Kiesgrube Wahn
A fenced-off Cologne nature reserve on a former gravel pit in Porz, home to species-rich wetland and aquatic habitats that may not be entered.
since 1988
The Wahn Gravel Pit (Kiesgrube Wahn) is a strictly protected nature reserve in Cologne's Porz district, formed on a former sand and gravel extraction site. The old pit has since developed into valuable wetland and aquatic habitats that today offer refuge to a wide range of rare animal and plant species.
At a Glance
- Location
- Porz district of Cologne, on the Bergische Heideterrasse (Bergische Heath Terrace)
- Protection status
- Nature reserve (N 16), established in 1988 on a former extraction site
- Area
- 5.43 hectares
- Origins
- former pit for the extraction of Quaternary sands and gravels
- Wider context
- part of the network of gravel-pit habitats around Cologne
- What makes it special
- a species-rich refuge with numerous Red List species; the eastern body of water is designated a Habitats Directive (FFH) habitat type
- Access
- fenced off, entry not permitted
Age comparison
Age compared with other places in Cologne.
Location & Landscape
The reserve lies in the south of Porz and belongs to the Bergische Heideterrasse. On the floor of the former pit, two larger bodies of water have formed to the east and south, reaching down to the water table; a further pond lies on the northern side. On the sandy, gravelly bare soil of the pit floor — which is kept clear on a regular basis — a site-typical vegetation has established itself, in places alternately damp, in places dry. Around the edges a willow-dominated mixed deciduous woodland with largely natural vegetation has grown up, while the old pit walls lie exposed on the sunny northern and north-eastern slopes.
Protection Status & Goals
The 1988 designation aimed to preserve the nutrient-poor bare soils and to encourage the natural development of the wetland and aquatic habitats. A first biotope management plan was drawn up as early as 1990, followed in 2015 by a revised care and development plan. The proposed measures include staggered mowing to keep the pit floor clear, regular cutting back of the steep banks, clearing vegetation from the smaller northern pond, removing non-native woody plants such as black locust (Robinia) and staghorn sumac, and creating temporary small pools for dragonflies.
Wildlife
Site monitoring by the NABU Cologne/Leverkusen station in 2012/2013 documents the reserve's biodiversity. Among the birds, 43 species were recorded, 29 of which breed here — including twelve species on the Red List or the early-warning lists, such as nightingale, yellowhammer, starling and moorhen. Kingfisher, goshawk, sparrowhawk and barn swallow appear as feeding visitors. Thanks to the high density of insects and old tree cavities, the site is an important hunting ground and summer roost for bats; seven species have been confirmed, among them Natterer's bat and whiskered bats. In addition there are four amphibian, seven grasshopper and twelve butterfly species, as well as 20 dragonfly species, three of them Red List representatives. The waters are home to the endangered swan mussel (Anodonta cygnea).
Plant Life
The vegetation survey recorded 190 higher fern and flowering plants, nine of them Red List species. The highlights include spring cinquefoil (Potentilla neumanniana), rarely found in Cologne's gravel pits, along with changing forget-me-not and creeping forget-me-not, common and lesser centaury, and the rough clove pink (Dianthus armeria). White water lily grows on the open water; the vegetation of the eastern lake is classified as a Habitats Directive (FFH) habitat type.
Access & Rules
The nature reserve is small in scale and highly sensitive to human disturbance. For this reason it must not be entered and is fenced off; on-site information boards point out the access rules. Watching and experiencing the reserve is therefore only possible from outside the fence — entering or crossing the grounds is expressly prohibited.
Map
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Address
Frankfurter Str.
51147 Köln
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Sources & links
Auto-generated, last verified: 2026-08-09
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