| Guadyerbas | |
| Mouth: | Tiétar |
| Mouth Location: | Oropesa |
| Subdivision Type1: | Country |
| Subdivision Name1: | Spain |
| Length: | 45km (28miles) |
| Source1 Location: | Navamorcuende |
| Source1 Elevation: | ~1200m (3,900feet) |
| Source1 Coordinates: | 40.1478°N -4.7436°W |
| Mouth Coordinates: | 40.0836°N -5.1919°W |
| Extra: | Tagus Basin |
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,[1] in turn a major tributary of the Tagus.
It has its source in the western reaches of the,[2] at the feet of the Pico Cruces, at roughly 1,200 m above sea level.[3] Featuring a total length of 45 km,[4] it flows westwards through the northwest of the province of Toledo, emptying in the Tiétar a few kilometres upstream from the,[5] in Oropesa.
Its waters are retained by the Navalcán Reservoir. The toponym is formed by the Arabic wadi (river) and the Spanish hierba/yerba (grass).[6]