Middle Snake River above Shoshone Falls

Twin Falls, Idaho

Middle Snake River at park above Shoshone Falls near Twin Falls, ID

Rugged mountains divided by rolling plains characterize the physiographically diverse watershed of the Snake River. The Snake River Plain was created by a volcanic hotspot which now lies underneath Yellowstone National Park, where the headwaters of the Snake River arise. This section of the snake is characterized by various canyons and ridges. The massive amounts of sediment deposited by the Lake Bonneville Floods in the Snake River Plain also had a lasting effect on most of the middle Snake River.
In the lower and middle portions of the Snake River watershed, several native species have been severely impacted by agriculture practices.

Along this stretch, the Snake River resumes its journey westwards, as it enters the Snake River Canyon of Idaho, where it drops over Shoshone Falls.

WATER QUALITY

Passed water quality tests at least 95% of the time
Historical Status
This status is based on the latest sample, taken on . Snake River Waterkeeper updates the status of this beach as soon as test results become available. These results were posted to Swim Guide on at

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MONITORING FREQUENCY

SOURCE INFORMATION

As part of its Water Quality Program, Snake River Waterkeeper monitors water quality at more than 100 sites on the Snake River and its tributaries for temperature, dissolved oxygen, pH, salinity/conductivity/total dissolved solids, ammonia, and nitrates. Data are collected at sample sites June-October and assigned safety ratings based on comparison to EPA's Recreational Water Quality Criteria for Human Health:

pH: 5 – 9 µg/L
Salinity/Conductivity/Total Dissolved Solids: 500 mg/L
Nitrates: 10 mg/L

A site is marked Green when single sample results meet all Human Health Criteria.
A site is marked Red when the results are equal to or above Human Health Criteria.
A site is marked Grey when there are no current results or no available information.
Sites found to exceed EPA's Aquatic Health Criteria are noted in site descriptions.

While criteria measured are useful indicators of contamination, there are many other potential sources of pollution that are not reflected in our Swim Guide, including E.coli and other bacteria, heavy metals, pharmaceuticals, fertilizers, and pesticides that harm aquatic life.

Download the free app for smartphone and learn about Swim Guide 3.0 at www.theswimguide.org. To learn more about our efforts to protect and restore the Snake River's water quality, visit www.snakeriverwaterkeeper.org.

WATER QUALITY GRAPH