Tag: Water

How Beijing Is Restoring Its Aquifer

Restoring depleted aquifers can have a significant impact on the provision of clean water to urban areas. Photo: ADB

To restore healthy aquifer systems, we need to carefully monitor and manage extraction, and recharge with surface water when available.

For many decades, Beijing had been coping with a water crisis, and has been successful in managing it to a large extent. From 2000 to 2018, the city’s population expanded from 13.6 million to 21.5 million, and its economy grew almost tenfold from CNY316 billion (USD 50 billion) to CNY3,033 billion (USD 500 billion). After an initial increase, Beijing managed to maintain water use at the same level or even lower depending on the end use sector.

The problem, however, is that a majority of the supply was from aquifers, which accounted for about half of total water supply in Beijing. Over-extraction sent the groundwater levels down significantly, although they have gradually recovered in the last few years.

The over-exploitation of groundwater has brought a range of environmental and ecological consequences, including rivers running dry, land subsidence and vegetation degradation. It also increases the risks of depleting Beijing’s emergency water supply.

Beijing is not alone in facing these problems. The North China Plain has more than 160 pocket areas of groundwater depletion. Unsafe levels of groundwater extraction have sunk the city of Jakarta 2.5 meters in 10 years, forcing the government to announce a plan to relocate the capital. The Indus Basin Aquifer is the world’s second-most overstressed aquifer. The overstressed Arabian Aquifer System is already depleted.

The idea of using water transferred from 1,432 km away to recharge the aquifer may seem crazy to many, but there are advantages.

To restore healthy aquifer systems, we need to carefully monitor and manage our extraction, and as is often required, recharge with surface water when available.

Managed aquifer recharge, a relatively new idea, is based on the principle of groundwater replenishment and water banking, which involves the intentional recharge of water to aquifers to maintain groundwater levels, and subsequent storage of this water for future use.

Groundwater aquifers are typically located in soils or deeper rock layers beneath the surface. It requires careful technical design to ensure that water of sufficient quality can infiltrate the ground, stay underground, and be pumped out when needed. It can be used as an underground reservoir, except that it is invisible.

Plenty of research findings support the viability of the technology. But actual implementation on a  large scale is still rare. There is often a lack of understanding of cost and benefits. Seeing water “disappearing” can also make it challenging for such an idea to be accepted.

Nonetheless, the city of Beijing decided to give it a try. Since December 2014 it has been receiving water from the Danjiangkou reservoir. By the end of 2019, this supply amounts to 5.2 billion cubic meters of water, which accounted for about a quarter of Beijing’s total water supply during the same period.

Apart from city supply, the Beijing Water Authority diverted some of the water to reservoirs and rivers, and some to aquifers as part of the comprehensive Beijing Capital Region Water Conservation Strategies.

They looked at groundwater storage capacity, recharge methods, different water sources, and water quality and conducted trials to see how the groundwater levels change with recharge and pumping.

The idea of using water transferred from 1,432 km away to recharge the aquifer may seem crazy to many, but there are advantages to this: while the transfer project supplies a stable flow of water, local demand and supply fluctuate.

The managed aquifer recharge can draw the excess water during low demand periods and help maintain a steady flow, and resupply through pumping when demand exceeds supply. In short, it adds an important dimension of flexibility to Beijing’s water supply system.

Innovative designs are critical for this relatively new method to work. For example, in Beijing, sandstorms carry dusts from the Gobi Desert, which can slow down the recharge speed and eventually clog up the system, when deposited into riverbeds.

Researchers can design recharge surface and depth in a way that utilizes wave actions from wind gusts to move deposits away from the center of the riverbeds, thereby increasing the speed the water goes down and reduce the costs of cleaning up.

More importantly, an investment framework is essential for putting managed aquifer recharge up to scale. Such a framework addresses not only technical design but other crucial elements, including social and environmental safeguards, as well as economic and institutional (regulatory, legal, organizational) dimensions, inter alia participation and monitoring. The capacity for the operation and maintenance is also key for the success of managed aquifer recharge.

A sound management plan is crucial for successful management of recharging the aquifer. This is not only related to technical operations and maintenance but also to cost benefit sharing mechanisms. It is easy to collect fees from connected consumers, but much more difficult if people are pumping on their own.

A good plan and strict enforcement therefore ensure the investment will not only see water “disappearing” into the aquifer, but also “coming back” with greater value at the times needed.

The experimental recharge in Beijing has been going on for several years and the results are promising. It shows that storing water underground is technically feasible. In addition to environmental benefits, recovering groundwater levels have shown to be economically and financially more cost effective compared with available surface storage options. An invisible storage with managed aquifer recharge is a better investment option for Beijing, and probably many other areas facing water scarcity.

Authors
Xueliang Cai

Xueliang Cai

Water Resources Specialist, East Asia Department, ADB

Mingyuan Fan

Mingyuan Fan

Principal Water Resources Specialist, East Asia Department, ADB

This blog is reproduced from Asian Development Blog.

