Urban River Restoration Research Articles

An urban rivers renaissance? Stream restoration and green–blue infrastructure in Latin America – Insights from urban planning in Colombia

AbstractWhile urban river restoration has become mainstream in the Global North, it remains scarce in Latin America, where most literature focuses on water quality, stream habitats, and watershed assessment, but planning and implementation lag behind. Colombia is undergoing a paradigm shift after pioneering the integration of green and blue infrastructure (GBI) into urban planning in the early 2000s (namely Estructura Ecológica Principal). A surge in river renaturalization initiatives is underway, with large and intermediate cities planning and executing projects. We systematically assessed the integration of rivers and GBI into local policies (Planes de Ordenamiento Territorial) and found widespread and strong recognition of streams, wetlands, and ecosystem services in urban planning, higher than previously reported. Most cities emphasize river multifunctionality, ecological connectivity, public space, and recreation, as well as disaster risk reduction, advancing toward sustainable urban water and drainage systems. However, significant gaps persist regarding climate change resilience, participation, and social justice. In a region marked by high inequality, pre-existing spatial exclusion could be amplified by urban renewal, greening, and tourism due to unfair resettlement conditions and gentrification. Such trade-offs can undermine the ecological and social benefits of restoration. We highlight the crucial role of civil society and grassroots activism in protecting and defending urban commons and conclude by recommending a critical examination of GBI and river restoration efforts in Latin America. Colombia’s case can serve as both a reference and a cautionary tale for other cities in the region to achieve outcomes that promote equity and justice amid pressing social and environmental challenges.

Urban River Restoration in India: The Challenges Ahead

Urban River Restoration in India: The Challenges Ahead

The destructive work of restoration: Fishing communities facing territorialization in Turag river

Urban river restoration efforts are growing worldwide. Along with restoring and conserving rivers, riverside land is slated for public recreation, property development, and infrastructure for adaptation to climate change. Riverine landscapes, embedded in larger watershed ecosystems and claimed by multiple communities, are sites of contested planning in contemporary cities. In this paper, we advance the scholarship on contestation over control and access of urban rivers and floodplains by analyzing the role of river restorative legislation and water-centered planning in managing Turag, an urban river in Bangladesh. While river degradation in urbanizing regions is often ascribed to lack of regulatory controls and enforcement, we argue that restorative legislation and interventions facilitate Turag River's ecocide by processes of territorialization. Territorialization refers to the co-constitutive dynamics of river restorative legislations and interventions as well as planned infrastructure and land use changes, which erase and displace river-based communities with reciprocal relations to the river. Riverine livelihoods and lifemaking, among fishing and farming communities in the case of Turag, are erased from planning and restoration practices, and are consequently expelled from the expanding city. Drawing on qualitative and counter-cartographic investigation of one severely polluted urban river in Dhaka, Bangladesh, we show how territorialization materializes through five co-constitutive dynamics involving environmental legislation, encroachment reporting, river demarcation, encroachment evictions, and wetland to land conversions. We draw out critical implications of how river restoration can be just and advance a riverine urbanism.

Connecting place and multilevel governance for urban river restoration

ABSTRACT River restoration in urbanising contexts faces multiple pressures and increased governance complexities. The aspiration for basin-scale policy integration has been widely promoted but is not well tested in urbanising rivers and implementation success remains disjointed across jurisdictions. We link the multi-level governance lens with the notion of place to facilitate a deeper examination of the unique assemblages of socio-material configurations that embed restoration practices across locations. Employing an embedded qualitative case study of the Citarum revitalisation in Indonesia, where a territorialised military operation co-existed with multi-level arrangements, we show that variability, rather than consistency, of governance approaches persisted across geographies. The variabilities were shaped by different place-based conditions – critical in influencing restoration practices and governance processes – such as place leadership, attachment to river, neighbourhood stewardships, issue-based networks and a sense of legitimacy. Thus, our study challenges the normative primacy of the basin-scale integration in existing water governance research and policy, while offering a more robust and critical approach towards gathering place-based insights and in situ evidence of governance complementarity and inconsistency.

The return of nature? Negotiating the 'renaturation' of the Isar as an envirotechnical landscape.

