Drought can appear in streams in two ways. One is from the atmosphere, with less water falling as rain and snow. The other is water from the ground, with less water entering streams from underground aquifers. This water from the ground, called baseflow, is particularly important during periods of meteorological drought (when dry weather patterns dominate an area) because it can keep a stream flowing despite a lack of precipitation.
New research from UC Riverside examined how baseflow responds to periods of low precipitation and how long it takes for baseflow to recover from meteorological drought. The study found baseflow droughts are more severe than meteorological drought, with baseflow droughts ranging from 9 to 104 months in duration. It also takes longer for a stream to recover from baseflow drought; drought impacts in baseflow last up to 41 months after meteorological drought has ended. Baseflow droughts are also growing longer and more severe amid rising temperatures under climate change.