Department of Geography and Environmental Studies


Greg George Yetman, 1996

A Strategic Environmental Assessment of Aggregate Extraction on Banquereau


As sources of high quality, land-based aggregates close to markets have been used up, marine aggregates have been considered as a potential source for meeting market demand. Marine aggregate extraction has also been considered as an industry that could help maintain the economic viability of coastal communities in Nova Scotia. The environmental impacts of aggregate extraction are a concern to stakeholders. These impacts need to be addressed before an industry such as this can proceed. A Strategic Environmental Assessment (SEA) is a good method of determining the environmental impacts of an aggregate extraction industry before it is established. A Geographic Information System (GIS) is a useful tool for storing and using data to assess impacts and their spatial implications.

An environmental database for the study area (Banquereau) of physical, biological, and cultural information was established in digital format for use in the Idrisi GIS. This information was utilized in the form of factors and constraints for a Multi-Criteria Evaluation (MCE) module within the GIS software. The results give two suitability maps for Banquereau: one of areas of medium and coarse sand, the other with areas of coarse sand only. These maps are spatial expressions of the factors used in the evaluation.

A series of recommendations have been made in this research project. These recommendations are: i) the estimation of database error should be an important part of new data collection and in the evaluation of established databases; ii) in any future assessments of aggregate extraction, stakeholder consultation using a consensus process should be undertaken to establish criteria for the evaluation; iii) the relevant government departments should establish a position on aggregate extraction; and iv) if the position of the government departments is determined to be in favour of offshore aggregate extraction, appropriate legislation should be developed to encourage and regulate exploration and development of such an industry.