Historical Vegetation Mapping of the Oldman River Valley

Project Name: Historical Vegetation Mapping of the Oldman River Valley downstream of the Old Man Dam
Study Area: Pincher Creek to Fort Mcleod
Client: Pikkani First Nation
Partners: Harmony Walker (Prime Consultant), and Iris Environmental

Work Completed

In 2012 Iris Environmental and Harmony Walker Ltd. contracted Tannas Conservation Services (TCS) to partner in the historical mapping of the Oldman River valley on the Piikani Nation territory. This project was commissioned to determine the long term impact of the Oldman Dam on the river valley ecosystem and allow for appropriate mitigations to be placed. Within this project TCS personnel mapped each unique plant community polygon, completed a detailed field assessment, and assessed the changes in each polygon over the past 60 years. In addition the health of each plant community was assessed and ecological problems were identified. From this assessment Iris, TCS, and its partners were able to determine the impacts of the dam on the river valley.


The project complexity involved approximately 1000 polygons that had to be mapped with the previous maps being so poorly completed that they could not be used and paper copies had to be digitized and then updated. These limitations forced the team to complete a significant amount of additional work but still maintain the integrity of the budget. In addition, field access was limited by the access points to the river valley. Within this work the TCS team had to work within the access limitations to fulfill the assessment. While conducting the survey incidental rare species surveys were completed and a detailed assessment of the plant communities and health of them was completed. Historical flooding and condition of each wetland was assessed within the field ground trothing portion of the work.

Staff assigned to this project included, Clare Tannas (rangeland ecologist), Kathy Tannas (plant taxonomist), Steven Tannas (rangeland ecologist), Eileen Tannas (plant taxonomist). Steven was responsible for all mapping and historical comparisons between the plant communities over the past 60 years while the rest of the TCS team was responsible for the field assessments to ground truth the plant communities and assess their health.