Search for: All records

Abstract Around the world, water rights systems govern the allocation of water to a multitude of users. Such systems primarily come into play during times of drought, when some users have to be shorted. Yet their management during times of excess can have implications for subsequent drought impacts. This is evident in the State of Colorado, where under “free river conditions” in which there is sufficient water to satisfy all water rights, anyone—including individuals lacking water rights—can divert as much as they want, unconstrained by the limit of their water right. Here, we estimate the amount of excess water used under such conditions within Division five of the Upper Colorado River Basin in the State of Colorado. Comparing the daily water withdrawals of diversion structures along the Colorado River and its tributaries with their (daily) water rights, we find that in 2017, 339 structures report days with excess withdrawals, amounting to 108 million cubic meters (87,577 acer feet). While such excess withdrawal is legal in Colorado, we argue that the free river condition is an antiquated rule that will make much needed reform of water allocation within the water‐stressed Colorado River Basin more difficult. We offer policy suggestions to address it. 

Virtual water describes water embedded in the production of goods and offers meaningful insights about the complex interplay between water, trade, and sustainability. In this Review, we examine the trends, major players, traded products, and key drivers of virtual water trade (VWT). Roughly 20% of water used in global food production is traded virtually rather than domestically consumed. As such, agriculture dominates VWT, with livestock products, wheat, maize, soybean, oil palm, coffee, and cocoa contributing over 70% of total VWT. These products are also driving VWT growth, the volume of which has increased 2.9 times from 1986 to 2022. However, the countries leading VWT contributions (with China, the United States, the Netherlands, Germany, and India, accounting for 34% of the global VWT in 2022) have remained relatively stable over time, albeit with China becoming an increasingly important importer. VWT can mitigate the effects of water scarcity and food insecurity, although there are concerns about the disconnect between consumers and the environmental impacts of their choices, and unsustainable resource exploitation. Indeed, approximately 16% of unsustainable water use and 11% of global groundwater depletion are virtually traded. Future VWT analyses must consider factors such as water renewability, water quality, climate change impacts, and socio-economic implications.