Testing utility of Landsat 8 for remote assessment of water quality in two subtropical African reservoirs with contrasting trophic states |
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Authors: | Mhosisi Masocha Timothy Dube Tamuka Nhiwatiwa Dennis Choruma |
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Affiliation: | 1. Department of Geography and Environmental Science, University of Zimbabwe, Harare, Zimbabwe;2. Department of Geography and Environmental Science, University of Limpopo, Polokwane, South Africa;3. Department of Biological Sciences, University of Zimbabwe, Harare, Zimbabwe |
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Abstract: | Water quality problems continue on a global scale and this creates the need for regular monitoring using cheaper technologies to inform management. The objective of this study was to test for significant relationships between the field-measured and Landsat 8 OLI sensor-retrieved water quality parameters. The study was carried out in two reservoirs with contrasting trophic states in Zimbabwe. Results show that the Blue/Red ratio had strong predictive relationships with Secchi disc transparency (R2 > 0.70) and turbidity (R2 ≥ 0.65). The Near-infrared/Red ratio was a strong predictor of chlorophyll-a in Mazvikadei (R2 > 0.84) whereas in Lake Chivero, which is more polluted, the red band was the most useful predictor (R2 = 0.69). Overall, our work demonstrates the utility of using Landsat 8 band ratios for remote assessment of water quality in African reservoirs as a value-addition to the traditional field-based methods, which are expensive resulting in data scarcity. |
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Keywords: | Chlorophyll-a Lake Chivero remote sensing Secchi disc turbidity |
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