Water science-exam 1
saqia
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shadouf
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tambour
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Three rules for determining watershed boundaries:
1. surface water generally flows at right angles across contour lines 2. ridges are indicated by the highest elevation contour line in an area 3. drainages ar indicated by contour lines pointing upstream
midsection discharge method
1.divide stream into 10 sections of equal width 2. quantify the depth and velocity of section from center point of each section 3. calculate the flow for each section using Q=AV where A is simply the width X depth of a section 4.sum the flow from all sections derive river discharge
Climate is affected by:
1.greenhouse effect 2.air currents 3.ocean currents 4.tilt of earths axis
Greenhouse gases in the atmosphere
H2O CH4-methane O3-ozone N2O-nitrous oxide CO2-carbon dioxide
non greenhouse gases in the atmosphere
N2 O2
topographic maps
USGS maps that show the slopes elevations, distances, and physical landscape features of the entire US
perennial
always flowing
potential evapotransporation
amount of water that will be lost due to evaporation and transpiration assuming an unending water source. developed by C.W. thornthwaite, this concept remains important for understanding the max water requirement of crops
humidity
amount of water vapor and aerosols in the atmosphere. Aerosols are very small liquid or solid droplets (not necessarily water Hot tropical day=4% water vapor cold dry day= .3% water vapor
arid
areas outside polar regions with less than 10 inches of annual precipitation
urban microclimates
average temperature and precipitation patterns change due to changes in major land cover patterns
climate
average weather conditions which can be generally predicted far into the future
heating
caused by three major processes: solar, adiabatic, and convention
adiabatic
change in atmospheric pressure that changes temperature, rapid increase in pressure warms air, rapid decrease in pressure cools air
surface tension
cohesion between water molecules creates
The Hydrologic Cycle
condensation precipitation run-off surface and groundwater storage evapotranspiration
solar
conversion of light energy to heat
orographic lifting
created when warm moist air is forced by wind over mountains. Collides with cool air to cause precipitation
relative humidity
current amount of water vapor in air relative to the maximum possible at current temperature and barometric pressure (ex. 50% humidity)
irrigation ditches
delivering non-potable water. modern version are enormously expansive
playa
depressional lake in relatively flat topography. common on high plains
Doppler effect
describes sound movement relative to moving objects
aspect
direction of exposure of sloping land
small dams
earthen dams provide flood control and store water for multiple uses including consumption, irrigation, and mill power
coriolis effect
earths rotation influences the path of directional winds making them "curvy"
aqueduct
elevated water delivery system made from stone. constructed ~300 BC. Municipal water supply, irrigation and waste removal
precipitation that hits the ground in a watershed either:
evaporates infiltrates flows over land surface
contour lines
follow a constant elevation above sea level. separated by constant spaces on maps (20ft contours)
How is precipitation measured
funnel rain gauge is more accurate, tipping bucket means almost no maintenance
orientation
general direction of the main portion of the river as water moves through watershed
earths greenhouse effect
greenhouse gases let the suns short wave radiation (visible light) reach the earth, but trap some of the long wave (infrared or heat) radiation coming from warm earth
thermocline circulation
gulf stream caused by this. cooler more saline water in bottom warmer and fresher water on top
convection
heating of atmosphere from latent heat of land surface
HUC
hydrologic unit code, larger numbers mean greater zoom on the watershed
tilt of earth crated our seasons
influences the angle at which radiation hits earth
interflow
lateral movement of soil water or shallow groundwater in the same direction as overland flow
Distribution of water on earth
liquid freshwater is <1% of total global water Surficial=.009% of total Groundwater=.62% of total
intertropical convergence zone
low pressure zone of air convergence at the equator
reservoirs
man-made lakes
locks and dams
modern engineered systems for water supply, transportation, and electricity generation
wind
movement of air from areas of high pressure to areas of low pressure
lakes
natural depressions in the landscape which are deep enough to store water perennially
ephemeral streams
no continuous flow, only storm flow
flash flood
occurs quickly in small areas due to precipitation occurring faster than drainage, difficult to predict but manageable
river flood
occurs slowly as river levels rise outside its banks, highly predictable but not easily managed
runoff
occurs when precipitation falls in sufficient quantities to cause water to gather and flow downhill
precipitation
occurs when water vapor condenses into clouds and undergoes further coalescence to form droplets
condensation
occurs when water vapor cools until it becomes a liquid. cloud formation is condensation
ocean gyre
ocean currents deflected by land mass
cohesion
opposite partial charges attract other water molecules
intermittent
period of continuous flow and periods of no flow
drought
period of dry weather long enough to produce a serious hydrologic imbalance
global trade winds
persistent winds caused by changes in air temperature and the rotation of the earth
air pressure
pressure induced by density of earths atmosphere. decreases with altitude. Low pressure unstable weather
most precipitation comes from ocean evaportation
proximity to the coast does not mean more precip
rating curve
quantitative relationship between river stage and discharge. often used to continuously measure stream discharge
semiarid
regions with annual precipitation between 10-20 inches
Map scale
relationship between the size of a map and the size of the features on the ground. US topo quads 1:24000 scale
overland flow
runoff water moving over the land surface toward a stream or river
wetlands
shallow depressions in the landscape that store water for various amounts of time (daily-perennially)
stream gradient
slope of a river that controls water velocity. typically decreases as stream and river size increases
infiltration
slow seepage of water down into the soil and ultimately into groundwater
doppler radar
sound waves sent from a tower bounce back in predictable patterns based on precipitation intensity and amount
weather
state of the atmosphere at a given time and place
ocean currents
steady and slow movement of ocean water caused by surface winds, tides, coriolis effect, and water density
weather characterized by:
temperature air pressure humidity heating wind speed and direction
dew point
temperature at which the rate of evaporation and condensation are equal
sublimation
the process by which solid water (snow or ice) is converted into water vapor without first becoming a liquid
surface water hydrology
the study of moving water found in rivers, lakes, open channels, and run off flowing across the open land surface
evapotranspiration
the sum of evaporation and the transpiration
evaporation
the transformation of liquid water into water vapor due to wind action and solar radiation
watershed
total land area that drains surface water to a common point or water body watershed=basin=catchment; basin larger than watershed and so on
qanat
underground water delivery systems. some as old as 1000BC. Still used in Middle east and parts of China. Municipal water supply and irrigation.
edmond halley
used pans of water to estimate the evaporation rate in the mediterranean sea
Lysimeter
used to directly measure evapotranspiration rates for different soil vegetation associations
pan coefficient
value needed to correct evaporation rates from Class A evaporation pans for any evaporation caused by heat energy conducted through walls of the pan
el nino
warm ocean currents forms in eastern pacific off the coast of Ecuador and peru which prevents upwelling, causes the southern oscillation which is the southward shift of the ITCZ
adhesion
water molecules are attracted to other charged molecules
transpiration
water molecules that enter a living plant as a liquid are released from leaves as water vapor
groundwater
water stored underground at various depths due to infiltration of precipitation
absolute humidity
weight of water in a given volume of air (g/cubic meter)