Schwarza (Leitha)

The Schwarza is a river in Lower Austria. It is one of the two headstreams of the Leitha River, the other being the Pitten. The Schwarza is approximately 60 kilometers long and originates in the Rax-Schneeberg Group of the Northern Limestone Alps, specifically from several karst springs near the Schneeberg.

The river flows generally eastward through the valleys of the Lower Austrian Prealps, passing through towns such as Schwarzau im Gebirge, Gloggnitz, and Ternitz. The Schwarza is an important source of drinking water for Vienna, Austria. A significant portion of its water is diverted to Vienna via a system of aqueducts, a system that has been in operation since the late 19th century.

The Schwarza's water quality is generally considered to be good. It is known for its relatively stable flow rate, even during dry periods, due to the karst springs that feed it. The river and its surrounding landscape are popular for recreational activities such as hiking, fishing, and kayaking. The Schwarza also plays a significant role in local industry, historically powering mills and other industrial facilities.

At Haderswörth, near Lanzenkirchen, the Schwarza merges with the Pitten to form the Leitha River. The Leitha then continues eastward to eventually join the Danube River.