Sustainable Urban Water Management Research Articles

Inaccessible and Unaffordable? The State of Water and Sanitation Services in Nairobi, Kenya

As the limited water resources become increasingly stressed by factors such as rapid urbanization, population growth, and climate change, the need for sustainable urban water management is more important than in the past decades. A large part of the world’s population still lacks access to clean water and sanitation, making achieving Sustainable Development Goals a challenge. Water is an indispensable resource and plays an important role in ensuring the achievement of Sustainable Development Goals. Therefore, there is a need to prioritize research on the availability, affordability, and access of water resources to promote sustainable water resource management. In this study, we reviewed academic articles and published reports from various institutions and organizations to assess water sources, infrastructure, coverage, accessibility, and affordability of water and sanitation services in Nairobi County. The study identified Nairobi’s main water sources as municipal water, primarily from surface water and groundwater. However, the capacities of the water sources, treatment plants, and wastewater treatment plants were found to be insufficient, resulting in water shortages in most parts of the city.Most of the infrastructures were also found to be insufficient and old, contributing to water distribution inefficiencies, frequent leakages, and pipe bursts which hampers water reliability. The study suggests prioritizing the water and sanitation sector in government budgets to increase infrastructure development investments and funding. Appropriate wastewater treatment methods should also be adopted and implemented to enable wastewater to meet water consumption standards and be potentially integrated into supply systems.

Regionalization of environmental and economic performances of rainwater harvesting systems

Study regionBeijing Region Study focusLimited studies have yet been done on regionalization of multi-performances of rainwater harvesting systems (RHS). In this study, the daily rainfall records from 77 stations are used, and a hydro-economic model is adopted to examine regional water saving, stormwater control and economic performances of RHS by proposing a regionalization approach. New hydrological insights for the regionHigher water saving efficiency (WSE) and reliability (R) of RHS are linked with lower water demand, larger tank size and greater rainfall conditions. Differently, higher stormwater capture efficiency (SCE) is related to higher water demand, larger tank size and lower rainfall. The WSE and R of RHS demonstrate substantial regional differences; their maximized obtainable values closely depend on water demand scenarios and range from 9% to 99%, with smaller values in western mountain area but larger values in northeast suburban and central urban areas. The maximum obtainable values of SCE range from 61% to 100%, with higher values in western mountain area, but lower values in northeast suburban and central urban areas. A 10 m3 tank size can provide the highest benefit-cost ratio of RHS across the Beijing region. The regionalization approach proposed is a useful guidance for the implementation of RHS and sustainable urban water management, and thus it has the potential for wide uses in other regions with high rainfall gradients.

Durability Evaluation of Polyurethane-Bound Porous Rubber Pavement for Sustainable Urban Infrastructure

Permeable pavements are vital in sustainable urban water management, addressing critical challenges while enhancing environmental resilience. This study focuses on the innovative polyurethane-bound Porous Rubber Pavement (PRP), which possesses high permeability and elasticity due to its unique composition of stone and crumb rubber aggregates with polyurethane binders. PRP’s useful benefits, such as noise reduction, efficient snow/ice management, and others, enhance its appeal, emphasizing the necessity for a thorough investigation into its performance and characteristics, especially in North America. To address these gaps, this paper comprehensively analyzes PRP’s durability and performance, including its strength range, failure criteria, and susceptibility to moisture-induced damage. Various testing methods are utilized, such as evaluating the abrasion loss of the stone aggregate, rutting, stripping due to moisture susceptibility, resistance to degradation from impact and abrasion, and permeability tests. This study evaluates five distinct mix compositions with varied proportions of aggregates and binders. Further, it investigates the effects of different binder types on PRP performance, such as aromatic and aliphatic binders obtained from various sources. Upon the analysis of the comprehensive test results, it was found that the mix characterized by increased rubber aggregates and a high binder content demonstrated a superior performance across various tests for PRP applications. This mix exhibited an enhanced resistance to abrasion, raveling, rutting, and permanent deformation, showcasing its durability and functionality. Additionally, when combined with an aliphatic binder, it displayed an optimal performance even in challenging freeze–thaw conditions, making it a recommended choice for long-term pavement solutions.

