Leyenweiher

Leyenweiher in Troisdorf is one of the oldest cultural ponds in the Wahner Heide and one of the quietest places to watch water birds, dragonflies and a classic wetland right on the edge of town. The pond sits in the southern part of the nature reserve, between woodland, heath and the trails that link Troisdorf with Fliegenberg, Telegraphenberg and Burg Wissem. Unlike a leisure lake, Leyenweiher is not for swimming. Its value is the still shoreline, the water-lily beds and the few permitted approaches where mallards, other water birds and, in summer, the blue emperor dragonfly can be seen. Benches turn the shore into a natural rest stop on circular walks. Anyone who wants the Wahner Heide as a water landscape as well as open heath will find that mix of cultural history and species richness at Leyenweiher.

The pond covers about 0.9 hectares. The banks are relatively steep and carry only a narrow reed belt, because the water was dammed artificially. Between reedmace, reed canary-grass and sedges, small windows open onto the surface. White water lilies cover parts of the pond in high summer. In spring and autumn, birds on passage shape the scene. Paths around the pond belong to the marked network of the Wahner Heide. The rule to stay on trails is absolute: the area was a military training ground for a long time, and unexploded ordnance cannot be ruled out off the paths. Staying on the permitted routes is how visitors see one of the dragonfly-richest ponds in the heath without damaging the shore.

History of Leyenweiher

The history of Leyenweiher does not begin as a natural lake but as a piece of historic water engineering. Before 1845 the Leyenbach was dammed so that floods could be controlled more easily. The basin was also used, time and again, for fish farming. That makes Leyenweiher one of the oldest cultural ponds in the Wahner Heide, alongside waters created as mill ponds, fish ponds or by peat and clay digging. The artificial shape explains the steep bank and the narrow zone of reed. Common plants here include broad-leaved reedmace and reed canary-grass, together with the regionally endangered tufted sedge. In deeper water, sizable stands of white water lily grow.

The later story of the pond is tied to the use of the whole Wahner Heide. Prussian troops trained here from 1817, and the range grew over the 19th and 20th centuries to several thousand hectares. Drainage, embankments and military infrastructure changed bogs and wetlands severely. Ponds such as Leyenweiher nevertheless survived as open water and later became witnesses of that cultural landscape. Today the fish stock is again of a near-natural size. Precisely because intensive pond farming receded, the water could become one of the richest dragonfly sites in the heath. About 15 species are recorded, including the blue emperor, on the wing from the beginning of June to the beginning of September. Mallards gather in noticeable numbers, partly because people feed them, although feeding should be avoided in the reserve.

The Wahner Heide was first designated a nature reserve in 1968. It is now both a Habitats Directive site and an EU bird protection area, and part of the Natura 2000 network. Around 700 red-list species, about 100 breeding bird species and more than 2,500 beetle species are cited for the heath as a whole. Leyenweiher stands for the wet side of that diversity. Beside open dunes and heather, still waters, reedbeds and carr woodland are why the area between Cologne, Rösrath and Troisdorf ranks among the most species-rich reserves in North Rhine-Westphalia. The viewpoints on the shore are not a built visitor centre. They are the few permitted approaches where this history can be read and watched at the same time.

Highlights of Leyenweiher

The main highlight at Leyenweiher is water lilies, water birds and dragonflies in a very small space. In summer, white water lilies lie in substantial beds on the surface and make the pond one of the strongest photographic stops in the southern Wahner Heide. Dabbling mallards are part of the everyday scene, swans are regularly reported by walkers, and with luck a turtle surfaces near the bank. Benches at the small approaches serve as rest points without any large boardwalk or viewing tower. Visitors who stay quiet see more than visitors who only pass through.

