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

Written by Em Casalena
Updated: August 9, 2023
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The Susitna River, a sparkling gem nestled in the heart of nature’s splendor, beckons adventurers and thrill-seekers alike with its enchanting allure. But before you plunge into its inviting waters, there’s a question worth asking: Is it safe to swim in this majestic waterway?

With a surge of curiosity and a dash of caution, we embark on a journey to uncover the truth about the Susitna River’s swimworthiness. Gushing through the picturesque landscapes of Alaska, this watercourse is celebrated for its beauty, wildlife, and recreational potential. But lurking beneath its inviting surface are potential hazards that demand our attention.

In this article, we’ll jump into a comprehensive investigation, examining water quality reports, wildlife interactions, and safety guidelines to decide if swimming in the Susitna River is a wise pursuit. 

About the Susitna River

The Susitna River, also known as the “Big Su,” is a majestic waterway nestled in the heart of Alaska, United States. The river travels 313 miles from its source in the Susitna Glacier to its mouth in the Cook Inlet, passing through the state’s south-central portion. An important natural landmark in Alaska, the Susitna River draws travelers, nature lovers, and fishermen from all over the 


The Susitna River is situated in the southern part of Alaska, originating in the Alaska Range. It winds its way through rugged terrain, passing through breathtaking valleys and dense forests, providing visitors with a stunning display of untouched wilderness. The river then empties into the Cook Inlet, a vast body of water surrounded by striking landscapes and home to diverse marine life.

Historical Significance

The Susitna River holds great historical importance for the indigenous people of Alaska, particularly the Dena’ina Athabascan tribe. For generations, they have depended on the river’s abundant resources for sustenance and cultural practices. The Dena’ina Athabascans hold a deep spiritual connection to the Susitna River, believing it to be a place of spiritual power and significance.

Exploration and Discovery

Russian fur traders entered the area in the 18th century in pursuit of expensive furs, and they were the first foreigners to investigate the river. The Susitna River basin’s beauty and wealth fascinated the explorers. As a result, fur trade facilities were eventually established along its banks. This signaled the arrival of European influence in the region and helped Alaska’s economy grow.

Hydroelectric Potential

In the mid-20th century, the Susitna River’s ability to generate hydroelectric power piqued the interest of scientists and engineers. Plans for constructing a large dam on the river to harness its energy were put into place. However, concerns over the price and environmental impacts prevented these concepts from being fully adopted. A compromise between the need for clean energy and the protection of Alaska’s natural ecosystems is still being worked out in the dispute surrounding the dam’s construction. The dam has still not been built as of 2023.

Recreation and Tourism

These days, outdoor enthusiasts go to the Susitna River for a variety of recreational opportunities. One of the main draws is fishing since the river is alive with different varieties of salmon, trout, and other fish. Rafting and kayaking also draw adventure-seekers who want to experience the rush of navigating the river’s thrilling rapids. The surrounding wilderness provides opportunities for hiking, camping, and wildlife viewing, making the Susitna River a haven for nature lovers.

Is There Pollution in the Susitna River?

Despite its stunning beauty and biological importance, pollution poses a serious threat to the Susitna River. This natural treasure has been degraded by human activities and industrial advancements, endangering both the ecosystem and the communities that depend on its supplies.

Sources of Pollution

Numerous sources contribute to the pollution of the Susitna River. Industrial discharges, agricultural runoff, and untreated sewage are among the major culprits. Additionally, logging activities and mining operations in the river’s vicinity can lead to sedimentation and chemical contamination. Trash and plastic waste from recreational activities and urban areas find their way into the river, exacerbating the problem.

Impact on Water Quality

Pollutants entering the Susitna River have a detrimental impact on water quality. Heavy metals and hazardous chemicals have polluted the water, making it unsafe to drink for both people and wildlife. High levels of pollution harm the river’s delicate environment, and also harm aquatic life, and lowers biodiversity. Unfortunately, the contaminants often seep into the groundwater, jeopardizing the availability of clean drinking water for locals.

Threats to Wildlife

The pollution in the Susitna River poses significant threats to wildlife. The pollution can cause toxic buildup in fish, rendering them unfit for human consumption and impacting local populations. Degradation of the river’s ecosystem might also interfere with the migratory routes and breeding grounds of different bird and animal species.

