1. Introduction

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Water is a fundamental natural resource that sustains life, supports economic development, and maintains ecological balance. As existing research indicates, water resources are essential for public health, industrial production, and social stability. Rapid urbanization has significantly increased the pressure on urban water systems worldwide, and the contradiction between rising demands and limited supply capabilities has become increasingly evident. Taking Shanghai, a megacity, as an example, the dense network of rivers, which form part of the Huangpu River system, serve both as important elements in maintaining the city’s landscape and drainage functions, as well as being influenced by various human activities in the surrounding area. This independent survey covered 7 administrative districts in Shanghai and 12 water bodies, covering a total of 20 monitoring points. Key parameters such as pH, electrical conductivity, total dissolved solids (TDS), dissolved oxygen (DO), and turbidity were measured on-site. The results were used to analyze the differences in water quality and their relationships with the surrounding environment and management policies. Additionally, proposals for water conservation measures suitable for residential areas were also proposed.

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2. Analysis on the Impact of Water Quality on Living

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The monitoring results show that the quality of the water bodies is significantly related to the types of land use in the surrounding area and population density. Variations in various indicators directly affect the daily life of residents and their experience of the waterfront spaces.

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 In the central urban areas, the water quality in the sections near high-density residential areas is most affected by human activities. Taking the section from Puhuitang Yishan Road to Tianlin East Road as an example, before rainfall, the dissolved oxygen level was only 5.6 mg/L, with a saturation value of 68.9%. The natural purification ability of the water is weak, which leads to incomplete decomposition of organic matter and the emergence of odors in the water, thereby reducing the utility of the river channel as a community landscape and recreational space. After rainfall, due to surface runoff, the total dissolved solids increased from 222 ppm to 317 ppm, and the conductivity also rose, indicating an increase in salt and pollutant ions in the water. This not only affects the sensory quality of the water but also exacerbates corrosion of pipelines along the river and the formation of scale on water-related equipment over time. In Zhangjiatang Gang Zhonghan to Guiping branch section, also located in high-density residential areas, TDS reached 482 ppm, conductivity was 956 μs/cm, and the dissolved oxygen saturation was only 65.6%. The water was heavily polluted by domestic sources; the turbidity was 19.4 NTU, and suspended particles in the water may carry pathogens and heavy metals, increasing the potential health risks associated with contact with water in the waterfront areas, as well as making water treatment more difficult and costly.

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In the sections near parks and schools, the water quality is relatively better. In the Kangjian Park area of Caohejing Port, dissolved oxygen reached 6.7 mg/L, with a saturation value of 83.6%. The ecological functions of the water are more stable. In the Meilonggang Libo industrial park section, dissolved oxygen could reach 7.0 mg/L, with a saturation value of 84.5%. However, due to surface runoff from the industrial park, turbidity reached 44.3 NTU, significantly reducing the visual quality of the water. In the low-density areas outside the city, the overall water quality is more stable. In the Chunchen Tang villa community section in Songjiang District, turbidity was only 7.6 NTU, while in the Xin Hengba Ecological Corridor area in Baoshan District, turbidity was as low as 4.9 NTU. Both areas had dissolved oxygen saturation above 72%, indicating higher livability and ecological value of the waterfront spaces.

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3. Global Urgency on Urban Water Resource Management

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In the context of rapid urbanization, global cities generally face four major challenges related to water resources.

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3.1 Growing Population and Demand

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Population concentration and economic development continue to increase the total amount of water used by cities, putting a strong pressure on the limited water resources available. Singapore is a typical example of this contradiction: as an island country without natural freshwater lakes or water collection areas, its population has grown from approximately 1.7 million in the 1960s to over 5.6 million today. The demand for domestic water is also increasing steadily. At the same time, water-intensive industries such as semiconductors and petrochemicals are expanding rapidly. It is expected that by 2065, industrial water will account for around 70% of the total water usage. The daily water demand in the country will reach 430 to 440 million gallons, and it is likely to double over the next few decades. The historical reliance on cross-border water transfers also makes the city’s water supply system vulnerable; this has forced the city to turn to alternative sources of water such as reclaimed water and desalinated seawater. For Shanghai, its large population size and high-density urban development also lead to ongoing competition among domestic water use, industrial water use, and ecological water use. The ecological capacity of the rivers in the central urban area continues to increase.

