Klimaatplein Gasthoes Horst

In the spring of 2021, several species of climate trees will be delivered for planting on Klimaatplein 't Gasthoês in Horst aan de Maas. A unique project in Dutch municipalities, as the square has an innovative underground water management system. The photos were taken in the autumn of 2022.

The 't Gasthoês climate square is located around the 't Gasthoês cultural centre in Horst, the capital of the municipality of Horst aan de Maas in northern Limburg, with a population of 13,000. About 40 trees were used. A varied selection, including ornamental trees with a trunk circumference of up to 45-50 cm, multi-trunk trees and fruit trees. The trees were selected for their attractiveness, biodiversity and insect attraction. All the trees are climate-tolerant, meaning they can withstand heat and drought. Prairie plants from Lageschaar Vaste Planten were also used. All the planting was done by Herman Vaessen.

Jeroen

den Brok

jeroen@vdberk.nl

+31 (0) 413 480 480

+310622662511

Kontakt oss

Water buffering materials

The trees are not planted in standard soil, nor do they receive water in the usual way. In fact, 't Gasthoês has an innovative underground water management system. All the rainwater that falls on the square and the roofs of 't Gasthoês is collected in ZOAK bricks, Rockflow infiltration buffers and a Permavoid buffer system.
ZOAK stands for Very Open Waste Ceramic; it is a recycled ceramic that quickly absorbs and retains rainwater. After a while, ZOAK allows the water to evaporate or sink further into the ground. ZOAK bricks were used to pave the square.
Rockflow is recyclable rock wool that can absorb up to 95% of its own volume of water. Rockflow also releases water over time in a controlled manner. By capillary action, the water benefits the plants or it sinks further into the ground, benefiting the water table. Rockflow has been applied as packs under the ground of the Climate Square. The material has also been mixed through the soil under the planting to see how the planting responds. The plots also have a top layer of lava pellets to retain moisture and stop weeds. This means there is no need for weeding.

Sensors everywhere

Sensors continuously measure how well the underground system is functioning. After all, measuring is knowing. The sensors collect data on the groundwater level, the temperature of the ZOAK clinkers and, for example, the air quality. Thanks to the sensors, Horst aan de Maas can measure exactly what the rainwater is doing in the ground.

The ultimate goal of Climate Square 't Gasthoês is to be climate-proof: both the paving and the planting should be able to withstand certain weather extremes. For example, by absorbing rainfall peaks, reusing water collected during dry and hot periods, and cooling the environment during such periods.

The months after planting in 2021 were on average normal, with enough rain but no real weather extremes, according to KNMI. However, 2022 started quite wet, while the 2022 growing season was characterised by several periods of drought and heat. In that year, the crop was watered 7 times: not a lot in one season in the year after planting. Given the underground innovations and the selected assortment, the municipality could have been satisfied with 4 irrigations in 2022.
The ZOAK clinkers and Rockflow packs are working well for now, but the Rockflow pack under the planting does not seem to be working optimally. In the long term, the performance of the whole system will become apparent. This will require several years of measurement data.

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