Effects of new-type urbanization on resource pressure: Evidence from a water-energy-food system perspective in China

To address the resource and environmental challenges posed by rapid urbanization, China has devised and executed the strategy of new-type urbanization (NU). This study aims to discuss the effects of NU on resource pressure in view of the water-energy-food (WEF) system. Taking 30 provinces in China from 2006 to 2020 as samples, this paper firstly establishes a comprehensive evaluation indicator system of NU from the population, economic, spatial, social and eco-environmental dimensions, and assesses the level of NU using the entropy weight method. Secondly, this paper uses the gray water footprint as a measurement indicator, innovatively integrating water quality into the WEF system for assessing WEF system pressure (WEFSP). Finally, the impact of NU on WEFSP is explored based on the panel fixed effects model. The findings revealed: (1) There is an inverted “U-shaped” relationship between NU and WEFSP, and China's current level of NU has exceeded the Environmental Kuznets Curve (EKC) threshold. (2) The impact of NU on WEFSP exhibits significant regional heterogeneity, with a significant impact in the eastern region. (3) NU consistently exacerbates regional water stress when water quality is considered, indicating that sustainable urban water management practices are essential. (4) The subdimensions of NU indicate that population and social urbanization are important factors that exacerbate the WEFSP, while economic and spatial urbanization reduce the WEFSP. The research results help to clarify the impact of NU on the WEFSP and provide a reference for the timely adjustment and optimization of NU policies to achieve effective resource management and regional sustainable development.

Implications of the transition towards water-wise approaches in urban areas: Elucidating the risk from micropollutants release

The transition towards circular and sustainable urban water systems, embracing a water-wise city approach, results in highly interconnected systems, introducing complexities in managing water quality due to the intricate interplay of pollutant sources, pathways, and receptors in urban environments. This study focuses on assessing the impact of transitioning to a water-wise city approach on water quality. The analysis employs an integrated model-based approach to evaluate the release of micropollutants (PFOA, PFOS, pyrene) in the urban water system, considering potential future changes. We considered Milan (Italy) as a case study and explored sustainable urban water management strategies related to the hydraulic reconnection of canals, including (i) the use of groundwater for energy purposes, (ii) the establishment of a separate stormwater sewer system, and (iii) the indirect reuse of reclaimed water for crop irrigation. Acute and chronic environmental risks were assessed at various locations of the recipients, under different water management and climate change scenarios. Uncertainties on projections related to rainfall and runoff concentrations were also considered. The model accurately predicted average micropollutants concentrations in the current situation. PFOA and PFOS exhibit chronic, but not acute risks in all scenarios; high removal efficiency is required to reduce the risk at acceptable levels. Pyrene poses higher risks for increasing separation fractions of the sewer system, with further increase for climate change, but concentration uncertainty has more influence than precipitation uncertainty on the risk extent. This study provides a water management framework, identifying critical sources and locations under current, future, and climate change scenarios.

A collaborative hybridity design approach: enhancing urban water resilience and spatial legibility

ABSTRACT Within the global transition to sustainable urban water management, Dutch polder cities are also contemplating revitalising their water traditions. One of the keys to this task is to integrate water management into urban design, which is explored but not yet practically instrumentalized in the urban design process. This article introduces the concept of hybridity and develops a Hybridity Design Approach as an interdisciplinary methodology to explore the possibility of realising the extreme low impact Closed City Concept. Integration of the water environment and urban space needs interdisciplinary cooperation and sharing knowledge, as well as an innovative way of thinking about water-resilient urban design, maximising the landscape quality of a polder city while minimising its hydrological footprint in the region. Effective visualisation tools and techniques for this collaborative design process are developed and tested in the area of Zevenkamp in Rotterdam.