How can we trace differing normative values, and especially in alternative imaginaries of environmentally sustainable futures? To address this issue, this article extends the sociotechnical imaginaries framework by providing conceptual tools to understand the underlying rationale of alternative environmental imaginaries-through an envirotechnical analysis. I analyse an urban river restoration project called the Isar-Plan in Munich, Germany, where the notion of 'renaturation' was at the centre a controversy over designs for the project. By positing the river as an envirotechnical landscape, the normative dimensions of nature, science and technology within environmental transformations can be constructively integrated within co-productionist analyses in science and technology studies. The article shows how existing societal values are shaped by prior systems and regimes, constructing local imaginaries of desirable environmental futures. Envirotechnical analyses also increase our ability to identify differing normative values, and could thus be further applied in cases where the normative assumptions behind opaque notions otherwise would be left underexplored.

Assessment and Comprehensive Evaluation of Large-Scale Reclaimed Water Reuse for Urban River Restoration and Water Resource Management: A Case Study in China

Replenishing reclaimed water into urban rivers, which suffer from reduced flow and deteriorating water quality due to anthropogenic activities, presents an opportunity for water resource management and ecological restoration, while the effect and evaluation need to be considered. This study investigated the feasibility of large-scale reclaimed water reuse in urban rivers, focusing on water quality improvements and reuse scheme evaluation, utilizing modeling software to simulate the water quality after implementing the reclaimed water replenishment scheme. After seven days of reclaimed water replenishment simulated, the water quality in the receiving urban rivers exhibited substantial improvements to different extents, with some rivers showing a decrease of over 90% in chemical oxygen demand (CODMn), ammonia nitrogen (NH3-N), and total phosphorus (TP) concentrations. A comprehensive evaluation method using the physical element extension–analytic hierarchy process (AHP) evaluation model was developed to evaluate the feasibility and efficiency of the large-scale project of reclaimed water reuse in urban rivers. The overall score of the large-scale reclaimed water reuse scenario reaches 89, approaching Level I and indicating a highly scientific and reasonable plan. This study contributes to the field of urban river restoration and water resource management by demonstrating the potential for improving water quality in urban rivers through large-scale reclaimed water reuse. The innovative comprehensive evaluation method offers valuable insights for guiding the implementation of similar projects in other urban river systems, addressing water resource challenges, and promoting ecological restoration in urban areas.

Enhancing climate-resilient urban river restoration: predictive modeling of geomorphic changes

Abstract Urbanization and climate change are two potent forces shaping the contemporary environment. Urban rivers, integral to city life, are profoundly affected by these dynamics. While restoration efforts have yielded promising results, a persistent challenge lies in the inadequate consideration of geomorphic processes and climate change impacts in restoration planning. This study addresses this critical gap by proposing a novel approach for designing stable urban river geometries in ungauged basins. Leveraging the Soil Conservation Service (SCS) method in conjunction with General Circulation Model (GCM) data, our research focuses on determining design discharge and channel stability. Our principal finding, based on the incorporation of parameters related to precipitation, runoff, and effective discharge, indicates a projected 35% increase in the width of stable urban rivers in the future. These results underscore the urgency of integrating climate change considerations into urban river restoration initiatives. Neglecting this imperative aspect risks the failure of restoration projects, particularly in addressing geomorphic challenges intensified by climate change. This research offers a valuable framework for future restoration efforts, ultimately contributing to the resilience and sustainability of urban river ecosystems.

Hybridity and Multiscale Compatibility in Landscape Infrastructure for Mountain River Restoration: A Pathway Toward Environmental and Socio-Ecological Sustainability

River rehabilitation has traditionally focused on hard-engineering projects, which often fail to address environmental protection concerns and social-ecological services in a larger territorial context. In particular, mountain rivers pose unique challenges due to their diverse hydrological and morphological conditions, which are often overlooked by traditional restoration methods. Consequently, water quality deteriorates and social-ecological imbalances arise. To address these challenges, we propose a holistic solution that integrates landscape infrastructure (LI), a soft-engineered biophysical structure and process. Our approach combines hydrological analysis, ecological sensitivity assessment, and ecological design solutions to develop an LI framework for the Xiaojiahe basin in the Chongqing Mountain range in southwest China. This framework emphasizes integration across the spatial scale of landscape networks and corridors. Our study reveals the existence of fragmented river systems and limited connectivity among green spaces in the research area. The adoption of a comprehensive Landscape Infrastructure (LI) framework facilitates the execution of culturally sensitive and practical design solutions for Mountain Urban River Restoration (MURR) at different levels. This approach reinstates the multifaceted environmental and socio-ecological benefits of the basin. We believe that our approach can be applied to other cases with similar contexts and challenges.

