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Geol 1200 Exam 3
Geol 1200 Exam 3
76
Geology
Undergraduate 3
03/22/2011

Additional Geology Flashcards

 


 

Cards

Term
Mississippi River Floods
Definition

1993

floodwalls act as a bottleneck for rising waters

STL

Term
Sheetwash
Definition

surface layer of water

moves down steepest slope

erodes substrate

creates rill channels

rills coalesce, deepen, and downcut into channels[image]

Term

Drainage Network

Catchments

Watersheds

Definition
Land areas that drain into a specific trunk stream[image]
Term
Sediment Load Types (3)
Definition

Bed Load (10%)

Suspended Load (90%)

Dissolved Load

Term
Sediment Competence
Definition

Measuring maximum size of the sediments transported

by river

Term
Sediment Capacity
Definition
Total amount of sediments a river is capable of transporting
Term
Discharge
Definition

 

The amt of water flowing in a channel

volume of water passing a point per unit of time

=water velocity * channel width * channel depth

cubic feet per second

cubic meters per second

Q=W x D x V

 

Term
Gradient
Definition
vertical drop over horizontal flowing distance, expressed in percentage, ft/mi, or degree of the slope
Term

Stream Velocity

 

Definition
Largely depending on stream gradient, discharge, channel shape, and turbulence
Term

Longitudinal Profile of a River

Towards the mouth (end)

Definition

Gradient flattens

Discharge increases

Grain sizes smaller

Channels describe broad meander belts

Term
Base Level
Definition

lowest point to which a stream can erode

streams cannot erode below sea level

lake serves as a local (or temp) base lvl

Term

Abrasion

River Erosion

Definition

sediment grains in flow sandblast rocks

-bedrock exposed in channels polished smooth

-potholes

Term

Dissolution

River Erosion

Definition
Mineral matter dissolves in water
Term

Scouring

River Erosion

Definition
running water picks up sediment and moves it
Term

Breaking and Lifting

River Erosion

Definition
the force of moving water can break chunks of rock off the channel or lift rocks off the channel bottom
Term

River Erosion Location

Downcutting

Definition
[image]
Term

River Erosion Location

Lateral

Definition
Concentrates on the outer bends[image]
Term

River Erosion Location

Headward Erosion

Definition
[image]
Term
Meanders on a floodplaine
Definition

Deposition on inside

erosion on outside[image]

Term
Riffle
Definition
fast, shallow flow over cobbles
Term

River Sediment Deposition Features

Natural River Levees

Definition
caused by flooding and deposition of sediment on banks
Term

River Sediment Deposition Features

Point Bar Deposits

Definition
Deposition of sediment on "inside" of river curve
Term

River Sediment Deposition Features

Island Bars/Braided Streams

Definition
carry lots of sediment
Term

River Sediment Deposition Features

Alluvial Fan

Definition

build at base of mtn front

sediment rapidly dropped near stream source- carried to mouth

Term

River Sediment Deposition Features

Deltas

Definition

stream enters standing water

sediment drops out

Term

Effects of Land Use Changes

Forest-> farmland

 

Definition

increases soil eroision

stream deposition

gradient & velocity

river channel erosion

Term
Effects of Land Use Changes
Urban Buildup
Definition

increases impervious cover

 inc. lower magnitude flood frequency

reduces lag time of flooding

Term

Flooding

Stage

Definition
the height of the water level in a river at a given location at a given time
Term

Flooding

Hydrograph

Definition
graphic representation of a river's discharge over time
Term

Flooding

Recurrance Interval

Definition

R= (N+1)/M

N= number of years of record

M= rank of individual flow within the recorded years

Term

Types of Flooding

Upstream Flood

Definition
Shorter Duration, smaller area
Term

Types of Flooding

Downstream Flood

Definition
longer duration, greater magnitude, larger area
Term
Flash Flood
Definition
high volume, short lag time, usually in upstream
Term
Factors affecting flood damage
Definition

land use changes

frequency and magnitude

lag time and duration

sediment load

effectiveness of forecasting

Term
Primary Effects of Flooding
Definition
injury, death, damage, destruction, erosion, deposition of sediments
Term
Secondary Effects of Flooding
Definition
water pollution, fire, diseases, displacement of people, interruption of social and economic activities
Term
Surface Water
Definition

runoff has effects on sediment transport and surface erosion

 

Term
Sediment yield in surface runoff depends on...
Definition

geologic factors (type and structure of soils and rocks)

topographic factors (relief and slope gradient)

climatic factors (type, intensity, duration, dist)

vegetation factors (type, size, dist)

land use practice factors

Term

The Water Table

Vadose

Definition

unsaturated zone

moisture sticks to grain surfaces

air pockets remain

Term

The Water Table

Phreatic

Definition

saturated zone

all pore space filled

Term
Water Table Topography
Definition

not flat

mimics land surface- high where land is high, low where land is low.

