Assessing the Effects of the Hong Kong-Zhuhai-Macau Bridge on the Total Suspended Solids in the Pearl River Estuary Based on Landsat Time Series

Total suspended solids (TSSs) can affect primary production through influencing light penetration and nutrient availability in aquatic environments. In this study, novel algorithms were developed for TSS in the Pearl River estuary using Landsat-derived reflectance corrected for Rayleigh scattering (R-rc). Comparisons between in situ and estimated TSS using the calibration and validation data sets resulted in R(2)s > 0.8 and mean absolute percentage errors < 35%. Landsat-derived annual TSS between 1987 and 2018 in the Pearl River estuary ranged from 16.5 to 41 mg L-1. It indicated a statistically significant decreasing trend with an annual rate of 0.26 mg L-1 and decreased by 58.5% from 1987 to 2018. It showed a higher decreasing rate after than before the construction of the Hong Kong-Zhuhai-Macau Bridge. Nonetheless, TSS 2 km upstream from the Hong Kong-Zhuhai-Macau Bridge on the western side increased after the construction of the bridge related to the change of flow influenced by piers and artificial islands.