streams and watersheds
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Streams and Watersheds. Authors: Gene Surber, MSU Extension Natural Resources Specialist Bob Ehrhart, Research Specialist, RWRP, Univ. of Montana. Introduction. Riparian Areas Uplands Watersheds. Importance of a Watershed. What happens in one part of the watershed – effects other parts - PowerPoint PPT PresentationTRANSCRIPT
Streams and Watersheds
Authors:Gene Surber, MSU ExtensionNatural Resources Specialist
Bob Ehrhart, Research Specialist,RWRP, Univ. of Montana
IntroductionRiparian AreasUplandsWatersheds
Importance of a Watershed
What happens in one part of the watershed – effects other partsRiparian areas – links between the uplands and the stream
Stream Classification1st order stream
starter stream
2nd order streamtwo or more 1st order
3rd order streamtwo or more 2nd order
Stream Classification, cont.
Perennial streamsIntermittent streamsEphemeral streams
Stream Classification, cont.
Gaining stream
Losing stream
Stream Classification, cont.
Channel Shape Method (Rosgen Classification)
SlopeSinuosityRatio (width to depth)EntrenchmentParticle size
Streams Reflect the Landscape
Steep, mountainous channelWide floodplain
Stream MechanicsStream hydrologyStream channels – “pipelines”
Average bankfull flowStable streams
Water/sediment IN = water/sediment OUT
Stream Mechanics, cont.“Out of Balance”
Water and sediment load changes
Stream Mechanics, cont.Energy = Mass x VelocityBiggest influence on a stream’s energy is speed
EnergyFriction slows waterSediment is depositedNo vegetation versus vegetated banks
Change is constantStreams are dynamicNatural versus man-made causes
StabilityDynamic UnstableStable streams change, but remain in equilibrium Unstable streams are “out of balance”
Nature has a different time scale
Stream InstabilityInstability:
Change in water flowElimination of streambank vegetationExcessive sediments
2 types:Lateral InstabilityVertical Instability
Stream Instability, cont.Vertical InstabilityDowncutting
More difficult to control than lateral cutting
Influences BOTH upstream & downstream
SummaryWhere we go from here…