A Legislative Framework for the Sustainable Development of the Yangtze River

The Trans-Caspian transport corridor links the rail systems and seaports between Asia and Europe. Photo credit: ADB.

The Yangtze River Protection Law sets a precedent for legislating policies that support the sustainable development and management of rivers.

Overview

Asia’s longest river, the Yangtze River in the PRC, has been facing environmental challenges brought about by rapid economic development and increasing population pressure. Pollution, industrialization, deforestation, unsustainable farming practices, biodiversity and habitat loss, and overexploitation of natural resources threaten the health of aquatic and riparian ecosystems. Failure to systematically curb these threats poses serious obstacles to achieving green and inclusive development.

In 2018, the PRC government saw the urgent need 1) to improve the Yangtze’s ecosystem within a framework of coordinated protection across the basin, 2) to establish a market-based and diversified ecological compensation mechanisms, and, 3) to uphold the protection of the river through the rule of law. These elements were formalized into a legislative framework now known as the Yangtze River Protection Law that took effect on 1 March 2021.

This article summarizes how this law can strengthen environmental protection and restoration of the Yangtze River basin, support the efficient use of resources, ensure harmony between people and nature, and contribute toward overall sustainable development.

This landmark legislation supported by the ADB 1 sets a precedent for developing legislative frameworks supporting the protection and management of other river basins in the PRC. This also serves as a blueprint for developing countries facing similar environmental challenges.

The legislative process for the development of this law involved solicitation of public comments. A total of 83 recommendations were submitted during the first round of public consultation while 17 recommendations were submitted during the second round.

This article is adapted from the study Yangtze River Protection Law of the People’s Republic of China: Overview of Key Provisions and Policy Recommendations published by ADB.

Key Features of the Framework

The Yangtze River Protection Law provides for the following:

The Yangtze River Protection Law stipulates the establishment of a national river basin coordination mechanism to provide centralized guidance and overall coordination of efforts. This includes creating a basin-wide information sharing platform, establishing local coordination mechanisms, and forming an expert advisory committee for professional consultations on major development strategies, policies, and master planning.

This law defines government responsibilities, extensively covering areas, such as river basin planning and layout; green development strategies; resource development, utilization, and conservation; pollution prevention and control; environmental restoration; and financial input for environmental protection, such as ecological compensation. The State Council is required to implement the accountability and evaluation system for environmental protection of the river. The central government and its offices will be responsible for evaluating the progress of local (e.g., provincial and county) governments toward environmental protection and restoration goals.

The Natural Resources Department of the State Council (as well as other relevant departments) is mandated by this law to carry out surveys of the different natural resources in the Yangtze River basin. This is to establish a basic database of these natural assets (i.e., land, minerals, water flows, forests, grasslands, and wetlands); conduct assessments of resource and environmental carrying capacities; and report their status. Survey results will determine the appropriate industrial structure and layout in the river basin, taking into consideration its ecosystems and environmental carrying capacities to give natural ecosystems the time and space to recover.

The law also promotes improved capabilities on disaster prevention, mitigation, resilience, and relief. It requires the strengthening of monitoring, forecasting, early warning, defense, emergency response, recovery, and reconstruction systems for the management of natural disasters, such as floods, droughts, forest and grassland fires, geological disasters, and earthquakes. The provincial governments in the river basin are required to develop the environmental zoning and management plan and the environmental access list based on the state of the ecological environment and resource utilization within their administrative regions.

The Yangtze River Protection Law adopts principles to support green development through measures to improve overall coordination and river basin governance, use of science-based planning, and adoption of innovative technologies. It promotes environmental protection and ecological restoration goals in parallel with a green development approach.

This law incorporates specific provisions on the application of ecological compensation policy measures. These include (i) establishing a compensation system for ecological protection, (ii) increasing financial transfer payments to compensate areas of ecological importance (e.g., sources of the Yangtze River mainstream and its major tributaries) and key water conservation areas in the upper reaches, and (iii) mandating the development of specific market-based measures to support policy reforms.

The Yangtze River Basin Environmental Supervision and Administration Agency, an agency under the Ministry of Ecology and Environment, is primarily responsible for environmental supervision, administrative law enforcement, and all related basin-wide management and monitoring activities. Strengthening its law enforcement capacity leverages its role in the overall supervision of pollution control and ecological protection. Sufficient fund and resources will enable it to effectively carry out its expanded responsibilities.

Recommendations

Efforts to promote law enforcement will remain critically important to ensure that the maximum extent of desired outcomes is achieved. As with any new legal framework, this law will be subject to ongoing review to adapt to varying circumstances and practical needs that arise from its implementation. 

At this point, the Yangtze River Protection Law has no clear provisions on climate change or technical guidelines for law enforcement. Land use and spatial planning for the Yangtze River basin needs to consider climate change impacts. The specific plans and goals may be subject to review and update depending on the climate change planning scenarios, the economic growth projections, and the state of environment and ecological systems.

