The 26 km (16 mi) long Kelchsauer Ache drains the entire Kelchsau area.

Between Hopfgarten and the section of river forming the boundary between Kirchbichl and Wörgl,[1] the Ache is again forced through a gorge, before it breaks out into the plains of the Inn Valley.

On leaving the gorge the Ache is impounded by a large weir and part of the water is diverted into a channel that leads to a small power station run by Tiroler Wasserkraft.

After having been fed by so much water from its large tributaries the Ache now dominates the landscape of the broad and densely settled Brixental valley.

After the now around 16 metres (52 ft) wide Brixentaler Ache has flowed through Wörgl, it discharges from the south into the Inn.