Innovative Turf Technology Offers Cooling and Flood Control Solutions

When summer temperatures soar in the city, sports fields with artificial turf can become dangerously hot, posing health risks. However, artificial turf equipped with an integrated water storage and capillary irrigation system can help cool the surface. 

Researchers at KWR Water Research Institute have discovered that this system can nearly halve surface temperatures, ensuring a safe, reliable, and cool environment for sports activities. According to the researchers, this system could enhance urban rainwater and flood management. The study was published in the journal Frontiers in Sustainable Cities.

It can be difficult for city dwellers to find outdoor space for sports. To accommodate heavy usage over time, more resilient artificial turf has recently taken the place of natural grass in parks and public sports facilities.

However, this approach has drawbacks for both individuals and cities as a whole. Researchers in the Netherlands are now working to alter that by including a capillary irrigation system and subsurface water storage beneath artificial turf sports fields.

Here we show that including a subsurface water storage and capillary irrigation system in artificial turf fields can lead to significantly lower surface temperatures compared to conventional artificial turf fields. With circular on-site water management below the field, a significant evaporative cooling effect is achieved.

Marjolein van Huijgevoort, Hydrologist and Study First Author, KWR Water Research Institute

Cooler Turf and Air

Directly beneath the shock pad and artificial turf is an open water storage layer that is part of the subbase system. Rainwater is stored in this layer of water. The cylinders in this water retention system move the stored water upward and onto the artificial turf's surface, where it evaporates.

The process of evaporative cooling and capillary rise is controlled by natural processes and weather conditions, so water only evaporates when there is demand for cooling.

Marjolein van Huijgevoort, Hydrologist and Study First Author, KWR Water Research Institute

When the sun shines, the surface temperature of conventional artificial turf can reach up to 70 °C. These are high enough temperatures to result in heat-related illnesses and burn injuries, ranging from minor rashes to potentially fatal conditions like heat stroke.

In an Amsterdam field test, the researchers discovered that temperatures decreased when self-cooling turf was substituted for traditional turf. They stated that on an exceptionally hot June 2020 day, the surface temperature of the cooled turf was 37 °C, only 1.7 °C higher than that of the natural grass, while the conventional artificial turf's surface temperature was 62.5 °C.

Above the plots, temperatures also differed.

We found lower air temperatures 75 cm above the cooled plots compared to conventional artificial turf fields, especially during the night. This is a first indication that the cooled plots contribute less to the urban heat island effect.

Marjolein van Huijgevoort, Hydrologist and Study First Author, KWR Water Research Institute

Artificial with Natural Advantages

The cooling turf combines the benefits of natural grass and artificial turf: it is self-cooling, long-lasting, and provides a safe space for sports. It is also nearly as capable of storing rainfall as real grass. The field's ability to retain rainwater reduces stormwater drainage, mitigating the risk of urban flooding. When there is insufficient rainfall, more water can be added straight to the system. As an alternative, one can water it like regular grass.

However, the installation cost may be up to twice as high as that of traditional artificial turf. According to the researchers, a thorough cost-benefit analysis needs to be conducted to determine the actual value of the investment. Initial results, however, are promising.

“People in urban areas, especially children, have a growing need for sport and play facilities. With this work, we show the benefits of the subsurface water storage and capillary irrigation system without negative effects of artificial turf fields,” said van Huijgevoort.

Journal Reference:

van Huijgevoort, et al. (2024) Climate Adaptive Solution for Artificial Turf in Cities: Integrated Rainwater Storage and Evaporative Cooling. Frontiers in Sustainable Cities. doi.org/10.3389/frsc.2024.1399858.