Article 79 of this law stipulates that citizens, legal persons, and unincorporated organizations have the right to access, upon application, information about the river basin in accordance with the law. Information disclosure will need to be supported by an integrated information sharing platform to assist basin-wide spatial planning and decision-making. This can be an avenue to share knowledge and inform legislative frameworks planned for other river basins in the PRC and other countries.  

To maintain the Yangtze River Protection Law’s momentum, an implementation plan that is regularly reviewed is critical. It should also specify the division of responsibilities of the relevant departments of the State Council and the provincial governments in the Yangtze River basin. Standards and targets should also be reviewed with each update of the plan to remain relevant.

1 The ADB provided technical support and policy advice in the formulation and design of the Yangtze River Protection Law, preparing a series of policy recommendations that were submitted to the Ministry of Ecology and Environment (MEE) and the National People’s Congress (NPC).

References

Asian Development Bank (ADB). 2021. Yangtze River Protection Law of the People’s Republic of China: Overview of Key Provisions and Policy Recommendations.  Manila.

Author
Au Shion Yee

Au Shion Yee

Senior Water Resources Specialist, East Asia Department, ADB

This blog is reproduced from Development Asia.

CAREC Institute Water Dialogue Series on Sustainable Water Governance in Central Asia

In April 2022, the CAREC Institute, in partnership with the ADB, RKSI and Xinjiang Institute of Ecology & Geography, CAS (XIEG), will deliver a regional water dialogue based on “Water Footprint Analysis of Central Asia”, an analytical study conducted by Water Footprint Implementation (WFI) and supported by Swiss Agency for Development and Cooperation (SDC) within scope of Blue Peace Initiative. This is the second dialogue on sustainable water management in Central Asia.

The overall aim of this dialogue is to facilitate open discussions among leading water management experts on pathways to sustainable, climate adaptive water management systems in Central Asian countries. Also, to discuss, analyze and select practical implications of Water Footprint report for Central Asia and to further explore potential coordination mechanisms among ADB/CAREC Water Pillar, regional projects, initiatives, and activities of all stakeholders in Central Asia.

In addition to organizing bodies and development partner experts, relevant experts and interested wider audience from across the CAREC region and beyond are expected to participate in the dialogue.

CAREC Institute has started series of water dialogues with development partners and stakeholders in the CAREC region. The main aim of the CAREC Institute water dialogue series is to analyze the crucial role of water in ongoing and post-COVID developments as well as longer term sustainable growth of the CAREC region. The first dialogue was conducted on 10 February 2022.

Register here to participate.

Agenda:
TimeProgram
10:00 – 10:20Opening Ceremony

Moderator: Ms. Li Linyi, Deputy Director of International Exchange Division, International Poverty Reduction Center in China (IPRCC).

Welcome Remarks:
Ms. Li Xin, Deputy Director-General of IPRCC.
10:20 – 12:00Country Presentation I

Moderator: Ms. Li Linyi, Deputy Director of International Exchange Division of IPRCC.

Commentator: Dr. Zhang Chuanhong, Associate Professor of China Agricultural University.

Speakers (20 minutes each):

1. Diversification of Income for Poor Farmers.
Mr. Horn Kimhong, Program Coordinator, Dan Church Aid, Cambodia.

2. PRC Aided Pilot Project of Poverty Reduction Cooperation in Myanmar.
Mr. Win Kyaw Myo, Director, Department of Rural Development, Ministry of Cooperatives and Rural Development, Myanmar.

3. Mr. Htun Htun Oo, Second Secretary, Embassy of Myanmar.

4. Exploration and Experience: Rural Revitalization in the PRC.
Dr. Xu Jin, Associate Professor, China Agricultural University.
12:00 – 14:30 Break
14:30 – 16:00Country Presentation II

Moderator: Ms. Maha Ahmed, Deputy Country Director, World Food Programme.

Speakers (20 minutes each):

1. Singapore’s Approach to Social Assistance and Community Development.
Ms. Lau Amanda, Manager, Ministry of Social and Family Development, Singapore.

2. Tourist Attraction/Learning Community, Baan Nam Sap Learning Center.
Mrs. Suttapak Panpapai, Foreign Relations Officer, Professional Level, ASEAN Unit, Office of Permanent Secretariat, Ministry of Interior, Thailand.

3. D-Hope Project Thailand.
Mrs. Nicha Premchan, Foreign Relation Officer, Professional Level, Department of Community Development, Thailand.

4. Case Introduction and Video Presentation of Hesilu Village in Zhejiang Province.
Mr. He Yunhui, Party Secretary of Hesilu Village, Zhejiang Province, the PRC.
16:00 – 16:20 Closing Ceremony

Closing Remarks:
Mr. Miguel Musngi, Senior Officer, Poverty Eradication and Gender Division of the ASEAN Secretariat.

基于生态系统的综合生态保护与绿色发展模式案例：中国黄山项目

Yangtze River Protection Law of the PRC: Overview of Key Provisions and Policy Recommendations

Daring to Aspire: Students as Partners in Water Stewardship in Uvurkhangai, Mongolia

Fuzhou Environmental Improvement Project in the People’s Republic of China

Restoring a River the Natural Way

Pu’er City used natural materials and processes to rehabilitate the Simao River. Photo Credit: CDIA/Rudini Baoy.

