When is water withdrawal data enough?
Hydrology and Earth System Sciences Discussions
Despite the centrality of the water balance equation to hydrologic and hydraulic science and engineering, in 2018 we lack empirical observations of consumptive use of water by humans and their economy. It is therefore worth considering what we can do with the withdrawal-based water use data we already possess, and what future measurements would be required to more accurately quantify consumptive use for the most common cases of human water use at census scales of space and time. Fortunately, a
... me. Fortunately, a wide range applied water management and policy questions can be addressed using currently available withdrawal numbers. When a more advanced water use census is implemented, Simple Net Consumptive Use (SNCU) methods are insufficient for most common cases of human water use. Presented here are the common special cases that complicate consumptive use calculations. This discussion clarifies the problems we need to solve to measure humans' consumptive use of water at census scales, and argues that &ndash; while we are waiting for these data &ndash; the withdrawal data we already possess are adequate for some of our most important scientific and applied purposes.