The Odelouca headwater sources are a number of small streams and brooks rising from springs between the Serra de Monchique and the Serra do Caldeirão. The rivers riparian margins are a dense and at times, lush with vegetation. These woody flanks are populated by Narrow leaf Ash, Willows, Poplar and Alder trees. In the lower reaches of the river can be found Tamarix and Oleander. Many of these riparian zones were lost following the construction of the Barragem de Odelouca. From it headwater sources the river runs for approximately until its confluence with the Arade River west of the town of Silves.