The Squaxin Island Tribe is conducting a season long study to find out when the Deschutes’ flows get low:

In order to establish how much water salmon need to survive during the summer months, the Squaxin Island Tribe is starting a lengthy examination of streamflow in the Deschutes River. “We want to look at the relationship between flows and salmon habitat,” said John Konovsky, environmental program manager for the tribe. “As flows decrease, available habitat also decreases. We’re trying to identify the point when that lack of flow and habitat becomes critical for juvenile salmon survival.”

The end result of the tribe’s research will be set of minimum flow targets or standards for the watershed between April and December. A state-adopted standard would mean that if flows drop beneath the minimum, the state can take corrective action to bring flows back up. The state set a minimum flow standard over 30 years ago for the winter months, but didn’t address summer flows.

A historical analysis by the tribe shows that in recent decades summer flows have gotten lower and winter and spring floods more frequent and larger. The analysis points to an increase in impervious surfaces and a loss of forest cover as prime causes of the change in hydrology. Those changes have decreased flow during the summer months by at least 20 percent.

Read the entire piece here.