The water flow diagram

IntroductionThe Water Flow Diagram (WFD) is a novel advocacy and communication tool that presents urban water supply and management in a simple visualization. Rapid urbanization, growing populations, and the climate crisis increase the pressure on water resources, particularly in urbanized areas. The WFD aims to foster a dialogue around conflict of interests and opportunities among different stakeholders, and trigger actions toward more sustainable urban water management (UWM), as well as a water secure future.MethodThe WFD is produced from data on water abstraction, water use of different sectors, water treatment, water recycling and contamination risks. The data were obtained from government services, wastewater and water utilities, large industries, universities and reports of intergovernmental organizations. If these sources did not have data, reports from NGOs or consultants, comparable contexts, default values or expert judgements were considered. The annual water flows are presented in a Sankey Diagram. An intuitive color code highlights the flows as “problematic” or “appropriate” and points to areas where UWM practices should be improved.Results and conclusionsThe final diagrams are a concise instrument that identifies challenges of UWM in the four application cases presented in this article. Key challenges that became evident included: pollution from agricultural production, the lack of wastewater and sanitation infrastructure, high water losses in the distribution networks, water exports leading to a lack in local supply and sewer overflows during heavy rainfalls. Opportunities identified were the need to: invest in sanitation and wastewater to protect resources, create coordination bodies to align conflict of interests, and/or invest in blue-green infrastructure for rainwater retention. The WFD triggered local actions, such as in-depth discussions between relevant actors, the formation of integrated water use committees and the interest of the national ministry in Senegal to replicate the diagram for other locations. This article presents the methodology, discusses the four case studies and deliberates on the prospective use of the WFD.

Assessing inequalities in urban water security through geospatial analysis

Water security, which is key for sustainable development, has been broadly investigated through different spatial scales, time frames and perspectives, as a multi-dimensional concept. Fast growth and the diversity of the urban environment add to the challenges of reaching good levels of water security in cities. Yet, few studies have focused on evaluating the heterogeneous distribution of water security in urban areas, which is a key step to highlight where inequalities in large cities are present and how to best guide interventions. The objective of this research is to investigate the spatial heterogeneity of urban water security as well as quantifying inequalities using the new assessment presented in this paper. A holistic indicator-based evaluation framework to intra-urban sectors of the city of Campinas in Brazil is applied, followed by an inequality analysis to describe the distribution of water security aspects. A spatial correlation analysis is then carried out to identify patterns for high inequality indicators. Results show that even though Campinas has established good overall water security conditions, spatial heterogeneity is still noticeable in the urban area. Quantification of inequality by the Theil index highlighted aspects, such as vegetation cover, social green areas, and wastewater collection, that are inequitably distributed in the urban area. The subsequent analysis of spatial patterns exposed areas on the outskirts of the city where infrastructure challenges and social vulnerability coincide. This novel approach has been therefore successfully validated in a city in Brazil, and it has been demonstrated that our water security assessment framework identifies what are the main water security challenges and where they are in the city. For the first time we show that associating spatial and inequality analysis with conventional evaluation of urban water security has the potential to help target areas in need and tackle specific water security issues in the urban area. This is crucial to inform urban planning and policy making for a sustainable and inclusive urban water management strategy.

Pathways to green urbanism: evaluating Jeddah’s environmental sustainability progress and prospects

Abstract This research provides a comprehensive analysis of environmental sustainability in Jeddah, focusing on the unique challenges and opportunities it faces as a rapidly urbanizing city in an arid region. The study evaluates Jeddah’s performance across multiple environmental areas, including energy and carbon dioxide emissions, land and building use, transportation, waste management, water use, sanitation and air quality. A detailed SWOT analysis identifies the city’s strengths, weaknesses, opportunities and threats in achieving sustainable urban development. The results reveal high per capita carbon dioxide emissions, energy consumption and waste generation, along with challenges in managing water resources and maintaining air quality. The study highlights Jeddah’s efforts in renewable energy policies, urban mass transportation and waste management strategies. The conclusion provides a set of comprehensive recommendations for policy improvement, focusing on the need for sustainable urban planning, energy conservation, improved waste and water management and public engagement. This research contributes significantly to the understanding of urban sustainability in arid environments, providing a valuable framework for policymakers and urban planners.

