Borkener See

Oligotrophic, nature reserve, resting place for migratory birds

The Borkener Lake is an artificial, in the course of lignite coal mining area in Borken, arising lake south-west of Borken in the Schwalm -Eder district in Hesse, Germany. Because of its ecological importance, including as a bird resting area, the lake is including its riparian zones under protection.

• 2.1 Water Quality
• 2.2 Protection Status

Geography

General

The Borkener lake is Schwalmaue, a part of the West Hessian Depression, and is an important resting place for migratory birds. The water surface is about 177 m above sea level. The area of ​​the lake is approximately 139 ha Its length is about 1250 m and the width of about 780 m. At the lake bordering the city and the districts of Borken wet Erfurth and Trockenerfurth.

Formation

Emerging from the former lignite mining pit Altenburg IV was created in the course of restoring 1975-1992 Borkener the lake. During the funding period (1954-1975), the operating area of ​​the open pit comprised 234 ha gave about 70 million cubic meters of overburden were moved around 9 million tonnes to promote lignite.

In the initial phase of reclamation consideration was given to whether the filling of the lake Borkener should not be accelerated in order to use it as a recreational area with weekend homes can. In studies at the beginning of the filling but it turned out that the lake is slightly basic and also low in nutrients ( oligotrophic ) was. It was then apart from the acceleration of the filling and initiated the designation of Borkener lake as a nature reserve.

Dramatic Landscape

In the southeastern mining sector, in the area of ​​the former underground Bausenwein reason - an area with recurrent extensive cuts and Böschungsrutschungen, about 20 ha for designation as a conservation area have been provided already. This area was referred to as "dramatic landscape," because in this area the fauna and flora constantly had to adapt to new circumstances.

Wetland

In addition, in the north of lignite opencast mine a wetland with approximately 5 hectares has been created. Special emphasis has been on a long shoreline with about 1.3 km in length, with a mere 2.6 acres of water down.

Use

The entire catchment area of ​​the lake is under protection Borken. Together, the Federal Republic of Germany and the State of Hesse have been bought by the foundation " Hessischer nature " to the land concerned. This should be prevented on the agricultural use of nutrients entering the lake.

Ecology

BfN profile

Water quality

Unlike most of the larger lakes in the state of Hesse Borkener lake is oligotrophic. Also, it is not expected due to its size so that it is rich in nutrients ( eutrophic ). In addition, he has, in contrast to similar mining lakes in their " teenage stage " a basic pH value. Thus he gives up this habitat specialized plants and animals a refuge.

Protection status

The entire lake including its riparian zones is under protection. Swimming, fishing and other water sports activities are therefore not permitted. The approximately 350 -acre nature reserve Borkener lake is an important resting area for waterfowl and waders. A leading around the lake loop trail with multiple views stalls invites for nature observation.

Hydrological data

The catchment area of ​​the lake is about 350 hectares Borkener including the sea area of 139 ha, the maximum water depth is 52.5 m. Its volume comprises 35,000,000 m³. The lake is fed by Borkener layer sources of sandstone with 72 l / s (= 104 m³ / day). The pH varies between 7.5 and 9