Mrežnica River Canyons

Karlovac, the town in central Croatia that is known as the city of four rivers, sits where the Kupa, the Korana, the Mrežnica and the Dobra come together, and of the four, the Mrežnica is the favourite of canoeists and walkers. Its course, from the hills south of the town to its meeting with the Korana at Karlovac, is only about sixty kilometres, but within that short distance the river passes through a series of shallow gorges and tufa terraces that give it an unusual variety. The Mrežnica River Canyons are the stretches where the valley narrows and the water runs between rock walls, forest and waterfalls.

The river's character comes from tufa, the soft, porous limestone, also known as travertine, that forms when lime-rich water flows over moss and other plants. Over thousands of years, the deposits have built low barriers across the bed, and the river spills over them in a long staircase of small waterfalls, of which there are said to be more than ninety. Between the falls, the water spreads into deep green and turquoise pools, so clear that fish and underwater plants can be seen from the bank. In places, the river splits around small islands, runs through narrow clefts in the rock and passes beneath old wooden bridges and the ruins of mills. The result is a landscape that is often compared with the Plitvice Lakes, though it is less crowded and offers more freedom to explore.

The river is a fine place for gentle outdoor activity. Canoes and kayaks can be hired at several points, and the current is gentle enough for beginners and families, with short stretches of faster water at the falls, where boats are usually carried around. A paddle between the villages along the river takes several hours and passes forests, meadows and mills. Swimming is popular in summer, and the water is cool and refreshing, though it is wise to check local rules, since parts of the river are protected, and to take care on slippery tufa. Anglers fish for trout and grayling, and riverbank paths and cycling routes link the villages.

The wildlife is rich. Otters, kingfishers, herons and dragonflies live along the water, and European tree frogs are among the amphibians that call the wet meadows home. The local community has worked to keep the river clean, and visitors are asked to take rubbish home, avoid soap and sunscreen in the water where possible and stay on paths. Access to the river is free, and the area is open at all times.

The canyons suit families, paddlers, walkers and nature lovers. Karlovac is about an hour from Zagreb by road, and there are cafés and restaurants in the villages. Late spring and early autumn are the best seasons.