Surface Water and Ocean Topography satellite data reveals flood depths and environmental flows in wetlands

Wetland ecosystems depend on water availability to function. However, detailed information on water surface elevations and depths within wetlands is often lacking, and management of these vulnerable ecosystems often rely on distant river gauge measurements or no water observations at all. Here we show that Surface Water and Ocean Topography (SWOT) satellite data can provide water surface elevation estimates across internationally recognised Ramsar wetlands in Australia - Coongie Lakes and the Barmah-Millewa Forest - with 3–10 cm accuracy. Combined with high-resolution elevation data, wetland water depths can now be monitored every ~10–11 days, providing crucial information on water availability to sustain ecosystems. The largest ever satellite-observed flood in the Coongie Lakes was tracked in detail as it flowed through interconnected channels and lakes of the system, and we mapped wetland extents from the SWOT data. Our approach can improve management of all wetlands lacking information on water surface elevations and depths. Water availability in wetlands can now be quantified with 3-10 cm accuracy using data from the Surface Water and Ocean Topography satellite mission, based on an analysis on water surface elevation estimates across internationally recognised Ramsar wetlands in Australia.