape patterns, which comprised 28, 34, and 38% of the case area, respectively. Three corresponding hydrological models were then built to illustrate distinct runoff control cost-efficiency in each region. Pressure distributions on runoff control, economic constraints, and ecological resource scarcity were quantitatively evaluated. And four pressure zones were clustered, which occupied 36, 29, 16, and 19% of the case area, respectively. Then the zonal weighted optimization decision-making matrix (with 3 hydrological models and 5 wt) was established by overlaying the pressure zone and built-up zone. In high, medium, and low built-up regions, optimized solutions reduced annual runoff volume by 86, 82%, and 77%The average runoff investments per square meter of impervious underlying surface in high, medium, and low built-up regions were 34.2, 18.7, and 7.9 RMB yuan, respectively. Medium and low built-up regions may only need 55 and 23% of the high built-up region for the unitary impervious underlying surface to balance runoff control and ecological benefits. Runoff control and financial utilization efficiency enhance with hydrological differentiation zones. Thus, the optimization solutions are zonal adaptive, refined, comparable, replicable, and implementable.

‘Water Sensitive Cities’: Planning and Evaluation of Its Theoretical Application in a Mexican City with High Hydric Stress

Cities can be viewed as a source of solutions to environmental problems. The Water-Sensitive Cities (WSC) model is part of the solution when trying to transform the current negative relationship between water and cities, since it has remained at the conceptual level, without evaluating the implications of its application in cities from developing countries. The primary aim of the article is to analyse a potential scenario under the WSC model, seeking an alternative solution to the problems of water availability and supply in cities in semi-arid environments with prominent levels of water stress from the Global South. We selected Aguascalientes City, Mexico, as a case study, and through geospatial analysis, it was possible to generate and assess urban planning strategies for stormwater harvesting and alternative sustainable infrastructure for urban and peri-urban areas. The results show that this analysis would imply a considerable reduction in groundwater extracted for urban consumption in the city, reducing local water stress; however, the various political and social implications intrinsic to the implementation of this model should be considered, as they may represent an obstacle to its execution.

Assessing the Inclusion of Water Circularity Principles in Environment-Related City Concepts Using a Bibliometric Analysis

Cities face increasing water pressure and supply issues, jeopardizing the balance between growth and sustainable water resource use. Green, resilient, smart, circular, blue, water sensitive, or water-wise city concepts are increasingly part of the design of strategies to rethink cities. These concepts have motivated many studies, but little is known about their relative relevance among the scientific community and how they consider water circularity. The objective of this study is to assess how these city concepts incorporate water circularity principles. The assessment is based on a bibliometric analysis of scientific articles recently published. The findings show that despite the wide number of articles dedicated to the various city concepts, water circularity-related challenges are still a small niche of concern, strongly driven by European authors. Moreover, our study showed that water circularity principles are not equally considered among the different city concepts. This uneven assimilation of principles in influential city concepts unveiled gaps regarding water circularity. This brings a new perspective to the use of more integrated definitions, highlighting the importance of such principles in the future use of these concepts when envisioning roadmaps toward sustainable water use in cities.

Characterising water sensitive cities through inquiry-based learning systems

ABSTRACT Transitioning to water sensitive cities (WSCs) in Australia is necessary for creating urban areas that are resilient to natural disasters, water shortages and climate change. In this paper we report research to enable systemic-transformations praxis. We brought together water practitioners from various sectors for a number of systemic inquiry events across five Australian cities to understand what was required to begin a transition to WSCs. Using an approach influenced by systemic innovation, we designed an inquiry-based learning system. Our learning system design made scientific knowledge available for interpretation, internalisation and contestation, by practitioners in different contexts. The workshops led to identification of characteristics of WSCs; relevant issues and opportunities; and commitments and constraints to action constituting a baseline data set for future evaluation of progress. Transitioning to WSCs requires leadership, a supportive institutional-sectoral environment, practical implementation of technologies in social contexts and increased collaboration involving knowledge co-production across disciplines and sectors. Systemic inquiry methods lend themselves to revealing the socially constructed nature of urban water as hybrids of the technical, natural and social. Despite some limitations, our approach enhanced institutional innovation and investment and offers insights into future research and planning for enabling systemic-transformations praxis in multiple sectors and contexts.

