Těrlicko Reservoir, reservoir in the Czech Republic

Těrlicko Reservoir is a valley reservoir on the Stonávka River in the Moravian-Silesian Region. Its earthen dam, with an inclined loess sealing core, holds 770,000 m³ of material and was built between 1955 and 1964. The reservoir covers 267.6 hectares and holds 27.4 million m³ of water.

Built from 1955 to 1964, the dam supplied operating water to the mines of the Ostrava-Karviná basin and the Třinec ironworks, and also served flood protection. Its construction flooded 141 buildings, among them public structures and the church, plus the stretch of road I/11 from Ostrava to Český Těšín, which was rebuilt along the southern edge of the reservoir.

The site is accessible year-round and features swimming beaches, walking paths, and cycling routes around the basin. Boat rentals, water skiing facilities, and dining and lodging options are available nearby.

The dam wall holds 770,000 m³ of earth with a slanted loess sealing core, and burnt spoil from local heaps was mixed into its stabilising section. A single-row grout curtain runs beneath the dam, which sits on the outer zone of the Carpathian flysch, where shales, claystones and sandstones alternate.