Hráz rybníka Kunžvartu, Dam ruin in Hliniště, Czech Republic

The Kunžvart Pond dam is a breached earthen dam about 529 m long, up to 51 m wide and up to 23 m high at the crown, crossing the Řasnice valley at 800–808 m above sea level. The river still flows through the gap from south to north, and no building stands by the dam today.

The dam was built by Petr Malovec of Chýnov and Vimperk probably between 1543 and 1547; Petr of Rožmberk protested to the Prague land records office, doubting the dam's stability. The pond was confiscated in 1547 and first mentioned as completed in 1553. It breached in 1587, and modern surveys found the dam founded on unstable alluvial sediment.

The dam has been recognized as a Czech cultural monument since 1963 and represents early engineering efforts in this region. It shows how people once used flowing water to maintain fish ponds as an important food source.

The site can be accessed via a marked green hiking trail starting from the Pod Lískovým vrchem intersection and leading to Brixův dvůr. The path through the valley provides straightforward access to the entire dam structure.

The dam's 1963 heritage listing records it as the oldest Czech valley dam, a claim based on a mistaken 14th-century dating. Research later showed Vladislav Petr Malovec of Chýnov built it in 1543–1547, and it breached in the 16th century.