Watershed health — Snake River update

We investigated the health of stream habitats in the Snake River Status and Trends Region in 2011 and 2016. From these two study years, the region showed a similar biological condition, with the highest indicators involving stream chemistry and human presence.

River with fallen woody debris and dispersed fir trees around it

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Regional summary

Benthic Index of Biotic Integrity scores in the Snake River Region show the proportion of stream kilometers classified as being in good biological condition slightly decreased from 2011 to 2016.
The most prevalent indicators for streams in the Snake River Region were elevated nutrient concentrations, increased human presence, more pH variety, and increased substrate embeddedness.

Biological condition

Invertebrate biological condition of streams (B-IBI) did not change substantially from 2011 to 2016 in the Snake River Region. However, the percentage of poor B-IBI scores decreased and the fair and good scores increased slightly. These could be positive trends but will need more data to confirm.

Graph showing slight decrease in the proportion poor streams and slight increase in fair streams. — We used B-IBI ratings from 2011 and 2016 to obtain the percentage of stream kilometers in good, fair, and poor conditions for the Snake River Region. Error bars represent 95% confidence intervals.

Significant physical and chemical indicators

In 2011 and 2016, three indicators were in poor condition for more than 50 percent of stream extent in the Snake River Region. The most prevalent indicators pertained to substrate, including low relative bed stability and a high percentage of sands or fines. Other prevalent indicators in this region were those associated with high nutrient levels and a lack of fish cover.

To interact with this graph and learn more about these physiochemical indicators, hold your mouse over each bar.

This interactive graph shows the percentage of stream kilometers assessed with poor physiochemical conditions in the Snake River Region for 2011 and 2016. The x-axis represents the percentage of river extent in poor condition. Error bars show 95 percent confidence intervals.

Flip through our field photos!

A person standing in a grassy stream, holding a net

Collecting macroinvertebrates give us an overall understanding of stream health.

A yellow fish being measured in a clear container

The Tucannon River has cool temperatures and rocky substrate that provide healthy habitat for this longnose dace.

A person wearing a backpack electrofisher while walking through a shallow river

Crews electrofish on the Walla Walla River.

A small creek with multiple man-made log jams

Large woody debris restoration on the south fork of Asotin Creek will give structure for retaining sediments and provide fish habitat.

A wide river with long, spanning logs in and above the river

Large woody debris on the Tucannon River retains substrate, slows high flows, and provides cover for fish and other animals.

This freshwater mussel was found in the sediment at Dry Creek.

A person on the bank of a river preparing field gear

Crewmember prepares supplies for a fish-assemblage survey.

A large fish with a pink stripe being held above a net

An adult rainbow trout from the Tucannon River is a sign of a healthy stream.

Tall poles holding wood in place on a grassy stream

This restoration project at Pataha Creek has large woody debris secured with structures to hold up during high flows.

Two yellow-brown fish in a clear container

Charley Creek has an abundance of Paiute sculpin.

A large brown fish with an oval shaped mouth being held by someone

Largescale suckers, like this one from the Snake River, need cool clean water to spawn and thrive.

A large western toad from Deadman’s Gulch indicates a healthy stream. These species are found in cooler water and are impacted by a changing climate.

Pacific treefrogs prefer moist habitats, such as Casey Creek.

Three people in a river holding measuring rods and tablets

Crews survey the Touchet River.