Blue City Water Quality Index

By Sunan Shen 20 September, 2019

IPE takes it up another notch with the Blue City Water Quality Map. Their Shen explains

By scoring 337 municipal cities & 25 counties, the first Blue City Water Quality Map helps the public better understand different regions' water qualities & identify those in need of improvement
Qinghai, Tibet & Guizhou have the best overall water quality vs. Tianjin, Shanxi & Hebei have the worst; a deeper dive to reveals different patterns for surface water, drinking water & groundwater
The first edition of the map is far from complete; however, being the first to display groundwater quality for every city, it hopes to improve groundwater quality monitoring & disclosure platforms

In China, local ecology and environment departments and local water and natural resource departments provide the long-term monitoring of surface water and groundwater quality. They continue to expand and optimise their monitoring networks to improve overall management.

The Institute of Public and Environmental Affairs (IPE) has collected water quality data issued by government departments across China since 2016, sorting and standardising the data that is then displayed on the Blue Map mobile app. The aggregate data illustrates changes in China’s environmental water quality. As the number of app users grows, more people are able to follow these trends. However, the original data may still be difficult for the public to understand due to its specialised nature.

The first Blue City Water Quality Map helps the public better understand regions with good water quality & those in need of improvement

In 2019, therefore, IPE developed the Blue City Water Quality Index (BCWQI) and scored 337 municipal cities and 25 counties on their overall water quality in 2018. The analysis is based on 600,000 water quality data points gathered the same year. The results formed the first Blue City Water Quality Map, now available on the Blue Map app, which helps the public better understand regions with good water quality and those in need of improvement across the country. Below we go into more detail on the map and how the results were calculated.

BCWQI data sources

The map uses 3 water metrics:

  1. Surface Water: The data is primarily based on surface water quality monitoring data published in 2018 by ecology and environment bureaus at all levels of government (Note: Some regions lack data from 2018, in which case data from 2017 or earlier was used instead). It also refers to monitoring data published by local departments of water resources.
  2. Drinking Water Sources: The data is primarily based on 2018 monitoring data for centralised drinking water sources published by ecology and environment bureaus at the provincial, municipal and county level and above, combined with water source remediation progress reports. Centralised drinking water sources (水源地) refer specifically to water bodies that support communities of 1,000 people or more, in both urban and rural areas.
  3. Groundwater: The data is based on groundwater monitoring data disclosed by ecology and environment bureaus at all levels across the country, as well as groundwater quality status reports listed in the Water Pollution Prevention and Control Action Plan (Note: Some regions have not published data on their present status, in which case 2020 water quality targets were used instead). It also refers to recent academic articles on urban groundwater research.

Score breakdown & calculation methodology

The 3 metrics mentioned above are weighted accordingly:

  • Surface water scores account for 50% of the total score;
  • Drinking water scores account for 30%; and
  • Groundwater scores account for 20%.

The distribution reflects the quality and availability of recent data, as well as each water sources’ direct influence on the public.

For surface water and groundwater quality assessments, each water quality classification, according to the Ministry of Ecology and Environment’s environmental quality standards (Class I – Class V), is given a quantitative value. Then annual scores for each monitoring point are calculated by taking the average of the monthly values. The city score is the average annual score of all the monitoring points in its jurisdiction.

Drinking water sources are comprehensively evaluated based on water quality classifications, transgressions of pollution standards and the progress of environmental rectifications.

Yangquan City of Shanxi Province ranked the lowest in water quality

Lower scores indicate higher water quality, with the highest water quality in Hainan Prefecture of Qinghai Province, with only 4.04 points in the BCWQI. Yangquan City of Shanxi Province ranked the lowest, with a score of 41.92.

Evaluation results – total scores

Key points to note from the 2018 Blue City Water Quality Map above:

  • Regions with the best water quality are primarily concentrated in the Qinghai-Tibet Plateau and its surrounding areas, especially in the first and second steps in China’s elevation above sea-level.
  • Pollution levels in the plains are high. Water quality is relatively poor in the North China Plain, the Northeast China Plain, the middle and lower reaches of the Yangtze River, and the Pearl River Delta.
  • Water quality to the south of the Yangtze River is better than water quality to the north of the Yangtze River.

Best national water quality – top 30 cities & provincial average ranking

According to the average BCWQI scores of provincial jurisdictions:

  • The worst water quality is in Tianjin, Shanxi and Hebei;
  • The best water quality is in Qinghai, Tibet and Guizhou.

Maps for three water metrics

1. National surface water quality map

Since the Action Plan for the Prevention and Control of Water Pollution was issued in 2015, China has implemented rigorous water pollution control and national surface water quality has improved each year.

In 2018, among the 1,935 surface water quality monitoring points managed at the national level, locations that achieved Class I to Class III good water quality comprised 71% of all monitoring points, up 3.1% from 2017. The proportion of Class V poor water quality points fell to 6.7%, down 1.6% from 2017.