Urban river restoration in Hong Kong: Assessment, impact, and improvement strategies

River restoration or improvement is widely practiced in cities around the world to promote sustainable urban development. However, post-project evaluation is not commonly performed, and even less evaluated is the social impacts of river restoration. Based on three recently restored river channels in Hong Kong, this study evaluated water quality, biodiversity, and societal perceptions of such projects. Focus was placed on perceptions, assessments, and improvement suggestions from 295 surveyed and interviewed respondents. Results show that the effects of river restoration on water quality were mixed—depending on restoration techniques and site conditions. Restored river sections generally had higher biodiversity as compared to unrestored ones. The restored river sections positively influenced the respondents’ visiting behaviors. The respondents at low-density sites generally reported more positive perceptions and higher ratings on the restoration projects than those at the population-density site. Data analysis shows that respondents’ emotional quality was significantly and positively related to biodiversity, visual attractiveness, air freshness, and auditory environment of the sites. The respondents also provided valuable recommendations on the importance of factors to be considered in the planning and design of river restoration, desired facilities, and decision process. The findings and recommendations are expected to help improve future river restoration in compact cities.

Willingness to Pay for Urban Inland River Restoration: Case of Nanyang, China

Ecologically rational restoration of urban inland rivers is crucial for sustainable development of modern cities. The research purpose is to assess and compare the value of urban inland rivers by identifying the willingness of Nanyang residents to pay for each of two types of rivers restoration — ecological (improving the ecological quality of rivers) and recreational (ensuring rivers to meet cleanliness requirements for residents’ recreational areas) as well as to identify the factors that determine the difference in the obtained estimates. The novelty of the study consists in the willingness to pay (WTP) for ecological and recreational restoration of urban inland rivers identification and comparison by using the two dichotomous choice questionnaires and in the determination of factors explaining the difference in ecological and recreational value estimates. A questionnaire survey was conducted in Nanyang City, and data was collected from a sample of 326 respondents. The results of the questionnaire survey revealed quite significant difference between the willingness of urban residents to pay for ecological and recreational restoration of the river — CNY109.56 (USD16.8) and CNY255.12 (USD39.84) per person annually, respectively. Factors influencing differences in WTP for ecological and recreational restoration of urban inland rivers — income level, gender, education level, environmental awareness, need for recreation, and distance to urban inland rivers — were identified. The study’s results indicate that urban inland rivers hold a significant economic value and highlight the importance of implementing measures for targeted ecological and recreational restoration as part of the overall urban river restoration system.

Construction of an adaptive river-based recreational network for urban river restoration: A case study of Rencheng District, Jining City, China

Recreation-oriented urban river ecological restoration can help restore damaged ecosystems and improve human well-being. This study selects the urban river network of Rencheng District, Jining City, China as a case to map and construct a river-based recreational network (RRN) in an urban river restoration context. Morphological spatial pattern analysis, connectivity evaluation methods, and an overlay method of ArcGIS are applied to identify river network connectivity and ecological sources, which are used to map RRN. The research findings show that except rivers in the Liangshan-Jining Canal, other rivers have medium, poor, or extremely poor ecological connectivity. The ecological sources are mainly distributed in the vicinity of Nanyang lake and Taibai lake. The distribution of river connectivity is largely correlated with the regional physical geography pattern (e.g., geological structure and topological position of water patches), as well as historical human activities (e.g., canalization). Furthermore, the continuous subsidence of coal mining subsidence areas, urban expansion and rural construction, environmental damage and pollution, natural changes (e.g., climate change) are the risk sources of river network connectivity. To restore the ecological and social connectivity of urban river network, an adaptive RRN is proposed according to the current environmental status and the factors affecting the river connectivity. Specifically, form-based and process-based restoration measures can be adopted in urban built-up areas and rural areas, respectively. The findings provide a holistic solution for the restoration and recreational use of urban river network at a regional scale, thereby promoting the coordination of urban ecosystems and sociocultural systems.