Term
Aquifer
Definition
sediment/rock that transmits water easily
Term
Aquitard
Definition
sediment or rock that hinders water flow
Term
Recharge Zone
Definition
area where water infiltrates downward from surface to groundwater
Term
Discharge Zone
Definition
area where GW is moved from an aquifer, such as a spring, well, river, etc...
Term
Influent Stream
Definition
above the water table, recharge water to GW, may be intermittent
Term
Effluent Stream
Definition
perennial stream with the addition of GW when precipitation is low
Term
Perched Aquifer
Definition
local zone of saturation above a regional water table
Term
Cone of Depression
Definition
[image]
Term
Watertowers
Definition

mimic artesian aquifers

elevation creates artificial potentiometric surface

pressure drives water through the distribution system

Term
Primary Porosity
Definition

originally formed with the material 

vesicles in basalt

May decrease with:

burial compaction

cementation

Crystalline rocks have very little primary porosity

Term
Secondary Porosity
Definition

develops later

fracturing

faulting

dissolution

Term
Hydraulic Conductivity
Definition
the ability of a particular material to allow a fluid to move through it
Term
Groundwater Flow
Definition

flows slowly under the influence of gravity

in unsaturated zone, it is straight downward

in saturated zone, it's governed by gravity and pressure

Term
Hydraulic Head
Definition
GW flow goes from higher to lower, increasing pressure below
Term
Rates of Water Flow
Definition

Ocean current=3km/hr

Steep river channel=30km/hr

Groundwater=.00002 km/hr

Term
Caves
Definition

develop when groundwater dissolves limestone

GW is weakly acidic (CO2)

 

 

Term
Speleothems
Definition

-formed from precipitation of dripstone

-develop when GW entering a cave degasses CO2

-CaCO3 is precipitated from this water on interior surfaces 

-over time CaCO3 coatings grow into stalagmites, tites, and columns

 

Term
Karst
Definition

  • disappearing streams
  • natural bridges
  • caves
  • speleothems
  • sinkholes
  • srings
  • irregular terrain

Term
Offstream Use
Definition

removal or diversion from its SW or GW sources temporarily, e.g. irrigation, thermoelectric, industrial use

 

Term
Consumptive Use
Definition
type of offstream use of water without intermediate return to the SW or GW, such as transpiration and human use
Term
Instream Use
Definition
navigation, fish and wildlife, recreation
Term
Unwanted substances in natural groundwater
Definition

hardness

dissolved iron, manganese, and hydrogen sulfide gas

dissolved arsenic

Term
Water Hardness
Definition

dissolution of carbonates add Ca2+ and Mg2+

reduce the effectiveness of soap

mitigated by ion exchange

Term
Human Activities adding pollutants to GW
Definition

dissolved and pure organic and inorganic compounds

dissolved metals

pathogenic microbes

 

Term
Strategies for remediating ground water contamination
Definition

pump and treat

volatilize and vaporize

steam clean

bioremediation utilizes bacteria to clean groundwater

Term
Oxygen Demanding Waste
Definition

Dead organic matter decomposed by bacteria, an oxygen demanding process

Biochemical Oxygen Demand (BOD): high BOD assoc with a high level of decaying org material in h20, reducing dissolved O for other healthy organisms

Sources of oxygen demanding waste: natural processes, ag applications, urban sewage, and runoff

Term
Common water pollutants
Definition

Cultural eutrophication- algae bloom, triggering BOD production

Fertilizer, feedlots, and discharge from wastewater treatment plants

Term
Common Pollutants: Thermal Pollution
Definition

-temp increases

-hot water discharge from industrial operations, power plants, abnormal ocean, currents, urban runoff

Term
Point Source of Pollution
Definition

Discrete, confined, and readily identifiable

Sources: landfills, discharge from industries, power plants, storm water runoff, etc...

Term
Nonpoint sources of Pollution
Definition

-diffused, intermittent and hard to specifically identif

-causes often regional, compound, and cumulative

-Influenced by land use, climate, hydrology, topography and geology

-Common sources: urban runoff, ag, mining

Term
Cones of depression are capable of reversing flow
Definition
[image]
Term
MCL
Definition
Maximum Contaminant Lvl
Term
MCLGs
Definition
Maximum Contaminant Level Goals
Term
SMCLs
Definition

Secondary Maximum Contaminant Levels

-color/odor

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