Chapter 5 Tarbuck Earth Science

factors of runoff and infiltration

rainfall intensity, surface material, vegetation, slope of land, saturation of soil

define drainage basin

area that drains to a specific river, divided by divides

river system

the drainage basin plus the river itself

three processes in rivers

sediment production, sediment transport, sediment deposition

define dendritic pattern

tree-like pattern in branches, forms in uniform areas

define radial pattern

stems from one place, common in volcanic cones

define rectangular pattern

right angle bends, forms when faults/joints criss cross

define trellis pattern

parallel streams, form when strong/weak rock alternate in bands

define laminar flow

flow parallel to channel, slow

define turbulent flow

flow is chaotic but fast

factors affecting flow velocity

shape, roughness, gradient, amount of water

define discharge

volume of water traveled through a cross section’s area per unit time (cubic feet per second)

define dissolved load

sediment is in water in solution, can go anywhere without limitation

define suspended load

fine particles traveling in suspension through water, gives rivers muddy look, determined by flow velocity and settle velocity

define settle velocity

speed a particle moves through still fluid

define bed load

heavy loads traveled on bottom of stream through rolling, sliding, or saltation

define saltation

jumping or skipping of rocks or particles

define competence

variety of particle sizes stream can transport

define capacity

amount of sediment river can carry

define alluvium

sediment deposited by river

define meandering stream

stream with fine sediment that winds back and forth

define point bar

deposited area in inner bank

define cut bank

eroded area in outer bank

define cutoff (meandering stream)

section that connects two meanders

define oxbow lake

lake that forms when cutoff eliminates meander

define braided streams

network of interlocking streams with mainly coarse sediment

define base level

lowest level a river can erode to

define ultimate base level

sea level :)

define local base level

relative base level (local lake, etc.)

define valley deepening

valley gets deeper when gradient is high and downcutting is primary force

define valley widening

valley getting wider when gradient lowers and energy goes side to side

define incised meander

meandering stream in deep narrow valley due to base level going down or land being uplifted

define delta

stream with sediment dumping as it hits water body but forming distributaries to maintain flow

define natural levee

slope formed at side of river during floods

define yazoo tributary

streams running parallel due to blockage from levee

define alluvial fan

cone like structure formed when narrow stream opens into floodplain

define belt of soil moisture

water that does not percolate to keep surface soil hydrated

define zone of saturation

zone where water accumulates and saturates rock

define water table

top of zone of saturation, levels vary with surface of earth

define unsaturated zone

area with less water above saturated zone

define porosity

percentage of volume is pores with water

define permeability

ability to transmit water

define aquitard

nonpermeable rock

define aquifer

permeable rock where groundwater is

define spring

area where water table intersects surface and water is exposed

define hotspring

spring with water heated by geothermal heat

define geysers

fountains that eject hot water due to fluctuations in water pressures underground

define wells

hole bored into zone of saturation for groundwater harvesting

define drawdown

lowering of water table when well is harvested from

define cone of depression

physical depression caused by drawdown

define artesian system

system where groundwater naturally comes to surface due to pressure

how groundwater harvesting causes land subsidence

Water harvested from aquifer releases pressure in rock, making sediment compact more, crushing land

define cavern

cave formed through limestone dissolving from acidic water

define stalactite

spikes on ceiling formed by precipitating calcite from dripping water

define stalagmite

spikes on ground formed by precipitating calcite from dripping water

define karst topography

landscapes formed by groundwater’s dissolving abilities, often involving limestone

define sinkholes

irregular terrain depressions common in karst areas

define karst tower landscapes

tropical areas with more water and CO2 dissolve more limestone creating towers