Impact on Indigenous Communities

The pollution of the Susitna River directly impacts the livelihood and cultural practices of the Dena’ina Athabascan tribe and other indigenous communities. Traditional subsistence practices, such as fishing and gathering, are threatened as pollution affects the availability and safety of resources. Furthermore, the spiritual connection that the Dena’ina Athabascans have with the river is disrupted by the degradation of this sacred waterway.

Efforts and Solutions

Recognizing the importance of preserving the Susitna River, various initiatives and organizations are working to address pollution issues. Advocacy groups and government agencies collaborate on monitoring and research to identify pollution sources and mitigate their impact. Implementing and enforcing regulations on industrial and agricultural discharges is essential to curbing pollution. Public awareness campaigns and community involvement play a crucial role in fostering responsible behavior and reducing waste.

Are There Dangerous Animals in the Susitna River?

Numerous potentially deadly creatures may be found in the Susitna River area. It’s important to learn and respect wildlife to protect the safety of both humans and animals, even if interactions with these creatures are few and none of them reside permanently in the waters of the river.

Brown Bears

Brown bears, commonly referred to as grizzly bears, are particularly abundant in the Susitna River area. These formidable carnivores can be seen searching for prey in woods, meadows, and along riverbanks. Brown bears are typically quiet and avoid people, but if they feel threatened, especially if they have cubs, they may defend themselves. To keep bears away from campsites, guests must use care, maintain a safe distance, and store food correctly.

Coastal Brown Grizzly bear carrying a salmon

Brown bears are important animals that control fish populations.

©Kirk Hewlett/ via Getty Images


Moose are iconic inhabitants of the Susitna River region. Despite their peaceful demeanor, they can become aggressive during the mating season or when they feel cornered. Encounters with moose can be dangerous, as they have sharp hooves and antlers. Observing moose from a distance and avoiding any attempts to approach them is essential for avoiding potential harm.


Wolves are elusive predators that inhabit the Susitna River area. While they generally avoid humans, they may act defensively if they perceive a threat. Wolf packs can be protective of their territory, so hikers and campers should be cautious about entering their areas and avoid leaving food scraps or attracting wolves unintentionally.

Black Bears

Black bears are another species found in the Susitna River region. Although generally less aggressive than brown bears, they can still pose a threat, especially if they feel their food source is at risk. Proper food storage and disposal are essential to minimize interactions between black bears and humans.


Wolverines are solitary and elusive animals that inhabit the rugged landscapes near the Susitna River. While they are not typically a threat to humans, they can become aggressive if they feel cornered or threatened. As with all wildlife, it’s best to admire wolverines from a distance and avoid any attempts to approach them.

Poisonous Plants Near the Susitna River

Along with beautiful vegetation, the Susitna River’s verdant surroundings are home to certain species that might be dangerous. Even if the majority of the local plants are benign, it’s important to be aware of the dangerous species and take safety measures to prevent coming into touch with them.

Devil’s Club

Devil’s Club is a prominent plant found in the Susitna River region. It has large, distinct leaves with sharp spines and can grow up to six feet tall. While it has traditional medicinal uses for certain indigenous communities, it’s crucial to handle this plant with care. The spines and the plant’s sap can cause skin irritation and painful rashes upon contact.

Water Hemlock

Water Hemlock is one of the most toxic plants in the Susitna River area. It grows in wet areas and is often found near streams or marshes. All parts of the plant contain the deadly toxin cicutoxin, which can be fatal if ingested by humans or animals. It’s essential to avoid any contact with Water Hemlock and prevent accidental ingestion by ensuring pets and children are kept away from these areas.

Close up of Water Hemlock (Cicuta maculata). Each flower head is composed of clusters of small, five-petaled white flowers. Photo taken on the Silver River in Ocala, Florida. Nikon D750 with Nikon 200mm Macro lens

Water hemlock is extremely poisonous and very abundant along the Susitna River.


Cow Parsnip

Cow Parsnip is a common plant in the Susitna River region, and it can be mistaken for other non-poisonous plants like Queen Anne’s Lace or wild carrots. The sap of Cow Parsnip contains photosensitizing compounds, which can cause skin irritation and blistering when exposed to sunlight. To avoid this, it’s best to handle Cow Parsnip with gloves or avoid contact altogether.


