Exam 2 Flashcards
Lentic
nonflowing, standing water (small pools to Great Lakes)
Lotic
running/flowing water (seeps to larger and wets)
Base Flow
not influenced by precipitation; no rain, all water in streams right now from ground water
Seep
where water starts to come out from a hillside
Ephemeral
there is a stream right after a rain storm and then it disappears
Intermitant
flows for a while, then dries up
Perennial
stays flowing throughout the year during normal rainfall
What shapes a river?
- climate
- geology
- topography
- vegetation
- human land use
Climate
heat, precip/rainfall, drought, snowpack
Geology
chemical identity and buffering capacity; including influences based on ions and minerals leached from bedrock and surficial (topmost layer) material; limestone has lots of perculation and granite not much at all; determines pH of a river
Topography
influences stream morphology; flow velocity (how fast stream moves); whether stream is carrying or depositing sediment/ sediment erosion transfer or deposition; substrate: boulders, bedrock; habitat: step pools, meander pattern: riffles or rapid area: riffle - pool - run
High gradient areas
v-shape cross section; erosional; often find step pool, boulders, cobbles
Entrenched
measure of vertical containment in a channel; determined by bankfull width and flood prone width; FP (flood prone width):BF (bank full width)=entrenchment
Sinuosity
a bend; meander pattern
Moderate gradient area
in a valley start to see sinuosity: riffle - pool - run; smaller deposits: cobble, gravel, sand; not erosional, more depositional; water starts to slow down; slightly entrenched; larger flood prone area
Riparian zone
land along the river/ floodplain
Vegetation
best vegetation to have along a river is riparian forest
Instream habitat
instream wood, branches, etc creates important habitat and diversity for fish and other organisms
Bank stability
root systems of trees on bank holds the bank together especially during storms; just grass you would get a slumped bank when the bank falls in
Autumn leaves
major energy source of streams; in summer canopy of leaves overhanging causes “drops” (falling insects) (another energy source)
Trees
cool the stream and regulate temps; higher order streams cooling effect is not as apparent because the stream is wider so trees do not overlap
Pollutants
are absorbed through the vegetation; nutrients phosphorus and nitrogen as well as toxins get absorbed
Human Land Use
riparian forests getting replaced by impervious surfaces which causes a lot of runoff; increasing impervious surfaces 10-20% you double the amt of runoff; more flash floods; dams also changes the habitat and fragments populations
Colluvial
sediment and organic matter accumulates at base of the hill
Alluvial
sediment and organic matter has been carried down from upstream
Power of water
determined by slope and volume of water
Longitudinal Dimension
downstream; can see erosion, deposition and connectivity; dams disrupt connectivity; riverine (lotic) -> impoundment (lentic); transport of nutrients and sediments is disrupted; disrupts exchange downstream
Latitudinal Dimension
lateral connectivity involves the riparian zone; material exchange between river and riparian zone; sediments/ soil accumulates; lots of agriculture along rivers because that’s where soils are good for farming
Vertical Dimension
- groundwater seeps down from water table into river; you get chemicals and ions and dissolved organic carbon
- hyporheic zone: diversity of species; nutrient spiraling; nutrients in sediments then water column; fish eggs sweep their tail to remove fine sediments to make nests
Stream segment
between 2 tributaries; within it you can have a stream reach