The Bow River ~ Where does it come from and where does it go?

During the last 20 years of guiding I've been asked many questions about the Bow River. Some I was able to answer and some not. The most memorable question concerned the provenance of the name "Policeman's Flats" a vital Bow River access. In the early years I would simply state that I didn't know. About that time we usually caught a trout and the question and my truthful answer was forgotten. After revealing my ignorance many times on the subject I decided to concoct an answer. I enjoyed my fabricated story tremendously and told it often - followed by the truth

My story goes like this: Policeman's Flats was a party location for the local constabulary. These parties became famous after one such night when one of the boys in blue had consumed too much, fell off the tail gate of a pick up truck just as it was backing up. The drunk was run over ~ thus the name Policeman's Flats. Colorful, eh?

The truth: Apparently the derivation of the name comes from the natives that would come out of the foothills down to the river where a RCMP fort existed. Here the land became flatter and the name was born - Policeman's Flats. Not so colorful............

While surfing recently I came across a Government web site that contained a wealth of knowledge about the Bow River. I'm not a fan of Gov't and have stated previously that if Gov't ran crime, it wouldn't pay! In this case they have done an excellent job of telling the story of the Bow River Basin Waterscape. Below is some of that wealth

Bow River Basin Waterscape

We live in the basin of the Bow River, a remarkable tract of land that extends from the Rocky Mountains, across foothills and the rapidly growing City of Calgary, to the broad prairie. This land has been home to First Nations for thousands of years. Within this basin, all waters flow into the Bow River. We share this water with plants and animals. Without this water, nothing could live. With this water, a great diversity of life, including humans, can thrive. As residents of the Bow River basin, we must protect the land that produces the life-giving waters. We face many challenges. Our rapidly growing population demands much of the land and water. Our climate is changing and the future of our water supplies is uncertain. To act wisely, we need first to understand our basin. The purpose of this poster is to introduce us to the local water cycle, to how humans use the basin waters, and to how we can live well on the land.

Where does the Bow River Go?

The Bow River joins the Oldman River near Medicine Hat to form the South Saskatchewan River. Bow River waters flow all the way to Hudson Bay. Downstream communities that use these waters, such as Medicine Hat and Saskatoon, depend on us to care for the quality of the water as it passes through the Bow River basin.

Bow River Basin

A river basin or watershed is high at its edge and low in the center where the river flows. The Bow River basin or watershed includes all the land that feeds water to the Bow River and its tributaries.

Mountains, foothills and prairies

Most Bow River waters come from the Rocky Mountains, an area largely protected within parks. East of the mountains, the Bow River flows through foothills and then through rolling prairie. The Bow River also flows through the City of Calgary, home to most of the basin's human residents.

The Bow River basin is the most densely populated river basin in Alberta. Less water is available per person here than in any other river basin in the province. And yet, in the last ten years, the population of the basin has grown by over a quarter of a million people. So we are facing a challenge!

The lands of the Bow River basin have been home to First Nations people for thousands of years. Today, the Stoney Nakoda Nation has reserve lands throughout the foothills of the Bow River basin. Tsuu T'ina Nation reserve lands extend west from Calgary to Bragg Creek, and Siksika Nation reserve lands straddle the Bow River valley near Bassano.

So effective are the Rocky Mountains at stripping moisture from eastward-moving air masses that little is left for the prairie areas, creating a 'rain shadow'. This is why irrigation is vital to agriculture. The Bow River is the only dependable source of water.

 

Sources of Bow River water

Water flows the entire length of the Bow River in less than two weeks. Why then doesn't the Bow River dry up between rainstorms? Because nature stores and slowly releases water throughout the basin. Water is stored in snow packs, glaciers, wetlands, and aquifers.

Almost all the water in the Bow River comes from the Rocky Mountains. This mountain chain forces air to rise and cool, causing moisture to condense and fall as rain or snow. This precipitation, together with the melt waters from glaciers that release ancient snowfalls, feed the Bow River through its many mountain tributaries. Even groundwater that feeds the Bow River begins its life as rain or snow.

