Hangeweiher

The Kaiser-Friedrich-Park is a park in the south of Aachen named after the German Emperor Frederick III, who died in 1888. The park was laid out together with the adjacent Kaiser-Friedrich-Allee between 1908 and 1910 according to plans by Aachen's city garden director Weßberge, after the city council had approved the construction costs of 180,000 Reichsmark. Among other things, the park was equipped with rare trees from the stock of the Aachen cloth manufacturer and amateur dendrologist Friedrich von Halfern, who had already had the family's own Von Halfern Park laid out.

Conceived as a public park, a small reservoir fed by the River Pau, the Hangeweiher, was initially redesigned as a barge pond. This was created in the 18th century as Aachen's first rainwater retention basin. The Hangeweiher open-air swimming pool was built in the immediate vicinity and its large pool was also used for sports competitions. The adjacent meadows were used as a so-called air bath. Originally, a soccer pitch in the west of the park and two children's playgrounds were added to the green area. The horticultural concept envisaged the creation of terraced flowerbeds, which visually gave the impression of an enclosed garden, but at the same time were easily visible.

The park was extended to the southwest in the 1920s by landscaping Kaiser-Friedrich-Allee. If you followed the course of the Paubach stream to the end of Kaiser-Friedrich-Allee, you would come to the Tritonenbrunnen fountain created by Carl Burger in 1906/07, which was fed by water from the Paubach. This fountain was moved from there to Kaiser-Friedrich-Allee in 1923 as part of the redesign of the station forecourt. The Pau enters the park - today relatively inconspicuously - via an artificial water cascade. The Aachen Observatory and the park of the old hospital are located in the immediate vicinity.

To this day, the park has remained largely in its original state despite the damage caused by two world wars. A boat rental service has been established on the pond and the playgrounds have been supplemented with a roller-skating rink.

Several tennis courts were also added. The outdoor pool, which still exists today, is the only outdoor pool in the city of Aachen and the only one with an official 50-metre competition track in the Aachen city region. Sufficient lawn areas have been left within the park, which are used in summer as sunbathing areas by those seeking relaxation. In addition, a small restaurant provides refreshments for visitors to the park.

The "predecessor pond" of the Hangeweiher was formerly used as a storage pond for the Weiße Mühle. The Weiße Mühle was first mentioned in writing on 30.06.1563 and was formerly a barn; at the beginning of the 19th century a spinning mill, oil and grinding mill, at the end of the 19th century a cloth factory and spinning mill).

The Pau itself was first mentioned in a document on 24.10.1720. For the water stored in the Hangeweiher pond, the people entitled to the Paubach had the right to use water from the Paubach and its tributaries and to take it from the Hangeweiher pond by means of a pressure pipeline and feed it to the individual people entitled to the water. The right to use this water was confirmed by a series of documents, the oldest of which is the imperial register in the town archives. The next document was the protocol of the "Wassergerechtssame" from 1821 and 1863. On the occasion of the conversion of the open Paubach course into a pressure pipeline, the Paubach statute was replaced in 1899 and renewed in 1929 by the Paubach water roll. When the Paubach Water Association was founded in 1971, the Paubach Water Roll was repealed and the right expired. The Paubachwasserverband had also taken over the maintenance of all waters, ponds and canals along the Pau.

The City of Aachen, as the legal successor to the Paubach Water Association, had assumed the water rights to use and consume the water collected in both basins (Hangeweiher as a swimming pool and Kahnweiher) and to dam up and collect the water from the Paubach and all other tributaries of the Hangeweiher in the two basins of the Hangeweiher. The only water user in 1993 was the Zimmermann company.

In 1955, the Hangeweiher was desilted and the entire bank area (3700 m²), with the exception of the section above the island, was concreted with a bed width of 10 - 15 meters.

Water is taken from the outlet tower of the Hangeweiher (Pau) via a pressure pipeline to supply the inner-city fountains via the Paubach pressure pipeline. The following municipal fountains are supplied with water from the Hangeweiher: Wehrhafter Schmid, Türelieschen, Fischpüddelchen, Hermann-Heuch-Platz, Maria Lörsch Platz, Karlsbrunnen, Mariensäule.

The total water surface of the Hangeweiher was determined to be 14,500 m².

The volume is 22,490 m³.

The overflow edge at the tower is 191.80 m above sea level according to the 2020 survey.

This means that the normal water level will probably be 191.82 m above sea level.

The lowest point is at 188.84 m above sea level, which results in a maximum normal water level of 2.98 m.

The vertical drop of the bank wall is approx. 1.35 m from the upper edge of the concrete wall (192.07 NHN) to the concreted pond bottom (also in the area of the landing stage).

The operational outlet created in 2020 is at 190.74 NHN. The catchment area covers 2.479 km².

The inflow at HQ50 is 2.23 m³/s.

The inflow at HQ100 is 2.45 m³/s.

The dam is operated via a spillway with two openings.

The Hangeweiher is fed into the system via

• the Paubach and Klotzweider Bach on the southern bank,
• the Kannegießer Bach on the western bank,
• the Brockenfeld rainwater drainage system on the eastern bank via a DN 500 pipe with a discharge volume of 189 l/s in accordance with water legislation
• the Kaiser-Friedrich-Alle stormwater drainage system on the southern bank via a 900/1200 mouth profile with a discharge rate of 800 l/s

The Pau, including the Klotzweider Bach, has a normal water inflow of approx. 25 l/s. The Kannegießer Bach flows in with a normal water volume of 1-2 l/s.

The dry weather discharge of the dam is led to the overflow of the spillway. The height of the permanent reservoir target

(full water level = Zv) is 191.82 m above sea level.

The reservoir targets for ZH1 and ZH2 have not yet been determined, as there is no dam structure due to the burial in the subsoil and therefore no investigations in accordance with DIN 19700 are required.

The overflow or outlet of the dam is into the piped Paubach DN 600 with an extension to DN 1000 after 42 meters, which flows after 3.12 kilometers into the piped Wurm at Rehmplatz and then after a further 0.94 kilometers only comes to light again downstream of Europaplatz.

The maximum capacity of the DN 600 drain is 363 l/s.