Dynamic cluster analysis of urban river ecosystem using water, climate, and economy nexus

Urban rivers have an undeniable importance in the ecosystem because they are a platform for providing water resources, a symbol of nature, and an environment for recreation and fishing (Hua & Chen 2019; Xu et al. 2023). In addition, rivers have significant ecological, economic, cultural, social, and environmental values. Many cities and civilizations have been established around rivers to provide drinking water, agriculture, industry, and transportation (Yin et al. 2022). Flood control, boating, fishing, and swimming are some of the advantages of having an urban river. Rivers have many functions such as connecting ecosystems and communities, and also bringing people together around the same idea for a creative and sustainable environment (Everard & Moggridge 2012; Qin et al. 2023). People from all sectors of society, as well as private and public stakeholders, should participate in the formulation of the river management plan, in order to find effective solutions for the use of natural resources (Wang et al. 2022; Gao et al. 2023a, 2023b). A high-quality design of an urban river ecosystem can increase the sustainability of the ecosystem and improve economy and urbanization (Acheampong et al. 2016). Urban rivers have been the most important focus of urban development in the post-industrial world. In addition, it is a place for the reconstruction of industrial towns, agricultural and industrial complexes, residences, as well as recreational and sports facilities. In recent years, the importance of the river ecosystem has been considered in long-term planning and design, even for seasonal or dry rivers.

Several studies considered design components of ecosystems for developing the evaluation indicators (Bai et al. 2023). Acheampong et al. (2016) examined the dynamics of urban water system transitions through management reforms using a multilevel framework. This study showed how political parameters in river ecosystem design affect the urban water regime through economic parameters. Pena et al. (2016) created an ecological model based on geographical information system principles to contribute to the delimitation of the maximum infiltration areas. The application of the model in Almada Municipality, from the Lisbon Metropolitan Area, allowed the integration of the maximum infiltration areas in planning, urban design, and municipal management. Amiri & Nakane (2009) used remote sensing, multivariate analysis tools, and geographical information systems to develop a multiple-linear regression framework for estimating the water variables of land cover in the river basins. Satellite data were used to generate the land cover map for representing the land cover-stream water linkage. Gao et al. (2020) simulated the relationship and correlation between river ecosystem patterns and flood rates by a geographically weighted regression model linked with the river ecosystem pattern change. The results showed that the river ecosystem indicators of grassland had a negative spatial impact on urban runoff.

Zhang et al. (2021) introduced the emerging soft-engineered framework of the ecological-social-infrastructural structure, the concept of river ecosystem infrastructure, and multiangle design solutions to address the challenges of ecological sustainability. This research can be considered as a basis that can be used to find sustainable development scenarios in the future. Li et al. (2021) evaluated the effect of urban rivers on the riverside perspective. For this subject, a quantitative river ecosystem factor was established based on a semantic segmentation model, using deep learning techniques to investigate human visual perception. The analysis process of the nonlinear correlation between public scores and quantitative indicators was carried out by a random forest model. Results showed that the prediction model was suitable for assessing the visual quality of the developed urban river ecosystem. Furthermore, the green visibility index was positively correlated, and the other three factors were negatively correlated with the visual quality. Pattacini (2021) reviewed the previous practices and theories to investigate the formation of conceptual ideas for urban river ecosystems. In addition, an attempt was made to provide a theoretical framework identifying the types of riverside ecosystems, including the relationship between urban forms and river corridors. These were of importance to inform practice and ensure responsive and responsible processes in planning and design. Urban design was considered as a craft requiring ‘savoir faire’ to ensure the functionality and quality of urban spaces. Results provided a critical assessment of theories to identify and categorize the components of urban riverside regeneration. Yang et al. (2022) analyzed the development mode of land cover and ecosystem pattern in the affected area of the Yellow River on a multi-spatial scale using a multiscale geographically weighted regression technique. This paper is a significant resource for finding an optimal strategy in urban river watersheds that can predict design changes in the ecological pattern and provide a framework for the safety and health of critical ecological processes. Moosavi et al. (2022) reported that flood prediction was related to river ecosystem patterns and water resource variables. The impact of the aspects of different landscape nature has been studied to combine spatial patterns with flood or drought flow, and monthly flow has been estimated using climatic variables in the Urmia Lake Basin, Iran. The results approved that the simulation of homogenous clusters significantly enhanced the prediction accuracy.