In the People’s Republic of China, rehabilitation of the Simao River took an ecological and green development path and was integrated into city plans.

Overview

The Simao River in Pu’er City, the People’s Republic of China (PRC) was rehabilitated to prevent flooding in the city, restore the area’s biodiversity, and improve livability for residents.

In 2012, the city government worked with the Cities Development Initiative for Asia (CDIA) to finalize the design of its rehabilitation project, which aimed to develop Simao River into an attractive landmark and improve its flood protection capacity. Soon after, KfW (German Development Bank) approved an $80-million loan to implement the key components of the project.

In 2018, CDIA development experts returned to Pu’er and saw that the measures implemented by the city, which largely adopted a nature-based approach, resulted in better flood control and more sustainable river management, improved water quality, and restored ecology of the river. Residents were also using green spaces near the river for recreation and social interaction.

Project information

PRC: Flood Control, Environmental Improvement and Water Reclamation Works in Pu’er

Project snapshot

      • Start date: January 2012
      • End date: June 2012
      • Total project cost: $410,000
      • Financing: 
        • KfW: $80-million loan for key components of project
        • CDIA: $410,000 in technical assistance
        • Municipal Government of Pu’er
      • Commissioning agency: Municipal Government of Pu’er

Context

Pu’er City is situated in the southwest of Yunnan Province. It covers a floodplain of about 45,000 square kilometers, framed by green hills and mountains where the famous Pu’er tea is grown. The city’s estimated population is 200,000.

Pu’er developed into a modern urban center in recent years, but increased urbanization brought pressing challenges. It experienced frequent floods that severely affected urban activities and the future development of the city. The foul odor of garbage and sludge from the Simao River further attested to environmental deterioration.

Challenges

The Simao River traverses the urban area of Pu’er. The 15-km long watercourse acts as a natural drainage channel for the city and serves as a home for wildlife and vegetation along its shores. In previous years, however, the river lost its capacity to provide these environmental benefits.

In 2012, the river had a very low flood risk management capacity that it could only cope with a 5-year flood event or less. Due to the characteristics of the river’s course and riverbeds, it could not effectively drain flood waters, thus putting the city at risk of flooding.

The Simao River was also polluted. Solid waste, sludge, and aquatic plants impeded its normal water flow, and informal settlers occupied some of its riverbanks. Pu’er’s inadequate wastewater management system compounded the problem, as only 22% of the urban wastewater was collected and treated. The rest was discharged directly into the Simao River and its tributaries.

With the river’s poor water quality and surrounding environment, biodiversity could hardly thrive. This was a stark contrast to the rich flora that Yunnan Province is known for.

Pu’er’s residents perceived the Simao River as a heavy burden; they did not see it as an integrated part of their city and did not regard it as an emblematic feature of Pu’er’s natural beauty.

Solutions

The Pu’er Municipal Government prepared a feasibility study of the Simao River rehabilitation project to develop the watercourse into an attractive landmark and to prepare the city to cope with severe flood events.

Comprehensive project preparation

The city government asked CDIA to review the feasibility study and finalize the preliminary design for the Flood Control, Environmental Improvement, and Water Reclamation Works in Pu’er project.

CDIA and the Pu’er government worked closely for 6 months in 2012 to prepare the project, involving all relevant stakeholders at each critical step of the planning process. They collected information and conducted surveys, analyses, and calculations to provide a strong foundation for the design of the Simao River rehabilitation project.

By the end of CDIA’s intervention, the city was set to pursue the following measures:

  1. Improve the water quality through a series of treatment wetlands at the confluences of Simao River tributaries and storm water channels;
  2. Provide a river layout that can withstand 50-year flood events;
  3. Allow the river water to flow through a combination of free-flowing stream and still water sections;
  4. Provide an open main flood channel with vegetation situated alongside riverbanks; and
  5. Divide project construction into three sections and three contract packages for the entire length of the river.

In December 2012, KfW signed an $80-million loan agreement with the PRC government to implement flood control and channel improvement works for the Simao River.

Use of ecological and green development approach

The city mostly used nature-based solutions recommended by CDIA to achieve a more sustainable river rehabilitation and create a healthy and livable environment for residents. It espoused the use of ecologically sound and diverse measures, natural processes and materials, and it based restoration efforts on the idea of the features being part of the natural environment and not exclusively built structures. It also planned to entirely use native plant materials for revegetation and for reinforcing flood beds and riverbanks.

The adoption of an ecological and green development approach ensures cost effectiveness in terms of construction and maintenance, and it can also recreate a natural river environment that protects against floods and provides natural habitats for biodiversity.

Integration of the project with city development plans

The city government integrated the planned interventions with their master plan and linked the river works with other relevant urban infrastructure projects, such as wastewater management, wetland park development, and urban renewal. This approach enabled the city to pursue a project design adapted to its existing and future development needs.

