100,000 IoT sensors line canal in China’s ambitious water diversion project
China’s South-to-North Water Diversion Project employs 100,000 IoT sensors
The starting point of the Central Route of the South–North Water Transfer Project

100,000 IoT sensors line canal in China’s ambitious water diversion project

A colossal water diversion project in China has installed a myriad of IoT sensors to help monitor the essential canal infrastructure.

The ambitious engineering scheme will see three canals, each over 1,000km long, divert 44.8 billion cubic metres of water annually from rivers in southern China and supply it to the arid north, including the cities of Beijing and Tianjin. Each canal route will support the rapid population growth and economic development of the northern provinces.

The project was expected to cost in the region of $62 billion when started in 2002, but with $79 billion spent by 2014 it has fast become one of the most expensive engineering projects in the world.

The middle canal runs from Danjiangkou Reservoir on the Han River all the way to Beijing, some 1,257km, supplying the city with 70 percent of its water.

With construction on this route completed in 2014, attention turned to how to monitor such a large and valuable infrastructural system – particularly in those sections where the canal uses tunnels to circumvent rivers and other obstructions, making human inspection difficult.

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Streams of data

The answer was to develop an internet of things (IoT) network, consisting of 100,000 sensors, along the waterway. Over the last year it has been scanning the canal for structural weaknesses, testing water quality and flow rates and watching for intruders (both animal and human). Planning for the system started in 2012, when technicians travelled the route to determine its monitoring needs.

The region’s vulnerability to earthquakes makes it particularly at risk of structural damage. Manually monitoring the canal, particularly its two tunnels, would be extremely difficult, making it a perfect candidate for an IoT solution.

While no industrial buildings are allowed within the route’s watershed, it’s vital to ensure that the water remains unpolluted. Sensors below the waterline can detect pollutants and toxins. All-in-all 130 different kinds of connected sensor were used to oversee the canal.

The IoT network’s technical lead Yang Yang, Director of the CAS Key Lab of Wireless Sensor Network and Communication at the Shanghai Institute of Microsystem and Information Technology (SIMIT), told IEEE Spectrum that lessons learned from the system will be applied to similarly large infrastructure projects, include the South-to-North Water Diversion Project’s two other routes.

“This system benefits more than 50 million people daily, not mentioning the people along the project,” said Yang. He also revealed that the technology could be put to use on skyscrapers, to monitor the integrity of their glass facades.

Yangtze river
The scheme will see 44.8 billion cubic metres of water diverted from the Yangtze River’s tributaries

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The challenges of rural IoT

With the canal producing such a wealth of data the team faced the challenge of relaying this information, particularly in remote areas without fibre-optic internet or reliable cellular connections. Yang’s team created a system called Smart Gateway that would receive data from nearby sensors and transmit it to a cloud server via whatever cellular, wired, Wi-Fi or Zigbee connection was available at that time.

“The Smart Gateway can learn the availability of the connection to the cloud. After a successful transmission, it will follow that network next time. Otherwise, it will try another one,” Zhang, told IEEE Spectrum.

The destination servers then feed into a web platform that allows the management team to see up-to-date information and respond immediately.

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Water under the bridge?

The scheme certainly hasn’t been without its controversies though. A utilitarian approach has seen hundreds of thousands of residents resettled to make way for the project. In Hubei and Henan provinces, almost 350,000 people were relocated to make way for the middle route. Many residents have complained that their new homes are poorly built and suffered the loss of their livelihoods.

US diplomatic cables released via WikiLeaks also criticised the project as misconceived, arguing that China’s water shortage should be solved by modernising and diversifying its water-intensive agriculture, rather than expensive engineering projects. China hasn’t been ignoring these needs though. Research into the likes of drip irrigation and less water intensive crops is ongoing.

The reality is that China will likely need a combination of both these approaches to protect and allocate its most precious resource. IoT will no doubt play a huge part in providing its population with food and water in the decades and centuries to come.

While China’s rise has, until now, been down to its snowballing primary industries and resource rich land, it is having to increasingly look to technology and policy reform to continue that growth in a more sustainable and responsible way – not least because the government wants to ensure those IoT sensors go on detecting drinkable water in its canals.