Quantifying suspended solids in small rivers using satellite data

Isidro, Celso M., McIntyre, Neil, Lechner, Alex M. and Callow, Ian (2018) Quantifying suspended solids in small rivers using satellite data. Science of the Total Environment, 634 1554-1562. doi:10.1016/j.scitotenv.2018.04.006


Author Isidro, Celso M.
McIntyre, Neil
Lechner, Alex M.
Callow, Ian
Title Quantifying suspended solids in small rivers using satellite data
Journal name Science of the Total Environment   Check publisher's open access policy
ISSN 1879-1026
0048-9697
Publication date 2018-09-01
Sub-type Article (original research)
DOI 10.1016/j.scitotenv.2018.04.006
Open Access Status Not yet assessed
Volume 634
Start page 1554
End page 1562
Total pages 9
Place of publication Amsterdam, Netherlands
Publisher Elsevier BV
Language eng
Abstract The management of suspended solids and associated contaminants in rivers requires knowledge of sediment sources. In-situ sampling can only describe the integrated impact of the upstream sources. Empirical models that use surface reflectance from satellite images to estimate total suspended solid (TSS) concentrations can be used to supplement measurements and provide spatially continuous maps. However, there are few examples, especially in narrow, shallow and hydrologically dynamic rivers found in mountainous areas. A case study of the Didipio catchment in Philippines was used to address these issues. Four 5-m resolution RapidEye images, from between the years 2014 and 2016, and near-simultaneous ground measurements of TSS concentrations were used to develop a power law model that approximates the relationship between TSS and reflectance for each of four spectral bands. A second dataset using two 2-m resolution Pleiades-1A and a third using a 6-m resolution SPOT-6 image along with ground-based measurements, were consistent with the model when using the red band data. Using that model, encompassing data from all three datasets, gave an R value of 65% and a root mean square error of 519mgL. A linear relationship between reflectance and TSS exists from 1mgL to approximately 500mgL. In contrast, for TSS measurements between 500mgL and 3580mgL reflectance increases at a generally lower and more variable rate. The results were not sensitive to changing the pixel location within the vicinity of the ground sampling location. The model was used to generate a continuous map of TSS concentration within the catchment. Further ground-based measurements including TSS concentrations that are higher than 3580mgL would allow the model to be developed and applied more confidently over the full relevant range of TSS.
Formatted abstract
The management of suspended solids and associated contaminants in rivers requires knowledge of sediment sources. In-situ sampling can only describe the integrated impact of the upstream sources. Empirical models that use surface reflectance from satellite images to estimate total suspended solid (TSS) concentrations can be used to supplement measurements and provide spatially continuous maps. However, there are few examples, especially in narrow, shallow and hydrologically dynamic rivers found in mountainous areas. A case study of the Didipio catchment in Philippines was used to address these issues. Four 5-m resolution RapidEye images, from between the years 2014 and 2016, and near-simultaneous ground measurements of TSS concentrations were used to develop a power law model that approximates the relationship between TSS and reflectance for each of four spectral bands. A second dataset using two 2-m resolution Pleiades-1A and a third using a 6-m resolution SPOT-6 image along with ground-based measurements, were consistent with the model when using the red band data. Using that model, encompassing data from all three datasets, gave an R2 value of 65% and a root mean square error of 519 mg L-1. A linear relationship between reflectance and TSS exists from 1 mg L-1 to approximately 500 mg L-1. In contrast, for TSS measurements between 500 mg L-1 and 3580 mg L-1 reflectance increases at a generally lower and more variable rate. The results were not sensitive to changing the pixel location within the vicinity of the ground sampling location. The model was used to generate a continuous map of TSS concentration within the catchment. Further ground-based measurements including TSS concentrations that are higher than 3580 mg L-1 would allow the model to be developed and applied more confidently over the full relevant range of TSS.
Keyword Empirical modelling
Philippines
Small-scale mining
Surface reflectance
Total suspended solids
Turbidity
Q-Index Code C1
Q-Index Status Provisional Code
Grant ID FT140100977
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
Sustainable Minerals Institute Publications
 
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Created: Fri, 27 Apr 2018, 02:57:59 EST