Results

CDIA visited the city 6 years after it completed its technical assistance and found that the city completed 85% of the project work, including flood control, sewage interception, and river ecology restoration measures recommended in the CDIA study.

Pu’er officials noted that the risk attributed to flooding has been minimized in flood-prone areas after completion of dredging and excavation works along the river. They also expect that the river will be able to withstand a 50-year flood event when the project is completed.

The river’s water quality improved after the city reformed its wastewater management program, and the foul smell coming from the river was eliminated.  There was also a noticeable increase in fish population in the still water sections of the river.

The landscape surrounding the river was rehabilitated, with 50 hectares of greening and restoration efforts along its banks giving residents new spaces for recreation.

The city used natural and indigenous materials and processes during the project and that resulted in low construction and maintenance costs. Pu’er officials are optimistic that an ecological and green development approach will improve biodiversity and promote the sustainable development of the river.

Informal settlers along the river that were exposed to flooding were transferred to relocation sites with better amenities and quality of housing units.  

Finally, the roads and bridges constructed and retrofitted near the river are expected to improve mobility and access to social services for residents.

The project is transforming Simao River into an ecological landmark while reducing flood risks and improving water quality. Photo Credit: CDIA/Rudini Baoy.

Lessons

Aided by the interventions and the commitment of relevant stakeholders, Pu’er is set to achieve its primary objective of developing the Simao River watercourse into an attractive ecological landmark while eliminating flood risks and improving the water quality of the river.

The integration of the project into the Pu’er City Master Plan paved the way for the coordinated implementation of relevant urban infrastructure projects. Meanwhile, the active participation of city officials and the affected communities in project planning and implementation strengthened their ownership of the project.

The city government linked the various project components with internal and external funding sources necessary to implement the project. It further established a governance structure, headed by the city mayor, to manage and maintain the river and its tributaries after project completion.

Key officials of the Pu’er Municipal Government are optimistic that Pu’er will serve as a model for other cities in the PRC on how to approach the problem of flood management the natural way and how to integrate flood management measures in a more sustainable manner.

References

Cities Development Initiative for Asia. 2012. Final Report: Flood Control, Environmental Improvement & Water Reclamation Works in Pu’er.

R. Baoy, E. Ringhof, and C. Yiyang. 2018. Pu’er Tracer Study. Tracer Studies on City Interventions. Cities Development Initiative for Asia.

Author
Brian Capati

Brian Capati

Urban Development Specialist, Cities Development Initiative for Asia

This blog is reproduced from Development Asia.

How to Increase Water Supply Efficiency with Artificial Intelligence

To remain competitive in the age of digital disruption, water utilities need to shift to Hydraulic Modeling 2.0, which uses artificial intelligence and big data to improve efficiency and accountability. Photo credit: Asian Development Bank.

A data-driven “smart” system can help water utilities to reduce losses from unaccounted-for-water more efficiently and improve service delivery.

Introduction

Artificial intelligence (AI) offers water utilities the potential to enhance service delivery, optimize investments, and reduce costs. It can improve the efficiency of water supply systems by maximizing information and data available to make better operational and planning decisions. For example, AI tools may be used to inform efforts to reduce losses from nonrevenue and unaccounted for water, such as from leaking pipes and inaccurate meter readings.

The availability of affordable big data from sensors, customers, and staff builds the case for the digital transformation of the water sector. However, many water utilities, particularly in developing countries, lack the capacity to use big data for day-to-day operations. Most of them start their digital transition with a supervisory control and data acquisition (SCADA) system linked to a network control center; then figure out how to turn these technology investments into real benefits to customers.

The digital transition of water utilities should be progressive, pragmatic, and target-oriented. From an “old school” operation or Hydraulic Modeling 1.0, water utilities need to shift to a new era of efficiency and accountability, or Hydraulic Modeling 2.0, supported by AI tools and big data analytics.

This explainer is adapted from an Asian Development Bank publication(link is external) that discusses the principles and applications of AI for water utilities to improve water distribution operation, how to pilot AI to address unaccounted-for-water problems, and policies to support digital adoption.

What is Hydraulic Modeling 2.0?

It is a new network analysis approach that encompasses the joint application of several methods to provide a dynamic, probabilistic representation of water distribution networks. It allows the numerical detection of unaccounted-for-water.

Hydraulic Modeling 2.0 is the way forward for water utilities to embrace AI or machine learning at the core of their planning and operations. It represents a qualitative step forward compared to the conventional Hydraulic Modeling 1.0 currently used. The key differences are summarized in the table below.

Hydraulic Modeling 2.0 combines physically based and data-driven methods for water distribution network analysis. Physically based methods draw on the combination of statistical tools, such as state estimation techniques and pressure sensitivity analysis, with hydraulic modeling.[1] Data-driven methods are based on the application of AI or machine learning algorithms as artificial neural networks (with their many variations generally known as deep learning methods), as well as support vector machines, classification trees, adaptive neuro-fuzzy inference systems, etc.

