Test 3 Flashcards
Transpiration
Process by which moisture is carried through plants from roots to small pores on the other side of leaves where pit changes to vapor and is released in the atmosphere
Hydrologic cycle
Precipitation Infiltration Run off Subsurface flow Transpiration Evaporation (from rivers, lakes, ocean)
Rivers
Water contained within a channel
Hydrology
The science of try and streams and rivers in the hydroloc cycle
Drain basin
Area drained by a single river (or system)
-where water will flow after rain, into what river
-based on the biggest river all other rivers flow into
—we ar cape fear river basin
Basins are separated by
Ridges called divides
Continental divide
Separation of water flowing to the Pacific Ocean vs the Atlantic Ocean
Pacific west
Atlantic east
Watersheds
The smaller areas river basins are divided into
-specific river that will eventually flow into the bigger river which is what the river basin is based off of
Riparian
Areas around and affected by river including habitat
-a minimum width of riparian habitat (including vegetation) is crucial to provide ecosystem services
—for the river to provide everything it should it needs a minimum width of riparian habitat so you can’t developed too close to a river
—-varies depending on type of stream but generally minimum of 100 feet
Floodplain
Area by a river that periodically floods
-can have more than one
—ie water street downtown
*not on the coast, inland
Alluvium
Sediments deposited by rivers
—finer size sediment particles
Formation of drainage networks
Stream flow begins as water is added to the surface (snow melt, precipitation, etc)
- steam flow begins as moving “sheetwash”
- sheetwash erosion creates tiny rills (channels)
- tributaries form
Sheetwash
Thin surface layer of water that moves down slope, eroding
Rills
Rills coalesce and deepen into tributary
How/when rivers/channels flow based on location
Ephemeral-above water table: don’t flow all year
Permanent- at or below the water table: flow all year
How is river flow based on geology
Bedrock: straight, found closer to the head (source) or steeper elevations
Alluvial:
-braided: broad, gravel, shallow, weave in and out of each other; often associated w glaciers
-meandering: deep, piedmont, squiggly like, found in coastal areas
*some streams can be more than one if it for example flows from the mountains to the coast
Straight (bedrock) river
Associated with mountainous river portions - closer to the head
— “young” stream stage
Braided (alluvial)
Form where channels are choked by sediment
- gravel bars are unstable, rapidly forming, and being eroded away
- flow occupies multiple channels across a valley
- often sssociated w glaciers (but not always)
Meandering rivers (braided rivers)
Head-source of stream
Mouth-outlet of the river (where it empties)
Cut bank-where erosion occurs (higher velocity)
Point bars-deposition occurs (lower velocity)
Natural levees-bank deposition
Oxbow lakes-abandoned loops (former remnants of the river)
River components (in most rivers)
Pools-deep pools beneath banks (usually higher velocity w large rocks or something surrounding it)
Riffles-shallow, course gravel (higher in oxygen than pool, higher number of organisms because of this)
-important habitats
River process controls
- Discharge
- Gradient
- Geology
- Sediment load
Discharge in a river
Volume of water that’s passing by a certain point in a given unit of time
-mostly cubic ft per second or cubic meters per second
Equation=(depth x width) x velocity
—velocity is not uniform throughout steam (highest in the center, lowest towards the banks bc as the water is coming into contact w sediment along side the stream it’s creating friction and slowing down the flow)
—wider and shallower more friction, narrow and deep less friction)
Gradient in rivers
Slope=rise/run
Longitudinal profile = change in evolution
Thalweg- profile that connects points of highest stream velocity
Gradient decreases w distance, works towards base level (flat area)
Sediment load
Materials moved by steams in the sediment loads: three types
- Dissolved load: ions that have been dissolved into the water from wether of minerals (smallest)
- Suspended load: fine particles like clay and silt that are carried in the flow of water but not dissolved, just light enough to be carried
- Bed load: large particles roll. Slide and bounce along (largest) ie boulders
Competence vs capacity
Competence: max size transported
Capacity: max load transported
Geology in river process
