Oxygen for improved water quality

The aeration plant
The aeration plant

Over the decades, the water in the Bootshafen (boat harbour) became ecologically moribund because it was cut off from the Kiel Firth. The water quality had to be improved alongside the structural changes to create the basis for an attractive place to spend time.

The Bootshafen includes approx. 4,200 square metres of water, with a volume of approx. 11,000 cubic metres. It serves as a rainwater reception basin and is linked to the Kleiner Kiel and the Kiel Firth by a pipe. Salt water flowing in from the firth and “lighter” fresh water from the rainwater channels running into it form layers, with the rain water above the “heavier” salt water, which reduces oxygen enrichment. For a long time this led to increased formation of algae and rotting processes, which caused an unpleasant smell.

Aeration system sketch
Aeration system sketch

For this reason, a deep-water aeration plant was installed to improve the water quality. This pumps large quantities of air into the water in the form of tiny bubbles, so that there is constant circulation of the water, and it is enriched with oxygen. The high oxygen concentration makes it possible to break down floating organic matter and deposits. This largely prevents rotting processes. The existing link with the Kiel Firth creates an effect that often surprises passers-by at high tide: the water level in the Bootshafen rise to the same height as in the main harbour, and leads to flooding of the lower promenade level with tides over 0.5 metres above normal sea level.

Pictorial material: Kieler Stadtarchiv, Stadt- und Schifffahrtsmuseum, Landeshauptstadt Kiel/Tiefbauamt

Where can you find this point?
Link to the city map