Upload
timothy-wheeler
View
217
Download
0
Tags:
Embed Size (px)
Citation preview
Riparian Areas: Functions and Conditions
Authors:Gene Surber, MSU ExtensionNatural Resources Specialist
Bob Ehrhart, Research Specialist,RWRP, Univ. of Montana
Riparian AreasWetlands
Riparian areasOverflow areasWet meadowsMarshesSloughs
Characteristics of Riparian Areas
“Green Zone” – link between aquatic and terrestrial
WaterLandformSoilVegetation
Riparian Areas
More dynamic than uplandsFloodingDeposition of sedimentAccumulation of organic matterDewateringChanges in location
Functions of Riparian Areas1. water storage 2. flow energy dissipation3. water quality4. sediment trapping5. bank building and maintenance6. primary biotic production
Store and Release WaterSoil – acts like sponge
Reduces floodingExtends time that surface water is available
Dissipate Energy of Flowing Water
Slows waterVegetationWoody debrisLarge bouldersCobbles
Provide Water QualityNatural pollution control
Trap sediments (nutrients, pesticides, toxic metals, bacteria)
Trap sedimentsTrap sediments – development of new streambanks and bars
Protect soil and waterShields soil and water from:
WindSunlightRain drop impacts
Enhances ProductivityMost productive parts of a landscape
Provide wildlife habitatWater, food, cover and travel routes
BirdsMammalsInsectsFish
Evaluating the Health of Riparian Areas
How well the riparian area carries out the functions
PhysicalBiological
Evaluating Physical Features
Channel downcuttingChannel wideningAmount, location, & causes bare groundAmount of fine materialsAmount of rock
Downcutting“Incisement” = erodes away the channel bottom
Channel becoming wider & shallower
Banks break downStream becomes shallowerStream temperatures rise
Amount, location, & causes of bare ground
Bare ground – erosionNoxious weedsCompaction or bank shearing
Amount of fine materials on channel bottom
Silts, clays, decomposing organic materialNot enough water running
Bank Rock ContentLarge rock versus Sand, silt, small gravelManagement considerations
Biological FeaturesTypes & amounts of plantsHow well they fulfill functionsAmount of foraging & browsingMix of age classes of wood species
Streambank protectionVegetation
Slows velocityStabilizes streambanksReduces erosion
Amount & Types of Vegetation
Canopy cover of desired plantsNoxious weeds
Presence of Trees and Shrubs
Woody plants (trees & shrubs)
Bank stabilizersFood & cover
Determining appropriate presence
Woody species age classDistribution of age class
All old treesAll young trees
Degree of BrowsingExcessive use
(50% of current or previous year’s growth)
Woody DrawsPerform functions of riparian areasHabitat
Cover, food, water
Grazing management plan