The Big Data Revolution in Water Management

Published: 25 August 2016

Satellite images provide a high resolution picture of the impact of human activities. Arrange these images in sequence and you see the changes taking place like in a film. Large-scale infrastructure projects such as the construction of water reservoirs and land reclamation are easy to follow from space. Also, natural changes, such as meandering rivers and the formation of deltas can be seen on satellite images.

The Aqua Monitor

The Aqua Monitor is a new web app that allows you to observe how water systems change over time. The Aqua Monitor uses Google Earth Engine and is available via the Internet to a wide audience. PhD researcher Gennadii Donchyts has developed an algorithm that automatically detects water in the satellite images.

Processing the satellite images is a computationally intensive process, which is done through the Google Earth Engine platform. During his PhD research Gennadii has processed many terabytes of data. Step by step he has improved his algorithms and explored new possibilities. He published his work in Nature Climate Change.

Video: The Aqua Monitor explained by Gennadii Donchyts, Fedor Baart and Jaap Kwadijk (Deltares).

Think global, act local

The special feature of the Aqua Monitor is that you can make a global analysis while zooming in on a local situation. A global issue such as drought can be illustrated with local examples of drying reservoirs. The Aqua Monitor allows you to observe the changes that occur in the water system in upstream regions. Such information is valuable for the preparation of water plans for catchments.

Aral Sea

The drying up of the Aral Sea on the border between Kazakhstan and Uzbekistan. The bright green colour shows the new land.

A modern historic atlas of the world

One of my favourite books is the historical atlas. The shifting boundaries of the old maps tell countless stories from world history. The Aqua Monitor provides something similar: you can now see how our world has changed in the last thirty years. It is exciting to seek out the most dramatic changes to the coastline, or secret projects in remote countries, whose existence you would not have expected.

Dubai

Land reclamation off the coast of Dubai. The bright green colour shows the new land.

The end of simulation models?

The launch of the Aqua Monitor also raises questions. Until now, animated films that show changes in water systems, were often made using simulation models. Will it soon be possible to find all the answers in the data that is collected with increasingly high resolution? The general public will also have access to information that was previously reserved for researchers only. Does this make the role of models and modellers redundant?

My answer to this question is nuanced.

Previously, in the absence of detailed data, a model would be used to create an animation that shows how a water system works. Now you can create an animation based on the data. It is no longer necessary to fill in gaps in data sets with model simulations.

Researchers and modellers have an added value, because they can interpret the data. They have knowledge of the processes involved in the water systems and can draw conclusions about causes, consequences and measures.

Besides, satellite images of the past, tell little about the future. To create future scenarios and designing measures you do still need models. The high resolution data can expedite the creation of simulation models, especially if the processing of import data for the models is automated.

Inspiration for modellers

The development of the Aqua Monitor is a sample of what we want to achieve with our simulation models.

We now have a number of global models, such as a Delft3D Flexible Mesh model that spans all the seas and oceans, and groundwater models for all continents on earth. We are working towards a situation in which, starting with a global model, you can zoom into a region where there is a problem.

grid_mediteranean_area-01-735x735

The global Delft3D Flexible Mesh model for the seas and oceans of the earth.

For zooming in from a global model we already have a number of ingredients available. Flexible computational grids make it possible to refine a local grid. With high resolution data, detailed terrain models can be provided for these fine grid cells.

The challenge lies in the sophistication needed to model processes on a local scale, and the inclusion of all kinds of control rules of man-made structures.

The Aqua Monitor in practice

Anyone can use the Aqua Monitor. The consultant who needs to answer a customer’s question and the interested citizen who wants to zoom in on his back garden. The freely available data allows for a level playing field for all stakeholders involved in water management. Everyone has the ability to make a quick initial analysis and to have information about the situation of the upstream and downstream neighbours.

Maasvlakte2_2

Changes in the Dutch delta between 2000 and 2015: land reclamation for harbour expansion Maasvlakte 2 (far left), the Sand Engine (along the coast) and a new water retention area in the Eendrachtspolder (far right). Bright green: new land. Bright blue: new water.

The Aqua Monitor focuses on changes in water and land area. Satellite images contain much more information. Researchers from Deltares are currently investigating how information about the ecological status of water can be similarly displayed, such as the occurrence of large-scale algal blooms.

Conclusion

The Aqua Monitor makes global data accessible to water management on a regional and local scale. The big data revolution gives all stakeholders involved in water management, an accessible analysis instrument. You can summarize all the changes in the water systems of the past few decades into a short and powerful film.

 

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