Background:
Suspended sediments are important indicators of river water quality because they influence light penetration, aquatic productivity, and pollutant transport.

Objectives:
This study investigated the spatio-temporal dynamics of suspended sediment conditions in the River Niger, River Benue, and their confluence, with the aim of identifying persistent hotspot and cold spot zones, assessing temporal variability, and evaluating long-term trends in suspended sediment conditions.

Methods:
Landsat 8 Collection 2 Level-2 Surface Reflectance imagery was used for this study. Image preprocessing and analysis was done using Google Earth Engine. Suspended sediment conditions were evaluated using the Normalized Difference Suspended Sediment Index (NDSSI). Descriptive statistics were used to quantify temporal variability. The Getis–Ord Gi* statistic was applied to identify statistically significant hotspots, while the Mann–Kendall (MK) test and Sen's slope estimator were used to assess long-term trends.

Results:
River Niger consistently exhibited moderate to high suspended sediment conditions, whereas the River Benue showed greater interannual spatial variability. Statistically significant hotspot clusters in the period-mean NDSSI distribution occurred along extensive sections of the River Niger and in parts of the River Benue, including areas around the Lokoja confluence. Mean annual NDSSI values ranged from 0.020 to 0.073, indicating notable interannual variability. The coefficient of variation ranged from 30.4% to 125.0%, demonstrating substantial interannual differences in sediment distribution. MK analysis indicated no statistically significant long-term trends in annual mean, minimum, or maximum NDSSI values (p > 0.05).

Conclusion:
Suspended sediment conditions in the River Niger and River Benue exhibit persistent spatial distribution despite the absence of significant long-term temporal trends. The identification of recurrent suspended sediment hotspots provides valuable information for water quality monitoring, sediment management, and sustainable river basin management in the River Niger, River Benue, and other major tropical rivers across West Africa.