Overview

The blog explores Tianjin’s comprehensive water management approach, detailing its water supply systems, infrastructure, and pricing mechanisms. The city faces complex water challenges with climate change, including water scarcity, pluvial flooding, land subsidence, and water pollution. Historically reliant on rivers like the Haihe and now dependent on large-scale water transfer projects such as the South-North Water Transfer Project, Tianjin has developed innovative strategies to address its water infrastructure needs. Regarding to higher frequency and intensity level of urban flooding, the city adopted the Sponge City Program (SCP), which aims to integrate green, grey, and blue infrastructure to manage urban water cycles more effectively

To help the city address or adapt to these challenges better, the author offer the One Water Approach as alternative solutions that emphasize integrated water management through five key interventions: financial incentives, comprehensive planning, infrastructure integration, enhanced monitoring, and increased public participation. This approach seeks to address the limitations of current water management strategies by promoting collaboration, technological innovation, and community engagement. As climate change continues to impact water resources globally, Tianjin’s evolving water management strategies offer valuable insights into creating more resilient and sustainable urban water systems.

Background

Tianjin is a coastal industrial city located in the Bohai Bay region of China, a part of the city cluster with Beijing and Hebei Province (Figure 1). Tianjin covers an area of 11,966 km². By the end of 2023, the total permanent population of the city reached 13.64 million, including 11.66 million urban residents and 1.98 million rural residents (Tianjin Statistical Yearbook, 2023).

Climate Characteristics

Tianjin has a monsoon continental climate characterized by warm, humid summers and cold, dry winters (Tianjin Statistical Yearbook, 2005). The city’s precipitation is highly seasonal and can be divided into three periods: pre-flood (January to May), flood season (June to September), and post-flood (October to December) (Figure 3). In 2023, for example, the flood season alone saw 500 mm of rainfall, accounting for 82% of the annual total of 608 mm. July was the wettest month, recording 297 mm of rain in 2023. (Tianjin Municipal Bureau of Water Resources, 2023).

Surface and Ground Water Distribution

Tianjin is responsible for discharging 75% of the floodwater in the Haihe River Basin. The river systems converge on the city from the north, west, and south, resulting in significant flood control exposure. The northern water systems, including the Ji Canal, Chao Bai River, Bei Yun River, and Yongding River, drain into the Yongding New River before flowing into the sea. The southern water systems, such as the Daqing River, Ziya River, and Nan Yun River, discharge floodwater through the Duliujian River, Ziya New River, and Zhangwei New River (located in Hebei Province) into the sea. The central Haihe main stream diverts part of the floodwater from both the northern and southern water systems. Except for the mountainous region of Jizhou, urban and rural areas of Tianjin are in low-lying topography and vulnerable to floodwater. The city primarily depends on pumping stations to discharge drainage channels (Figure 3).

Most of Tianjin’s groundwater is saline, covering about 80% of the area, particularly in the southeast near the coast. Only 20% of the groundwater, found near the northern mountains, consists of fresh and mountain karst water. Additionally, there is a shallow aquifer overlaying a small section of the saline aquifer in the transitional zone between the mountains and the floodplain (Tianjin Municipal Bureau of Water Resources, 2022) (Figure 4).

History of Drinking Water in Tianjin

Historically, Tianjin was a colonial city between 1860 and 1945, with nine countries, including Britain, France, and Italy as primary ones, establishing concessions along the Haihe River. The city’s first water plant was built in 1898 and began supplying drinking water to the foreign concessions a year later. However, the local population primarily relied on water from the Haihe River, which was brackish due to saltwater intrusion from the ocean, making it unsuitable for drinking.

In the 1970s, as Tianjin’s population grew and more freshwater from upstream was diverted to Beijing as well as continual droughts, the city faced severe water scarcity and salinization of the Haihe River. To address this, the Luanhe River Transfer Project was completed in 1983, spanning 234 km, and became the city’s primary drinking water source. However, the Luanhe River and its reservoir also faced shortages during drought years, prompting the introduction of the South-North Water Transfer Project, which channels freshwater from the Yangtze River to Beijing and Tianjin through two canal systems over 1,000 km in length (Xinhua News Agency, 2023).

Currently, most of Tianjin’s drinking water comes from the Luanhe River Transfer Project and the South-North Water Transfer Project. The city operates 31 drinking water plants with a total daily supply of 3.86 million tons (Tianjin Municipal Bureau of Water Resources, 2022).

