Dam different! How the physical properties of beaver dams influence water storage dynamics
Date
2021-01-26
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0002-1811-911X
Type
Thesis
Degree Level
Masters
Abstract
The North American beaver (Castor canadensis) is regarded widely as an ecosystem engineer and the dams they create are well known for their ability to drastically alter the hydrology of river basins. As a result, beavers are increasingly being included in green infrastructure practices to combat the effects of climate change and enhance ecosystem resilience. Both drought and flood mitigation capabilities have been observed in watersheds with beaver dam structures; however, how dams can possess such contrasting mitigation abilities is not fully understood as most studies neglect to acknowledge the incredible variation in beaver dam structures. In this study, an extensive cross-site survey of dam properties and water flow through dams in the Canadian Rocky Mountains in Alberta was conducted. The dam flow type classification from Woo and Waddington (1990) was evaluated in this new context and adapted to include two new flow types not found in the original study. The survey revealed significant differences in dam structure across the different sites. Physical differences in dam structure altered the dynamics and variance in the ponds’ storage and certain dam attributes related to landscape setting. However, a closer analysis of large rain events surprisingly showed little influence of dam physical structure on storage and recession limbs. These results reveal that variation in dam structure alters the temporal dynamics of pond storage but also emphasizes that some metrics, including response to rain events, may remain constant regardless of dam structure. This combination of variability and stability may be the secret to the contrasting mitigation abilities possessed by beaver dams. Further research may be able to use these results to better predict streamflow routing through beaver ponds and improve the prediction and modelling of beaver dam effects.
Description
Keywords
beaver dams, dam flow type, pond water storage, surface hydrology
Citation
Degree
Master of Science (M.Sc.)
Department
Geography and Planning
Program
Geography