Igneous and metamorphic: younger. Straighter streams
Sedimentary rock: easily stored, meandering and alluvium streams
How do the four factors interact
Higher gradient means velocity will increase as will the sediment load (capacity) and discharge
Change the geology and river may straighten or start meandering and discharge more or less
Rapids
Turbulent water, reflect geological control
Represents:
-flow over resistant bedrock steps or over large coasts
-abrupt narrowing of channel
-sudden increase in gradient
What’re rapids classified as
Classes 3-4 are white water
Waterfalls
Streams that cascade or free fall
-waterfall energy scours base of waterfall and may cause erosion imitating collapse of overlaying rocks
—in nc the “fall line” represents change from hard rock into softer sedimentary rocks and can sometimes result in a water fall
Deltas
Deltas form when a stream enters standing water
- current slows and loses competence (can’t carry larger particles) sediments drop out and settle
- stream divide into a fan of small distributaries (opposite of tributary)
Landscape evolution
Steam flow is the cause of most landscape changes Time 1. Young stream -steam cuts into former surface -straight streams -good drainage Time 2. -meanders begin down strea -valleys widen, hill erodes Time 3. Mature -landscape eroded to base level
Dynamic equilibrium
Base level achieved
Forest to agriculture
Trees removed, roots support for soil gone, more erosion
- river capacity increases: deposition increases, slope increases
- velocity increases until river can carry new sediment load
Agriculture to forest local example
Early on (1800-1900s) the piedmont was converted to agriculture
After 1930s some areas converted back to forest land
Less sediment-stream eroded more-deepening
Wetland
Land areas inundated of ground saturated more than a few days every year and composed of:
Swamps: dominated by trees and shrubs
Marshes: frequently to continuously inundated w water , not dominated by trees or shrubs
Bogs: accumulated peat deposit (peat from dead vegetation)
Prairie potholes: small mash like ponds
Wetland benefits
- Buffers for inland areas from coastal erosion and storms
- Act as natural filters (trapping sediment/pollutant)
- Freshwater wetlands absorb excess water (reduce flooding)
- Special nutrient rich ecosystems
- Freshwater wetlands are commonly groundwater recharge zones
Concerns of wetlands
- Half of all us wetlands lost in last 200 years
- 90% of these post wetlands are freshwater (drained for urbanization)
- drained got agriculture
- drained for urbanization
Places earths water is in and how much
70% earths surface Including Rivers and flooding Groundwater Coastal Glaciers
How does water break down by a source
Oceans 97.2% residing for 1000s years
Glaciers2.15% residing for 10000+ years
Groundwater (and everything else ) residing for days to 1000s years
What falls under all else in ground water
Lakes or freshwater .0090% time there 10s year
Atmosphere .0010% there for 9 days
Rivers and streams .0001 two weeks there
Why are rivers crucial for humans
Drinking water Transportation Waste disposal Recreation Commerce Irrigation Energy
Reasons river are Important
Crucial for humans
Stream runoff causes flooding (lives and property)
River stream run off is an important geological agent
Why is stream runoff an important geological agent
Flowing water erodes,transports, and deposites sediments which
Sculpt landscapes and
Transfer mass from continents to water basins
(Earth perhaps the only planet in the solar system w flowing water)
Stream
Smaller river
Tributaries
Streams that are part of a larger river
Groundwater what percent
> .30%
Groundwater
Vadose zone/unsaturated zone
Water table
Saturated zone
Sedimentary properties affecting groundwater flow
Porosity Permeability -fine sediments low porosity -Note: high porosity does not mean high permeability —clay
Hydraulic properties
Hydraulic gradient
Groundwater flows from HIGH pressure to LOW pressure
-high elevation to low elevation
Recharge zone
Groundwater infiltrations start at
Influent streams
Streams above the water table do not flow all yer long,
-usually lose water to water table
(Ephemeral streams)
Effluent streams
Streams below the water table, that flow layer long
Permanent perennial stream
Aquifer
Porous and permeable layer of rock
Aquiclude
NonPorous and non permeable layer of rock
Confined aquifer
Surrounds by acquiluids
Unconfined aquifer
Open to the environment
Hydronic conductivity
