Priehrada

Priehrada is a barrier built across a river or other watercourse to hold back water and form a reservoir. The term is used in Slovak; in Czech the corresponding word is přehrada. Priehrady are constructed for multiple purposes, including hydroelectric power generation, water supply, flood control, irrigation, and recreation.

Design and types: Priehrady can be embankment dams (earthfill or rockfill), concrete gravity dams, or arch dams. They typically include a dam body, an upstream reservoir, and a spillway to pass surplus water safely. Other key elements may comprise intake structures, outlet works, tunnels, and hydroelectric power stations.

Operation and safety: Dams are operated by water authorities or utility companies and require ongoing monitoring, maintenance, and emergency planning to prevent overtopping, structural failure, or unintended releases. Reservoirs behind priehrady provide storage to mitigate drought and regulate river flow, but they also affect sediment transport and ecosystem processes downstream.

Environmental and social aspects: The construction and operation of priehrady can alter habitats, affect fish migration, displace communities, and change water quality. Mitigation measures include fish passes, sediment management, environmental flow requirements, and careful land-use planning.

Examples and terminology: In everyday Slovak usage, priehrada can refer to both large dams and smaller structures that raise water levels. The Czech term přehrada is more common in Czech contexts. See also dam, reservoir, hydroelectric power, and flood control.