WSUD - Water Sensitive Urban Design

The WSUD concept has been known in Denmark since the early 1990s. It refers to the rainwater management principle in which traditional closed piping systems are supplemented with or replaced by various techniques for  local rainwater  harvesting, so-called WSUD elements (see figure 1). Also known as WSUD elements (see figure 1), these techniques are based primarily on attenuation and infiltration and are the only two mechanisms used to determine the dimensions of the drainage system. Evaporation is too slow to play any role in the management of the statistically estimated rainfall, even though the evaporation from infiltration areas and green roofs can play an important role for an area’s overall water balance, including the water table. In addition to attenuation and infiltration elements, WSUD solutions require water transport elements – and in some cases special water treatment elements. As well as the technical elements, WSUD offers obvious opportunities for harvesting rainwater in future, over and above conventional discharge. This would achieve a more natural water balance while creating striking blue and green structures in the urban landscape.

Figure 1: The structure of WSUD solutions is based on these elements (from left to right): attenuation (temporary storage, damming), seepage into soil (infiltration), evaporation, transport and treatment. Pictograms: Marit Reisegg Myklestad