The Kacha (Russian: Ка́ча) is a river in Krasnoyarsk Krai, Russia.

The Turkic name of the river is Izyr-Su, and it has been suggested that the Russian name is derived from Izyr-Kichi "Izyr people", the self-name of the Turkic people that inhabited the river valley and adjacent lands.

Both streams flow from the range northward, cross the Trans-Siberian Railway, and join.

The most serious pollution sources were several unfiltered sewage pipes and numerous solid wastes on the river banks.

Currently, due to the administrative work of the mayor Pyotr Pimashkov, most of the sources were removed and the river banks in the city center have been turned into an attractive recreational area.