• An area of land, from ridge top to ridge top, that collects, stores, and releases water to a common point, such as a river or a lake
Clackamas
Columbia
Sandy
Tualatin
Willamette
Lower
Middle
Portland Area Watersheds
What’s in a Watershed?
Streams
Rivers
Lakes
Wetlands
Hills
Mountains
Farms
Cities
Houses
Humans
Animals
Plants
Human Impacts on Watershed
Land UsePollution
Too much of a good thingPoint SourcesNon-Point Sources
ErosionNaturalHuman-accelerated
Urban Runoff
Runoff from:
Streets
Parking lots
Roofs
Driveways
Lawns
Erosion
Watershed Functions
COLLECT
STORE
RELEASE
Watershed – COLLECT
GeologyMountains, valleys, etc
VegetationInterception
Manmade surfaces
Watershed – STORE
Wetlands, Lakes, Reservoirs
Soil
Groundwater
Snow and Ice
Biology
Watershed – RELEASE
Streams and Rivers
Groundwater
Evaporation
Human Engineering
4 Dimensions to streams/rivers
Longitudinal
Lateral
Vertical
Temporal/seasonal
Watershed Sciences
“Geo” sciences
Hydrology
Chemistry
Biology
Ecology
Geomorphology
Physical shape
Parent material
Soils
Hydrology
Chemistry
Most “water quality” parameters are chemical measurements
Nutrients
Temperature, pH, DO, etc
Biology
Bacteria
Algae
Plants
Animals
Ecology
TerrestrialRiparian and Upland Vegetation
Animals
AquaticHabitat (pools, LWD, etc)
Vegetation
Animals
How do we study a Watershed?
If our sampling site is at the red dot on the stream, the water we are testing could have interacted with any of the watershed area upstream of that point.