Investigating Conflicts between Gold Mining and Water Protection by Remote Sensing Imagery

Water is a scarce resource and is therefore subject to manifold competing interests and conflicts. This is exemplified best by the mining sector which requires large quantities of water and can make it unusable for other purposes. This is an important aspect, especially in developing countries, as our research in Ghana shows. We investigated how space technologies and optical remote sensing can be used to determine surface water quality from space and to track pollution in areas affected by mining. In addition to a technical report, we analysed the existing public policies in Ghana regarding safeguarding water quality using remote sensing. Based on an intensive literature review, the analysis of policies, expert interviews and an exhaustive search for available datasets we identified several loopholes and pitfalls that hamper the usage of remote sensing: Firstly, there is a clear lack of readily available datasets allowing fast analysis of surface water bodies and their quality. Secondly, in-situ reference data required for calibrating and validating workflows and algorithms based on remote sensing are hardly available for developing countries such as Ghana since existing governmental data is not freely available. Especially in Ghana we can see that practitioners and policy makers are aware of the potential of space technologies and remote sensing because they are cost effective and comprehensible. In practice, however, these technologies are hardly used due to the limitations described. In addition, remote sensing-based approaches to water quality assessment and pollution tracking have to take into account complex interference effects between the local population, legal and illegal mining activities, which makes in-situ references and local expertise indispensable alongside the use of these technologies. We therefore recommend the development of in-situ reference and knowledge databases for managing space-borne water quality retrieval. Thus, we strongly advice expert knowledge about local conditions to be systematically recorded and to make data available to the public using standardised web services and data exchange formats.