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3.2 Contamination and Water Quality

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Rapid urbanization, combined with a mismatch between environmental infrastructure and governance capabilities, directly leads to water pollution and deterioration of water quality. In developing cities in Southeast Asia such as Jakarta and Manila, industrial wastewater containing heavy metals, along with untreated domestic sewage, is discharged into rivers without proper treatment. Many informal settlements lack adequate sanitation systems; thus, domestic sewage and solid waste directly enter the water bodies, exceeding the natural capacity of the environment to purify these substances. The effects of water quality degradation are dualistic: on the level of public health, polluted water bodies can spread water-borne diseases such as cholera, dysentery, and typhoid fever. Heavy metals, when accumulated through the food chain, can cause long-term organ damage and developmental problems. At the ecological level, organic pollutants consume dissolved oxygen in the water, leading to fish deaths and changes in the structure of aquatic ecosystems, ultimately reducing biodiversity. The low levels of dissolved oxygen and the significant increase in TDS and turbidity after rainfall observed during the monitoring of river conditions in Shanghai’s residential areas are essentially results of pollution from domestic sources. Although the extent of this problem is less severe, its nature is similar to those described in the above examples.

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3.3 Influence of Climate Change

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Climate change is increasing the risks associated with urban water resources from both supply and demand perspectives. A typical example is the “Day Zero” water shortage crisis in Cape Town in 2018. Years of insufficient rainfall have put the city on the verge of a complete water cut-off. Such extreme droughts are not simply due to weather fluctuations; they are a direct result of climate change: rising temperatures accelerate evaporation, reduce soil moisture levels, and increase the frequency and intensity of droughts. Additionally, changes in atmospheric humidity cause rainfall to occur more frequently and in smaller amounts. Short-term heavy rains cannot effectively replenish reservoir capacity; instead, they can lead to urban flooding and cause a large amount of surface pollutants to enter the water bodies, creating a complex risk of sudden shifts between drought and flood conditions. In Shanghai, the frequency of extreme rainstorms has increased in recent years. The significant fluctuations in water quality parameters in areas such as Puhuitang River before and after rainfall observed during this monitoring campaign are a direct manifestation of pollution caused by rainflows. Climate change is exacerbating the instability of urban water quality.

 

3.4 Equallity in Access to Clean Water

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United Nations Sustainable Development Goal 6 (SDG 6) calls for “providing water and sanitation for all people, along with sustainable management of these resources”. However, ensuring fair access to water within cities remains a significant challenge. In cities such as Jakarta and Manila, wealthy communities have access to stable municipal water supplies, while residents living in informal settlements often have no access to formal water networks and are forced to rely on polluted river water or unregulated wells, thereby facing higher health risks. During the water crisis in Cape Town, vulnerable groups suffered even more due to the lack of emergency water sources and adequate infrastructure. This shows that water issues are not merely technical or environmental problems; they also relate to social equity. Sustainable water management must cover all residents, regardless of their income or location. In Shanghai, there is a significant difference in the quality of water environments in different districts and communities. The treatment of rivers surrounding old, high-density residential areas is relatively poor, and the public services available to residents along the waterfront are not equal. This is a manifestation of the issue of water fairness at the local level.

 

4. International Comparisons of Water Resource Management Approaches and Shanghai’s Practices

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4.1 Grading Management and Sponge City Construction in Shanghai

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Shanghai implements a three-level management system for rivers at the municipal, district, and town levels. The treatment standards and investment requirements for different levels of rivers directly affect water quality. Municipal rivers, such as the Xuhui section of the Huangpu River, serve key functions related to navigation and flood prevention. Therefore, there is more investment in their treatment and maintenance, with dissolved oxygen levels reaching up to 7.1 mg/L and saturation being 87.5%; as a result, water quality is more stable. District and town-level rivers focus on landscape and flood control functions. However, the allocation of resources for their treatment is uneven; some rivers near old residential areas receive insufficient maintenance, leading to greater water quality fluctuations. In recent years, policies related to sponge city construction have been implemented. Natural methods such as rain gardens and permeable pavements are used to reduce surface pollution. These measures have shown significant results in new areas outside the city center. However, in old residential areas within urban centers, due to aging underground pipelines and high proportion of hard surfaces, rainfall-induced surface pollution remains a major cause of water quality fluctuations. There is still room for improvement in terms of the precision of policy implementation and community coverage; the participation of grassroots communities needs to be enhanced.

