Heavy rains and flood events can wash large amounts of organic matter, such as leaves and wood, from the forest floor and floodplain into waterways. This can cause water to turn a dark colour. This is often referred to as blackwater. It can cause short-term harm, such as fish deaths. Bushfires and recreational water quality (publication 1817) has more information about blackwater.

You can report fish deaths to EPA on 1300 372 842. We are available 24 hours. Interim response guide – Fish death events (publication 1793) has more information about EPA’s role in responding to fish deaths. 


Reviewed 16 November 2022