Quantitative Assessment and Geospatial Monitoring of Total Dissolved Solid indicator for Surface Water Quality

Abstract

Continuous check of water quality is a vital element that supports lives, aquatic ecosystem and the natural environment. Fresh water solid pollutants must be monitored to ensure water safety, avoid water quality decline and impairment. This study examines total dissolved solid (TDS) a viable water quality indicator in Hartbeespoort dam located in South Africa, Northwest province. The study utilized Landsat 8-9 (OLI & TIR) multi-spectral bands with 30m resolution and higher spatial wavelength. Band combination algorithms such as NDSI, Salinity equation I and 2 was employed for TDS estimation. Models were generated using band ratio combinations with high correlation coefficients and were tested with linear, polynomial and exponential regression equation analysis. Validation was done using real time in-situ data measurement. The result uncovered a viable correlation such as (NDSI in polynomial (R<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>= 0.99), Salinity Index 1 in polynomial = (R<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>= 0.98) and Salinity Index 2 in polynomial recorded a lower value of R<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>= 0.47), TDS mapping using the chosen algorithm showed high values range of 5.332 and 3.931 (dissolved solid). The highest value derived were noted to be above water quality permissible limit for (TDS). The study equally established the expediency of utilizing satellites acquired data of Landsat 8-9 to examine TDS concentration in freshwater dam.