of the Sylvenstein Dam and numerous regulations relating to the river (pushed through in the early 19th century) have strongly enhanced its character. The construction of the Sylvenstein dam has prevented the river from overflowing its banks. Lately, there have been attempts to bring the Isar closer back to a natural character. For example, since May, 2000, the river is being re-naturalized in the southern part of the river’s passage through the city of Munich, between Großhesseloher Brücke and Reichenbachbrücke. To achieve this the riverbed is being widened, the banks are flattened and small gravel islands are built along with near-natural ramps to slow the waterflow. Also, the dams are enlarged in width and height. Besides an improved protection against flooding the river was, thus, brought into an almost natural state and this resulted in an improved quality of the recreational area within the city of Munich. The quality of the water has also improved due to the upgrading of the sewage plants along the river. The number of germs, however, is still relatively high. Together with other cities and communities along the Isar, Munich has set a goal to reduce the number of germs until the water quality is good enough to allow bathing in the river. If this is achieved, Munich would be one of the few big cities in Europe with a river with water of good enough quality to allow swimming in it. The sewer plants on the upper river are now treating the sewage with ultraviolet light, which greatly reduces the number of germs, but still the Isar cannot be guaranteed safe to bathe in because of the entrance of polluted rainwater into the river, especially during strong precipitation. There are a number of natural reservations along the Isar, including special protection areas for birds, for example the natural reserve Vogelfreistätte Mittlere Isarstauseen northeast of Moosburg. This area is an important resting place for migrating water birds. There has been evidence for more than 260 different species of birds, among them rare species like the common tern and the bluethroat. To preserve the beauty of the Isar valley Gabriel von Seidl founded the Isartalverein in 1902. This first civil initiative from Munich purchased of land, and today maintains more than of hiking trails. Recreation There are several areas along the river Isar that have been designated since the 1960s as nudist resorts. However, along much