Another word for permeability which depends on a variety of sedimentary factors
-size
-rock type
Sedimentary: higher porosity generally
Shist: higher porosity generally (bc can fracture easily)
Hydrologic gradient
Creates a pressure surface (also called the potentiometric surface)
Artesian Wells
Wells that produce below the pressure surface do not need to be pumped
Wells above the surface must have water
Pumped
Piezometers
Instruments that measure groundwater pressure (head)
Cones of depression
Wells,often many wells, create this around where the water table intersects the wall
—overtime the water table can be depleted by this
Overdrafts
I many instances groundwater is pulled out faster than is recharge
How many Americans use groundwater for drinking water
Overdrafts
Overdrafts cause
Subsidence and saltwater intrusion
Why has water usage gone down since 1980’s
Better management, conservation, changing usage
Since 1980’s uses of water
Industrial use and rural domestic and livestock used for less
Ocean water versus consumable water
Ocean 3.5% salt
Potable water .05% salt
Desalination drawbacks
Costs of desalination are falling but are still prohibitive
Costs of transporting fresh water may be less than local desalination
May prices about one million ft cubed of freshwater
Water pollution in nc
-One pig produces two tons of waste per year… and we have 2-10 mil pigs! Usually pig farms in flood plains
manure and urine palaces in four meter deep unlined lagoons
—June 1995 25 million gallons of lagoon waste flood into the New River
—hurricane Floyd in 1999 250 million gallons of pig waste was flooded into rivers
—-bodies of animals were buried and decaying bacteria entered ground water
What happens when water gets polluted
Organic matter (dead plants or animals) consumed by bacteria (microorganisms)
- bacteria needs oxygen to survive (aerobic bacteria)
- bacteria can remove oxygen from water- may kill fish, etc
How do we measure amount of bacteria proceeds in water during pollution
Biochemical oxygen demand (BOD)
-is a measure of the amount of oxygen indication level of havgrtialtovrss*****
—high BOD = high level of decaying organic matter
Why else is pollution scary
Pathogenic (disease causing) bacteria
-May be aerobic (oxygen breathing) or anaerobic (without oxygen)
—cholera, typhoid infections, dysentery and hepatitis
—monitored by tracking levels of fecal coliform bacteria
E. coli
Causes illness sand death
- from cow manure to public water supply during flooding
- contaminated meat
Nutrient pollution from human activity
Phosphorus and nitrogen
-fertilizers, detergents, sewage refuse
-part of the n-p-k rating seen on fertilizers
—forest land low concentrations
—agriculture/urban high concentrations
High amounts of p and n in water = cultural eutrophication
—increase in plant life especially algae
—like bacteria, removes oxygen may cover the lake, blocking sunlight
Oil petroleum spills
Major pollution
-match 1989 Exxon Valdez (250,000 barrels or 11 million gallons)
-bp deep water horizon oil spill 2010
—4.9 mil barrels or 2206 million gallons
—still seeping slightly
Comparison: Exxon Valdez releases just 5% of the oil bp spill
Toxic substances
Hazardous chemicals
-example mtbe (methyl tertbutyl ether) and trichloroethylene (tce)- gasoline additive added to increase oxygen in gas and reduce co emissions
—very sullenly often detected in ground water
—mtbe contaminated groundwater in Santa Monica ca caused them to stop pumping, eliminating 50% of their total drinking water
Heavy metals
-lead, cadmium, zinc, mercury
—deposited in sediments (if in flood plains may dissolve in water and get into plants and animals)
Mercury as a pollution
Natural and manmade sources
—volcanic eruptions, erosion of mercury deposits (minerals), burning coal, waste incineration, processing of metals
Hg joins with other metals forming amalgams often used to concentrate gold
-such processes may allow into the atmosphere and into aquatic systems
-methylation from bacterial activity converts Hg2+ to methylmecury which is v toxic
-biomagnification: as methyl mevity makes its way through the good chain amount increases as size increases
Gen-X
Hydrological units with detectable PFASs
Groundwater contamination
There are many sources of groundwater contamination
- Sanitary waste: failing septic system or animal feedlot runoff (remember hogs)
- Agricultural wastes: fertilizers and pesticides
- Toxic chemicals: industrial wastes: paints and thinners, and degreasers and solvents