Rodrigues et al. (2021) proposed a framework to categorize regions for the allocation of best management practices to counteract the various impacts of urbanization. The developed method identified places that most needed intervention. The result of the study indicated that the allocation of practices can be successfully applied, which allowed local policymakers to improve the measures of water security and ecosystem sustainability. Moreover, qualitative evaluation has a key role in ecological sustainability (Lin et al. 2021; He et al. 2023; Ran et al. 2023). Chang et al. (2022) investigated the pollutant sources of different river ecosystem patterns to develop relationships between environmental and hydro-geological variables and water quality. Fifteen river ecosystem parameters and hydro-geographical parameters were evaluated as explanatory parameters. Correlations between the explanatory variables and the response variables were analyzed using the multiple-linear regression method. Wang (2022) studied the distribution pattern of aquatic plants in the river ecosystem using the aggregation intensity index, variance/mean ratio, Cassie index, negative binomial parameter and α–diversity index, for evaluation. The results approved the effect of aquatic plants on ecological restoration. Wang et al. (2023) evaluated ecological risk in the Hailar River basin in the recent 30 years, using temporal and spatial evolution characteristics, for the scientific formulation of ecological management strategies. In the study, ecosystem services were used to improve the ecological risk assessment method for the traditional ecosystem, and its theoretical basis was clarified using the human-nature system method. The results showed that the ecological spatial risk was higher in the middle areas of the region.

A comprehensive approach in the design and evaluation of urban river ecosystems refers to a mutual relationship between the constituent elements, which should be evaluated in the form of economic, social, and environmental aspects (Chen et al. 2022). This structure requires the combination of natural, social, technical, and economic layers that are defined in an integrated system. Another attitude in ecosystem design is to look creatively and take advantage of artistic aspects in combination with its historical nature. The outcome of these approaches will lead to an ecosystem that responds to the biological needs of human societies and natural river ecosystems. In addition, these approaches show that the design of a river ecosystem should be based on the three goals of improving land cover, promoting sustainability, and defining a social dimension. Coping with water scarcity, increasing socialization to improve human interactions, and strengthening the ecological characteristics of the river for ecosystem sustainability are other peripheral goals. Therefore, this study evaluates the relationship between Lijiang urban river and ecosystem design components according to the principles of climate, economy, ecology, and society.

The sustainability of the ecosystem is another goal in the evaluation of the sustainable urban river ecosystem, which is considered in the form of permeability, environmental indicators, flood control, and industrial development (Zhang et al. 2022a, 2022b). In urban river ecosystem design, priority is given to social security and the satisfaction of citizens. Therefore, the connection between the mentioned issues requires an expert opinion from different perspectives, which has been tried to be provided by completing a questionnaire by 130 experts in the fields of ecology, economy, society, and water resources.

Therefore, to develop the evaluation framework, the following steps were carried out: (1) Analyzing Lijiang River at the scale of Guilin city; (2) Identifying the ecological, economic, climate, and social elements of the river ecosystem in 4 points (URL1, URL2, URL3, and URL4); (3) Land use evaluation for natural, permeability, and economic measures; (4) Evaluating the river morphology and flood control infrastructure; (5) Identifying the applied strategies for a sustainable ecosystem; (6) Investigating the solutions including floodplains management.

