The Use of Landsat and Sentinel-2 for Detecting Gold Mining in Colombia Based on River Water Turbidity

The Chocó department suffers from extraordinary amounts of alluvial gold mining resulting in increased river turbidity. A gap has been identified where a replicable means of identifying such turbidity was absent, and a developed method shrinks the gap with Landsat and Sentinel imagery; a GIS is used to assess the temporal mining change of Chocó and utilise a Normalised Difference Turbidity Index to quantify turbidity.
Mitigating effects clouds had on results was a challenge, and time constraints meant additional in-situ values could not be acquired. Nonetheless, turbidity quantified easily using the index and related well to identified mining sites highlighted from NDVI change. Classifications were accurate when verified with photographic evidence and revealed mining on the Quito profoundly increased turbidity for the Atrato while also identifying other sites. The method used simple tools and open-source data that can benefit decision-makers and communities of such regions, allowing them to monitor their own rivers.

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Figures in this paper include OS Data © Crown copyright and database [2018], Digimap License.
This research did not receive any funding from agencies or other sectors.