A Water Retention Landscape is made up of a series of interconnected retention spaces, from pond-sized up to lake-sized, in which rainwater collect behind a dam constructed from natural material. The retention spaces themselves are not sealed with concrete or any other artificial film, so the water can slowly but steadily diffuse into the earth."
Banks are never straightened or reinforced, but created with meandering forms with both steep or gently sloping parts so that the water can swirl. At least one part of the shore is planted with aquatic and waterside plants.
Bernd Mueller, "Water Retention Landscapes," Resurgence and Ecologist, Jan/Feb 2012