Groundwater Vulnerability in a Megacity Under Climate and Economic Changes: A Coupled Sociohydrological Analysis

AbstractGroundwater depletion has become increasingly challenging, and many cities worldwide have adopted drastic policies to relieve water stress due to socioeconomic growth. Located on the declining aquifer of the North China Plain, Beijing, for example, has developed plans to limit the size of the city’s population. However, the effect of population displacement under uncertain macroeconomic and climate change remains ambiguous. We adopt a sociohydrological model, with explicit consideration of the dynamics of human‐water interactions, to explore the groundwater vulnerability of Beijing. We investigate how human response might shape the development trajectories of the groundwater‐population‐economy system under different macroscale economic and climate scenarios. Furthermore, we use a machine learning algorithm to identify the decisive factors to be considered for reducing groundwater vulnerability. Our results show that while rapid external economic development or larger annual average precipitation would enable recovery of the groundwater table in the short term, they may slacken human water shortage awareness and result in more acute groundwater depletion in the long run. Strengthening policymaker perceptions of groundwater depletion would prompt timely response policies for controlling population size. Improving the quantity and quality of labor force input to economic development would avoid downturns in the economy due to labor shortages. The outcomes of this study suggest that these strategies would effectively reduce groundwater vulnerability in the long run without causing severe socioeconomic recession. These findings highlight the importance of endogenizing human behavioral dynamics in sustainable urban water management.

Impacts of net cages on pollutant accumulation and its consequence on antibiotic resistance genes (ARGs) dissemination in freshwater ecosystems: Insights for sustainable urban water management

There has been increasing interest in the role of human activities in disseminating antibiotic-resistance genes (ARGs) in aquatic ecosystems. However, the influence of pollutant accumulation on anthropogenic pollutant-ARG synergistic actions is limited. This study explored the association of net cages with the propagation of anthropogenic pollutants and their consequences for influencing the enrichment of ARGs using high-throughput metagenomic sequencing. We showed that net cages could substantially impact the ecology of freshwater systems by enhancing i) ARG diversity and the tendency for ARG-horizontal gene transfer and ii) the overlap of mobile genetic elements (MGEs) with biocide-metal resistance genes (BMRGs) and ARGs. These findings suggested that the cotransfer of these three genetic determinants would be favored in net cage plots and that nonantibiotic factors such as metal(loid)s, particularly iron (Fe), displayed robust selective pressures on ARGs exerted by the net cage. The resistome risk scores of net cage sediments and biofilms were higher than those from off-net cage plots, indicating that the net cage-origin antibiotic resistome should be of great concern. The combination of deterministic and stochastic processes acting on bacterial communities could explain the higher ARG variations in cage plots (8.2%) than in off-cage plots (3.4%). Moreover, MGEs and pollutants together explained 43.3% of the total variation in ARG communities, which was higher than that of off-cage plots (8.8%), considering pollutants, environmental variables, MGEs, and assembly processes. These findings will inform the development of policies and guidelines to more effectively limit the spread of antimicrobial resistance and achieve the goal of sustainability in freshwater systems in urban areas.

Assessing the effectiveness of site real-time adaptive control for stormwater quality control

Urban sprawl, excessive rainfall, and resource limitations have challenged the performance of conventional water-sensitive urban designs (WSUD). To address these issues, there is a growing interest in adopting site real-time adaptive control (SRAC) for integrated and real-time water management. This research evaluates the effectiveness of SRAC technology in reducing stormwater pollutants in a highly developed urban area, comparing it with conventional WSUD methods. The study focuses on examining the impact of the SRAC-WSUD method on stormwater quality. Findings indicate that the SRAC-WSUD method reliably reduces stormwater pollutants under varying rainfall conditions. Moreover, it enhances the resilience and performance of existing stormwater systems without the need for additional infrastructure upgrades. For the whole year scenario, the SRAC-WSUD method resulted in reductions in total pollutant loads. Notably, there was a 196.72 kg/year decrease in total suspended solids (TSS), a 0.07 kg/year decrease in total phosphorus (TP), and a 0.78 kg/year decrease in total nitrogen (TN). These findings highlight the potential of SRAC-WSUD in improving stormwater quality and its implications for sustainable urban water management. Overall, this research contributes to advancing the understanding and practical implementation of SRAC technology in stormwater management, offering valuable insights for urban planning and water resource preservation.

