Water quality and remote sensing: A case study of Lake Naivasha, Kenya

Abstract

Freshwater resources are losing their quality posing a threat to human and aquatic life. Remote sensing has shown potential to monitor these resources. This study aimed to retrieve diffuse attenuation coefficient (Kd), to map euphotic depth (Zeu) of Lake Naivasha, Kenya, using Medium Resolution Imaging Spectrometer (MERIS). Radiometric data was collected at Lake Naivasha. The Kd model was calibrated using in situ data and validated using MERIS 490 nm band, giving an RSME 0.43 and MAE 31%. Zeu validation gave an RSME 0.24 and MAE 20%. Atmospheric correction processors, MERIS Neural Network processors, and the ODESA software, were applied to MERIS images. Eutrophic Lakes was the most accurate at 490nm with MAE 43% and RSME 0.49. The Zeu maps show the spatio-temporal variation of Zeu, indicating the suitability of MERIS to monitor water quality of inland waters. Routine production of similar products for South African waters is currently being developed.