The Gumme is a relic of the ice age course of the Rhine .
It was around 11000 BC until the end of the last ice age . A back arm of the Rhine 100–300 meters wide, which began north of Bonn - Mehlem and extended northwards to Wesseling - Urfeld . Later, a geological seam channel developed from it, which was only fed by slope, smoke and floodwater , with numerous, sometimes seasonal watercourses from the foothills . Today you can see almost only dry valleys and depths of this. As a body of water, the Gumme is only at the Roisdorf Mineralbrunnen, as a channel in the landscape betweenBornheim and Widdig and at Sechtem received.
In Bonn, the Gumme was a marshland until the middle of the 19th century, today the Left Rhine route partly runs in its former bed.
- Gerlach, Kopecky 1997, p. 172.
- Renate Gerlach , Britta Kopecky: What is Gumme? The location of the Roman pottery district Bonn Bastion . In: Archeology in the Rhineland 1996, Cologne 1997, pp. 172–174.
- Renate Gerlach: The importance of the geological history of Bonn for the Romans . In: Manfred van Rey : History of the city of Bonn. Volume 1: Bonn from prehistory to the end of Roman times . Bonn 2001.