The Curoca River marks the northern side of the Iona landscape, intermittent for much of the year but capable of leaving lagoons and green pockets in an otherwise dry region. Lagoa dos Arcos, on the Curoca system north of the park, is the best-known expression of that desert-oasis contrast.
If your route to Iona comes through Tombwa, the Curoca lagoons help explain the park before you even enter it. Water, reeds, acacias, and wildlife tracks suddenly appear where the map suggests only desert, a reminder that dry-country rivers are not empty just because they do not flow all year.