Many people wonder what will happen to the river if the glaciers melt away. In fact, glacier melt waters contribute less than 1% of the total annual flow to the Bow River so their overall contribution is small. However, the portion of Bow River water derived from glaciers rises during the summer as snowmelt wanes. During a drought year with reduced snowfall and rain, the relative contribution of glacier melt water to the Bow River is higher. Without glaciers in the Bow River basin, water supply during drought years would be much more challenging. However, as long as it snows and rains every year, we can expect the river to keep moving.

 

Ground Water ~ the Hidden Reservoir

 

 

Rain and snowmelt infiltrate the ground. Soil and rock act as giant sponges full of tiny pores and cracks that are usually less than millimetres in size. Below the water table, these holes are full of water. This is groundwater. Groundwater slowly travels through connected pores and cracks, just centimetres to hundreds of metres per year. Any rock or sediment that yields useful amounts of water is an aquifer. The volume of groundwater below us dwarfs the volume of water stored in glaciers, lakes, wetlands, and rivers.

Groundwater and surface water are one connected water system. Water wells intercept groundwater that may be on its way to springs that feed streams and rivers.

In southern Alberta, oil and gas drilling has shown that groundwater is found to depths of four kilometres or more. However, most of this groundwater is very salty. Only shallow groundwater is potable or fit to drink.

 

The Bow River and Climate Change

 

 

 

Sharing Bow River Water

 

 

Some water use occurs in the river, such as by wildlife and for fisheries and recreation. Some water is withdrawn from the river, used, and returned (non-consumptive use). Municipalities return over 90% of the water they use as treated sewage. Some water is withdrawn from the river and not returned (consumptive use). In dry years, irrigation returns about 20% of what it withdraws. Most of the rest is used by plants, whereas some evaporates and a small amount sinks into the ground. Withdrawal of water from the river reduces river flow and can have an impact on wildlife habitat in and along the river.

 

Keeping the Bow River Clean

Riparian areas occur along streams and wetlands where moist soils and shallow water tables allow water-loving plant communities to establish. These 'green zones' are vital ecosystems in the prairie and foothills that provide habitat for wildlife, stabilize stream banks, and protect water quality. Cattle grazing in riparian areas must be managed carefully so that these delicate landscapes are not degraded.

 

 

Down the Drain

There is a widespread myth that water that goes down storm drains flows to water treatment plants. This is not true. Storm drains are only meant for rainwater and snowmelt. Many street drains flow through pipes straight to the river.

 

Credits and Citations

Turner, R.J.W., Franklin, R.G., Grasby, S.E., and Nowlan, G.S.
2005:  Bow River Basin Waterscape; Geological Survey of Canada, Miscellaneous Report 90, 2005.

R.J.W. Turner, R.G. Franklin, S.E. Grasby, and G.S. Nowlan

R.G. Franklin and R.J.W. Turner

Bow River Basin Council: M. Bennett

Alberta Environment: J. Horgan

Natural Resources Canada, Geological Survey of Canada: S.E. Grasby, G.S. Nowlan, R. Smith, R.J.W. Turner

Agriculture and Agri-Food Canada, Prairie Farm Rehabilitation Administration: M. Parry

Environment Canada: R. Herrington

Parks Canada: H. Dempsey, C. Pacas

City of Calgary: M. Beeston, P. Fesko, S. Trosch

University of Calgary: C. Ryan

Climate Change Central: F. Walter

Calgary Board of Education: W. Campbell, S. Hollinshead, L. Johnston, D. Stretch

Calgary Roman Catholic Separate School District No. 1: C. Szata, L. Morello

TELUS World of Science: B. Struble

SEEDS Foundation: D. Lunn

Rundle College Junior High: B. Ross

 

 

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