Table 1: A Comparison of Hydraulic Modeling 1.0 and 2.0

Hydraulic Modeling 1.0 (Conventional)Hydraulic Modeling 2.0
Deterministic
System represented by average values of the state variables (flows and p		Probabilistic
All variables treated as probabilistic with their density functions and cross-correlations.
One-off calibration
Hydraulic model calibrated once a year (at best) based on aggregate error functions.
Model parameters are usually fixed.		Continuous learning
Hydraulic model real-time learning with new data generated: calibration constantly updated with past and current data.
Limited data
Hydraulic model set up with limited data without the need for real-time data, except to update water consumption.
More data does not imply better model.		Big data
Hydraulic model maximizes all data available (the more data, the better): well suited to a data-rich and real-time environment.
Simplification
Uncertainty in water demand at the nodes not quantified and not considered		Uncertainties
Water demand reflects the uncertainty from the meters’ errors and the aggregation of nodes when no meter is available.
Shortcut
Measurements’ errors for flows and pressures not considered.		Holistic
Measurement errors from sensors introduced into the model with a non-negligible impact on the results.
Anomalies
Anomalies mostly not detected or if so, not characterized, nor classified.		Classification and sorting
The algorithm analyzes the residuals values (differences between field data and model results) and classifies them into categories: illegal connections, water leaks, pipe bursts, malfunctioning sensors, abnormal water consumption patterns, etc.

Source: Asian Development Bank.

What are the first steps toward a smart water system?

From the point of view of operations, physically based methods are the starting point for water utilities into their digital transformation. The next step is to integrate data from SCADA with advanced hydraulic modeling tools—comprising AI in water supply—through data-driven approaches. This supplements the physically based methods with powerful optimization and decision support tools, business intelligence, and knowledge management.

For a medium-size water utility (less than 100,000 connections) with little experience in smart water, the initial operational assessment would identify where digital transformation brings the largest benefits (“low-hanging fruits”), and then a smart water road map should be drafted. A typical starter digital transformation package would look into

  • defining operational targets and key performance indicators (KPIs);
  • integrating network analysis tools that provide the diagnosis and the decision support to achieve the KPIs;
  • developing an optimal monitoring network to obtain the maximum amount of information based on a minimum number of strategically placed sensors with the lowest ratio of flowmeters versus pressure gauges to minimize costs; and
  • implementing a SCADA basic solution for the distribution network.

How can AI improve unaccounted-for-water reduction?

Unaccounted-for-water is a key indicator of the operational and financial performance of a water utility. It is a benchmark of a water utility’s efficiency in reducing both physical losses (e.g., water leaks and pipe bursts) and commercial losses (such as illegal connection and metering errors).

Techniques to physically detect water leaks combine special equipment (acoustic sensors, gas tracers, etc.) with human skills. A current trend is to incorporate AI in some of the hardware (for instance, acoustic correlators) to replace humans in interpreting the data (water leak noises). Advances in numerical modeling of the hydraulics of water distribution networks also now make it possible to detect potential leaking pipe sectors through numerical methods, as long as the hydraulic models are fed with a sufficient amount of calibrated field data such as pressure, flow, and node consumptions.

A 2019 white paper shows that smart water technologies could reduce a water utility’s total cost by 7.4% (baseline costs), with most of the savings coming from efficient utilization of capital expenditures and improved unaccounted-for-water reduction. Although the AI algorithms’ contribution is not broken down, most of the gains are assumed to come from data processing and analysis, since sensors and data on their own provide little direct benefit.

How to pilot test AI for unaccounted-for-water

Water utilities can test the potential benefits of AI techniques by embarking on low-risk, low-scale pilot projects that can also be used to assess their technological capacities and define a realistic smart water road map.

Piloting the concept of AI and Hydraulic Modeling 2.0 for unaccounted-for-water would demonstrate how advanced network analysis algorithms improve operational efficiency and service delivery. This involves harnessing the power of AI combined with big data sourced from the SCADA system, as fed from the various sensors on the water distribution network.

An AI pilot analyzes numerical unaccounted-for-water and pipe burst detection as well as sensor failure routines on the primary water distribution network (pipe diameter of over 200 millimeters). The AI algorithms are tested on one water distribution network sector or a small water distribution system.

The AI pilot starts with an off-line demonstration making a hindcast based on historical records collected by the water utility on the selected portion of the water distribution system. A hindcast (also known as back-testing) involves testing using a mathematical model. Known or closely estimated inputs for past events are entered into the model and compared with output against known results.

A typical pilot project (phase 1) would consist of several sequential tasks over 9–12 months:

  • Task 1: selection and validation of the pilot site in agreement with the water utility’s representatives (1 month);
  • Task 2: initial analysis of the pilot site and data provided by the water utility to check for inconsistencies, data gaps, and other issues (1–2 months);
  • Task 3: setting up and localization of the AI algorithms (3–4 months); and
  • Task 4: exploitation of AI algorithms using historical data in a hindcast mode (4–6 months).