- petroleum storage: underground storage tanks
Problem with contamination groundwater
Pollution is often not recognized until damage occurs
Cleanup is slow,expensive,and limited
Types of groundwater treatment
Treat and pump
Most common treatment of groundwater contamination: pump and treat
-remove source, put in extraction well, pump bad stuff out of ground and put it somewhere less armful
2. Bioremediation utilizes bacteria to clean groundwater- or coastal waters
Clean water act 1972
The purpose was to maintain the biological, physical and chemical integrity of the nations water, which includes: rivers, streams, lakes, and wetlands
-the goal was by 1983 to make all the nations rivers drinkable and swimmable and to achieve zero discharge from point source pollution
Flooding
Idk was there
Flood results exacerbated by
Torrential rains Saturated soils as a result of prior rainfall Urbanization Topography Biology (vegetation buffers) Snowmelt (not around here)
Flash flood
Higher elevation
Rapid heavy rainfall
Short duration and lag time
Ie Las Vegas
Downstream floods
Wide area
Longer rainfall
Longer lag time
Ie hurricane Florence
Flood stats
Most rivers have a stream gage to measure discharge
- many have over 100 years of flood data
- understanding flooding history of a river can help us predict future flooding
Discharge formula
Discharge=Area of river channel x velocity
D=AxV
Magnitude measures
Place specific
Put the discharges in decreasing order and number one to whatever
Recurrence interval and probability
R=(N+1)/M
Probability is 1/R
How does discharge relate to recurrence interval
More extreme, less frequently
Less extreme, more frequently
Good estimation rule
You can only estimate twice the number of years on record
Calorie
The amount of energy required to raise the temperature of one gram of water one degree Celsius
Water cycle through the states of matter
- Solid—> melts(absorbs 80 calories)—>liquid»evaporation(absorbs 600 calories)>gas
- Solid>sublimation(absorbs 680 calories)>gas
- Gas>condensation (release 600 cal)>liquid>freeze(release 80 cal)>solid
- Gas>deposition (loses 680 calories)>solid
Meteorology
Study of the atmosphere and the phenomena therein
-term. Coined in 340 bc by Aristotle
Wether
The state of the atmosphere at any particular time and place
Climate
A generalization of weather for an area, the “sum of all statistical weather info” NOT just an average
—old phrase: “climate is what you expect, weather is what you get”
Wilmington climate
Car
Humid subtropical
Atmospheric hazards
Thunderstorms Hurricanes Tornadoes Blizzards Hailstorms FreeIng rain Heat waves
What is atmosphere
The envelope of gases surrounding the earth or another planet
The atmosphere to scale
Thickeners of atmosphere: 100 km
Wilmington to Raleigh is 215 kilometers, aka two thickness of the atmosphere
Four most dominant gases in the atmosphere
- Nitrogen 78.084%
- Oxygen 20.946%
- Argon .934%
- Carbon dioxide .036%
Atmospheric pressure
Simply the weight of the air above
Gravity affect on earth (atmospheric pressure)
- gravity pulls air molecules closer to earth
- molecules of different masses are affected by gravity different
Air pressure increasing or decreasing as you leave earth
Air pressure decreases as you leave earth
Why does the air pressure decrease as you go up in altitude or increase as you scuba dive?
Fewer air molecules = lower density = low air pressure
More air molecules = higher density = higher air pressure
Temperature trend through atmospheric layers
Sum of all things sign, backwards 3
Troposphere
- Extends from the surface to about 18km
- Thickeners varies: thicker in tropics vs play region
- Home of the vast majority of weather and life on earth
- Temperatures decrease with altitude
- ends at tropopause
Tropopause
Temperature inversion after troposphere, it gets warmer instead of colder as you go up
Stratosphere
- starts at tropopause
- extends from 18-50 km
- temps increase with altitude
- home of ozone layer
- ends at strotopause
Stratopause
Another temp inversion (gets colder higher elevation)
Ends stratopause and starts mesosphere
Mesosphere
Starts at stratopause
- extends 50-80 km
- contains coldest portion of the atmosphere average inn -90 degrees calculus
- ends with mesopause
Thermosphere
Starts at mesopause
- outermost portion of the atmosphere, everything greater than 80 km
- upper limit (not well defined) of the thermosphere is called the Thermopause
- very hot at the thermopause
Why is it so hot in the thermopause if so cold in outer space?
