Mapped: U.S. Rivers Resized by Their Water FlowsKey TakeawaysThe Mississippi carries an average 593,000 cubic feet of water per second, more than twice the flow of the Ohio River.Several famous western rivers appear surprisingly small when resized by water flow, including the Colorado and Rio Grande.What would a map of U.S. rivers look like if their size represented water flow rather than geography?This visualization from the Pacific Institute redraws major American rivers according to their average discharge, or the volume of water flowing through them.The result dramatically changes the familiar map of the country’s waterways. The Mississippi system dominates much of the central and eastern United States, while many rivers across the West become remarkably thin.U.S. Major Rivers Scaled by Water FlowThe Mississippi immediately dominates the flow-adjusted map, reflecting both its enormous discharge and the vast river basin it draws from.Below are the five largest rivers in the contiguous U.S. by average discharge, measured in cubic feet per second (cfs):RankRiverAvg. discharge1Mississippi593,000 cfs2Ohio281,000 cfs3Columbia262,000–273,000 cfs4Atchafalaya225,000 cfs5Missouri70,000–76,000 cfsThe Mississippi is the world’s seventh most powerful river by annual flow rate and ranks first in North America.The map also highlights an important distinction between river length and discharge. The Missouri stretches farther than the Mississippi by some measurements, but carries only a fraction as much water.Of the five rivers above, only the Columbia lies outside the Mississippi River system. The Ohio and Missouri are tributaries of the Mississippi, while the Atchafalaya is a distributary.West vs. EastOne of the map’s sharpest contrasts is between the water-rich river network of the East and the much thinner waterways of the West.The Columbia is the major western standout. Its full river system is even larger than shown here, since its considerable tributary network extends into Canada.The Pacific Institute notes that the Colorado is particularly interesting because its flow rate decreases as it approaches the ocean, largely because of significant withdrawals by cities and farms.The Rio Grande, which forms much of the U.S.-Mexico border, is barely visible in this context. Once much more powerful, climate change and increasing withdrawals have contributed to stretches of the river struggling to reach the ocean.Another Look: River Basins of North AmericaFor another perspective on the rivers of the United States and North America, the image below maps river basins across the continent:River Basins of North America (Credit: Adam Symington)See all of the maps, which visualize the river basins in North America as well as on every other continent, in this post here.