Sustainable and climate-specific rainwater management by water-permeable pavements

Starke, P., Göbel, P., Coldewey, W. G.
University of Muenster, Department of Applied Geology; Corrensstr.24; 48149 Muenster; Germany; starkep@uni-muenster.de

The temporal variance in the availability of (rain-) water is characteristically for the Middle East climate. In contrast, the water demand caused by the fast growing population of the United Arab Emirates increases. Natural water resources are already used over capacity. The groundwater recharge is low, while a part of stormwater is discharged by surface runoff. By this, a big amount of water is lost for water supply. Water-permeable pavements can increase the groundwater recharge and prevent surface runoff in urban areas.

In an actual research project, the evaporation rates of water-permeable pavements were measured and afterwards optimized. The evaporation rates of different water-permeable pavement designs were detected with the tunnel-evaporation gauge and are completed by several laboratory tests.
The results show, that the evaporation rates from normal water-permeable pavements are already 16% higher than from impermeable pavements. Furthermore, the results allow developing new water-permeable pavement designs, which are adapted to the climatic and to the regional hydrological conditions. By these new designs, it is possible to…

a)
… increase the evaporation about further 20 % (in regard to normal water-… permeable pavements), to get a more natural-near water balance and prevent sultriness and dry heat in urban areas.
b)
… decrease evaporation rates, even lower than from impermeable pavements. In regard to the high permeability of the pavements. This will lead to a higher groundwater recharge.
c)
…to store water in the sub-structure layers. About 29 l/m2 can be retained against gravitation. If this type of pavement is built on impermeable undergrounds, the storage capacity is even a multiple higher. This water can be shielded from evaporation by porous paving stones above and can be used for irrigation.
Based on this knowledge, water-permeable pavements can be used as one instrument in regional-specific rainwater management and ensure a prospective water supply.