Potential of supervised machine learning algorithms for estimating the impact of water efficient scenarios on solids accumulation in sewers

Understanding the negative effects of widespread implementation of optimal water efficient solutions may have on existing centralised sewer systems is still limited – one of these effects is the accumulation of solids in sewer pipes. Predicting these effects requires setting up and simulating complex detailed hydraulic sewer network models. Often, precise details of the sewer network layout and diurnal patterns of the wastewater flows are not available, limiting the applicability of using model predictions for such phenomena. In this study, the applicability of supervised machine learning (ML) algorithms for the development of a simplified surrogate model to predict solid accumulation in sewer pipes was investigated. A large number of highly variable sewer networks were synthetically generated and used to produce results that can be generalizable within the limitations of the current study. A hydrodynamic sewer model was set up and simulated for each synthetic sewer network and various scenarios in which different water-efficient solutions were considered. Simulation results indicated that the most impacts are expected to occur in the upstream part of the sewer networks, and that with 50% reduction in (waste-)water flows, 3–20% more pipes are expected to accumulate solids. It was further found that ML algorithms can be used to successfully predict locations of solids accumulation in sewer pipes without using hydrodynamic models. A simple tool based on the findings of this study, sparing the need to conduct complex hydraulic simulations, was developed. It allows the user to enter a set of pipe characteristics and the proportion of flow that is reduced due to the implementation of water efficient solutions, and it predicts whether the pipe will accumulate solids or not. The study results and the proposed ML algorithms can support the implementation of optimal water-efficient solutions that will promote designing and managing the water sensitive cities of the future.

Developing an integrated investment decision-support framework for water-sensitive urban design projects

Traditional centralized water-management systems have tended to fall short in delivering environmental and amenity benefits in urban areas. Water-sensitive urban design (WSUD) projects have been proposed as an alternative due to their ability to generate multiple benefits, including improving water quality, water supply, aesthetics, urban cooling, spaces for recreation, and habitat for biodiversity. However, in most cities, investment in such systems has been relatively low, in part due to the difficulty of monetizing the multifunctional benefits of WSUD projects and including them in comprehensive economic analyses. We describe the development, testing and application of INFFEWS (Investment Framework For the Economics of Water Sensitive cities), an economic decision-support system for investment in WSUD projects. INFFEWS is based on a Benefit: Cost Analysis (BCA) framework and is consistent with standard BCA. A prominent feature of the framework is its strong emphasis on quantifying the monetary-equivalent values of intangible (non-market) benefits from WSUD projects. Development of the tools and their supporting materials has involved extensive consultation with intended users, review of existing tools, and primary research over eight years (2013–2020). The frameworks can be applied to business-case development and decision making at multiple levels in public-sector and private-sector organisations.

How boundary objects facilitate local climate adaptation networks: the cases of Amsterdam Rainproof and Water Sensitive Rotterdam

New networks of public and private parties co-produce urban climate adaptation measures, for which different viewpoints and interests have to be bridged. While previous research has focused on individuals and organizations as intermediaries, little attention has been paid to boundary objects: conceptual or material objects that help to bridge competing values. This article aims to understand how local climate adaptation networks co-develop boundary objects and how they benefit the development of adaptation measures by conducting a qualitative case study comparison of two front-running Dutch networks: Amsterdam Rainproof and Water Sensitive Rotterdam. The conceptualization of a “water-sensitive city” attracted multiple stakeholders (professionals from different disciplines, communities, businesses), while material objects, such as interactive 3 D-models, addressed information needs. The objects contributed to adaptation measures by convening stakeholders, translating viewpoints and initiating collaborations. The limited diversity in the networks suggests that, rather than enabling participatory decision-making, the networks are instrumentally used by water authorities.