Spatio-temporal variability (up- and down-stream and three seasons) of response patterns of macroinvertebrates to commonly applied low-head concrete weirs under reclaimed water intervention in urban river restoration

Understanding how aquatic communities respond to various structures is important for assessing ecological effectiveness, developing theory and guiding sustainable river restoration. However, there is still minimal understanding on spatio-temporal variability of response patterns of macroinvertebrates to commonly applied low-head concrete weirs and reclaimed water in urban river restoration. Our results showed that the presence of above two structures and their interactions sometimes produce varying distribution of macroinvertebrate before and after each structure in different seasons. At higher taxa level, it is not a bad choice to utilize various structures and their composite construction to increase biological heterogeneity, to reduce costs and risk of failure, and to improve reasonably designed structures for recovery aquatic communities. Reclaimed water mainly played three major functions, sustaining more taxa; reversing the relationship of values between up and down weir on a 150 m reach-scale; maintaining macroinvertebrates indexes on a 1500 m reach-scale. These results could highlight ongoing challenges in designing structures to meet multiple goals. For stakeholders, the recommendations of this study are most suitable for river restoration focused on improving diversity of specific aquatic groups. Although case-specific, the results are analyzed within a wider framework to emphasize the importance of using various structures and composite construction in river restoration, the significance of extensive and repeated post-restoration monitoring to explore project effectiveness and provide valuable insights to river restoration.

Water quality status response to multiple anthropogenic activities in urban river.

Water quality evaluation and degrading factors identification are crucial for predicting water quality evolution trends in an urban river. However, under the coupling of multiple factors, these targets face great challenges. The water quality status response to multiple anthropogenic activities in an urban river was evaluated and predicted based on comprehensive assessment methods and random forest (RF) model. We found that the distribution of each physicochemical parameter exhibits an obvious spatial clustering. The mean pollution level and trophic status of the urban river are medium pollution (water quality index = 59.79; Nemerow's pollution index = 2.00) and light eutrophication (trophic level index = 57.30). The water quality status is sensitive to anthropogenic activities, showing the following order of TLI and NPI values: residential district > industrial district > agricultural district and downtown > suburbs > countryside. According to the redundancy analysis, constructed land (F = 15.90, p < 0.01) and domestic sewage (F = 14.20, p < 0.01) evinced as the crucial factors that aggravated the water quality pollution level. Based on the simulation results of the RF model (variation explained = 94.91%; R2 = 0.978), improving domestic sewage treatment standards is the most effective measure to improve the water quality (increased by 40.3-49.3%) in residential and industrial districts. While in a suburban district, improving the domestic sewage collection rate has more effectively (23%) than those in the residential and industrial districts. Conclusively, reducing exogenous pollution input and improving domestic sewage treatment standards are vital to urban river restoration. Clinical trial registration Not applicable.

Environmental information disclosure and public choice decisions for urban river restoration: A comparative study between Brussels (Belgium) and Guangzhou (China)

Worldwide environmental information disclosure (EID) has been widely promoted as a policy approach to establish transparent governments, enhance public environmental awareness, and foster participatory environmental governance. While information disclosure and transparency are inherently incentivised within democratic regimes, how and through what pathways an increased flow of environmental information in the absence of democracy could lead to favourable public support for environmental/ecological projects remain under-investigated. Particularly, there exists very limited literature which compares how EID is associated with public environmental choices between different sociopolitical contexts. Taking Brussels (Belgium) and Guangzhou (China) as a comparative case, this study examines the association between citizens' perceived trustworthiness of various environmental information sources and their choice decisions regarding urban river restoration initiatives in contrasting socialpolitical contexts. Latent class modelling of two paralleled discrete choice experiments unveils a consistent classification of three distinctive groups for each city and also the combined sample, including Enthusiastic Supporters (Class 1, who are cost-insensitive and supportive of all proposed changes), Pragmatic Supporters (Class 2, who are cost-sensitive, prefer some changes they favour), and Non-Supporters (Class 3, who are unwilling to support the proposed initiatives). Incorporating respondents' trustworthiness in information sources as covariates in class membership likelihood function, respondents' membership is found to be associated solely with the most trusted information source, i.e., social contacts in Guangzhou, third parties in Brussels, and social contacts for the whole sample. Holding trust toward the most-trusted information source can increase the probability of being a member of Class 1, otherwise, more likely being a member of Class 3. Taken together with the insignificance of the variable denoting a respondent's city in explaining class membership, this study reveals that the variations in the EID levels (matured vs. emerging) and sociopolitical contexts (democratic vs. non-democratic) cannot significantly shape citizens' environmental decisions. Instead, it is respondents' perceived trustworthiness of information outlets that plays a positive role in their supportive decisions. These analytical results offer new insights about the role of EID in environmental governance and call for instilling institutional trust in China and relational trust in Belgium for facilitating effective communication and pro-environmental behaviours across the whole community.