Water quality in non-state-controlled areas may be generally inferior to state-controlled sections

In contrast, however, comprehensive data including 9,514 national and non-state-controlled surface water quality data points collected in the Blue Map Database in 2018 indicate that monitoring points that achieved Class I to Class III water quality comprise only 51.6% of all monitors, while Class V monitors account for 15.2% of the total. It follows that water quality in non-state-controlled areas (mainly in shorter and smaller tributaries and lakes) may be generally inferior to state-controlled sections.

2. National drinking water quality map

The BCWQI scores of drinking water sources comprehensively examine their water quality classification, the number of times they exceeded pollutant standards, and if they received any environmental remediation.

Some water sources have not completely rectified their environmental problems…

…which has affected their scores

Judging from the general compliance of drinking water sources, the annual water quality compliance rate of centralised drinking water sources at the county level or above in 2018 (referring to all monitoring up to the standard in 2018) was 91.79%. Some water sources have not completely rectified their environmental problems or have not released the overall improvement in time, which has affected their scores.

3. National groundwater quality map

China’s Report on the State of the Environment began disclosing groundwater conditions in 2009. The first publication included results from only 641 monitoring points in eight provinces. In 2018, however, the report included statistical results from 10,168 monitoring points, demonstrating the gradual improvement of information disclosure and the government’s present emphasis on groundwater quality issues.

According to the national Report on the State of the Environment over the years, groundwater quality in the country shows a deteriorating trend. Monitoring points classified as Good or Excellent have declined in both quantity and proportion, while those with Poor or Relatively Poor water quality have increased year by year.

As the first map to display groundwater quality for every Chinese city…

…we hope to improve the groundwater quality monitoring & disclosure platforms

Due to the fact that existing groundwater data must be gathered from multiple sources with various record years, depths of monitoring points, and types of groundwater, this first edition of the BCWQI is far from complete.

However, as the first map to display groundwater quality for every Chinese city, we hope that it can help the public understand the severe status of groundwater pollution and encourage the improvement of groundwater quality monitoring and disclosure platforms.

For more information, please see the full Blue City Water Quality Index report.


Further Reading

  • Too Big To Fail! Protect At All Costs – Multiple policy innovations have been unleashed to protect the Yangtze River as it is too big to fail – corporates and investors need to get on top of the YREB to avoid regulatory shocks
  • Yangtze River: Actions Toward Ecological Compensation – With RMB5bn already allocated to supporting ecological compensation along the Yangtze River, what’s next? Chinese Academy for Environmental Planning’s Dr Zhanfeng Dong highlights what needs improving
  • Capital Two Zones: Protecting Beijing’s Upper Watershed – The Capital Two Zones plan is set to protect Zhangjiakou, upstream of water stressed Beijing & host of the 2022 Winter Olympics – how will this impact industry and development? China Water Risk’s Yuanchao Xu explores
  • Thirsty And Underwater: Rising Risks In Greater Bay Area – How will water & climate risks, including rising sea levels & droughts, threaten the already water-stressed Greater Bay Area (GBA)? CWR’s Tan & Mirando explain in their latest CLSA report and highlight companies’ failure in climate risk disclosures
  • No-Sense Climate Strategies: From DSD To HSBC – Hong Kong’s shortsighted & unrealistic climate plans will leave key assets & infrastructure exposed that mean the government, companies, investors and the public are even more exposed. China Water Risk’s Dharisha Mirando & Debra Tan expand
  • 2018 State Of Ecology & Environment Report Review – It is one year on since the Ministry of Ecology and Environment (MEE) reform, has it impacted China’s water? What has worsened & what has improved? We review the latest 2018 report
  • Real-time Monitoring: Cleaning Up Textiles – There’s now nowhere to hide. The latest IPE Blue Map app integrates real-time emissions data with violation records plus there’s an interactive module linking with brands’ CITI Index scores IPE’s Kate Logan on what this means value for brands, suppliers & consumers
  • 12FYP Water Quality Report Card – Bao Hang & Deng Tingting from Greenpeace East Asia share key findings from their report on provincial performance in the 12FYP. Which provinces met water quality targets? Which failed?
  • 3 Takeaways From CEWP’s 2019 Groundwater Policy Dialogue – With China and Europe joining forces to tackle groundwater over-exploitation, China Water Risk’s Yuanchao Xu was on hand to bring us the latest policy and tech ideas from the Jinan forum
  • Key Water Policies 2018-2019 – Haven’t been following China’s environment & water-related policies? Get on top of them now with China Water Risk’s review, including China’s first Soil Ten Law & renewable energy quotas

Sunan Shen
Author: Sunan Shen
Shen Sunan is Senior Researcher of Institute of Public and Environmental Affairs (IPE). She joined IPE in 2007 and contributed her groundbreaking work in IPE’s core projects on green supply chains, green securities and pollution source information disclosure. In recent years, her work focuses on environmental big data applications and environment policy research.
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