A multi-regional input-output analysis of direct and virtual urban water flows to reduce city water footprints in Australia

This study focused on understanding what sector-region combinations could be targeted to reduce total city water footprints? We used multi-regional input-output analysis of direct and virtual water, across five Australian capital cities and their supporting regions. The key novelty of this study is the high spatial resolution policy-relevant sub-sectoral analysis to identify sector-region combinations to reduce city water footprints. Virtual water footprints were 8-10 times higher than direct water consumption (per capita) in all studied cities. Virtual water from outside the city boundary is almost 20 times higher than the virtual water sourced from within the city boundary in all studied cities. Water-efficiency programs can significantly reduce the virtual water footprints of the studied cities. This includes water-efficiency and recycling on farm, and in food processing (e.g. livestock feed growing, dairy cattle farming, vegetable growing and processing) in rural regions of New South Wales, Queensland, and Victoria. The results are relevant to strategic city water footprints reduction, sustainable sourcing and planning for future disturbance of product supply, and water-sensitive city developments considering both direct and virtual water flows.

Ensuring Perth, Western Australia, transitions to a leading water sensitive city

Ensuring Perth, Western Australia, transitions to a leading water sensitive city

Sustainable Urban Water Management in China: A Case Study from Guangzhou and Kunming

In China, the notion of a water sensitive city has gained popularity in urban water management as a result of the detrimental effects of flooding and pollution caused by developmental activities. Urban systems and their interrelationships are critical for long-term urban water management and water sensitivity. This article is a case study considering how a strength, weakness, opportunities, and threat (SWOT) analysis-based approach to urban water management interventions in Guangzhou and Kunming cities (China) enables decision makers to identify solutions for cities to become more water-sensitive and resilient. The similar difficulties and rewards with respect to the contexts of both cities were synthesized using SWOT analysis. The contextual SWOT analysis, in conjunction with the comprehensive inclusion of Sustainable Development Goals (SDGs) in intervention planning in these cities, revealed that a water-sensitive-cities approach requires the establishment of a comprehensively multi-objective rainwater management system; this approach would have the goals of reducing rainwater draining sources, controlling processes and adaptive measures, and governing the system to make it more resilient. The water strategy should be holistic and adaptive, capable of providing a broad range of ecological services and other social benefits consistent with the fulfilment of the Sustainable Development Goals, and adaptable to other Chinese cities seeking to achieve water sensitivity.

Water Sensitive Cities: An Integrated Approach to Enhance Urban Flood Resilience in Parma (Northern Italy)

Climate change is globally causing more intense meteorological phenomena. Our cities experience increased rainfall intensity, more intense heat waves, and prolonged droughts providing economic, social, health and environmental challenges. Combined with population growth and rapid urbanization, the increasing impact of climate change will make our cities more and more vulnerable, especially to urban flooding. In order to adapt our urban water systems to these challenges, the adoption of newly emerging water management strategies is required. The complexity and scale of this challenge calls for the integration of knowledge from different disciplines and collaborative approaches. The water sensitive cities principles provide guidance for developing new techniques, strategies, policies, and tools to improve the livability, sustainability, and resilience of cities. In this study, the DAnCE4Water modeling approach promoting the development of water sensitive cities was applied to Parma, an Italian town that has faced serious water issues in the last few years. The city, indeed, had to face the consequences of flooding several times, caused by the inadequacy of both the network of open channels and the sewerage network due to the urban expansion and climate change of the last 30 years. Through the model, the efficiency of decentralized technologies, such as green roofs and porous pavement, and their integration with the existing centralized combined sewer system was assessed under a range of urban development scenarios. The obtained results show that the adoption of an integrated approach, including soft engineering hydraulic strategies, consisting in the use of natural and sustainable solutions, can increase resilience to urban flooding. Further, the study shows that there is a critical need for strategic investment in solutions that will deliver long-term sustainable outcomes.

A Community of Practice Approach to Planning Water Sensitive Cities in South Africa

