The Color of Rivers

Rivers are among the most imperiled ecosystems globally, yet we do not have broad-scale understanding of their changing ecology because most are rarely sampled. Water color, as perceived by the human eye, is an integrative measure of water quality directly observed by satellites. We examined patterns in river color between 1984 and 2018 by building a remote sensing database of surface reflectance, RiverSR, extracted from 234,727 Landsat images covering 108,000 kilometers of rivers > 60 m wide in the contiguous USA. We found 1) broad regional patterns in river color, with 56% of observations dominantly yellow and 38% dominantly green; 2) river color has three distinct seasonal patterns that were synchronous with flow regimes; 3) one third of rivers had significant color shifts over the last 35 years. RiverSR provides the first map of river color and new insights into macrosystems ecology of rivers.

Automated summary

RiverSR database, extracted from Landsat images spanning from 1984 to 2018, reveals that 56% of rivers in the contiguous USA are dominantly yellow and 38% are dominantly green; river color shows three distinct seasonal patterns synchronized with flow regimes; one-third of rivers have experienced significant color shifts over the past 35 years, providing new insights into macrosystems ecology of rivers.