Assessment of Green Infrastructure for sustainable urban water management

Assessment of Green Infrastructure for sustainable urban water management

Pathways to Greening Border Cities: A Policy Analysis for Green Infrastructure in Ambos Nogales

Green infrastructure (GI) has been proposed as a decentralized solution to complex urban water management issues. However, public policy remains a critical challenge for the wide adoption of GI, which is exacerbated in transboundary settings. We draw from public policy theory to analyze GI policies at the US–Mexico border. We examine the case of Ambos Nogales—two sister cities grappling with complex water management challenges. We examined existing policies and evaluated their impact on the implementation of GI at multiple levels (local, state, national, and binational). We also conducted interviews and a focus group with stakeholders. Our analysis unveils a set of barriers to the adoption of GI and a suite of opportunities for the enactment of GI policies. We outline five pathways for greening border cities, including (i) creating market-based GI incentives, (ii) adopting the net-zero urban water approach, (iii) engaging with existing institutions for greening efforts, (iv) planning for a GI network at the watershed scale, and (v) supporting local champions. By addressing shortcomings of policy and regulatory frameworks hindering local capacity, border cities will be more likely to adopt and widely implement GI solutions for more sustainable urban water management.

Managing water scarcity via rainwater harvesting system in Kathmandu Valley, Nepal: People's awareness, implementation challenges and way forward

More than 750 million people in developing countries do not have access to better water sources and over 2.6 billion people lack basic sanitation. Transition towards more sustainable urban water management is an urgent need because supply of water in rapidly urbanized areas like the Kathmandu Valley (KV) of Nepal is deficient. Supporting such a transition requires the development of alternative methods such as rainwater harvesting (RWH) system, recycling, desalination, wastewater reuse, etc. Using semi-structured questionnaires for 403 households (203 users and 200 non-users of the RWH system) of KV, this study critically examines the major developments taken place in Nepal in the RWH system, measures the RWH awareness index, identifies the implementation challenges and provides managerial solutions. Measuring the awareness index in users and the non-users of the RWH system in terms of the four dimensions (financial, socio-environmental, technical and institutional), we found that the user groups are more aware of the issues of water and climate change (CC) than the non-users. Around 70% of our respondents suggested that the scarcity of water, user's self-commitment and cost-friendly technology, among others can help to address the RWH system challenges. Possible reasons of differences in attitude, behaviors and perceptions of RWH system users and non-users are discussed and managerial solutions are provided. Promoting the use of rainwater harvesting in the KV would require a multi-stakeholder approach that involves collaboration between the government, NGOs, and the private sector to create an enabling policy environment and provide the necessary resources to promote and scale up rainwater harvesting initiatives.

Heavy Metal Accumulation and Source Apportionment in Urban River under Ecological Restoration: Relationships with Land Use and Risk Assessment Based on Monte Carlo Simulation

The assessment of heavy metal (HM) distributions, sources, and potential risks is the first step of high-efficiency contaminant degradation and sustainable water resource utilization. In this study, the assessment of nine HMs from a typical urban river (Yongding River) in Beijing, China was implemented. Results evidence that the mean HM concentrations decreased in order: Mo > V > As > Zn > Ni > Mn > Fe > Cr > Co. The concentration of As, Zn, Mn, Fe, and Mo has a significant increase in the middle reaches, indicating agricultural and industrial pollution sources nearby. Three factors were extracted via principal component analysis, suggesting that As, Ni, Co, Mo, and V are mainly derived from anthropogenic inputs. Mn and Cr likely originated from natural sources, while Fe and Zn stemmed from mixed origins. The HM contamination levels are moderate and concentrated on As and Cr. Strong correlations among HMs and regional land use also confirmed the result. The noncarcinogenic and carcinogenic risks of HMs were evaluated based on four age groups by Monte Carlo simulation. Although the results of environmental modeling revealed a weak carcinogenic risk of As in adults (6.20 × 10–5), the risk for juveniles cannot be ignored. Target hazard quotients analysis implied relatively low noncarcinogenic risk when consuming fish tissues from rivers, and the carcinogenic risk of inorganic As in fish was acceptable. In total, this study provided powerful support for restoring HM contaminations and maintaining sustainable urban water management.

