Surface water temperatures are expected to rise due to warming air temperatures

Submitted by dshannon on

Stream-water temperatures are expected to warm as a result of warming air temperatures, earlier snowmelt, and altered hydrology throughout the year (Knouft and Ficklin 2017). Stream water temperatures have risen over the last century (0.009–0.077˚C per year) and are projected to continue increasing with warmer ambient air temperatures (Kaushal et al, 2010). Models project that summer stream temperatures will increase of 1.4 to 7.2°F by the end of century (modeled with 15 models and multiple emission scenarios) (Lyons et al, 2010). Water temperatures in cold-water stratified lakes are predicted to increase by as much as 2.9 to 3.02°F by the end of the 21st century (Herb et al, 2013). Prolonged warming of surface waters is expected to result in degraded water chemistry, eutrophication, and anoxic conditions. Warming surface waters can significantly degrade cold-water habitats and aquatic communities, reducing growth and even causing aquatic organism mortality, particularly for fish at younger life stages (Ficke et al. 2007, Knouft and Ficklin 2017). All surface waters are expected to warm, yet within a watershed some areas may be more or less sensitive to warming air temperatures due to locally unique factors such as the position in watershed, upstream land-uses, watershed characteristics, magnitude of groundwater contributions, and exposure to solar radiation (Knouft and Ficklin 2017).