Water Infrastructure

Tianjin also has a great number of water management infrastructures, including 27 reservoirs (3 large, 10 medium-sized, and 14 small), with a total storage capacity of 2.622 billion cubic meters. There are 99 water treatment plants, treating wastewater 417 m³/day. After treatment in sewage plants and meeting the discharging standard, the wastewater is discharged into drainage rivers and eventually flows into the ocean (Tianjin Municipal Bureau of Water Resources, 2023).  The city operates 3,307 water gates for draining floods and tidal control, 13 of which are large, 54 medium-sized, and 3,240 small (Figure 1). The city’s seawall stretches 140.64 kilometers. Additionally, there are 13 flood storage and detention areas, covering 2,952 square kilometers, designed to manage floodwaters with a total capacity of 5.571 billion cubic meters and affecting 1.13 million residents across 8 districts and counties. In terms of water reuse, Tianjin has 12 recycled water plants with a daily supply capacity of 0.4 million tons, and 3 desalination plants providing 0.3 million tons of water daily (Tianjin Municipal Bureau of Water Resources, 2022). (Figure 5)

Water Supply and Use Portfolio

The current water supply portfolio of Tianjin with total amount of 3.272 billion m³ in 2023 include: surface water, groundwater, recycled water and desalinated water. The water amount transferred from Luanhe River and South-North Water project is 0.37 billion m³ and 1.03 billion m³ separately, taking up 30% of the surface water supply.

The water use portfolio of Tianjin, with same amount of water supply, includes four types: domestic, industrial, agricultural and environmental/ ecological water use. (TMBWR, 2023). The domestic (including drinking water) water consumption of per person is 145 L/day while the average water consumption in China is 176 L/day. (Figure6).

Drinking Water Supply and Wastewater Management

In Tianjin, water supply is predominantly managed by Tianjin Water Supply Group Co Ltd (Tianjin Water Group), a state-owned enterprise established in 2016. This unified urban water operation platform, emerged from the reorganization of 13 state-owned and 4 private enterprises, serves 12 out of 16 administrative districts, provides 77% of the city’s total water supply, operates under state controlling interest. The remaining four northern administrative districts (Wuqing, Baodi, Jixian, and Ninghe) maintain their own local district water supply companies, also operating as state-owned enterprises (Dong, 2020).

Tianjin Water Supply Group is a large, comprehensive company that owns multiple subsidiary companies for drinking water supply and sewage treatment plants throughout the city. In addition to managing water supply, it also collects wastewater fees on behalf of the municipal Bureau of Finance. The Tianjin Water Bureau supervises the collection of wastewater fees and manages wastewater treatment facilities.

Water Pricing

Water pricing in Tianjin is governed by a government-regulated structure, with residents paying a bill that includes three components: 1) Drinking water rate, which covers the operation and maintenance of the water supply company; 2) Water resources tax, collected by the supplier and transferred to the state; and 3) Wastewater rate, which is collected by the supplier, paid to the city treasury, and allocated to wastewater treatment enterprises. If the revenue from wastewater treatment fees falls short of covering operational costs, local governments provide supplementary subsidies to ensure continuous service (Zou & Wang, 2024).

Drinking Water Pricing

There are three types of drinking water consumption: residential, non-residential and special industry. Drinking water consumption for residential use follows a block rate structure of three tiers. When households exceeding 4 members receive additional allowances of 36 m³ /person per tier. Drinking water consumption for non-residential use contains two types: Regular commercial/industrial use and social welfare institutions, covering religious venues and community organizations, like schools, nursing homes and childcare facilities. The special water consumption indicates high water consumption but not necessity industries, like Car washing facilities, High-end bathing establishments, Golf courses, Ski resorts and Purified water production facilities (Table 1).

There are three categories of drinking water consumption: residential, non-residential, and special industries. Residential drinking water follows a block-rate structure with three tiers, where households with more than four members receive an additional allowance of 36 m³ per person per tier. Non-residential drinking water consumption is divided into two types: regular commercial/industrial use and consumption by social welfare institutions, including religious venues and community organizations such as schools, nursing homes, and childcare facilities. Special water consumption applies to industries with high water use but not essential for daily living, such as car wash facilities, high-end bathing establishments, golf courses, ski resorts, and purified water production plants (Table 1).

