As the climate changes and the number and frequency of rainfall events increases, so does the need for intelligent rainwater management solutions. This White Paper presents insight into lessons learned from Danish stakeholders within rainwater management and Sustainable Urban Drainage Systems (SUDS).

From Climate Adaption to Green Urban Development

Many factors such as population growth, increased pollution of available drinking water, floodings and more frequent periods of droughts encourage an optimised use of our rainwater. In addition, there is an increased focus on reducing the urban heat island effect by cooling the cities locally and on reducing pollution of surface water, securing sufficient drinking water supply and building cities that are attractive for people to live in.

According to the projections from the UN’s Intergovernmental Panel on Climate Change, many countries will experience a change in precipitation over the coming years with more frequent rain of high intensity and longer periods of dry weather. When combining these projections with the fact that many cities are covered with extensive areas of impermeable surfaces, the need for infiltrating or delaying rainwater at the source becomes even more urgent to reduce the risk of flooding.

Using Rainwater as a Resourse

In this white paper, we present the various possibilities of using rainwater as a resource as opposed to considering it as something that simply needs to be hidden in sewers. The aim of using rainwater as a resource is partly to reduce the risk of flooding by optimising the rainwater management and partly to contribute to creating more green and liveable cities.

The key is to have the right tools and models to ensure the right prioritisation of efforts and sufficient designing of the various rainwater management solutions as well as involving the right stakeholders at the right time throughout the process. Several benefits can be achieved by using rainwater to help cities keep a sustainable water balance through various treatment technologies. These ensure proper treatment of rainwater to allow for infiltration to the groundwater aquifers or discharge into the local water environments such as lakes or streams. Finally, in areas suffering from water scarcity, local rainwater harvesting and recycling can be a valuable source of non-potable water which can be used for watering plants, flushing toilets or washing clothes instead of using the precious drinking water.

Partners featured in this publication