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The effects of urban land use on stream temperatures. Angela Perez-Toro, Delyn Martinez, Evan Portier , Jennifer Daugherty, Jian Ang and Kendyl Crawford. Natural causes of stream temperature rising. Air temperatures
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The effects of urban land use on stream temperatures Angela Perez-Toro, Delyn Martinez, Evan Portier, Jennifer Daugherty, JianAng and Kendyl Crawford
Natural causes of stream temperature rising • Air temperatures • Physical aspects of a stream (location, i.e. glacier, lake, spring, wetland, etc.) • Physical characteristics (shading shoreline, depth) • Watershed Elevation & Tributaries (mix velocity)
Temperatures are changing in stream and rivers in the U.S. • Annual mean increased by 0.009-0.077°C • More rapid in, but not confined to, urbanizing areas. • Typically correlated with increases in air temperatures, which could be caused by global warming and urbanization. (Source: Sujay S Kaushal, Gene E Likens, Norbert A Jaworski, Michael L Pace, Ashley M Sides, David Seekell, Kenneth T Belt, David H Secor, and Rebecca L Wingate)
Causes of stream temperature rising • Streamside trees are usually removed. • Drainage from hot paved surfaces increase stream temperatures. • Exposed irrigation channels are also another source of heat. • Shading of streams by vegetation can reduce stream temperatures by as much as 10°C.
Streams in urban landscape expected to be higher in temperatures Forested Landscape Urban Landscape
Hogue Creek Flat Lick Branch above Frog Branch
The effects of rising water temperatures • Could have important effects on eutrophication, ecosystem processes, contaminant toxicity and loss of aquatic biodiversity.
Why do we care? • Increased water temperatures = decreased dissolved oxygen. • Some species of fish have high oxygen demands, such as trout & salmon. • Temperature also influences the rate of photosynthesis by algae. • Increases metabolic rate (fish) = need more food and release more waste.
Potomac River uses • Recreational fishing • Commercial fishing • Crabbing • Oystering • Clamming
Mitigation can decrease negative human impact • Pavement coloration • Storm water treatment ponds • Streamside buffers • Shading • Green infrastructure planning • Pervious surfaces • Pipe materials
Socioeconomic factors • Improve air quality • Increased fishery yield • Enhance appearance of a community • Increased property values
Sources • http://www.bluecrab.info/forum/index.php?topic=28253.0 • http://www.waterencyclopedia.com • http://files.dep.state.pa.us/Water/Watershed%20Management/lib/watershedmgmt/state_water_plan/regional_committees/potomac/may08/potomacregion-31-45.pdf • www.esajournals.org/joi.abs/10.1890/090037