A much-used method of storing water underground is the so-called gravel or lava box, also known as an infiltration box. A lava or gravel box consists of a thick layer of stones. The gravel or lava stone retains the water and ensures that the rainwater is slowly released. One disadvantage of this type of box is its limited absorption capacity. Gravel and lava stone have a porosity of approximately 35 to 45%. This is the percentage of the material that is available for water storage. This means that many or deep trenches must be excavated in order to apply this infiltration method effectively.
An alternative with a higher porosity is an infiltration crate. This has a porosity of 95%. Infiltration crates are also used to buffer water and release it slowly back into the ground. Stacking the crates gives a high buffering capacity. One disadvantage is that the crates, just like the lava and gravel boxes, must be packed in geotextiles. In theory, the infiltration speed of water into the subsoil is good. In practice, the bottom surface of the crates silts up, considerably reducing the infiltration capacity.
Rockflow provides a solution: the benefits of stone wool
How can water be stored more efficiently, now that the importance in smart water management is increasing? An infiltration solution using stone wool can provide a solution. Stone wool has been used successfully as insulation material for some eighty years now. It is sustainable, versatile and has a long life. With the innovative Rockflow infiltration system, which is made up of stone wool elements, the water is absorbed and released gradually into the ground. With an absorption capacity of 95 %, stone wool has a considerably higher absorption capacity than, for example, lava stone and gravel. As a result, much less material is needed to reach the desired buffer volume. Furthermore, thanks to its fine fibre structure, no geotextiles are needed to keep sand out. This ensures that the entire ground surface is available to be infiltrated.