In the eastern part of the city, within the direct neighbourhood of the Old Town there is a dyke which was dug during the years 1530- 1540 in order to protect the town against the water of Great Bieruń Pond, non-existent today, where fish were breed at industrial scale. Jan Thurzo, at that time he was the head of the Pszczyna Free State, was the person who made the decision to construct the Great Bieruń Pond. Nowadays, there is almost 1 km long dyke. Another hydro-technical construction of this type can be found in the southern part of Bieruń Nowy, the so called Kopania. The Kopania Dyke was constructed in the 17th century with the purpose of protecting nearby rural lands against the water of the historical Kopania Pond. At present it is one of the most valuable places on the area of Bieruń in respect of its natural features. Apart from old trees, hornbeams and oaks that complement the landscape in a picturesque way, a great number of rare and protected plans grow here, they are plants such as: European cranberry-bush, glossy buckthorn, lily of the valley. What is more, the dyke is also the place where numerous protected birds, such as Green Sandpiper, build their nests.