Stewart Rood, Professor of Biology at the University of Lethbridge, discusses floods and floodplains in Alberta, and John Mahoney, Senior Environmental Biologist for Alberta ESRD, discusses functional flows in the same province.
Rood explains his comparison of Bow Rover, Bassano and Oldman River, and Lethbridge's annual flow of water from the last one hundred and eleven years. Assessing this data, it can be determined that Alberta's recent floods were unusual but not unprecedented. A flood of this magnitude is about a 1 in 75 year event. He also explains that floods are not worsening in Alberta. There is actually a statistical decline as a result of the regulation of the rivers.
Mahoney explains that flood flows are a natural and healthy process. There are ecosystems that depend on these high flows of water. From a scientific perspective, it can be understood as a normal part of a river's existence. Low flows meet the basic needs of organism, such as temperature and dissolved oxygen. High flows meet less common needs, such as floodplain forest regeneration. For example, Oldman river deposited fine sediments in the area in 2010. When the water receded again, it exposed moist barren substrate which became available for poplar seedling arrival, leading to new growth.
This presentation was a part of the CWRA Alberta Branch Annual Conference from March, 2014.
