Estimation and mapping of water quality parameters using satellite images: a case study of Two Rivers Dam, Kenya

Abstract

The continuous water quality monitoring (WQM) of watersheds and the existing water supplies is a crucial step in realizing sus- tainable water development and management. However, the conventional approaches are time-consuming, labor intensive, and do not give spatial–temporal variations of the water quality indices. The advancements in remote sensing techniques have enabled WQM over larger temporal and spatial scales. This study used satellite images and an empirical multivariate regression model (EMRM) to estimate chlorophyll-a (Chl-a), total suspended solids (TSS), and turbidity. Furthermore, ordinary Kriging was applied to generate spatial maps showing the distribution of water quality parameters (WQPs). For all the samples, turbidity was estimated with an R 2 and Pearson correlation coefficient (r) of 0.763 and 0.818, respectively while TSS estimation gave respective R 2 and r values of 0.809 and 0.721. Chl-a was estimated with accuracies of R 2 and r of 0.803 and 0.731, respect- ively. Based on the results, this study concluded that WQPs provide a spatial–temporal view of the water quality in time and space that can be retrieved from satellite data products with reasonable accuracy.