Multi-Temporal Analysis of InSAR Coherence, NDVI, and in Situ Water Depths for Managed Wetlands in National Wildlife Refuges, California

California has lost most of its historical wetlands and it is in urgent need to conserve and protect the remaining wetlands. One of the key elements for wetland management is monitoring changes in surface water depths, which is challenging due to inaccessibility and dynamic hydrology of wetlands. Particularly, many California wetlands are privately owned with small areas (e.g., 40 ha) and bounded by levees, resulting in differences in hydrological regimes. Managed wetlands are characterized by high water depths in winter season and low depths in summer season, with a rapid transition in between. Considering the complicated spatiotemporal hydrological pattern, it is difficult to monitor regional water level variations based on in-situ measurement alone. This study explored the possibility of using multi-sensor observations for hydrological applications by investigating the relationship between satellite observations (Interferometric Synthetic Aperture Radar (InSAR) coherence, and Normalized Difference Vegetation Index (NDVI)) and in-situ water depth measurements.