Global patterns in river water storage dependent on residence time

Earth’s rivers are the most sustainable source of freshwater, making accurate knowledge of global river flows and stores critical for informing water management1. However, previous estimates of global river flows are widespread1–16 and prior estimates of river stores are sparse17. Challenging accuracy, global estimates of river flows and stores are plagued by uncertainties in land runoff18, an unobserved quantity that provides water input to rivers. Here, we leverage global river flow observations to simultaneously correct continental runoff and river flow together, and further quantify river water storage, generating the first globally corrected monthly river flow and storage dataset. We estimate global river storage mean and monthly variability as 2165 ± 415 km3 and global continental flow as 37455 ± 6925 km3/yr. Our analysis reveals flow wave propagation time as an unexpected, but fundamental driver that can double or halve river water stores and their variability, while also reconciling past debates on global river flows. We identify previously underappreciated freshwater sources to the ocean in water discharged from the Maritime Continent (Indonesia, Malaysia, and Papua New Guinea) amounting to nearly 1.5 times the Congo River, and illustrate our capability to detect severe anthropogenic water withdrawals.