Gravel has been mined in the Lower Rhine Bay since industrialization. Large "holes in the landscape" and industrial structures of sometimes bizarre beauty have been and continue to be created here. In the beginning, people dug and excavated right down to the groundwater. This is how the "Herseler See" was created, for example. In just a few years, nature healed these landscape wounds under its own power, creating lush flora and fauna. Today, the lake is a nature reserve. A brief episode - given the age of the gravel deposits from the ancient Rhine and North Sea. They were formed around 65 million years ago.

Excavations down to the groundwater are no longer permitted because they endanger the drinking water supply of the conurbation. The gravel is now only excavated to a depth of eight meters and the pits are then slowly backfilled and recultivated.

The gravel and sand deposits in the Rhenish Bight are the largest in the state of North Rhine-Westphalia.

As part of the Green C project, the Link trail system around Lake Hersel is being expanded and two landscape gates and a station on the subject of "gravel extraction" are being built.