Recycled Water Pricing

Recycled water is primarily used for non-potable applications, including irrigation, industrial processes, and ecological maintenance. It is prohibited for use in drinking, swimming, bathing, daily washing, or food production. Facilities using recycled water must be clearly marked and operated separately from domestic drinking water systems. The price of recycled water is approximately half of the cost of drinking water, with the goal of encouraging its use. National policies also exempt recycled water from the water resources tax, urban public utility surcharges, and wastewater fees to further promote its usage (Wang, 2021). New real estate developments in Tianjin now feature advanced triple-pipe systems, with separate meters for drinking water, domestic-use water, and recycled water, highlighting the city’s commitment to sustainable water management (Yang et al., 2005). (Table 1)

Wastewater Charges

Businesses and individuals who discharge sewage and wastewater to treatment plants within Tianjin’s administrative area are required to pay a wastewater fee. These fees are collected by water supply companies when billing for public water users or directly by drainage authorities for those using self-supplied water. The funds generated are used for the construction, operation, and sludge treatment of wastewater treatment facilities (Tianjin Municipal Finance Bureau et al., 2021) (Table 1).

Stormwater Charges

In Tianjin, stormwater fees are applied only to newly constructed neighborhoods in the form of a one-time drainage fee. This fee is included in the overall housing construction costs and cannot be separately charged to homebuyers. The fee is set at ¥29 ($4.1) per square meter, with ¥12 allocated for stormwater management and ¥17 for sewage. For public construction projects, the fee is negotiated between the developer and the Municipal Bureau of Water. Once the project is completed, the municipal drainage department oversees the connection of sewage pipes from the septic tanks to the main municipal drainage line. The property management company of the new community is responsible for the operation and maintenance of the septic tanks serving the buildings, while the municipal drainage department manages the stormwater pipes within the community.

Water Challenges

Tianjin faces several water challenges, including water scarcity and pluvial flooding, both of which are linked to land subsidence and water pollution. Water scarcity is driven by both physical and managerial factors. The region experiences uneven rainfall distribution, with northern areas receiving far less than the south of China. Tianjin’s population growth—from 2.93 million in 1960 to 13.6 million in 2023—has further strained water resources (Bai & Imura, 2001; Macrotrends, n.d.). Managerial challenges, such as poor water management, exacerbate the scarcity, leaving many water consumers inadequately served (Molle & Mollinga, 2003). Additionally, Beijing controls 85% of the Haihe River’s flow, significantly reducing water flow to Tianjin, from 16 km³ in the 1950s to just 2-3 km³ during drought years (Jowett, 1986). Tianjin’s total water resource (surface water and groundwater) is 166 billion m³, with per capita availability of just 122 m³ in 2023, far below the national average of 1918 m³.

Pluvial flooding results from multiple factors, including extreme precipitation, urban expansion with increased impervious surfaces, low-lying topography, and an aging sewer system. The combined sewer system, especially during heavy rainfall, can overflow, transferring pollution into rivers. Over-extraction of groundwater to mitigate surface water shortages has caused land subsidence, posing risks to the population’s safety (Figure 7).

City’s Response

In response to these challenges, Tianjin has implemented several strategies, such as the South-North Water Transfer Project (Figure 8), wastewater recycling, desalination, groundwater recharge, and the Sponge City Program (SCP). Policy interventions like water pricing reforms, regulations, and subsidies have also helped mitigate water challenges.

However, there are concerns about the long-term sustainability of these measures. While the South-North Water Transfer Project has alleviated water scarcity, it may negatively impact the Yangtze River’s water quality and ecosystem. Additionally, this transfer risks depleting local water resources in Hebei and other regions. The cost of water from the South-North project is higher than local water sources, with prices ranging from ￥5-20 ($0.7-$2.9) per cubic meter. The government maintains affordability through subsidies, which is not a sustainable long-term strategy (Quan, 2007).

Inspired by Low Impact Developments, the Sponge City Program integrates grey, green, and blue infrastructure to manage the urban water cycle (Pyke et al., 2011, Ma et al., 2017; Chan et al., 2018) (Figure 9). The program aims to recycle 70% of stormwater through enhanced permeation, detention, storage, purification, reuse, and drainage systems (Chan et al., 2018). While SCP has improved urban drainage, reduced flash floods, and alleviated water shortages (Figure 10), issues persist, such as financial deficiencies, lack of comprehensive planning, insufficient monitoring, and low public participation. Despite progress, flooding events still occur during extreme weather, highlighting the need for further interventions to address rainfall management.

