Malheur River

Ontario, Oregon

THIS SITE KNOWN TO CONTAIN DANGEOUS LEVELS OF SEDIMENT AND NITRATE. DO NOT SWIM OR EXPOSE CHILDREN TO WATER UNLESS FLAGGED GREEN.

The Malheur River (local pronunciation: "MAL-hyure") is a 190-mile-long (306 km) tributary of the Snake River in eastern Oregon in the United States. It drains a high desert area, between the Harney Basin and the Blue Mountains and the Snake. Despite the similarity of name, the river does not flow into nearby Malheur Lake, which is located in the enclosed Harney Basin southwest of the watershed of the river. When water levels were higher, Malheur Lake would drain into the Malheur River.

The lower Malheur River is used for irrigation in the agricultural potato-growing in the Snake River Plain along the Idaho-Oregon border. There are approximately 370 miles (600 km) of irrigation-related canals and ditches in the lower basin of the Malheur River and its tributary Willow Creek. The streamflow of the Malheur and its tributaries is heavily influenced by a complex system of irrigation diversions, siphons, and canals, which begin near Malheur river mile 65, near Namorf and Harper, Oregon. This irrigation system extends downstream to the mouth of the Malheur at Ontario, Oregon.

WATER QUALITY

Failed to meet water quality standards
Special Status
This status is based on the latest sample, taken on June 30th, 2018. 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

For water quality icon legend, click:

CURRENT WEATHER

2°C

Mostly clear

Report Pollution

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

Malheur River

Ontario, Oregon

Managed by Snake River Waterkeeper

WATER QUALITY

Failed to meet water quality standards
Special Status
This status is based on the latest sample, taken on June 30th, 2018. 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

For water quality icon legend, click:

CURRENT WEATHER

2°C

Mostly clear

MONITORING FREQUENCY

SOURCE INFORMATION

WATER QUALITY GRAPH

Beach	Location	Water Quality
Middle Snake River at Ontario State Rec Park Ontario, Oregon	Ontario, Oregon	Historical Status
Payette River at Kiwanis Park Payette, Idaho	Payette, Idaho	Historical Status
Weiser River Weiser, Idaho	Weiser, Idaho	Historical Status
Lower Boise River Parma, Idaho	Parma, Idaho	Historical Status

Other Beaches Near This One

Beach	Location	Water Quality
Middle Snake River at Ontario State Rec Park Ontario, Oregon	Ontario, Oregon	Historical Status
Payette River at Kiwanis Park Payette, Idaho	Payette, Idaho	Historical Status
Weiser River Weiser, Idaho	Weiser, Idaho	Historical Status
Lower Boise River Parma, Idaho	Parma, Idaho	Historical Status

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	Green means the beach’s most recent test results met relevant water quality standards.

	Red means the beach’s most recent test results failed to meet water quality standards.

	Grey means water quality information for the beach is too old (more than 7 days old) to be considered current, or that info is unavailable, or unreliable.

	Green means the beach passed water quality tests 95% of the time or more.

	Yellow means the beach passed water quality tests 60-95% of the time.

	Red means the beach failed water quality tests 40% of the time or more.

	Green means the beach has historically excellent or pristine water quality, but there is no current data.

	Red means the water at the site has water quality issues or there is an emergency.

	Grey means there is no current water quality information, the beach is under construction, there has been an event that has rendered water quality information unreliable or unavailable.