Land, Water, People - Through Foothills and Under Hoodoos
The Milk River Watershed contains a diverse array of landforms and plant communities that all play a role in the functioning of the watershed. Arid landscapes dominate because of the low precipitation across most of the watershed. Over 68% of the watershed remains in native vegetation. This is much higher than most watersheds in Alberta.
Dry Mixed Grass
Most of the Milk River Watershed sits in the Dry Mixed Grass Natural Region. The low precipitation and high evaporation result in a mixture of short and medium-height grasses such as blue grama grass, spear grass and June grass.
Mixed Grass
A small area of the Mixed Grass Natural Region is found in the Milk River Watershed. This region supports a mixture of grasses such as western wheatgrass, spear grass and June grass.
Foothills Fescue
The western part of the watershed sits in the Foothills Fescue Natural Region, characterized by tall moistureloving grasses such as rough fescue (Alberta's Provincial Grass). Foothills Fescue is also found in higher parts of the watershed, such as the Milk River Ridge and Cypress Hills.
Riparian Areas
Healthy riparian areas alongside creeks, rivers, wetlands and other water bodies are vitally important to the watershed. Riparian areas filter nutrients and sediment before they reach the water body. They also help to store water and provide excellent wildlife habitat.
The Sweetgrass Hills
Although not in Alberta, the Sweetgrass Hills are a prominent part of the landscape, rising 1,000 metres above the surrounding prairie. Consisting of hard igneous rock that solidified below ground, they have become exposed as a result of uplift and the subsequent erosion of the overlying sediments. A smaller example, Black Butte, is found in Alberta, about 30 km northeast of the Sweetgrass Hills. These hills are important collection areas for water. Their wetter climates help replenish aquifers and surface water in the watershed.
Native Rangelands
Extensive rolling grasslands are a prominent and important part of the Milk River Watershed. Well-managed native rangelands contribute significantly to the quality and quantity of water. Healthy grasslands absorb water, acting like a sponge, thus reducing surface runoff and increasing the amount of water stored. They also filter nutrients, thereby protecting water quality. Healthy native grasslands reduce the amount of sediment that runs off into creeks and rivers. Native rangelands are resistant to drought and make efficient use of available water - a very suitable landuse for this dry area!
Sandstone Outcrops
East of the Town of Milk River, unique and spectacular sandstone formations flank the river. Wind and water erode the soft sandstone, creating mystical shapes and surreal-looking topography. DIfferential erosion of sandstone layers of varying hardness results in rock pillars, called hoodoos. The eroded sediment ultimately ends up in the Milk River, causing the high turbidity and milky colour.
The Cypress Hills
The Cypress Hills represent one of the few forested parts of the landscape. Because the hills rise 600 metres (1968 feet) above the surrounding plains, they receive an average of 430 - 500 mm (17-20 inches) of precipitation annually. This is significantly more that the surrounding prairies, which receive 300 - 450 mm (9.5 - 11 inches), making the hills an important water source for the rest of the watershed. The many springs that seep from the rocky substrate on the south side of the hills eventually feed into to the Milk River. The Cypress Hills also contribute significantly to groundwater recharge in the watershed.
A Few Sizes Too Small...
The Milk River looks a little out of place in the wide, dramatic Milk River Canyon. How could it have possibly created such a wide, deep valley? The answer - it didn't. The canyon was cut when almost all of the runoff from southwestern Alberta was diverted into the Milk River because ice sheets were blocking drainage to the northeast. Many wide coulees, such as Verdigris Coulee, and the Whiskey Gap in the Milk River Ridge were formed at this same time. They drained water from the melting ice sheets into the Milk and Missouri Rivers. As the edge of the continental glacier receded past the Cypress Hills, the water was able to drain to the north of the Hills, eventually forming the South Saskatchewan River.
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