Term
|
Definition
local: the limiting level below which a stream cannot erode the land
absolute is typically global sea level |
|
|
Term
| what does a stream longitudinal profile typically look like? what other parameters change as you go from a streams head waters to its terminus? |
|
Definition
| longitudinal profile relfect downstream trade off between discharge and slope in setting transport capacity and thus moving sediment and incising rock |
|
|
Term
| what are different types of river terraces and how do they differ? |
|
Definition
fill, strath; paired, unpaired
based on erosion, uplift, discharge and sediment supply |
|
|
Term
|
Definition
| changes in whether a stream is eroding or depositing in a given location. can be caused by tectonic uplift,m change in base level downstream, change in climate modifying systems discharge |
|
|
Term
| where within the fluvial system are sediment stored? |
|
Definition
| alluvial fans: deposition from a sudden change in gradient, like leaving a mountain range |
|
|
Term
| how do rainfall and vegetation influence sediment yields? |
|
Definition
| higher rainfall and vegetation means lower sediment yield |
|
|
Term
| how do certain human activities affect sediment yield? |
|
Definition
| construction and urbanization increase sediment yield |
|
|
Term
|
Definition
| describe the input, transport, storage and export of sediment from a system |
|
|
Term
| what type of river regimes are there? |
|
Definition
snow and ice melt dominated
temperate oceanic environments
tropical/equitorial rivers |
|
|
Term
| what else controls catchment runoff? |
|
Definition
| drainage network, regional climate, soil, topography, land use, vegetation, geology |
|
|
Term
| what is drainage density? how is it calculated? what does it correlate to? |
|
Definition
drainage density: a meausre of how many channels per given drainage basin size
D=L/A, channel length/area
loosely correlates to sediment yield |
|
|
Term
| what statistical realtionships are generally true for all river systems? |
|
Definition
| stream length, stream order, number of stream segments of a particular stream order, drainage area |
|
|
Term
| what are laws of drainage network composition? |
|
Definition
-as # of streams decrease, stream order increases
-as mean stream length increases, stream order decreases
-as mean drainage order increases, stream order increases |
|
|
Term
|
Definition
| a method of classifying or ordering the hierarchy of natural channels; correlates well with drainage area but is also regionally controled by topography and climate |
|
|
Term
| what affects drainage pattern? |
|
Definition
-vegetation cover, climate, and underlying geology
-drainage density |
|
|
Term
| what are common types of drainage pattern and what causes them? |
|
Definition
| dendritic, parallel, trellis, radial, rectangular |
|
|
Term
| what factors control the evolution of drainage basins and their patterns? |
|
Definition
| shape or pattern develops in response to local topography and subsurface geology |
|
|
Term
| what zones are drainage basins typically broken up into and why? |
|
Definition
| they are classified on form and texture; their shape or pattern develops in response to local topography and subsurface geology |
|
|
Term
|
Definition
| only smaller streams that feed larger streams within a drainage basin |
|
|
Term
|
Definition
-bank protection: armoring, spur dykes, groynes
-bed protection: weirs, sills |
|
|
Term
| common human-induced river-channel modifications |
|
Definition
| realignment, dredging, clearing of bank vegetation, levees and embankments, dams |
|
|
Term
|
Definition
-rising flood waters breach natural levees
-deposits show normal gradation |
|
|
Term
|
Definition
| deoposition adjacent to the channel during floods as a result of a sudden loss of competence of streams as they overtop their banks |
|
|
Term
|
Definition
| abandoned meander isolated from the river by a cutoff |
|
|
Term
|
Definition
| uring floods, erosive power of water breaches narrow necks separating meanders of very sinuous channels |
|
|
Term
| what facilitates river bank erosion? |
|
Definition
| repeated wetting and drying, freeze thaw action, river and vegatative processes and mass failure like collapse, slumping and sliding |
|
|
Term
|
Definition
| characterized by a single, sinous channel with broadly looping curves |
|
|
Term
|
Definition
characterized by a network of dividing and rejoining channels separated from one another by sand or gravel bars
-supplied with more sediment than it can transport |
|
|
Term
|
Definition
|
|
Term
|
Definition
| maximum particle sixe a stream can transport, based on velocity |
|
|
Term
|
Definition
| maximum load a stream can transport |
|
|
Term
|
Definition
-sands, gravel, boulders
-short travel times
-forms bars and other bed forms |
|
|
Term
|
Definition
-clays, silts and sands
-travels over considerable distances |
|
|
Term
|
Definition
| show peak points of precipitation, a shorter amount of time and what changed on a typical hydrograph |
|
|
Term
|
Definition
| show discharge versus time past a specific point in a river |
|
|
Term
|
Definition
-describes seasonal varations in flow
-influenced by seasonal distribution of rainfall and balance between rainfall and evaporation |
|
|
Term
| why do we monitor discharge? |
|
Definition
| helps engineers design bridges and reservoirs, identivfy changes in stream flow due to climate and human influences, flood planning and prediction |
|
|
Term
|
Definition
| amount of water flowing past a certain point in a given unit of time |
|
|
Term
| what influences channel shape |
|
Definition
|
|
Term
| what influences stream flow? |
|
Definition
gradient/slope
shape, size, roughness of channel
discharge |
|
|
Term
|
Definition
| the ability of a stream to erode and transport material is directly related to velocity |
|
|
