In recent years, a new recreational spot has been developing at the city boundaries of Dortmund-Mengede and Castrop-Rauxel-Ickern. Constructed as a flood retention basin (german “Hochwasserrückhaltebecken”, short: HRB), the about 46 soccer fields big property with a retention volume of about 1.1 mil. cubic meters will first and foremost protect the residential areas located downstream. The river Emscher flows through the “HRB”, which helps it establish unique landscapes and provide new breeding and resting grounds for many rare bird species.