Gräpel, C 2025, 'Recent case histories for dam decommissioning in Alberta', in S Knutsson, AB Fourie & M Tibbett (eds), Mine Closure 2025: Proceedings of the 18th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1-14, https://doi.org/10.36487/ACG_repo/2515_16
(https://papers.acg.uwa.edu.au/p/2515_16_Grapel/)
Abstract: In 2018 the Government of Alberta (GOA) released the Alberta Dam and Canal Safety Directive (ADCSD), including decommissioning, closure, and abandonment of dams and canals (Part 9) and a requirement that public infrastructure and its possible decommissioning should be evaluated when it either becomes a public safety issue or requires rehabilitation. 
Three recent dam removal projects are described in this paper, in terms of how they meet the requirements of the directive, with technical details provided on permitting; design; and construction in the context of each project.
The first project (Klein Lake Dam) is a former water storage dam, constructed to expand a lake for recreational opportunities, which was removed instead of reconstructed after it experienced overtopping failure. 
The second project (Billy Goat Dam) is a mine water diversion dam for a mine pit that will be removed after cessation of mining, as part of long-term mine reclamation plans. 
The third project (Southeast Dyke) is a low consequence dyke for a cooling pond at a thermal generating station with consequences of failure that have decreased over time, due to mining activities modifying the downstream environment. 
These three projects are in different steps – from the process of design to completion of construction – with Klein Lake Dam removal being completed, Billy Goat Dam permitted but not decommissioned, and Southeast Dyke being in the process of obtaining permits to decommission. Additional perspectives from assessment of fish habitat, revegetation, soil nutrients and soil chemistry are also discussed as applicable to illustrate how environmental science informs dam removal design, supports obtaining regulatory permits for dam removal works, and guides construction planning for dam removal.
The application of the ADCSD to dam removal and dam decommissioning projects is presented in this paper, with description of site-specific conditions that lead to selecting the dam removal or dam decommissioning option and discussion on how environmental studies inform design and permitting. The value of detailed environmental evaluations, hydrologic flood routing, assessing downstream impacts on third parties and environmental features, the importance of soil science and vegetation ecology to reservoir bottom revegetation, construction details where applicable, and relationships with regulators will be discussed.

Keywords: dam removal, decommissioning