Setting a Baseline Residential Water Demand Management Solution in Urban Towns of Ethiopia

Due to the country’s expanding population, inadequate urban water management practices, limited community knowledge of water management, and urbanization, urban water management in Ethiopia is of great importance to the administration of the country. This study draws on a qualitative and quantitative research approach to evaluate the available water supply resources and management techniques in three Ethiopian metropolitan districts, factor in the sustainability of the urban water supply services, and then recommend a workable plan for a sustainable urban water management system. Open-ended and semi-structured questionnaires were used to interview urban water utility officials to reveal important information on water demand management and current water supply services. Documented secondary data analysis and field observations are also used to identify the existing problem in order to draw future suggestions. The findings of this study indicate that some of the common issues with urban water supply systems in towns include outdated water supply infrastructures, rapid population growth and corresponding water demand, high water losses in the distribution system, poor water management practices, and a lack of appropriate institutional framework. The assessments of the three study regions demonstrate that while the percentage of water supply coverage hasn’t changed significantly over the previous 10 years, both the number of customers and the overall population growth have increased by nearly 50%. In order to address this, the Ethiopian government would need to put up a lot of effort into developing water use policies and raising consumer understanding of water demand management techniques.

How Can We Adapt Together? Bridging Water Management and City Planning Approaches to Climate Change

Different dynamics of climate change, population growth, and urbanisation challenge water service providers (WSPs) and those managing urban planning. The scientific community has been evidencing the concept of sustainable urban water management (SUWM) as a driver to foster the integration of the urban water cycle with its environmental, economic, and social sustainability dimensions. This article studies the approaches addressed by recent research on sustainable urban water management, focusing on the attention given by the scientific community to the way WSPs and city planners address the new challenges brought by climate change. A systematic review of existing literature shows how emergent challenges address the articulation between urban water cycle management and city planning. The results underline the need for the technical and economic evaluation of the overarching concept of SUWM systems, integrating values that go beyond financial issues; the need to address water scarcity not only from the supply side but also from the demand point of view; and the deepening of the relationship between new sources of water, such as the reuse, with the city planning in a context of climate change. Nevertheless, strategies for collaboration are still poorly addressed. The insights and gaps emerging from the analysis suggest new paths for research and practice in the field.

A strategy for sustainable urban water management using water network partitioning with optimal booster pump configuration: A case study

The functionality of water distribution networks (WDNs) plays an important role in preserving human welfare and the sustainable development of cities and society. Like administrative units in urban governance models, a large-scale WDN is partitioned into district metered areas (DMAs) to improve operation and management efficiency. Conventional approaches for water network partitioning (WNP) into DMAs mainly focus on the determination of DMA sizes and configurations (i.e., the clustering phase). They subsequently form a set of boundary pipes to optimally locate flowmeters and gate valves (i.e., the sectorization phase) aimed at minimizing costs and water leakage and improving network reliability. Alternatively, this paper presents a new approach that considers the phasing of the optimal booster pump installation combined with the design of a DMA configuration aimed at optimizing the operation cost and hydraulic performance. The proposed method combines the overall sectorization process to simultaneously optimize the locations of the flowmeters, gate valves, and booster pumps, as well as the pump sizes. The proposed method was applied to a real-world WDN and the results showed two advantages: first, the boundary pipes are good candidate locations for booster pump installation, which makes it possible to improve hydraulic performance; and second, operation costs are reduced when compared to those of the source-connecting central pump configuration. This study provides a methodology to select the most suitable pumping configurations for DMA design/operation in WDNs.

Towards water resilience through Nature‐based Solutions in the Global South? Scoping the prevailing conditions for Water Sensitive Design in Cape Town and Johannesburg

Water Sensitive Design (WSD) is gaining attention as a Nature-based Solution (NbS) to urban water problems. It incorporates green infrastructure with engineered urban water systems through innovative design of the built environment and urban landscape. In Africa, Johannesburg and Cape Town are two cities engaging with WSD at a policy level. This paper uses the Strategic Niche Management (SNM) approach in a comparative analysis of ongoing engagement with WSD in Johannesburg and Cape Town. We explore the extent to which this engagement signals the launch of the transition towards water resilience. WSD represents a niche that is in synergy with the visions of sustainable urban (water and environmental) management in both cities. Results indicate a progressive engagement with WSD by different actors at regime and niche levels. However, the lack of coordination and capacity deficiencies due to limited social networks and higher order learning are challenges that constrain take-off and further consolidation of the WSD approach in the transition towards water resilient futures. Furthermore, we find urban governance practitioners struggle with reconciling the pursuit of visions of sustainability to be realised through nature-based urban development with the pressing infrastructure deficits that persist in most African cities.