Stormwater ponds are a technical necessity to cope with new demands in urban development. In the wake of the so-called Weser ruling by the European Court of Justice, cities are being asked to clean dirty water from roads and houses before it is discharged into the environment. At Exercisfältet in Uppsala, we, commissioned by Uppsala Municipality and Uppsala Vatten, have gone one step further to ensure that the dam will also create new values in the area.