Combining unmanned aerial vehicle-based remote sensing and stable water isotope analysis to monitor treatment peatlands of mining areas

Abstract Treatment peatlands are water purification systems located on existing mires. They are commonly used to treat different types of waters, ranging from municipal wastewaters to mine effluent. This study evaluated the capacity of unmanned aerial vehicle (UAV)-based thermal infrared (TIR) imagi...

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Bibliographic Details
Main Authors: Isokangas, E. (Elina), Davids, C. (Corine), Kujala, K. (Katharina), Rauhala, A. (Anssi), Ronkanen, A.-K. (Anna-Kaisa), Rossi, P. M. (Pekka M.)
Format: Article in Journal/Newspaper
Language:English
Published: Elsevier 2019
Subjects:
UAV
Online Access:http://urn.fi/urn:nbn:fi-fe2019112944816
Description
Summary:Abstract Treatment peatlands are water purification systems located on existing mires. They are commonly used to treat different types of waters, ranging from municipal wastewaters to mine effluent. This study evaluated the capacity of unmanned aerial vehicle (UAV)-based thermal infrared (TIR) imaging, color infrared imaging, and stable water isotopes as a combined method for monitoring the functioning of a treatment peatland purifying mine process effluent water under boreal conditions in northern Finland. The results showed that TIR was an efficient tool for pinpointing cold groundwater seepage points in the peatland area that were not otherwise visible. Color infrared imaging was used to define Normalized Difference Vegetation Index (NDVI), as an indicator of plant health in the treatment area. A NDVI map of the area, measured on a day representing the main growing season (summer, +12 °C day temperature), revealed areas with stressed coniferous trees. This was probably due to excess water in these areas, resulting from successful spread of the process effluent water to the treatment peatland. Stable water isotopes were able to spatially differentiate the treated process effluent water, surface waters, and groundwater in different parts of the treatment peatland. This first attempt at combining these methods in monitoring of treatment peatlands was promising, as the results obtained with different methods complemented each other. While they produce only a snapshot of prevailing conditions, all three methods, singly and in combination, could be valuable tools in treatment peatland management.