Last May two thermal walks were conducted with participants in Hengelo to test five different locations where the municipality has implemented blue/green infrastructure. While some findings were in line with expectations, large trees with more shadow providing a more comfortable environment than small trees, the results on water fountains were more difficult to interpret.
The summarized results: "dense-canopy trees were the most effective intervention, lowering Wet Bulb Globe Temperature (WBGT) by up to 5.3 °C and having the highest comfort ratings. Sparse-canopy trees also provided substantial cooling (up to 4.1 °C decrease in WBGT) and are more feasible to plant with their lower spatial requirements and easier to implement in narrower streets of Hengelo’s city centre. The green square presented moderate cooling and mostly positive thermal comfort ratings, although, its use is spatially and financially constrained. Water features were less effective, since the sensors at the water pond recorded consistent warming effects despite positive feedback from the participants, while the water fountain recorded measurable cooling, but had low perceived comfort, as it lacked shade and surrounding vegetation."
You can read more details in the thesis by Katarzyna MartaOłdak, titled 'Evaluation of the Local Cooling Effect of Existing Green-Blue Infrastructure in Hengelo Through Thermal Walks', at the UTwente repository.