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4.2 Comparison with Governance Approaches in Other Asian Countries

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Looking at urban water management practices in Asia, each country has adopted different strategies based on its resource conditions. Singapore, a country with extremely limited land and freshwater resources, has developed a world-class closed-loop water circulation system through the NEWater program. Advanced membrane filtration and ultraviolet disinfection technologies are used to treat domestic wastewater, producing high-quality reclaimed water that can be used for industrial purposes or indirect drinking. This reduces reliance on rainfall and cross-border water transfers, representing a “source-driven” strategy. Israel also has implemented one of the most efficient reverse osmosis desalination systems in the world, while reusing a large proportion of wastewater for agricultural purposes. The main goal is to ensure an adequate supply of water resources. In contrast, China’s water management policies, represented by “sponge cities,” focus more on managing runoff and restoring ecosystems during urbanization. By naturalizing urban landscapes, rainwater is absorbed, purified, and reused. The focus is on addressing issues such as flooding and surface pollution caused by rapid urbanization. This approach involves both reducing consumption and improving the ecological environment. The underlying differences between these two models stem from different resource constraints: Singapore and Israel face “total water scarcity,” while Chinese cities like Shanghai deal with “water quality scarcity” and runoff pollution. Nevertheless, Singapore’s approach to water circulation and public participation in governance can serve as a valuable reference for Shanghai in promoting joint management of rivers in residential areas.

 

5. Water Quality Protection Advocation

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In response to the issues of water quality fluctuations in residential area rivers and pollution caused by rainfall runoff, based on the results of this field monitoring, it is recommended to take action in three aspects: continuous monitoring, public education, and community communication, in order to promote water environment protection from individual investigations to community participation.

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5.1 Establish a short-term continuous water quality monitoring dataset: Select representative river locations in residential areas and conduct continuous water quality monitoring for 6–8 weeks. Regularly record indicators such as pH, conductivity, total dissolved solids (TDS), dissolved oxygen (DO), and turbidity. Also record the sampling dates, weather conditions, and surrounding human activities. By organizing and comparing data from different periods, observe trends in water quality indicators, and focus on the differences in water quality before and after rainfall, providing traceable data for subsequent community discussions on water environment issues.

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5.2 Create visual reports on water quality for the community: Compile the monitoring data into charts, map of locations, and concise text descriptions, to produce visual reports on water quality for residents. These reports should be based on actual measurements, showing water quality indicators at various locations and their changes. Discuss possible factors affecting water quality in the surrounding environment, avoiding assumptions about sources of pollution without sufficient evidence. Present the results through community bulletin boards, online platforms, or personal project websites, helping residents understand the meaning of water quality indicators and their relationship to their living environment.

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5.3 Conduct community water protection education activities: Using the monitoring reports, organize small-scale community activities to inform residents about common water quality indicators, the potential impact of rainfall runoff on rivers, and ways to reduce water pollution in daily life. Activities can include charts, brief explanations, and interactive Q&A sessions, to encourage residents to pay attention to the water environment around their homes and enhance their awareness of not dumping trash into rivers or properly disposing of household waste.

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5.4 Submit suggestions for improving the water environment to relevant authorities: After completing the periodic monitoring, combine the observed changes in water quality, abnormal phenomena, and the environment around the sampling points with the data, and write concise suggestions for improving the water environment. These suggestions should specify the corresponding monitoring points, measured data, and identified problems, and propose targeted further investigations or management measures, such as focusing on sections where indicators change significantly after rainfall or investigating suspected abnormal drainage. Through this process, students’ independent investigations can become information useful for communities and management departments, helping to explore practical ways for public participation in urban water environment protection.

 

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