Value of floodplains for fish and flood management




What Features are Important


Main ChannelLogjamsMeandersFloodplain channelsBeaver PondsMid-Channel Islands

Edge Habitat

Shallow shoreline
Heterogeneous
Vegetation cover
Cutbanks
LWD



HydrologicEffects

Flood storage
Groundwater recharge
Summer low flows
Hyporheic flows



FloodManagement



LeveeVegetation



Storage of water, wood, sediment and nutrients
hunts road v

Salmonid Habitat

pess et al figure 7 smaller .jpg
Pre Dam Removal SC Source Extended Groundwater

Better Condition Factor




Functional vs Degraded Floodplains
healthy forest river coordors abbe.jpg

How do we alter floodplain functions
Duwamish1995
IMG_0639

Adverse alterations
Removal of vegetation
Bank Armoring
Channel straightening
Habitat Isolation
Reduced storage capacity
Degraded water quality
Construction effects (noise and turbidity)


Causes of Habitat Isolation


Summary

What is a floodplain?What features are associated with floodplains?—
Slower water areas, accompanying vegetation & obstructionsWhy are floodplains important to aquatic ecosystem function?

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Repository and increased residence time of water, wood, & nutrients

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Attenuate peak flows, enhance low flows

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Slower water environments for juvenile salmonidsduring critical times of their life cycleHow do we disturb and alter floodplains?

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Isolate or disconnect the floodplain from its main channel