Question | Answer |
What is the principal driving force of mass wasting? | Gravity |
What factors control slope stability? | Solid Bedrock |
What may trigger mass wasting? | Torrential rain,earthquakes,volcanic eruptions |
Mass wasting process are based on: | A.Typeof Material,Type of Motion,Rate of Movement |
What processes might be involved in moving water from the atmosphere to groundwater? | The Hydrologic cycle |
Where is most of the Earth's freshwater involved? | Oceans |
Where is most of the water on Earth located? | oceans |
Drainage basin/watershed | total land area from which precipitation reaches a stream |
Mass Wasting | downslope movement of rock, sediment and soil under the direct influence of gravity |
Water | excessive amounts can cause stable slopes to fail |
Oversteepened slopes | |
Slope composition | solid bedrock is more stable; unconsolidated material remains stable until slope exceeds angle of repose |
Creep | (mm or cm per year)caused by expansion/contraction of loose sediment due to wetting and drying or freezing and thawing |
Solifluction | movement of loose material over a layer of permafrost |
Fall | rock or sediment breaks free from a steep or vertical slope and falls (through the air)to the ground below |
Slide | a single intact mass of rock, soil, or unconsolidated material detaches and moves downward along a plane of weakness, or slip plane |
Slump | movement of rock of regolith as a unit along a curved surface |
Flow | fluid movement or rock fragments/soil |
Earthflow | usually form on hillside in wet climates when water saturates the soil |
Debris Flow and mudflow | rapid movement of sediment and water in stream channels, usually in semiarid, mountainous regions |
Rock avalanche | swift and dangerous. Occurs on steep slopes. Huge volume of material detaches, crashes to the ground and continues at high velocity downslope. May move on cushion of compressed air. |
| Ft/miles=80 ft/3 miles=26.66 ft/m |
The hydrologic cycle | movement of water from one reservoir to another in the Earth system |
Stream | water that flows in a channel |
Drainage divide | area of high topography which separates one drainage basin from another |
Velocity | distance/time; Not uniform within a stream; Faster in deep part of channel; faster on the outside of a curve |
Gradient(slope) | =vertical drop/horizontal distance decreases downstream |
Discharge | volume of water passing by an area per unit of time |
Base level | the lowest level to which the stream can erode(often sea level) |
Graded | there is little net erosion or deposition |
Incised meanders | meandering channel in steep, narrow rocky channel |
Stream terraces | remnants of a former floodplain |
Drainage patterns | Dendritic, Radial, Rectangular, Trellis. |
Suspended load | small particles that remain suspended in the water |
Bed load | larger particles that move along the stream bottom |
Saltation | bouncing |
Traction | rolling along the bottom |
Capacity | maximum load a stream can transport |
Competence | the maximum particle size that a stream can transport |
Meandering channels | forms sweeping bends(meanders) |
Braided channels | stream choked with sandbars, no clear main channel |
Point bar | inside bank of a meander |
Channel bar | mid channel |
Cut bank | eroding outer bank of a meander |
Oxbow lake | lake formed when a meander is cut off |
Meander scar | oxbow lake filled in with sediments |
Backswamp | wetland on a floodplain |
Natural leaves | deposited on stream bank during a flood |
Yazoo tributary | flows parallel to main stream because natural levee is present |
Alluvial fan | deposition at the Foot of mountains |
Delta | Deposition into Standing Water |
Zone of aeration(unsaturated zone) | pore spaces contain both air and water |
zone of saturation | pore spaces are filled with water |
water table | top of zone of saturation(a.may change seasonally or year to year,b.generally follows surface topography) |
recharge | infiltration of water(mostly from precipitation)into the groundwater system |
gaining streams | gain water because groundwater flows into streambed(if water table is above the stream) |
losing streams | lose water that flows through streambed underground(if water table is below the stream) |
porosity | volume of pore space in rock or sediment(expressed as percent %) |
permeability | ability of a material to transmit water |
aquifer | a body of geologic material that can store and can transmit significant amounts of groundwater |
unconfined aquifer | aquifer that has no overlying impermeable rock or soil |
Confined aquifer | aquifer that is sandwiched between impermeable rock layers |