Baneberry is a small, attractive plant found in wooded areas near the Susitna River. It produces bright red or white berries that can be enticing to children and wildlife. However, if consumed, the plant’s other parts and the berries are both deadly, leading to symptoms including vomiting, diarrhea, and in extreme circumstances, cardiac arrest. Children and adults alike must be made aware of the risks associated with eating wild berries and taught not to consume any strange vegetation.

Is the Susitna River Safe to Swim in?

Those traveling to the area and looking for a way to cool down while taking in the breathtaking Alaskan scenery may find swimming in the Susitna River to be an alluring possibility. But before diving in, it’s important to think about several things that affect how safe it is to swim in this magnificent river.

Strong Currents and Cold Water

Particularly during the height of summer when snowmelt and glacier runoff enhance the water flow, the Susitna River is renowned for its fast currents. Even seasoned swimmers may find it difficult to negotiate these powerful currents. Just as well, because of the river’s glacial origins, the water stays frigid all year round, increasing the danger of hypothermia, especially for people who aren’t used to swimming in cold water.

Unpredictable Hazards

The river’s natural environment can present unpredictable hazards, such as submerged rocks, logs, and other debris. These hidden obstacles can pose dangers to swimmers, causing injuries or entrapment. Moreover, the water’s turbidity may limit visibility, making it difficult to spot potential hazards.

Wildlife Encounters

The Susitna River region is home to diverse wildlife, including fish and mammals. While swimming, there is a possibility of encountering animals, such as salmon, which may not pose a direct threat but can startle or disturb swimmers. Additionally, bears and other wildlife may visit the river’s banks, necessitating caution and respect for their space.

Water Quality and Pollution

The water quality of the Susitna River can vary, and it is essential to consider potential pollution sources upstream. As mentioned earlier in this article, runoff from agricultural areas, industrial discharges, and other human activities may introduce contaminants into the river. Before swimming, it’s advisable to check for any advisories or warnings regarding water quality and pollution.

So, is it safe to swim in the Susitna River? Yes, the river is safe for swimming, but only if the proper safety measures are taken. Wear a life jacket and swim only in designated locations if you choose to go swimming in the Susitna River.

Animals in the Susitna River

The waters of the Susitna River teem with a diverse array of aquatic life, thriving in the pristine Alaskan ecosystem. From fish to invertebrates, the river sustains a delicate balance of species that contribute to its ecological health and richness.


Salmon play a crucial role in the Susitna River ecosystem, as they are anadromous fish, meaning they are born in freshwater, migrate to the ocean to mature, and then return to their birthplace to spawn. Several salmon species inhabit the river, including Chinook, Coho, Sockeye, Pink, and Chum salmon. These magnificent fish serve as a vital food source for various predators and are integral to the nutrient cycling of the ecosystem.

A black streak along the gum line of the Chinook Salmon gives them the alternate name of blackmouth.

Chinook salmon, among other species, are abundant in the Susitna River.

©Martin Rudlof Photography/Shutterstock.com

Trout and Char

In addition to salmon, various species of trout and char thrive in the cool waters of the Susitna River. Rainbow trout, Dolly Varden char, and Arctic grayling are among the prominent fish found in the river. These species contribute to ecological diversity, supporting the food web and offering recreational opportunities for anglers.

Freshwater Mussels

The Susitna River is also home to freshwater mussels, which play a vital role in maintaining water quality. These filter-feeding mollusks help purify the water by consuming suspended particles and improving clarity. They are an indicator species, reflecting the river’s overall health and water conditions.

Arctic Lamprey

The Arctic lamprey is a primitive, jawless fish found in the Susitna River and its tributaries. These eel-like creatures are parasitic during their larval stage, attaching themselves to fish hosts and feeding on their bodily fluids. While they may seem unusual, they are essential to the river’s food chain, providing sustenance for larger predators.

There’s a lot to love about this natural wonder of Alaska! Next time you find yourself near the Susitna River, it would be worth exploring the depths of the river as well as the natural wonders that surround it.

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

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About the Author

Em Casalena is a writer at A-Z Animals where their primary focus is on plants, gardening, and sustainability. Em has been writing and researching about plants for nearly a decade and is a proud Southwest Institute of Healing Arts graduate and certified Urban Farming instructor. Em is a resident of Arizona and enjoys learning about eco-conscious living, thrifting at local shops, and caring for their Siamese cat Vladimir.

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