Global characterization of inland water reservoirs using ICESat-2 altimetry

Abstract:

Freshwater reservoirs provide critical services (e.g. water supply, irrigation, hydroelectric power) to societies around the world. However, global knowledge of reservoir water levels is limited because gauge data are often proprietary, difficult to access, or non-existent, and the current generation of satellite radar altimeters can only resolve the world's largest reservoirs. Here, we demonstrate the potential of ICESat-2 for accurately and transparently characterizing global reservoirs. First we demonstrate high accuracy of ICESat-2 surface water observations in comparison to hundreds of in situ reservoir level gauges. Then we retrieve water level changes for 4,062 reservoirs with surface areas ranging from < 1 to > 10,000 km² in just the first eighteen months of the ICESat-2 mission. From this new global dataset, we identify distinct regional patterns in reservoir level change that can be attributed to both water availability and management strategy. Our findings demonstrate that ICESat-2 will form a crucial component of any reservoir level inventory and enable new insight into how reservoir management responds to climatic variability and increasing human demand.