Further downstream it continues through the Ōpārara Basin Arches, both of which are popular walking destinations.

These sections of the Ōpārara River, while still in dense native forest, can be reached by a forestry road.

The river's colour varies from tea-like shades of golden brown to red from the natural organic tannins released into the water by several of the plant species in the area.

Leaves and other plant matter on the forest floor release these tannins as they decompose – this eventually leeches into and stains the water, with the shade and intensity varying depending on rainfall and season.

The river and contributing streams in the area are a habitat for the endangered South Island whio; the area used to sustain a large population of whio and is now a location for a recovery programme run by the New Zealand Department of Conservation.