Reduce flooding risk in cities in a sustainable way
For this interview, we talked with Rickard Granath – Stormwater Solution Manager, and Jean Saarinen – Stormwater Sales Manager at Uponor Infra. Our fireside chat was recorded at The World Water Congress 2022, in Copenhagen, Denmark.
Welcome to the Urbanista blog where we discuss water management challenges of Nordic cities. From safe drinking water distribution and stormwater collection, to building sustainable urban living environments. The Urbanista blog is based on the Urbanista podcast episodes. This post is based on the interview with Rickard Granath – Stormwater Solution Manager, and Jean Saarinen – Stormwater Sales Manager at Uponor Infra. Our fireside chat was recorded at The World Water Congress 2022, in Copenhagen, Denmark.
How do we take care of the most precious element (water) that we have on our earth?
It seems that often the current infrastructure is not enough. How do we build new things to both future proof and be sustainable? What are the challenges that you are seeing from the perspective of the customers that you are helping?
How to reduce flooding risk in cities?
(RG: Rickard Granath, JS: Jean Saarinen)
RG. Starting with rain intensity, we are seeing more extreme events, more intense rain but also longer periods between rain. So, it creates challenges with a lot of rainfall but also droughts. We are building cities on top of an old network, so capacity is a challenge. When you have a rain event, it will wash the city clean and take pollution (traffic pollution and building materials, etc) with the stormwater to the recipients (lakes, ponds, seas, etc.) which may then cause a lowering of the status in these recipients.
So, this polluted water needs to be filtered?
Yes. There are solutions, but one challenge is the space to build these solutions. They could require big facilities, so compact solutions are also important.
How do we squeeze our solutions into the system?
JS. We have solutions for treatment and sampling. Of course, we need to protect the recipient so we need to go upstream and select some good solutions for those projects, rain gardens for example, to help the cleaning of stormwater; retention tanks to collect runoff and control the speed of the flow back into the water system; and many others like stormwater chambers and pipe solutions that can help clean heavy metals and phosphorus. This is really important because it’s the future of our children and coming generations who want to swim in clean water in the lakes.
You mentioned sending water downstream. Are there regulations that control this release?
JS. Usually the city regulates how many litres per second can be released into a river or pipe-system, so we don’t get floods upstream. Therefore, the retention tanks are really important. Retaining water is a much cheaper way to save the city from floods, instead of changing all the pipe network.
RG. These systems help when using old or pre-existing water management systems, but in practice, most systems will be put in place when you are building a new part of the city.
So how do you tackle the problem of a new development?
RG. Well, you would like to build ponds, green areas, structured soils, swales and so on, and we can provide components for that. There can be a lot of cost in maintaining these facilities, but we also have smart components upstream to collect sediments and help reduce the cost of that kind of facility.
Money is always a problem. If most infrastructure is paid for by municipalities, who are operating on a tight budget, how should their funds be allocated?
JS. Of course, the cost is an issue, but in the end, it is the environment we need to save. We need to raise awareness of the issue, and make it a discussion topic to understand it more. We have solutions for everything, and we can invent new solutions as well, and I feel it’s my responsibility to create those with the end result of saving the environment.
What does it mean to make a storm water system sustainable?
RG. Stormwater systems are by their nature sustainable, but sustainability can also be considered in the choice of materials and installation calculations. We can use fossil-free plastics for example, to lower the carbon footprint by up to 70%. The environmental product declaration (EPD) shows the environmental impact not only from the product but also from the production chain, installation and lifetime, so different products can be compared based on their environmental impact.
How do we consider sustainability in the operating and running of the systems?
JS. Stormwater can also be considered a resource. Many times, it can be used instead when watering green areas and flowers or for flushing the toilet. Currently, we are often using drinking water which is a waste. Naturally, you have to consider what the use is for. For example, watering green areas should be okay, edible products maybe not. So, this has to be considered. There are different aspects of reusing, but there are also simple ways to reuse a lot of water.
RG. You may need two separate systems for different types of water, but it’s a possibility and interest is growing because water is a resource and times of low rainfall are increasing. There are so far only small projects that are doing this, and some football fields reusing water, but it is coming.
What is the most pressing challenge we need to focus on as an industry? Where do we start?
RG. Because the question is so big, it seems many people in the industry are waiting for a perfect solution that solves everything. But how do we eat an elephant? In smaller pieces. Let’s try smaller projects and learn from the results: make pilots, and together with industry and society research we can increase the cooperation together. We are becoming a member of DRIZZLE - Centre for Stormwater Management, and we should soon have PhD research on stormwater. Maybe in the next interview we can reveal some of the results.
JS. One final challenge I must mention, is having clear regulation. Then the development in this area will speed up.