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Canyon Creek Waterway

The Canyon Creek Waterway is the lifeline of native tree population at the Yellowstone Arboretum. It supplies the immediate area with many species that have spread onto the arboretum itself some good, some invasive but nevertheless it brings new life. We've described some of the species you can find along the creek banks along with the native commerce of wildlife and water.

Canyon Creek, as it runs 16 miles from Buffalo Trail Road to the Yellowstone River between Laurel and Billings, is showing the wear and tear of development over the past 20 years.


Growth and subdivisions are changing the historically agricultural landscape between the two communities into an urban setting. According to the 2000 census, an estimated 5,600 people live within two miles of the stream along the 16-mile reach.

Increased demands on the waterway are causing severe erosion along its banks. And the erosion is leading to a large amount of sediment being carried into the Yellowstone. Bank erosion also threatens bridges over the creek.


In addition to stream bank erosion, noxious weeds like knapweed and saltcedar are beginning to infest the drainage.


Technically, the creek is classified by the Montana Department of Environmental Quality as impaired from streamflow alterations. The primary flow alteration is caused by the return to the creek of irrigation water taken from the Yellowstone River through ditches.


Examples of the trees found in riparian areas can be found throughout the arboretum, some in these locations:

Willows-Old Pond Collection, Asian Habitats, Homestead Collection

Buckthorn- Asian Habitats, Lynx Pathway, Waterways

Narrowleaf Cottonwood-Asian Habitat, Back Bridge to Wolves (north of bridge-photo above)

Russian Olive-Waterways, Wolf habitat, Asian Habitats

 NOAA and the National Weather service in conjunction with the State of Montana conducts river gauge readings for Canyon Creek at ZooMontana. The gauge can be seen from the bridge just west of Dottie's Garden  (LAT 45.73140 N /LONG-108.62400 W). More information and current reading can be found by clicking the following:


Complete information about the Canyon Creek at Billings (Zoo Montana) 
 NWS Billings, MT


Note: Graphical forecasts are not available for the Canyon Creek at Billings (Zoo Montana).  During times of high water, forecast crest information can be found in the text products.

“Eventually, all things merge into one, and a river runs through it. The river was cut by the world's great flood and runs over rocks from the basement of time. On some of those rocks are timeless raindrops. Under the rocks are the words, and some of the words are theirs. I am haunted by waters.”                                                                                  ― Norman Maclean, A River Runs Through It

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Cottonwood riparian forest

A cottonwood seed bobs in a river current, kept afloat by a tuft of fluffy white hairs. Swept onto a sandbar, the seed grow…

If given the chance, the seedling will mature, its roots stretching down into the riverbank and branches reaching for the sky, forming a crucial part of the riverbank ecosystem. Over time, other plants will join these hardy pioneers, forming a strip of vegetation along the river called a riparian forest – a complex, multilayered ecosystem overflowing with a diversity of life.

Ecological significance

Cottonwood riparian (from the Latin ripa, meaning bank) forests are a biological treasure house, full of an amazing variety of plants and animals.
Cottonwoods don’t mind wet feet, sprouting on sand and gravel bars along flood plains. Fast-growing trees, they suck up hundreds of litres of water daily, nourishing an impressive growth rate of two metres per year.
Riparian shrubs shade streams and provide browse and cover for larger mammals. Meanwhile, cottonwoods are often decapitated by windstorms, lightning strikes and heavy snow. Big cottonwoods are also prone to heart rot and have hollow trunks.
These standing dead and dying trees provide habitats not found in younger forests. The dead limbs and trunk cavities provide living space for many different birds and mammals, including black bears, which have been observed hibernating high up in hollow cottonwoods.

There are many areas along Canyon Creek that form natural Riparian Forests not only of Cottonwood but some of these native and not-so-native trees below.

of the


Common buckthorn is an invasive plant  and should not be planted. It forms dense thickets and reproduces very freely, crowding out other plants and disrupting  ecosystems in forest preserves and other natural areas. In woodlands it can completely replace existing understory plants, including native wildflowers. Buckthorn has berries that are spread by birds. The seeds germinate at a very high rate and remain viable in soil for two to three years. Buckthorn is a large shrub or tall tree with glossy oval leaves that can easily be recognized in fall, when it remains green after most other leaves have fallen.


Willows are deciduous trees or shrubs in the genus Salix, in the willow family Salicaceae. There are more than 300 species in this genus, mostly found in the Northern Hemisphere. Willows bear flowers in spikes of drooping clusters (called catkins) early in the spring before leaves unfurl. Individual flowers are small but the catkins for some species are conspicuous and very attractive.


Populus angustifolia, commonly known as the narrowleaf cottonwood, is a species of tree in the willow family (Salicaceae). It is native to western North America, where it is a characteristic species of the Rocky Mountains and the surrounding plains It ranges north to the provinces of Alberta and Saskatchewan in Canada and south to the states of Chihuahua, Coahuila, and Sonora in Mexico. Its natural habitat is by streams and creeks between 3,900 to 7,900 feet (1,200 to 2,400 m) elevation.

Elaeagnus angustifolia is a shrub or small tree that can grow to 35 ft. (10 m) tall. The young branches are silvery while the older branches are brown. They are occasionally thorny and covered with scales.
The leaves are simple, alternate and lanceolate to oblong-lanceolate. They are 1-4 in. (3-10 cm) long and have silver scales on both sides.
The fragrant flowers are 0.5-0.6 in. (1.2-1.5 cm) wide, silvery outside and yellow within. There are 1-3 flowers within the leaf axils. They appear in May to June.
The fruit are 0.4 in. (1 cm) long, are yellow and almost completely covered by densely silver scales. The fruit contain one large seed that can be up to 0.4 in. (1 cm) long within.
Ecological Threat
Although Elaeagnus angustifolia is not considered to be invasive in some parts of the U.S., in the western part of the United States it is considered invasive as well as a noxious weed in some states. It grows especially well in riparian situations and has been documented as out-competing the native plains cottonwood (Populus deltoides). It has been planted along roads and highways in New England because of its drought and salt tolerance. Nitrogen-fixing nodules allow this plant to survive in adverse conditions. Autumn olive (Elaeagnus umbellata), its invasive relative, has a similar biology and is already widely invasive in New England.

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