After completing the off-line testing of the AI algorithms, phase 2 can start using the AI algorithms in real-time operation, including for the prognosis of unaccounted-for-water. The need to integrate the numerical results with the current operation and the development of complementary algorithms suggests another 18 months to implementation for phase 2. Based on the real-time results and experience, the AI pilot can be upscaled to the entire water distribution system.

For a water utility with less than 25,000 connections, corresponding to a city of 100,000 inhabitants, the cost of implementing a smart water project with an AI pilot would be around $2 million ($10 to $20 per person, or around $0.5 to $1 per month and service connection, in variable terms).

What are the key areas for policy action to support digital transformation?

The use of AI has several policy implications to improve the performance of water utilities and the quality of the service delivery.

  • Ethics and governance deal with the protection of personal and financial data from consumers, and technical and financial data from water utilities.
  • Regulation deals with benchmarking, since unaccounted-for-water is one of the key operational parameters to determine the efficiency of a water utility.[2]
  • Technical policies deal with line ministries and water associations to update the national and water “Code of Practice,” and to guide water utilities in their digital transformation.
  • Financial policies address short-term capital expenditure requirements to finance smart water utilities with new financing instruments.

Development partners can support line ministries and water associations in developing technical guidelines and strengthening regulations, governance, and ethics resulting from the introduction of powerful AI numerical tools.

The financing requirements of smart water utilities can be supported by customizing the energy savings business model (with energy savings companies) through funding based on a digital and smart water road map and payback, and secured through operational improvements guaranteed by water tariff increases resulting from the enhanced service delivery to customers.

[1] D. Jung and J. H. Kim. 2018. State Estimation Network Design for Water Distribution Systems. Journal of Water Resources Planning and Management. 144 (1); S. G. Vrachimis, D. G. Eliades, and M. M. Polycarpou. 2018. Real-time Hydraulic Interval State Estimation for Water Transport Networks: A Case Study. Drinking Water Engineering and Science. 11 (1). pp. 19–24; S. Díaz, J. González, and R. Mínguez. 2016. Uncertainty Evaluation for Constrained State Estimation in Water Distribution Systems. Journal of Water Resources Planning and Management. 142 (12); H. R. Asgari and M. F. Maghrebi. 2016. Application of Nodal Pressure Measurements in Leak Detection. Flow Measurement and Instrumentation. 50. pp. 128–134; and R. Pérez et al. 2011. Methodology for Leakage Isolation Using Pressure Sensitivity Analysis in Water Distribution Networks. Control Engineering Practice. 19 (10).

[2] The International Benchmarking Network for Water and Sanitation Utilities (funded by the World Bank Group and the International Water Association with the support of other development partners and stakeholders) promotes good benchmarking practices among water and sanitation services. See International Benchmarking Network. https://www.ib-net.org/.

Resources

D. Jung and J. H. Kim. 2018. State Estimation Network Design for Water Distribution Systems. Journal of Water Resources Planning and Management. 144 (1).

H. Jenny et al. 2020. Using Artificial Intelligence for Smart Water Management Systems. ADB Briefs. 143. June. Manila: Asian Development Bank.

H. R. Asgari and M. F. Maghrebi. 2016. Application of Nodal Pressure Measurements in Leak Detection. Flow Measurement and Instrumentation. 50. pp. 128–134.

International Benchmarking Network.

R. Pérez et al. 2011. Methodology for Leakage Isolation Using Pressure Sensitivity Analysis in Water Distribution Networks. Control Engineering Practice. 19 (10).

S. Díaz, J. González, and R. Mínguez. 2016. Uncertainty Evaluation for Constrained State Estimation in Water Distribution Systems. Journal of Water Resources Planning and Management. 142 (12).

Sensus. 2020. Improving Utility Performance Through Analytics: Market Research Report. White Paper.

S. G. Vrachimis, D. G. Eliades, and M. M. Polycarpou. 2018. Real-time Hydraulic Interval State Estimation for Water Transport Networks: A Case Study. Drinking Water Engineering and Science. 11 (1). pp. 19–24.

Author
Wang Yihong

Wang Yihong

Senior Investment Officer, East Asia Department, Asian Development Bank

Eduardo Garcia Alonso

Eduardo Garcia Alonso

Consultant, Asian Development Bank

Roberto Mínguez Solana

Roberto Mínguez Solana

Consultant, Asian Development Bank

Disclaimer: The views expressed in this blog are those of the authors and do not necessarily reflect the views of ADB, its management, Board of Directors or members.

Applying Ancient Wisdom to Disaster Risk Mitigation

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Built in 256 BC, the Dujiangyan system harnesses the power of nature to irrigate farmlands and prevent floods in the People’s Republic of China.

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Introduction

A water resource management system built more than 2,000 years ago is still used for flood control and irrigation in Sichuan province in the People’s Republic of China (PRC). It is a feat of nature-based engineering that uses indigenous wisdom and materials.

