Archaeology and the June 2013 Floods in Southern Alberta

In June 2013, heavy rainfall triggered catastrophic flooding in southern Alberta that has been characterized as some of the worst in the province’s history. Areas along the Bow, Elbow, Highwood, Red Deer, Sheep, Little Bow and South Saskatchewan Rivers, and their tributaries, were affected. Estimates of property damage from the flood make it one of the most costly in Canadian history. Personal property, however, was not the only casualty. The torrents of water accelerated natural erosional and depositional processes, resulting in significant alteration to many of southern Alberta’s river systems.

Debris-flow fan on the Highwood River, caused by the June 2013 flood.

Debris-flow fan on the Highwood River.

Erosional exposure on the Sheep River, caused by the June 2013 flood.

Erosional exposure on the Sheep River, caused by the June 2013 flood.

The potential for finding archaeological sites along southern Alberta’s river systems has always been high. The distribution of known archaeological sites in Alberta indicate the importance of the major river systems to precontact and historic people as sources of fresh water, food resources and travel corridors.  As a result of these associations, a number of archaeological sites were also identified as casualties of the June 2013 flood.

Between summer 2013 and 2015, the Archaeological Survey of Alberta Culture and Tourism contracted 10 projects related to studying the effects of the flood on archaeological resources. These studies included site inventory and assessments along the Bow, Highwood, Kananaskis and Sheep Rivers and Jumpingpound, Fish and Tongue Creeks, as well as excavations at two precontact campsites on the Bow River.

The extent and location of the 2013-2015 archaeological survey carried out on flood-affected creeks and rivers.

The extent and location of the 2013-2015 archaeological survey carried out on flood-affected creeks and rivers.

The assessments included nearly 485 kilometres of waterway and the evaluation of approximately 491 river and creek bank exposures (ranging from 5 metres to 830 metres long) that had been created during the flood. From this, 100 new archaeological sites were identified, while the status of another 87 previously recorded sites was updated. Flood impact to these sites was found to range from almost negligible to the removal of as much as 220 metres of some lower river terraces.

Flood Work by the Numbers_CH_2

The sites investigated included both precontact and historic period materials. They were most often identified by deposits of bison bone, fire broken rock (indicative of a hearth), or cobbles that had been used as the raw material to create stone tools. Many of the sites are thought to date to approximately 400 to 150 years before present. Although rarer, earlier sites were also found, including one on the Bow River associated with a volcanic ash known as the Bridge River ash (dating to 2300 years ago) and a bison killsite and campsite on the Sheep River that was used between 3000 and 6000 years ago. The oldest find was a bison skull that has been radiocarbon dated to 10,840 years old, but was not found in association with any cultural materials. However, it still provides an intriguing glimpse into the environment that existed in Alberta just following the last glacial period.

Bison skull found in a cutbank of the Bow River (left) and bison vertebrae found in a cutbank of the Highwood River (right), both exposed by the June 2013 flood.

Bison skull found in a cutbank of the Bow River (left) and bison vertebrae found in a cutbank of the Highwood River (right), both exposed by the June 2013 flood.

The investigations conducted as part of the 2013-2015 Southern Alberta Flood Assessment Program has resulted in the collection of much evidence that will help us understand the landscape and lifeways practices in Alberta’s ancient past. In many ways, however, the work has only just started, as analysis will be ongoing to understand the intricate relationship between human adaptation and the rivers that sustained them.

Erosion of river and creek banks continues as a result of the June 2013 flood along many of southern Alberta’s waterways. If you see archaeological remains that are in threat of being eroded, you can assist in their preservation by reporting the find to Alberta Culture and Tourism’s Report-A-Find program.

Information on many of these flood projects will be presented at the upcoming Archaeological Society of Alberta conference in High River from April 29-May 1, 2016. 

Written By: Jo-Ann Marvin (Regulatory Approvals Coordinator), Wendy Unfreed (Plains Archaeologist) and Courtney Lakevold (Archaeological Information Coordinator)

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