Due to absorption of shortwave, high emerge solar radiation
Thermopause
Moves in response to solar activity (500-1000 km)
Notice:
Temp decreases in the troposphere
Simple decrease in the density of air molecules
Notice: temp in crease in the stratosphere
Presence of o3 molecules absorbing uv radiation
Notice: temp decreases (to lowest point) in mesosphere
Less o3 and reduced density of air molecules
Notice: temp increase in the thermosphere
Absorption of short wave solar radiation by N and O
What generates weather
How much solar energy we receive depend on the location, time of day, and season of the year so as a result the earth is heated unequally and this reduces winds and currents and eventually weather
Primary earth motions
- Rotation
-earth spins on its own axis every 24 hours, day night cycles
-one half of the circle is lit by the sun at any one time (circle of illumination) - Revolution (around the sun)
-counterclockwise once every 365.25 days
—determines seasons
-follows an elliptical path within the plane of the elliptical
Plane of the elliptical
Two dimensional surface that divides the earth and sun into two equal halves at all locations in the earths orbit
Aphelion and perihelion
Aphelion: July 4th, furtherest point from the sun
Perihelion: January 3, closes point to the sun
Important dates and latitudes
Equinox: sun vertical at equator, March 21-22 and September 22-23
Solstice: latitude 23.5 N (June 21-22)/S (December 21-22)
Air mass
Two types (>1600 km2) stays over the scourge region for an extended period and takes on the characteristics of the source region
Two types of air masses
- Cold (polar or p), warm (tropical or t), or very cold (arctic or a)
- Dry (continental or c) or humid (maritime or m)
Frontal weather
Narrow zone of transition between air masses that differ in density
—density due to temp and humidity contrasts
What happens when air masses meet at fronts
The folder, denser air forces the water, less dense air to rise
-this induces adianatoc cooling (decreasing pressure) and often cloud-precipitation development
The slope of the front influence the types of clouds that form
1. Warm front: v shallow slopes
2. Cold fronts: much steeper slopes
Three types of fronts
- Warm front
- Cold front
- Occluded front
Warm front
Just ahead of the front, steady precipitation usually gives way to drizzle and sometime frontal fog
- if advancing war air is unstable or conditionally sunstanle, more vigorous uplift can occur with thunderstorms embedded in the overrunning zone
- shallow tong
- red semicircles
Cold front
The slope o a cold front is much steeper than the slope on a warm front
- upLift is confined to narrow area at or near the fold fronts leading edge
- if the warm air is unstable, thunderstorms may form and a squall line (line of t storms) can develop
- if the warm air is relatively stable, nimbostratus and altostratus clouds may form
- blue pyramids
Occluded font
- Cold type
- air behind cold front colder than cool air ahead of warm front
- like a cold front at the surface - Warm type
- air behind cold front is not as cold as the air ahead of the warm front
- like warm front at the surface
Stats on t storms
2000 thunderstorms at any moment
45000 every day
16 mil annually
What is a thunderstorm
Instead of winds rotating around the center, t storms are composed on updrafts and dowmdrafts (somewhat)
- short lived
- accompanied by lightening and thunder
- composed of a single cumulonimbus cloud or clusters of cumulonimbus clouds covering a large area
Two types of t storms
- Air mass thunderstorm
-form as a result of the unequal heating of the earth
—typically a result of warm humid moist tropical air masses coming up the Gulf of Mexico - Severe thunderstorms
Three stages of development of thunderstorms
- Cumulus stage : sucks up rain and humidity
- Mature stage :sucks hot air up while raining down cold air
- Dissipating stage:hot air spreads out up top and cold air is released as a light rain
Tornados
Local storm of short duration (most small tornadoes last 3 minutes or less)
-in touch with the ground can be up to 2.5 miles wide and produce winds topping 300 mph
Intense pressure differences, Drop of 100 mb was recorded by a tornado in 2003 (less than the storm it formed from
Tornado shape
Also called Twisters or cyclones and take shape of a vortex
-some tornados are composed of several vortices called suction votices that orbit the center of the tornado
—multiple vortex tornados
Tornado formation
- Supercell thunderstorm with strong vertical wind shear (both speed and direction)
- weaker winds lower tot he ground with stronger winds aloft - This sheer causes air to rotate about a horizontal axis in a rolling motion
- 295( strong updrafts this ruling motopn ca he pushed vertically forming a mesocyclone
- updrafts draw humid rain cooled air in the system that (expands) condenses at a lower altitude forming a wall cloud - As the mesocyclone narrows it spins faster and faster eventually extending down towards surface as a tornado
- the spinning lowers the temp usually below the dew point causing a dark ominous cloud to form - picking up dust and debris (what we see as a tornado)
Tornado intensity
Measured by the amount of damage done and the wind speed achieved
—the enhanced Fujita scale (EF0-EF5)
