The most important mountain rivers in the Erzgebirge/Vogtland Nature Park are the Weiße Elster (White Elster), the Göltzsch, and the Zwickau Mulde and Freiberg Mulde including the Zschopau and Flöha tributaries. Over a thousand years of erosion, they have carved wild, romantic valleys and gorges deep into the landscape. We find these on the sides of the Elster at Pirk, in the Schwarzwassertal and Preßnitztal valleys, and in many other stunning areas. Nearly all the region’s streams and rivers flow northwards following the incline of the mountains. However, the Zwota (Svatava) and Rote Pfütze tributaries are notable exceptions.

Although some mountain streams are naturally acidic as a result of their origins in the upland moors, the overall increase in the acidity of the watercourses is becoming an ever-greater problem for the region. Recent research shows that the pH value of the water has been dropping consistently over the past decades. In addition to acid rain, which is primarily caused by the brown coal power plants in the Most Basin in the Czech Republic and nitrogen oxide emissions from countless vehicles, the problem is compounded by the extensive spruce stands in the forested regions of the mountains. The needles lost by the spruce trees do not decompose easily. This leads to soil rich in humic acid, which is flushed into the watercourses. This naturally has an effect on the animals in the water. Trout used to be a common sight in the Schwarzwasser river from Johanngeorgenstadt onwards, but nowadays they have long since disappeared.

Particularly when the snow melts, mass fish dieoffs are recorded near the Neunzehnhain dams due to the sudden reduction in the pH value of the water. And it is not only fish that are affected; many invertebrates such as stoneflies, caddis flies and mayflies suffer as a result of this trend.

Stabilising the ratio of pH values is critical to preserving these characteristic habitats in the long term – and to ensuring good-quality drinking water. In addition to lasting reductions of SO2 and NOx emissions, establishing diverse forests with a high proportion of deciduous trees is a crucial requirement. The example of the bodies of water in the mountains demonstrates particularly clearly the diverse connections and interrelationships in the ecosystem – and the need to interact with these natural assets thoughtfully and responsibly.