Urban Land-Use Type Influences Summertime Water Quality in Small- and Medium-Sized Urban Rivers: A Case Study in Shanghai, China

(1) Background: Small- and medium-sized rivers in urban areas are unique environments that serve as blue-green corridors for urban residents. The relationship between land-use types and water quality in these rivers provides important information for effectively addressing urban river restoration and pollution management. However, not much attention has been paid on these small- and medium-sized rivers, especially in large urban agglomerations with dense river networks. (2) Methods: This study undertook a field investigation on 130 sampling small- and medium-sized rivers during the late summer and applied data-driven water quality index and landscape analysis techniques to evaluate the direct impacts of riparian land-use types on the summertime water quality in Shanghai’s small- and medium-sized rivers. Riparian land-use types were derived from OpenStreetMap (OSM) datasets, including industrial, commercial, residential, and green spaces. (3) Results: Residential and green space are located closer to these sampled rivers than industrial and commercial land types, suggesting a tentative link between anthropogenic activities and water quality. Further analysis concluded that urban resident settlements, characterized by specific land-use types, DMSP-OLS nighttime lights, OSM road density, and OSM river density, strongly affected the water quality at the sub-catchment scale. We further determined the critical radii for impacts of land use types on urban rivers. Industrial types may influence water quality within a maximum radius of 5 km, followed by green space (4 km), residential areas (3 km), and commercial developments (2 km). These mathematically and statistically computed radii provide updated visions for river health assessment. For a specific land-use type, the assessed water quality index will be biased by using an assessment area with a radius higher or lower than the above-estimated radii. The study also quantified the spatial extent and transmission efficiency of non-point source pollution in a super built-up area of central Shanghai. We observed that contaminants transported by river pathways can reach a larger area than those transported by roads. (4) Conclusions: The high-quality environments in small- and medium-sized rivers are tightly linked to riparian landscape patterns. It is therefore urgent to control domestic pollutions as part of the restoration of megacity’s urban rivers and grapple with the complex challenges of risks to water supply. This study elaborates the importance of integrating land-use planning and water-quality management to maintain the functions and services of small- and medium-sized urban rivers.

Water dynamics and blue-green infrastructure (BGI): Towards risk management and strategic spatial planning guidelines

This work aims to demonstrate the importance of concretely defining blue-green infrastructure (BGI) in non-consolidated urban areas as an active element to achieve integrated risk management and strategic spatial planning guidelines to structure future urban development. BGI is seen as a city's structuring element more than an element integrated into a city. For this, a method is proposed and a demonstration of its application is conducted for the city of Paraty, in Brazil. It starts with a diagnosis of the current situation, maps the conflicts experienced by the city regarding water dynamics, and establishes cause-effect relations. Then, the past reference situation and the future trend situation are evaluated, and, with lessons learned, a future urban occupation alternative is defined, using BGI and river restoration approaches. Finally, the two future situations are compared in terms of environmental enhancement. The analyses are supported by mathematical modelling and a multicriteria index (Urban River Restoration Index). The results indicate that the future trend situation worsens flood risks, while the BGI proposal reduces them, besides improving the watersheds environmental quality and setting strategic spatial planning guidelines. Thus, understanding the role of water in a city is crucial to define a BGI approach focused on delivering urban water management solutions and strategically structuring future urban development, being the water a structural part of the city itself.

Measuring the economic value of urban river restoration

Rivers are under enormous threat worldwide and large amounts of money are invested in river restoration. Contrary to the costs, the benefits of river restoration are much harder to quantify. In this study, the benefits of restoring different sections of the Yongding River in Beijing, China, are estimated through a discrete choice experiment (DCE). Place attachment is measured by sampling residents upstream and downstream and using the river sections as labelled alternatives in the DCE. As expected, the improvement of water quality is valued highly by all river basin residents, and place attachment and spatial preference heterogeneity play a significant role in public willingness to pay (WTP) for river restoration. Although respondents are willing to give up only a small share of their disposable income, public WTP for improved river water quality is a factor 2 to 4 higher than the current household water bill. These findings provide important guidance for the recovery of the investment costs associated with river restoration projects.

