tributary

Biologists from the California Department of Fish and Wildlife have spotted fall-run Chinook salmon in tributaries miles upstream from where Iron Gate Dam was removed.

Water is the eternal conundrum in this state, especially as climate change has diminished the summer monsoons and the Rio Grande and its tributaries slowly dry up.

One section of the river is lined with concrete, and the remnants of tributary creeks sit in straight ditches.

This undammed river, a tributary of the Klamath River near the California-Oregon border, is one of the last remaining strongholds of a type of salmon that is increasingly at risk of extinction: spring-run chinook.

The Madeira river, a major tributary to the Amazon, had fallen to just 48cm in the city of Porto Velho on Tuesday, down from an average of 3.32m for this day, official data showed.