How we tackle Nordic water challenges

WSP has extensive experience in planning and developing sustainable stormwater and cloudburst management that can cope with future climate change.

Extreme weather with heavy precipitation is becoming more common in the Nordic countries and old, undersized water and sewage systems have difficulty coping with the increased amounts of water, which often leads to flooding and contamination of other water sources.

The Nordic countries have traditionally had a relatively easy time with water. In most places, we have had good access to clean freshwater and have been spared extreme weather events such as droughts and torrential rain. However, as climate change has become more apparent, this has changed, and we have had to get used to headlines about flooding. This places higher demands on water planning, not just for water systems but for all types of facilities. They need to be able to handle downpours while ensuring access to clean water. WSP has experience in mapping and planning for increased rainfall from projects all over the world. In the Nordic region, it is an area that has grown significantly in recent years.

- All the Nordic countries have experienced both flash flooding and flooding from the sea, sometimes in combination. In the future, we will see more examples of extreme weather and therefore need to plan for both the current situation, as well as prepare for the future. We need to find solutions that have multiple uses,” says Peter Bornhardt, Manager Water Resources Engineering.

Denmark faces major challenges with extensive plains used for agriculture. This means that water runs off slowly, while the soil contains high levels of nutrients and minerals. This is beneficial when growing wheat, but problematic when these nutrients get into the drinking water. Meanwhile, many areas that were originally wetlands have been developed and are now home to many people, but due to climate change and increased rainfall, groundwater levels are also rising, increasing the risk of flooding. Although there are clear requirements both from the EU and at the national level, higher water levels and climate change are sometimes not considered at the local level, which can be difficult and expensive to solve afterwards. WSP has supported clients in several cases to ensure that all requirements are met. A common example is the requirement for stormwater to be managed above ground, where a stormwater pond can be a solution.

Location

Sweden

Our main goal is to bring water management into the construction process early on and reserve space for stormwater management to avoid surprises later on. By addressing this in an early stage, we can also add value to the area by, for example, reducing the carbon footprint and creating habitats for different animals.

Simon Smetana Christensen Experienced Water Resources Engineer

Simon Smetana Christensen Experienced Water Resources Engineer

Christensen cites an example from the Netherlands, where there were challenges with both too low and too high water levels at times. The solution was a system that infiltrated the area with water at low water levels, and at high flows, the same system led the water away from the area.

- “This choice of solution also made it possible to meet other challenges that come with climate change,” says Simon Smetana Christensen.

In Finland, they have also noticed a sharp increase in rainfall, and recent summers have been unusually wet. To prepare for a future where this type of extreme weather becomes more common, WSP in Finland often works to account for a 20% increase in water volumes from rain. This is one way to future-proof sewers and other water solutions.

Today we are quite well prepared for floods and there is an increasing focus on stormwater management. This is reflected in the various reports and data produced to support this work.

Olli Hakala Project Manager

Olli Hakala Project Manager

Hakala has started to break down all the analysis into the three stages of the projects to ensure they get the best possible solution. In the first stage, the pre-design and concept phase, they look at the flood map to get an overview of the risks of an area. In the next phase, the system design, they look at the requirements and solutions that exist, and make sure to add supporting structures such as flood barriers. In the final phase, they go into detail and look at how all the systems will be implemented and how it will affect the area.

- “It's in the last phase that we look at where we need to install flood barriers in the sewer system and calculate how efficient the stormwater pumps need to be,” says Olli Hakala.

Norway's topography has long spared the country from serious flooding, but extreme weather has now made its mark here too. The challenges of managing stormwater in a way that doesn't overload the sewage system have opened the door to creative solutions with buildings that try to delay and infiltrate water rather than just drain it away. WSP has worked with Diakonhjemmet Campus, which due to its location on top of a basement and close to the metro tracks, needed to find a way to handle large amounts of water without affecting the tracks or basement.

We needed to think of water as a resource to be used instead of a problem. To achieve this, we worked in a multidisciplinary way to create multifunctional solutions in close collaboration with the client.

Johanne Grøndahl Klausen Civil Engineer

Johanne Grøndahl Klausen Civil Engineer

Part of the solution was to use the roofs to take care of the water. Instead of flat water-repellent surfaces, vegetation was planted on top of an additional layer of material specially adapted to handle as much water as possible. As the students also wanted to be able to use the roof, it was not possible to plant vegetation over the entire surface, but the water-absorbing layer is also placed under the roof terraces that were built. The water is then transported to the green areas.

- “We are often asked if it is expensive to build a structure that can handle this weight, but in the Nordic countries, we are used to building for wet snow so the structure is not affected,” says Johanne Grøndahl Klausen.

Situated on top of a basement, there was little chance of managing the water at ground level. Instead, stone was chosen as a base through which the water is led. In the limited space above the basement, a system has been installed to direct water away to a stormwater pond. The water is then circulated through a small treatment plant, ensuring that clean water is always available for plants, while the pond enhances the students' experience of the environment and serves as a home for many plants and animals.

-This water is great for watering, and we are also looking at a system to use it to flush the toilets,” says Johanne Grøndahl Klausen.

In total, the building can now handle 570 cubic meters of rainwater using natural solutions.

Sweden has been hit by several severe floods in recent years. What has become clear in these floods is that drinking water is at risk of being contaminated. Here, WSP in Sweden has experience in managing and reducing the risks. The challenges range from the quality and availability of raw water to the capacity of water pipes. Surface water sources, which account for about half of Sweden's drinking water, are particularly vulnerable to contamination during floods, but wells can also be affected by torrential rain. While more water is at risk of contamination due to climate change and extreme weather, many people wonder how long groundwater in Sweden will last.

- One challenge with higher temperatures is that surface water becomes warmer, and the risk of organic pollution increases. This raises the question of whether the water can be purified at an acceptable economic cost. At the same time, higher temperatures mean that more groundwater is needed to irrigate crops, which means that the amount of groundwater may decrease faster than before,” says Anna Dahlman Petri, Senior Principal Business Strategy.

Depending on the situation and needs, municipalities in Sweden have tested different solutions to find robust and more suitable drinking water production. One example is Stockholm, which relies on Lake Mälaren for its drinking water. A study found that although the treatment plants and pumping stations can cope with a flood, other infrastructure is less resilient.

“One of the big insights from the feasibility study of this project was that power stations will be affected before the water system, so even if we could pump water in, there is no electricity to do so if Lake Mälaren were to flood. This could mean that Stockholm would be without drinking water in a flood. So, in addition to looking at capacity, Stockholm Vatten is now investigating the best and alternative locations for water intake,” says Anna Dahlman Petri.

These are some examples of the challenges the Nordic region faces in developing a future-proof and robust water supply. WSP is at the forefront of both planning and technical knowledge in this area.

-“Within our Future Ready® program, we are constantly evaluating and challenging our solutions to ensure that they meet the megatrends in four areas: climate, society, technology and resources,” says Peter Bornhardt.