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)