Assessment of the Spatiotemporal Variations of Turbidity Flow in Lake Pontchartrain Using Remote Sensing (NDTI Method)

Abstract

Turbidity flow plays a critical role in sediment transport, water quality degradation, and ecosystem functioning in lacustrine and estuarine environments, particularly in urbanized coastal regions. Lake Pontchartrain, one of the largest estuaries along the Gulf Coast of the United States, has experienced increasing turbidity driven by sediment inflow, resuspension processes, hydrodynamic forcing, and anthropogenic pressures. This study assesses the spatiotemporal variations of turbidity flow in Lake Pontchartrain using multispectral remote sensing and the Normalized Difference Turbidity Index (NDTI). Sentinel-2 MSI imagery acquired monthly throughout 2023 was processed using Google Earth Engine and ArcGIS Pro to generate turbidity distribution maps. The Normalized Difference Water Index (NDWI) was first applied to delineate open water, followed by NDTI computation to classify turbidity into low, medium, and high categories using a quantile classification scheme. Results reveal pronounced seasonal and spatial variability in turbidity patterns, with higher turbidity concentrations predominantly observed along nearshore zones, river inflow areas, and during periods of increased runoff and sediment resuspension. Conversely, lower turbidity conditions prevailed during periods of reduced discharge and calmer hydrodynamic conditions. The findings demonstrate the effectiveness of NDTI-based remote sensing for monitoring turbidity dynamics and highlight critical zones of sediment influence within Lake Pontchartrain. This study provides valuable insights for environmental monitoring, water quality management, and sustainable conservation planning in estuarine lake systems.