Dolina Dretulje, Natural reserve in Plaški, Croatia

Dolina Dretulje is a 590.77-hectare site of community importance in the municipality of Plaški, Karlovac County, Croatia. It covers the Dretulja lowland around Plaški and the lower course of the Vrnjika up to its confluence with the Dretulja. The valley is almost entirely covered by wet and moist habitats, with calcareous fens of particular importance.

The area was recognized in 2013 as a site of community importance under European nature protection law. This designation was part of an international effort to protect natural networks.

The site is named after the Dretulja, the river whose lower course and surrounding lowland it covers around Plaški. Two protected plants are listed for the area, Apium repens and Scilla litardierei, alongside the European otter. The Vrnjika flows into the Dretulja within the protected land.

The valley is easily accessible from Plaški and has trails for exploring the wetlands. Spring and summer are ideal times to visit when trails are drier and plants are in bloom.

The site covers 590.77 hectares and was declared a site of community importance in July 2013 to protect two plant species, Apium repens and Scilla litardierei, and one animal, the European otter (Lutra lutra). Three further plant species have also been recorded there.