As South African cities urbanise alongside climate change, resource constraints, and socio-economic challenges, water sensitive (urban) design (WSD) is slowly gaining traction as a framework to address water security goals and entrench resilience. This article reflects on the progression of WSD in South Africa and discusses the broadening of its initial association with stormwater and physical infrastructure to include critical governance and institutional arrangements and social engagements at the core of a water sensitive transition. The approach is being adapted for the socio-economic challenges particular to South Africa, including basic urban water and sanitation service provision, WSD related skills shortages, a lack of spatial planning support for WSD, and the need for enabling policy. Since 2014, a national WSD Community of Practice (CoP) has been a key driver in entrenching and advancing this approach and ensuring that the necessary stakeholders are involved and sufficiently skilled. The WSD CoP is aimed at promoting an integrative approach to planning water sensitive cities, bridging the gaps between theory and practice and blending the social and physical sciences and silo divisions within local municipalities. Three South African examples are presented to illustrate the role of a CoP approach with social learning aspects that support WSD : (1) the “Pathways to water resilient South African cities” interdisciplinary project which shows the institutional (policy) foundation for the integration of WSD into city water planning and management processes; (2) the Sustainable Drainage Systems training programme in the province of Gauteng which demonstrates a skills audit and training initiative as part of an intergovernmental skills development programme with academic partners; and (3) a working group that is being established between the Institute for Landscape Architecture in South Africa and the South African Institution of Civil Engineering which illustrates the challenges and efforts of key professions working together to build WSD capacity.

Urban household uptake of water sensitive urban design source control measures: an exploratory comparative survey across Cape Town and Pretoria, South Africa

ABSTRACT Water Sensitive Urban Design (WSUD) presents a process towards the objective of a water-sensitive city. An integrated approach requires community acceptance to implement WSUD at household level. An exploratory comparative survey was conducted amongst 250 households across Cape Town and Pretoria, South Africa, to determine actual uptake of rainwater harvesting, greywater recycling systems and permeable paving, factors affecting uptake, and the perceived effectiveness of assistance to implement WSUD relative to other water demand-side management instruments. Actual uptake of rainwater harvesting and greywater reuse is noticeable amongst water-saving middle-to-high income home owners. Although loglinear analyses suggest that Cape Town’s recent drought is unlikely to contribute towards more established levels of uptake, assistance to implement WSUD is nevertheless perceived as the second most effective instrument. Three directions for more systematic research are proposed to better inform the practical implementation of WSUD at household level.

Transformation in Urban Planning with a Localized Model of Water-Sensitive Urban Design

On the eve of the year 2021, about a century has passed since the establishment of municipalities, and more than half a century has passed since the establishment of development planning laws and the beginning of the implementation of urban planning projects. The purpose of creating these laws and establishing structures and organizations to implement them was to monitor the creation and development of cities to provide suitable conditions for citizens in life. The results of the implementation of urban development projects show that these projects, despite spending a lot of money and energy, in many cases do not achieve their goals. Despite these problems, for many years, the lack of coordination of organizations related to urban management, the lack of appropriate methods for preparing and implementing urban plans and the lack of technical and financial capacity in the organs have been raised as important issues in project inefficiency. But the importance of not paying attention to the infrastructure that can affect urban management and planning has been overlooked and among all the factors, water has the most fundamental role as the main source of life and the basis of development. This grounded theory method first examines the causes and known factors of inefficiency of urban planning in Iran, explains the relationship between this issue and the critical factors of inefficiency and then identifies the effect of paying attention to the pivotal role of water in eliminating many of these factors , By presenting a local model for using the basics of water-sensitive city design in urban planning, offers a proposal for operationalizing and making more practical the methods of urban planning, which, if used in the future, can solve the problems of urban planning in the country. Sensibly reduce and eliminate.

System Dynamic Model for Sustainable Water Supply Strategy in Sentul City Area

Good management of water resources is a requirement for an area that has a high population development. Sentul City, which is an independent city in Bogor Regency which has a high population, is in an area that lacks water, because of this Sentul City requires infrastructure and policies that are able to ensure the availability of water for its residents. One of the paradigms of water management in urban areas is a water sensitive city. One of the steps in this paradigm is wastewater management and rainwater harvesting. The dynamic system modelling method is used to predict the impact of implementing several policies that will be taken to manage water resources. The objectives of this study are to build dynamic models to predict water supply and demand and to analyze policies for wastewater management and rainwater harvesting. Sentul City water demand is estimated will reach 122 105 000 m3 and a water crisis will occur in 2027. The wastewater recycle policy can inhibit the water crisis until 2030 and the negative water balance will last until 2040. Combining wastewater recycle and rainwater harvesting can increase water availability by 240% and prevent a water crisis.