Unlike many countries, virtually all Danish drinking water is drawn from groundwater. Although groundwater abstraction brings its own challenges, what Denmark demonstrates is that if done correctly, sustainably managed groundwater fosters benefits that carry forward throughout the water cycle and beyond.
Rune Kier, strategist at one of Denmark’s leading water utilities, Skanderborg Utility and AquaGlobe – Water Solution Center, observes: ’Because of their importance, we have a widespread political and societal agreement that groundwater resources must be protected from pollution and other harmful impacts of human activities — that water should be protected, not treated.’
It follows that a key prerequisite for protection is thorough insight on groundwater resources which can inform effective action plans and legislation that prohibit the use of pesticides, and other industrial activities, in drilling areas.
Kier explains that this protect-not-treat ethos has therefore prompted a number of initiatives to secure its intentions, and as he says, "has led to all sorts of sustainable practices and knock-on benefits for the rest of the water supply sector, and the environment.” A fundamental initiative has been groundwater mapping.
So as to develop a sound understanding of aquifers from which to work, some twenty years ago Denmark committed to mapping its groundwater resources. The work was guided by ambitions of securing aquifers from pollution, as well as facilitating sustainable management of water resources.
Pia Jacobsen, chief engineer – water reuse, at one of Denmark’s largest water utilities, Aarhus Vand, explains: “A great number of state and private companies have been involved in the mapping work, all bringing specific expertise to the development of the solutions we now have at our disposal.”
The integrative effort involved identifying all national aquifers, gathering volumetric data on them, and developing tools for structuring, modelling, and visualizing data into usable formats.
An industry player supporting groundwater management initiatives has been the Danish engineering consultancy company, NIRAS. Mette Neerup Jeppesen, manager for water supply at NIRAS, describes several projects involving collecting and modelling groundwater data, in which the company partnered with water suppliers: “We developed and deployed a lot of high-tech systems for the mapping, but it’s been well worth the effort. It’s clear that careful management and protection of aquifers provides a route to avoiding a lot of expense and effort on treating drinking water.”
As an example of this, Kier explained: “With assurance on aquifers, we can use only the simplest of filtering techniques for treating groundwater, in fact just two types of filter. It’s simple and low-tech, without the need for disinfectants like chlorine or complex processes, and saves on operational and infrastructure expenditure.”
Broad aquifer data has also been used to build groundwater resource management tools. In the city of Odense for instance, aquifer data is utilized by an intelligent control system for water abstraction. The system is fully integrated with existing supervisory control and data acquisition (SCADA) systems, and helps ensure abstraction is optimized across time and seasons, and with usage.
Aquifer mapping has also facilitated efforts which carry the dual benefit of protecting resources, whilst contributing to the environment. A prime example is afforestation to protect groundwater and well-field catchment areas, which aid in reducing the national CO2 footprint by absorbing CO2 from the atmosphere.
Developing the right tools
Specialists in geographic information systems and geoscience, Danish software outfit I•GIS, played a key role developing novel tools to support groundwater mapping. Together with input from other stakeholders, the work has culminated in what’s come to be known as the so-called Danish Model for mapping and protecting groundwater.
Tom Martlev Pallesen, head of production & consultancy at I•GIS, expanded on the development of new 3D software for inspecting and visualizing geologic models.
“In the beginning of the mapping campaign, new mapping methods were developed and refined, especially geophysical methods. The data from those created a new demand for geological mapping software able to handle these new datatypes and the rapidly growing amount of data. In this context the modelling software GeoScene3D, as we see it today, was developed.”
A key strength of GeoScene 3D is its overcoming traditional problems associated with modelling with different approaches and different softwares, which led to creating a large, inhomogeneous datasets.
Instead, when a geological model is made in GeoScene3D it can be exported in different file formats, including the Danish Model database format, which makes it possible to upload a geological model directly from GeoScene3D to the national model database, where other stakeholders (modelers, hydrologists, utilities, comities, etc.) can download and use the results.
GeoScene3D can also be connected to the Danish borehole database and the geophysical database GERDA for data import. It’s this kind of streamlining — enabling better insights and interoperability between stakeholders — that has empowered water utilities and other actors to take a proactive approach to sustainable groundwater management.
“The option of visually integrating many different data types into one software, especially geophysical data, is quite unique,” said Martlev Pallesen, adding that the GeoScene3D solution has become a central component in multiple international partnerships established to export the Danish model.