Dragonflies are the second reason for a deliberate stop. Leyenweiher is regarded as one of the dragonfly-richest waters in the Wahner Heide. About 15 species are named for the pond. The largest and most conspicuous is the blue emperor, flying from early June to early September. Smaller species hunt between club-rush, reedmace and rushes. Frogs and a near-natural fish stock share the same habitat. Dense scrub surrounds the shore, so the views are narrow. That tightness is exactly what makes the spots worthwhile: you are not standing on a panorama terrace above the landscape, but right beside the water.

For walkers, Leyenweiher is a fixed stage on the Fliegenberg Tour and on other loops between Burg Wissem, Fliegenberg, Telegraphenberg and the Agger. The Fliegenberg Tour is about 8.4 kilometres and is marked with a heath-sheep symbol. From the pond, heathland, the sandy Fliegenberg and the view toward the Sieg valley can be joined in one outing. Brunnenkellerweg leads past the water to the remains of the spring cellar, where the Heimbach was once dammed to keep milk cool. Arriving from the car park at Aggerstadion or from Taubengasse, the pond is reached on forest and sand paths without much climbing. In late summer the violet heather is only a short walk away. In spring, yellow gorse colours the open ground. Leyenweiher remains the wet counterpoint to the dry sand heath.

Opening Hours, Tickets & How to Get to Leyenweiher

Leyenweiher is open all year and free of charge. There is no ticket office, no fixed opening time and no admission fee. The pond lies inside the Wahner Heide nature reserve and may be reached only on marked paths. Red-topped posts show the permitted routes. Leaving the paths is forbidden, both because remnants of munitions cannot be excluded on the former military land and because banks, reedbeds and breeding sites are protected. Dogs must be kept on a lead, litter taken home, plants left unpicked and animals not fed. Camping, barbecues and fires are not allowed.

By car, the most practical starts are the walkers’ car park behind Aggerstadion on Taubengasse and the car parks on Altenrather Straße at Fliegenberg. Brunnenkellerweg leads close to the pond. From Burg Wissem, Burgallee 1, 53840 Troisdorf, Leyenweiher is also easy to include in a short loop. By rail and bus, travel to Troisdorf station. From there several lines, including buses toward the Wahner Heide, Fliegenberg and Altenrath, serve the entrances to the reserve. The walk from the chosen car park or stop to the shore is short to moderate, depending on the loop. Sturdy shoes help, because sandy sections and soft ground after rain are common. A simple pause by the water takes 15 to 30 minutes. A combined walk over Fliegenberg and Leyenweiher takes about two to three hours.

The best season for dragonflies runs from June to early September, water lilies peak in high summer, and heather on the neighbouring heath flowers in August and September. In winter the pond remains an open sheet of water in an otherwise bare heath, as long as the paths are passable. There is no official ticket page, because access is free. Current notes on closures and on behaviour in the reserve are published by the City of Troisdorf through the Burg Wissem portal.

Attractions Near Leyenweiher

Immediately around Leyenweiher are further stops in the southern Wahner Heide. Fliegenberg holds the largest continuous carpets of heather and the view into the Sieg valley with the abbey on the Michaelsberg. Telegraphenberg, at about 134 metres the highest point of the heath, recalls the optical telegraph station on the Berlin–Koblenz line from 1833 to 1852. Ravensberg, with the Ringelstein and the remains of the Franciscan hermitage founded in 1670, lies on the same Fliegenberg Tour. Kronenweiher, already protected in 1914, shows as a former heath bog the slow return to silting up.

Burg Wissem joins the nature visit to culture. The Wahner Heide portal offers a free exhibition on trails, military history and species diversity. The same grounds hold the picture-book museum and the deer park. The forest and bird park, and the woodland inn Heidekönig on the Mauspfad, add food and further wildlife watching to a longer day. Toward the town centre, the TROPFAD trail and the Agger floodplain are quickly reached. In Altenrath, the Wahner Heide information centre stands on Flughafenstraße. Cologne and Bonn are each about 20 minutes by car, and Cologne/Bonn Airport is closer still. A stop at Leyenweiher therefore turns easily into half a day of water, heath and town history.