Potential Intervention

The One Water Approach can help address key challenges in Tianjin’s Sponge City Program (SCP) by integrating stormwater use and optimizing existing water resources. This approach aims to unify all water management sectors to enhance sustainability (U.S. Water Alliance, 2016).

Financial Incentives

Challenge: Despite receiving $57 million in subsidies for SCP’s first phase, Tianjin faces a significant funding gap, with the cost of SPC projects estimated at $14 to $20 million per km².

Interventions

• Optimizing Resources: The One Water Approach advocates for the use of recycled water and stormwater for non-potable purposes. Tianjin could offer financial incentives, such as discounts and tax credits, to encourage water reuse and introduce a stormwater charge for residents. Adjusting drinking water prices would also reduce dependence on freshwater resources.
• Community Engagement: The SCP follows a Build-Operate-Transfer (BOT) model, involving private-public partnerships (PPP) for financing. Engaging in the community can ease the financial burden of operation and maintenance.

Comprehensive Planning and Management

Challenge: SCP often suffers from fragmented planning, with separate management of stormwater, wastewater, and flood control, leading to inefficiencies.

Interventions

• Holistic Water Management: The One Water Approach promotes integrating all water resources into a single, comprehensive planning framework. This would involve assessing flood risks by integrating extreme precipitation, exposure to flooding and vulnerable groups in the watershed, ensuring that water management addresses scarcity, flooding, and pollution together.
• Unified Planning and Governance: The approach calls for coordinated planning among government levels and stakeholders, aligning policies for water reuse, stormwater management, and flood control. This would enhance the effectiveness of the SCP by fostering collaboration between departments such as water, finance, and environmental protection.

Integrating Infrastructure

Challenge: SCP prioritizes green infrastructure but often delays the construction of separate stormwater systems due to high costs and long-time construction.

Interventions

• Cost-Effective Infrastructure: The government could reduce costs and shorten construction times by adding smaller-radius sanitary sewer systems for low-volume sewage while isolating the existing combined sewer system for stormwater.
• Integrated Infrastructure Design: The One Water Approach advocates for integrated solutions, such as dual-pipe systems for potable and non-potable water. While new developments incorporate these systems, they should be gradually adopted in older neighborhoods to enhance long-term water resilience.

Strengthen Monitoring and Evaluation

Challenge: Monitoring and evaluating SCP’s effectiveness is challenging, hindering the assessment of water management strategies and necessary adjustments.

Interventions

• Data Integration: The One Water Approach encourages the use of advanced monitoring technologies and data-sharing platforms to track water use, quality, and management performance. Real-time data collection and analysis would enable continuous improvements.
• Performance Metrics: Establishing clear metrics—such as water recycling volumes, flood reduction, and water quality improvements—would help evaluate the success of SCP initiatives under the One Water framework.

Encourage Public Participation

Challenge: Public participation in SCP is often low due to the top-down implementation with limited involvement opportunities and a lack of awareness about water management issues.

Interventions

• Public Education: The One Water Approach can raise awareness of water conservation, reuse, and stormwater management. By framing water as a shared resource, cities can engage the public in sustainability efforts.
• Community-Based Monitoring: Tianjin could establish an online platform for reporting flooding issues, encouraging residents to submit location and site photo of each flooding event. This low-cost method could validate digital monitoring systems, bridging gap in data scarcity place and foster a sense of ownership, empowering citizens to actively manage local water resources.

Conclusion

Tianjin faces complex water challenges, including water scarcity, pluvial flooding, land subsidence, and water pollution. The city’s approach to addressing these issues is evolving, with innovative strategies like the South-North Water Transfer Project and the Sponge City Program. To help the city improve addressing or adapting to these challenges, I propose the One Water Approach, offering alternative solutions that emphasize integrated water management. This means creating collaboration between different departments, using advanced technologies, and involving the community. As climate change continues to impact water resources, Tianjin’s approach provides a valuable paradigm for other cities facing similar challenges. By treating water as a comprehensive resource rather than separate systems, Tianjin can create a more resilient and sustainable water portfolio.

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