Ees 230: Hydrology Test 1

Front 1

Hydrology

Back 1

Geoscience that describes and predicts the occurrence,
circulation, and distribution of the water of the earth and its atmosphere

Front 2

Precipitation

Back 2

any form of solid or liquid water that falls
from the atmosphere to the surface

Front 3

Relative Humidity

Back 3

Ratio of amount of water vapor in air
To the maximum amount air can hold

Front 4

Dew Point

Back 4

Temperature at which air reaches saturation (Relative humidity =100%)

Front 5

Ground Based Weather Radar

Back 5

Measures the rate of return of the
radiant energy reflected by precipitation

Front 6

Snow Water Equivalent

Back 6

The height of water if a snow cover is completely melted, on a corresponding horizontal surface area.

Front 7

Isohyets

Back 7

Contours of precipitation, linear gradation between gages

Front 8

Rainfall frequency distributions

Back 8

Probability that a given rainfall event will occur

Front 9

Return period

Back 9

average period of time in years expected
between high intensity storms

Front 10

Probability of a given return period storm (T)
will occur within a certain number of years (n)

Back 10

P(T, n) = 1 – (1 - 1)n

Front 11

Hazen Method

Back 11

Fa = 100(2n – 1)/2y= 100/Return Period, T

Front 12

Inverse Distance Weighing Method

Back 12

1) D= (1/x+1/y+1/z)
2) 1/D=
3) (d)*[1/xA+1/yB+1/zC]

Front 13

Soil

Back 13

unconsolidated aggregate of
mineral and rock fragments
(clay to silt to sand to gravel)

Front 14

Infiltration

Back 14

flow of water from ground
surface down into the soil

Front 15

Porosity

Back 15

Full of small openings:
Volume of Void Space (Vv) / Total Volume (Vt) *100

Front 16

Weighing Approach (Porosity)

Back 16

n = 100[1 - pb /pd]

pb = Bulk density (aquifer material)
pd = Particle density

Front 17

Volumetric water content

Back 17

Ratio of water volume to soil volume

Front 18

Degree of saturation (S)

Back 18

proportion of pores that contain water

S= (vol. water content)/ # of pores

Front 19

Capillary Fringe

Back 19

Zone above water table that is effectively saturated. Water held by tension

Front 20

Field Capacity

Back 20

maximum water content that a soil can hold in a free draining situation. Varies as a function of grain size.

Front 21

Plant Available Water

Back 21

moisture content at which plants exhibit permanent wilting. Plants cannot suck any more water from the soil. Lowest moisture threshold at which a plant can extract water.

Front 22

Soil Moisture Deficit

Back 22

Amount of water needed to raise the moisture content to the field capacity

Front 23

Matric Potential

Back 23

force needed to exert water from soil matrix. As soil moisture gets less, matric potential increases.

Front 24

Soil moisture retention curve

Back 24

Apply increasing tension and
track moisture changes in soil sample

Front 25

Water input rate

Back 25

rate at which water arrives at the surface due to precipitation

Front 26

Infiltration rate

Back 26

rate at which water enters the soil from the surface

Front 27

Infiltration Capacity

Back 27

the maximum rate at which infiltration can occur
under specific moisture conditions

Front 28

Permeability

Back 28

rate at which fluid flows through a material

Front 29

Macropores

Back 29

soil water passing quickly to a stream through root canals, animal tunnels or pipes produced by subsurface erosion

Front 30

Horton Equation

Back 30

f = fc + (f0 – fc)e-βt
Measures infiltration rates from Time (0) to Time (final)

Front 31

Green-Ampt Equation

Back 31

f = A/F + B
Analytical solution for infiltration under constant rainfall. Assumes sharp wetting front.

Front 32

Soil Water Balance

Back 32

Change in SM = P + IR – Q – G – ET

Front 33

Guelph Permeameter

Back 33

Measures constant head rates at certain depths

Front 34

Evapotranspiration

Back 34

process that returns water to the atmosphere. Includes evaporation of water from water bodies, bare soil, and vegetative surfaces.

Front 35

Latent Heat of Vaporization

Back 35

The energy (heat) needed to transform water from liquid phase to gas in evaporation

Front 36

Dalton's Law

Back 36

Evap rates controlled by: The saturation deficit and windspeed.
E = Ke*Va(es – ea)

Front 37

Transpiration

Back 37

Process by which water vapor escapes from living plants and enters the atmosphere. Includes water which has evaporated from leaf stomata as well as intercepted water which has re-evaporated.

Driven by vapor pressure deficit (i.e. Dalton's Law)

Front 38

Transpiration Ratio

Back 38

Ratio of the weight of water transpired
to the weight of dry matter produced by the plant. Measure of how efficiently plants use water.

Front 39

Consumptive Use

Back 39

Total amount of water needed to grow crop
(sum of water used in ET + water stored in plant tissue)

Front 40

Oasis Effect

Back 40

isolated body of water set in large vegetated area
air crossing over has lower relative humidity
than if it had been crossing over a lake
so it will take up more vapor and overestimate evaporation

Front 41

1 inch

Back 41

2.54 cm

Front 42

1 m

Back 42

3.281 ft

Front 43

1 mile

Back 43

5280 ft

Front 44

1 ft3

Back 44

7.48 gallons

Front 45

1 acre

Back 45

43,560 ft2

Front 46

Watershed

Back 46

Area that appears on the basis of topography
to contribute all of the water that passes through
a given cross section of a stream