A retrospective study of the local impacts resulting from the Shellmouth Reservoir, the use of cost benefit analysis in pre-development reservoir assessment

Abstract

One compelling rationale for ex-post development review is to improve current and future practices in resource management by assessing the strengths and weaknesses of past analyses, conducted to review project options and identify impacts. The Shellmouth Dam, near the anitoba-Saskatchewan border, is an example of a water resource project that was predicated on a series of engineering and economic studies. They were designed to assist decision-makers in selecting between various flood control measures for th Assiniboine and Red Rivers. An ex-post development review of the Shellmouth project reveals a variety of limitations with cost-benefit analysis (CBA) in its role as a pre-development assessment tool. This ex-post study includes an assessment of local impacts, a literature review of CBA, and a review of the Shellmouth CBA conducted between 1958 and 1961. It would be inappropriate to criticize the project's original CBA on the basis of today's perspectives on environment, equity and other social values. However, this ex-post review considers today's value system and experience with reservoir projects. This is not to pass judgement on the original CBA, but to provide valuable insight into opportunities for improving the use of CBA for the assessment of future reservoir projects. The ex-post review of the Shellmouth Reservoir noted a number of positive and negative environmental and socio-economic impacts, that have accrued to the local area as a result of the project, but were not identified in the CBA. The study looks at the Shellmouth CBA, in an effort to determine where improvements can be made that would better address local costs and benefits, to ensure a core comprehensive CBA of future reservoirs.