Guadyerbas

The Guadyerbas is a river of Spain located in the centre of the Iberian Peninsula. It is the main left-bank tributary of the Tiétar, in turn a major tributary of the Tagus.
It has its source in the western reaches of the, at the feet of the Pico Cruces, at roughly 1,200 m above sea level. Featuring a total length of 45 km, it flows westwards through the northwest of the province of Toledo, emptying in the Tiétar a few kilometres upstream from the, in Oropesa.
Its waters are retained by the Navalcán Reservoir. The toponym is formed by the Arabic wadi and the Spanish hierba/yerba.