What’s in the Clearwater River and Is It Safe to Swim In? 

Planning a trip to the Clearwater River? If you’re looking to hang out in or along this river, it’s important to learn about some of the local ecosystem. By learning about the ecology of the places we visit we can be better prepared for out trip as well as better appreciate the natural world around us.

Read on to learn about what’s in the Clearwater River and if it’s safe to swim in.

Overview of the Clearwater River

Located in north-central Idaho, the Clearwater River flows 74.8 miles westward from the Bitterroot Mountains along the Idaho-Montana border to the joining of the Snake River at Lewiston, Idaho.

Three main tributaries feed the main Clearwater River- these are the North Fork, Middle Fork, and South Fork Clearwater Rivers. The Middle Fork, although short, is a particularly high-volume tributary. It’s formed at the confluence of the Lochsa and Selway rivers. The Middle Fork and South Fork rivers meet to join at the easternmost end of the main Clearwater River. From the north, the North Fork drains into the Dworshak Reservoir. After this point, it heads into the northernmost, central portion of the Clearwater River.

Climate and Geography

This river spans a highly diverse topography, ranging in elevation from about 9,000 feet to 725 feet at its lowest. Along much of its path, conifer-covered and grassy hills rise in a rolling to sharp manner from the banks.

The climate along and surrounding the river is temperate with four distinct seasons. In the winter, snow and ice spread along the river’s edges and in some areas, patches of ice can form across the waterway.

During the summer, this river averages about 53 degrees Fahrenheit. Sections of this river move quite rapidly, offering plenty of whitewater activities.

What’s in the Clearwater River: Pollution Threats

In the mid-2010s, one of the largest pollution threats to the Clearwater River was from the proposal to allow megaload trucks carrying oil-related equipment access to travel scenic Highway 12. Much of this highway winds along the Clearwater River. These trucks and their industrial cargo can weigh over 300 tons and, according to environmental and indigenous activist groups, presented multiple pollution threats to the Clearwater River. After years of litigation and direct action protests, a court settlement in 2017 banned megaloads from any future use of Highway 12.

Today, human-caused climate change and agricultural and industrial activities contribute to increased erosion that washes fine and coarse sediment into the Clearwater River. Increased levels of sediments can negatively impact some vulnerable fish populations including salmon. Finally, suction dredge mining for gold and other valuable minerals can cause pollution to this river, affecting aquatic populations and water quality.

What Animals Live Around and in the Clearwater River?

The Clearwater River provides an aquatic home, freshwater source, and hunting ground for a range of animals. These animals are all part of an interconnected ecosystem. Below, we’ll cover some of the amazing animals that call the Clearwater River region home.

Black Bear

Among the forested regions that border the Clearwater River, black bears (Ursus americanus) live and thrive. The Clearwater provides a drinking source and hunting opportunities for these beautiful animals. As non-specialist omnivores with few natural predators, American black bears have adapted to living in a range of wilderness and human-occupied environments. This species averages 50-80 inches long from nose to tail, 2-3 feet tall at the shoulders, and 175-400 pounds.

While these large and powerful critters can certainly maim or kill a human, black bears are overwhelmingly non-confrontational and certainly don’t hunt people. Black bear attacks are extremely rare and fatalities are even rarer. Still, it’s the best and most respectful course to keep your distance if you spot a black bear in or along the Clearwater River. Instead, enjoy watching these lovely animals from afar. By chance, if you happen upon one at close range by surprise, calmly back away and speak in calm tones. If the bear approaches, waving your arms, shouting, and throwing items toward them is often enough to deter these typically shy animals.

If you spot a black bear along the Clearwater River, you may observe them drinking, cooling off in the water, or hunting prized fish species like Chinook salmon and cutthroat trout.

What’s in the Clearwater River: Chinook Salmon

The populations of Chinook salmon (Oncorhynchus tshawytscha) that inhabit the Clearwater River are federally listed as threatened. This means the Clearwater River populations of Chinook salmon, also called king salmon, are likely to become endangered in the foreseeable future, as they are in other areas of their range. Climate change, damming, habitat degradation, overfishing, and habitat loss due to development are severely threatening populations of this incredibly important species.

In the spring and summer, Chinook salmon spawn in the streams that branch off the Clearwater River. Hatchlings live in these streams for about a year. After, they migrate through the Clearwater River on their long journey to the Pacific Ocean. On average, Chinook salmon reach about 3 feet long and weigh around 30 lbs. However, some massive specimens exist that can weigh over 100 pounds and grow up to 5 feet long.

Northern Pacific Rattlesnake

There are three venomous species of snake native to Idaho. The species with a range that includes parts of the Clearwater River is the Northern Pacific rattlesnake (Crotalus oreganus).

This beautiful snake typically reaches around 36 inches long. They feature a large triangular head and a distinctive, dark brown post-ocular eye stripe. The base body color can range quite widely on this species, depending on its environment. The body coloration usually presents as olive-gray, olive-brown, copper-brown, or light brown-gray. Along their back, they display large blotches that are the most distinctive when the snake is young. As they age, this distinctive pattern tends to fade. Towards the tail, the blotches shift to banding which ends at their prominent, segmented, and hollow rattle.

Safety Around Snakes

Hikers exploring the grasslands and forests around and banks of the Clearwater River are encouraged to avoid stepping underneath tight rocky overhangs, into tall grass, or on wood piles in this area, especially around dawn and dusk during the warm months.

Contrary to myths and exaggerated accounts, rattlesnakes don’t set out to chase or attack people. Instead, snake bites typically happen when someone accidentally steps on or is way too close to the snake. Less commonly, people even ignore the warning signs of a rattlesnake. Signs like coiling with a raised head and rattling should serve as a warning to back off. This species, like other rattlesnakes, most often choose to freeze and camouflage themselves, or flee, when presented with a threat. This is a safer option for them than risking injury in a conflict. The best way to avoid a snake bite is to be mindful of your environment and be respectful of their space.

What’s in the Clearwater River: Is It Safe to Swim In?

Fast, strong currents in sections of the Clearwater River is likely the biggest threat to swimmer safety. If you do choose to swim in the Clearwater, make sure to choose a location without prominent white water rapids or particularly strong currents. You can likely find spots, especially in slower flow seasons like August, where the waters are much gentler.

The photo featured at the top of this post is © CSNafzger/Shutterstock.com

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