Designed and constructed in 256 BC, the Dujiangyan system controls flow and diverts water from the turbulent Min River without the use of dams. It has irrigated farmlands on the Chengdu Plain, which produced bumper crops that earned Sichuan its reputation for being a “Land of Abundance.”

How does it work?

Dujiangyan uses the natural topographic and hydrological features of the area to regulate the water from the river for irrigation, flood, and flow control, and to drain sediments.

The Min River is the largest tributary at the upper reach of the Yangtze, Asia’s longest river. It originates from the southern side of the Min Mountains at an elevation of about 3,700 meters (m).

The headworks of Dujiangyan is located at the mountain exit of the Min River and at the top of the fan-shaped Chengdu Plain. It comprises three structures: the fish mouth levee, flying sand weir, and bottleneck channel. These work seamlessly together in directing the flow of water and sediments and for flood discharge.

The fish mouth levee is a man-made island in the shape of a giant fish that lies in the middle of the river. It is constructed at a big curve, and it is about 80 m long, 39 m wide, and 6 m high.

The levee splits the water into two channels: the outer stream, which is the original course of the river, and the inner stream, which was built to be deep and narrow. In the dry season when the water level is low and velocity is slow, more water flows toward the inside of the bend or the inner stream, which directs water into the Chengdu Plain. In the rainy season when the water level is high and velocity is fast, more water is discharged, especially during floods, into the relatively shallow but wide outer stream.

The levee structure also creates the helicoidal flow phenomenon: a corkscrew-like flow of water rushing toward the river bend (inner stream) that causes massive whirlpools to spill rocks and sediments into the outer stream and then into the main river because of centrifugal force.

The flying sand weir is located at the outer edge of the inner stream. It is about 200 m long and 2.15 m high. It partners with the bottleneck channel for a second round of flood discharge and silt removal. The inner stream rushes to the narrow bottleneck channel, causing the water level to rise. When the water level is higher than the flying sand weir, the overflow spills into the discharge channel. During a large flood, the weir will collapse to allow more water to be diverted into the outer stream.

The centrifugal force of the water flowing along the river bend toward the bottleneck spins out the remaining sediments over the flying sand weir. The system removes up to 90% of sediments.

How was it built and how has it evolved?

The Dujiangyan system was designed by Li Bing, governor of Shu Prefecture, who was given the task of diverting the Min River to Chengdu.

The original construction materials were bamboo, wooden piles, and stones. The stones were loaded into woven bamboo cages to build dikes and weirs and reinforced with the wooden tripods or macha. The wooden tripods were weighed down with soil, pebbles, and other materials to form a temporary retaining wall to block the flow of water. The bamboo cages with stones were used to combat floods or to also block water during maintenance and construction.

The bottleneck channel, which is about 40 m high and 20 m wide, was cut through Mount Yulei manually to allow the water to flow into Chengdu Plain.

To maintain the efficiency of the system, the levee and weir were repaired, and the waterways were dredged regularly. Stone horses were buried in the middle of the inner stream to mark the proper depth of the riverbed. Too much dredging will result in flooding, while too little will result in insufficient water flow. The stone horses were later replaced by iron rods or wotie.

The Dujiangyan system has been improved throughout history. Water diversion facilities and reservoirs were built in the 1970s.

What has been its impact on local communities?

Before the Dujiangyan was built, the Chengdu Plain was prone to floods in the summer and droughts in winter. Sediments accumulated in the riverbed.

The water resource management system broke the vicious cycle of natural disasters year after year. It is still functioning after more than 2,000 years. Today, it benefits 23 million people by providing irrigation to 10 million mu (667,000 hectares) and domestic and industrial water supply as well as flood management.

Ecotourism also flourishes in the area because of the Dujiangyan and other cultural and natural attractions. Dujiangyan was added to the UNESCO World Cultural Heritage List in 2000 and the World Irrigation Engineering Project Heritage list of the International Commission on Irrigation and Drainage in 2018.

What best practices does it offer?

Nature-based solutions offer a way to provide economic, social, and environmental benefits simultaneously.  Using natural systems can be effective in improving climate resilience and in mitigating disaster risk.

Dujiangyan is a good example of how to take full advantage of natural topography and geographic conditions in harnessing the power of nature. It does not use large-scale grey infrastructures yet has withstood the test of time. It is a sustainable system with low operation costs, and it uses locally produced and readily available “circular” materials. There is little negative impact on the natural environment.

Holistic, integrated, and strategic planning went into the project. The headworks, irrigation channels, and other associated structures were designed as an integrated system. All structures work seamlessly together.

References

X. Yang. 2020. Nature-based Approach in Climate and Natural Disaster Risk Management: Dujiangyan Water Resource Management System. Presentation made at the ADB–PRC seminar series. 5 August.

Ministry of Water Resources, the People’s Republic of China. 2019. Dujiangyan—The Oldest Functioning Dam-Free Water Diversion Project. Article. 20 March. 

Author
Xiaoyan Yang

Xiaoyan Yang

Senior Programs Officer, East Asia Department, Asian Development Bank

This blog is reproduced from Development Asia.

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