Water’s digital twin

Water is life. While this may sound like a truism, it does show us how important it is to know how to manage water. Water was once used where it was found – cities were founded by rivers, trade routes stretched from one oasis to the next, and wells were dug and cisterns constructed to catch rainwater. But as population density increased and cities grew, some initial problems became apparent: not everything you take from a river is fit for consumption, especially when people dispose of their sewage in the very same river. There’s a reason why the Babylonians used beer as a relatively uncontaminated and non-perishable substitute for water.

These days, it’s a question of sourcing, distributing, using and disposing of water as a resource. DMT provides services in this area around the world, both for public-sector customers, such as with infrastructure projects, and for industry, for example groundwater management. The aim at all times is to consider the water cycle in its entirety and to optimise use of this resource – because this saves money. And using a vital resource sustainably is, of course, extremely prudent for society as a whole. After all, it’s a question of using water, but not using it up.

Forecasting with box model

With these projects frequently being large, time-consuming and costly, their success can hinge on analysis, forecasting, planning and monitoring. Here, we draw on our centuries of experience in the field of mining: the need to keep water under control underwater has led to some major progress. We benefit from the expertise we have garnered to this day – thanks to ever better analysis techniques and innovative technologies, we are able to offer solutions that were previously not available. For example, digitalisation allows us to generate a complete, three-dimensional image of the groundwater and surface water in a certain area. This gives us a ‘digital twin’ that makes complex analyses possible. We are then able to anticipate the impact of technical interventions in various scenarios and recommend the right measures.

In addition to the familiar and well-known numerical models, we use our own unique and specialised software such as ReacFlow3D, Heatflow and Box3D. The box model is a 3-D finite-volume program for modelling the direction and speed of mine water and groundwater flows, including temperature, dissolved substances and chemical reactions. The software makes it possible for all sorts of flow spaces to be discretised, flexible cell figures and connections to be defined and turbulent flows to be presented. The model has already been used for projects in Germany, Spain, France, the UK, Poland, Bulgaria, South Africa and Ukraine.

A concrete example is the East Rand Basin outside of Johannesburg. This is where the world’s largest gold deposits can be found, and they have been being mined there since the late 19th century. Mines which have been exhausted are closed and water is no longer pumped out of the tunnels, so they gradually fill with water. Firstly, this can adversely affect adjacent mines and secondly, there can be unwanted contamination of the groundwater, usually with salts, iron or heavy metals. This contamination poses a threat to the local drinking water and needs to be carefully monitored in order for appropriate steps to be implemented. To do this, the digital box model was used to generate a comprehensive water cycle model encompassing groundwater, river water, surface water and mine water. The results of the various scenarios can now be used as the basis for policy decisions and technical implementations.

The value of water

Making economic use of water as a resource will become even more important in the future: we need to analyse and plan the changes needed due to climate change. Expanding cities such as Singapore and Bangkok need a clean and safe supply of drinking water, ideally in a self-contained water cycle. We want to protect our groundwater, for example at major construction sites and in infrastructure projects. We want to promote the sustainable use of water, for example by means of the fully automated management of fountains based on weather forecasts. And let’s not forget issues such as microplastics in water and the contamination of water with pharmaceuticals and hormones. The more we know, the better we can react – and act. This is what ‘Engineering Performance’ means to us.

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