The results showed that URL1 had the highest percentage of flood protection (Table 2). The use of rock formation and maintaining the natural state of the river have been the two main factors in this regard. Therefore, modeling this ecosystem for the design of other areas can be recommended. In terms of social security, URL3 has the best score with 0.87. Increasing the distance between the river bank and the sports venue and the use of separating walls will increase the rank of other areas. URL3 has the best index in special access and social ability. These criteria showed that the ecosystem design of the river in this area was consistent with the social approach. Visual influence obtained the highest value in URL4, while other areas were also more than average. The sustainability index for all areas is estimated at 0.52. In general, it is not possible to increase the sustainability index by more than 0.47 because the use of plants in the river ecosystem reduces sustainability and increases visual influence and compatibility with nature. One of the basic criteria in ecosystem evaluation, especially urban rivers, is land cover. In various studies, land cover is one of the basic factors of ecological restoration, prevention of erosion, and water and soil resources’ productivity. In this paper, permeability, economic value, and natural measure are considered as three valuable criteria for land cover. First, it is necessary to briefly define each of the three mentioned components. Permeability refers to the rate of water penetration in the ground cover compared to the final infiltration rate. For example, if in the designed river ecosystem, the average penetration of water into the ground is 0.5, the reduction of permeability is estimated to be 0.5. Economic value is the amount of investment made in relation to residential areas. Natural measure is defined as the percentage of the area covered by plants compared to artificial cover. In terms of land cover criteria, all areas had relatively the same conditions, and have the ability to improve for the future. Vulnerability to drought was the last criterion examined, which is defined as the need for water supply, excluding the amount of water that is provided in circulation or treatment. URL4 performed best in terms of the drought vulnerability index. This area has reduced vulnerability due to the use of drought-resistant plants and artificial cover.

Urbanization and population growth have made fundamental changes in the ecosystem, climate, and water resources. Human activities have also had ecological implications such as in urban rivers. Urban river ecosystems are environments with special ecological characteristics that play an important role in urban ecosystem design. Exploiting more than the inherent power of the river without building environmental capacity causes disturbances in water balance and disrupts life in urban areas. Various kinds of aquatic plants are addressed by researchers that can be cultivated for the urban ecosystem. Results showed that five aquatic plants can be recommended namely, lotus, reed, water hyacinth, black algae, and soft-stem club-rush. Reed plants grow in lowland areas and transfer oxygen from their shoot zone to their root zone. Lotus (Nelumbo lutea) is a conspicuous emergent aquatic plant that frequently grows in local ponds. Black algae is an extremely resistant strain of algae. It grows well in water on walls, floors, and surfaces. Water hyacinth is an aquatic plant native to South America, naturalized throughout the world, and often invasive outside its native range. Soft-stem club-rush plants tend to flourish in damp conditions, often being found close to or in standing water. These evergreen perennials are popularly used in ponds or water gardens, providing shelter and a food source for wildfowl. Traditionally, some species are woven into baskets, mats, and even homes.

From an ecological point of view, river ecosystem design is an essential component that, taking into account climatic factors and human activities, makes the urban river ecosystem sustainable. The areas with a high capacity to infiltrate are especially important in ecosystem planning, whose protection is crucial for the continuity of water flow, minimizing flooding risks, maximizing the recharge of aquifers, and reducing soil erosion (Pena et al. 2016). Scientific assessment of the hydrodynamic conditions of the water system connection is of great significance and value in guiding the ecological construction of urban water system connection and building healthy river–lake relationship (Zhang et al. 2021; Zhou et al. 2022). The agricultural land was the main pollution source, leading to a higher concentration of pollutants in rivers. Therefore, quality can be a necessary factor in the cluster analysis of the urban river ecosystem (Kang et al. 2022). Simulation and analytical studies have shown the relationship between floods and land use change, as well as the need to restore river ecosystems to control floods (Liu et al. 2014; Ren & Khayatnezhad 2021).

Rivers have always been considered as an important part of natural systems. The role of rivers in the formation of relationships between living organisms and the surrounding environment is very important from an ecological point of view. When rivers pass through cities, their importance increases because human relations and economic issues are also added to this issue, and it turns from a natural flow into a focus of planning and decision-making. Urban rivers as natural-social heritage need protection and stabilization. In this study, various aspects of an urban river in urban river ecosystem design have been investigated. The social, ecological, economic, and climatic parameters that affect the relationship between humans and the river have been evaluated and their importance has been analyzed. The results showed that the importance of social criteria is more than climatic issues, and ensuring the security and maintaining the natural conditions of the river is more important than the parameters that emphasize the preservation of water resources.

This work was supported by study on the realization mechanism and path of eco-product value in Fujian province (KY-010000-04-2021-024).

All relevant data are included in the paper or its Supplementary Information.

The authors declare there is no conflict.