Ever wonder about the origins of this tranquil spot? This is the Kollauteich, a seemingly ordinary pond with a history stretching back to the Middle Ages. The Kollauteich is a remnant of the “Düwelsmoor” also known as Teufelsmoor. This was once a marshy lake that dried out long ago.
Now, standing before the Kollauteich, you might not realize it’s not actually the source of the Kollau stream. The Kollau begins its journey about 450 meters away near Vielohweg. The spring itself is on the other side of the A7 highway. So, the Kollauteich is more of a rest stop than a starting point for the Kollau.
Imagine this area centuries ago. The Düwelsmoor was a wild place. Over time, it transformed and the Kollauteich remained. Today, it covers about 0.63 hectares. It has a length of 110 meters. The Kollauteich has a circumference of 320 meters and reaches a maximum depth of five meters.
The Kollauteich plays a crucial role in flood management. Since 2011, the Kollau has been diverted around the Kollauteich. During heavy rains, when the Kollau overflows, the Kollauteich acts as a reservoir. This prevents flooding downstream.
The Düwischgraben is the only stream that flows into the Kollauteich. Technically, the Düwischgraben is a tributary of the Kollau. But, because the Kollauteich and Kollau connect sometimes, they exchange water. This makes their relationship a bit complicated.
The Kollau itself has an interesting story. Around 1789, the Kollau was expanded from its source to where it meets the Mühlenau. Back then, the name “Kollau” only applied after that meeting point. Maps from the 19th century show the Kollau starting at the Brookgraben. It originated from a network of streams including the Düwischgraben and Vielohgraben.
The Kollau winds its way through Schnelsen, Niendorf, and Lokstedt. It finally joins the Tarpenbek near Groß Borstel. The water flows into the Eppendorfer Mühlenteich and then into the Alster river.
Historically, the Kollau has seen changes. A section in Lokstedt is now called the Alte Kollau. It is now a separate stream that flows into the Kollau. Part of the Kollau near the Schillingsbek used to belong to the Schillingsbek itself. The Kollau’s final stretch once flowed through a pond before reaching the Tarpenbek.
Even with some human alterations, the Kollau is recognized as a near-natural stream. It does face challenges from straightened banks and flood control measures. But there are still areas with rich vegetation. These natural sections are protected under Hamburg’s conservation laws.
So, next time you pass the Kollauteich, remember its long history. It’s a small pond with a big story. It’s a reminder of Hamburg’s changing landscape. It also shows Hamburg’s efforts to balance nature and urban development.