Wr304 Exam 2

Front 1

Stefan Boltzman Equation

Back 1

LW = epsilon*sigma*Tk^4

(epsilon = emissivity ~1)
(sigma = stefan boltzman constant)
Tk = temp in Kelvin

Front 2

soil is saturated =

Back 2

a soil cannot hold anymore water in its pores. It cannot retain additional water until water is depleted from some of these pores. This promotes anaerobic conditions (w/o oxygen).

Front 3

soil at field capacity =

Back 3

the amount of water soil can hold against the force of gravity.

Front 4

soil at wilting point =

Back 4

the amount of water in a soil when a plant cannot obtain enough water to remain turgid.

Front 5

which soil has the most water at saturation, a sand or a clay?

Back 5

clay

Front 6

which soil holds the most plant-available soil water, a loam or a clay?

Back 6

loam

Front 7

once a soil is at field capacity, how is it most likely to lose water?

Back 7

Evapo-Transpiration

Front 8

what is the proximal cause of surface runoff?

Back 8

low infiltration rate

Front 9

why is surface runoff usually considered a problem in watershed management? (3 reasons)

Back 9

1. erosion
2. sediment transport
3. flooding

(to prevent runoff, improve soil infiltration rate)

Front 10

name 5 factors that are likely to cause surface runoff.

Back 10

1. low soil infiltration rate
2. high rate of rainfall
3. long duration of rainfall
4. not much surface roughness
5. steep slope

Front 11

infiltration rates normally decline as a storm continues. why?

Back 11

soil reaches field capacity and eventually saturation.

Front 12

why might an overgrazed rangeland have a lower infiltration rate than a properly grazed one?

Back 12

-compaction
-less vegetation

Front 13

what is "interception" and why is it important in the hydrologic cycle?

Back 13

interception is when water is caught in the vegetation and evaporates before it reaches the ground.

interception = precip on veg - streamflow - throughfall