| Windauer Ache | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Austria |
| Subdivision Type2: | State |
| Subdivision Name2: | Tyrol |
| Subdivision Type3: | Location |
| Subdivision Name3: | in the Windautal / Kitzbühel Alps |
| Length: | 22km (14miles) |
| Source1 Location: | Reinkarsee on the Kröndlhorn |
| Mouth Location: | In Haslau / Hopfgarten into the Brixentaler Ache |
| Basin Landmarks: | Villages: Westendorf and Hopfgarten |
| Progression: | Brixentaler Ache→ |
| Tributaries Right: | Miesenbach, Rettenbach |
| Tributaries Left: | Falberbach, Dürrnbach |
| Waterbodies: | Lakes: Reinkarsee |
| Custom Label: | References |
The Windauer Ache is a mountain stream in Tyrol, Austria, in the scenic Windautal valley in the Kitzbühel Alps.
The Ache rises on the Reinkarsee at about, at the foot of the Kröndlhorn, and its middle reaches run through a roughly long gorge. In Hopfgarten the Windauer Ache discharges into the Brixentaler Ache at a narrow point in the valley; the Brixentaler Ache in turn empties into the River Inn at Wörgl.
The Ache flows through the municipalities of Westendorf and Hopfgarten.
The Windauer Ache is very popular for whitewater canoeing (grade WW II to WW V).
At the end of July 2006, a severe storm caused enormous damage throughout the entire Windau valley. The flood of the Windauer Ache tore away the stream shoring, bridges and road sections. The investment sum for the restoration - and simultaneous shoring and regulation of the river - amounted to approximately 860,000 euros.