The challenges of urban river restoration and the proposition of a framework towards river restoration goals

River restoration is gaining significance as an approach for river system management, even in urban areas, where the flood risks and morphological imbalances are more evident. In cities, the highly modified environment and the lack of open spaces make it harder to apply the concept of river restoration in its whole extent, raising doubts about the feasibility of adopting restoration approaches for urban rivers. In some cases, the implementation of green and blue infrastructure strategies alone is not enough to support the river restoration goals so the adoption of gray infrastructure is necessary. In order to explore aspects related to the theme, this article discusses four questions proposed from a bibliometric study of urban river restoration: Is it worth restoring urban rivers? How much does it cost? If the watershed is heavily modified, can it sustain the restored fluvial spaces? How can the success of this approach be measured? Throughout the discussion, it is clear that due to cities’ complexity and the absence of available open spaces, there is no simple answer to these questions, each case being unique and deserving particular assessment. However, even when performed partially, without significant positive impacts on the natural environment, river restoration can bring several benefits to the urban environment, creating an opportunity of reintegrating the river as a valuable element of the landscape. Additionally, we propose a framework to assist managers in identifying and implementing potential river restoration actions.

Distribution Characteristics and Influencing Factors of Phytoplankton Community in Harbin Urban River Network During Wet Season

In this study, 23 typical sampling points were selected from the Harbin urban river network during the wet season from June to August in 2019, including the Harbin section of the Songhua, Hejiagou, Majiagou, and Ashi rivers to study the distribution of phytoplankton communities. Characteristics and driving factors influencing the water environment were determined, and a total of 174 taxa of phytoplankton were identified. During the wet period from June to August, the composition of the phytoplankton community in the urban river network of Harbin was dominated by Diatom and Chlorophyta, which gradually shifted toward Diatom and Cyanophyta. The dominant species mainly include:Cyclotella meneghiniana Kützing, Nitzschia palea (Kützing) W.Smith, Synedra ulna (Nitzsch) Ehrenberg, Ankistrodesmus angustus Bernard, Pseudanabaena limnetica (Lemmermann) Komárek, and Cryptomonas ovata Ehrenberg. One-way crossed similarity analysis (One-way crossed ANOSIM) revealed significant differences in phytoplankton composition among different sections of the river during the study period (P<0.05). The Harbin section of the Songhua River was richer in phytoplankton than other sections. Redundancy analysis (RDA) shows that TP and pH are the main environmental factors that cause differences in the structure of the phytoplankton community in each section of the Harbin urban river network. This research aims to enrich the research on the ecological evaluation of urban river network by studying the phytoplankton community and environmental relevance of Harbin urban river network and provide a theoretical basis for future urban river network ecological monitoring, management, and restoration.

Integrating river restoration goals with urban planning practices: the case of Kebena river, Addis Ababa

In the urban environment, rivers are most affected by development mismanagement to the extent that some of the essential services such as habitat for biodiversity conservation, recreation and domestic uses to communities are critically impaired. Consequently, river restoration is presented as practical solution to address urban river degradation issues and to revitalize urban rivers and river buffers. Goal setting along with clear and measurable goals in urban river restoration processes is one of the critical tools to guide restoration activities. This study aims to assess the qualitative effects of clearly defined river restoration goals and analyze their tangible effects on river restoration efforts in Kebena river watershed, Addis Ababa. Qualitative data from expert interviews, stakeholders’ consultation, document review and institutional analysis are used to inform this research. The results show that the Environmental Protection Authority and Structural plan of the city have vaguely defined river restoration goal in the planning and implementation phases of river restoration projects. On the other hand, the goals of different institutions varied in context, while others were redundant and lacked synergy. As a result, urban rivers and river buffers accommodate various land uses that are negatively affecting the potential of rivers and river buffers in benefiting communities. Finally, the study forwarded critical methodological steps to guide the formulation of a well-defined goal and setting priorities for concrete actions to restore the river.