A mine by the Stern cement works

Lake Szmaragdowe (the Emerald Lake) lies in Szczecin's Zdroje district, within the boundaries of the Szczecin Landscape Park “Beech Forest” (Szczeciński Park Krajobrazowy “Puszcza Bukowa”). According to Wikipedia it is an artificial lake. It formed in the pit of a former chalk and marl mine, worked by the nearby “Stern” Portland cement factory, founded in 1862. In the area of today's lake, industrial extraction of a marl raft (porwak) about 40-60 metres thick began in the same year. A porwak is a block of rock torn off and carried by an ice sheet.

At first the raw material was extracted above the groundwater level, later the pit began to be deepened until it was about 20 metres deep relative to the surrounding terrain. The output was carted to the cement works on today's Batalionów Chłopskich Street, and the unneeded overburden was dumped on a heap that we now call Wzgórze Widok. The mine bore the German name Katharinen Kreidegrube. According to Wikipedia, the owner of the “Stern” cement works was Albert Eduard Toepffer, who in 1880 initiated the construction of the artificial grotto “Za Łukami” north-west of the lake. The plant was later managed by his son Helmut.

16 July 1925

According to Wikipedia, on 16 July 1925 a layer of water-bearing sands was struck in the southern wall of the pit. Water rushed in through it and flooded the open-cast working. The water emerged from beneath a high, roughly 50-metre vertical wall of marl. All the workers present at the time managed to escape. At the same time part of the pit wall collapsed and a landslide cone formed. A second landslide in the southern part occurred in 1959 and reduced the surface of the lake by about 0.4 hectares. The same date also appears in information about the Beech Forest cited by the management of the landscape parks complex.

According to Wikipedia, the remains of mining machinery and equipment still lie on the bottom, and at the shore rises a concrete bridge left over from the track of the light railway that carried the output away.

Where the emerald colour comes from

The lake owes its name to the colour of the water. According to Wikipedia it results from the content of calcium carbonate, coming from the dissolution of calcite. Before 1945 the lake was called in German Herta See and Kreide See, that is, Chalk Lake. Because of the large amount of calcium carbonate in the water, intensive biological life has not developed. There are no reeds or rushes on the banks, so waterfowl are rarely seen here.

Wikipedia gives the following dimensions: 289 metres in length, up to 165 metres in width, 18 metres in depth and 28,540 square metres in area, with the water surface at 42 metres above sea level. Groundwater still flows into the lake, which can be seen when walking along the path right by the shore, and its excess drains into a manhole by the viewing bridge. The steep walls of the former pit are still changing: new gullies, landslides and niches appear. The Beech Hills were shaped, according to Wikipedia, by the ice sheet, and the present relief was given by the last glaciation, about 14,500 years ago. The glacier also carried rafts of rock and erratic boulders here.

The legend of the spirit Skarbek

A local legend is linked with the flooding of the mine. It says that from the beginning of the 14th century a greedy spirit called Skarbek haunted the mines, and hid enormous riches at the foot of the southern cliff. When a miner's pick uncovered the hiding place, Skarbek was said to have flooded everything with water. This is a tale, not a historical fact. It also clearly conflicts with the data: according to Wikipedia, industrial extraction began only in 1862, not in the 14th century.

A walk around the lake

According to Wikipedia, the forests around the lake grew up spontaneously after extraction ceased after 1925. First birches and poplars appeared, later black locust, wych elms, pines and maples, and today Pomeranian beech forest predominates. The lake lies in the Zdroje Forest Park. Around it runs the Family Trail, a yellow marked trail 2.5 kilometres long. It starts at the viewing bridge, passes the Polana Widok clearing with a panorama of Szczecin, the “Za Łukami” Grotto and the high southern shore of the lake, and ends at Skórcza Góra. The description of the route dates from 2007, so the waymarking should be checked on the ground.

About 0.6 kilometres south-west of the lake lies the Zdroje nature reserve, which protects a site of the common yew. It was created on the site of the former Toepfer park, laid out by the owner of the nearby chalk mine.

A second such lake on Wolin

A similar history belongs to Lake Turkusowe (the Turquoise Lake) in Wolin National Park. It too occupies the pit of a former chalk mine, from which the raw material went to the cement works in Lubin, founded by Johannes Quistorp.