Lecture 14: Hydrologic Cycle, Soil Moisture

Question 1

_____ is the study and distribution of water in all its forms

Answer 1

Hydrology

Question 2

______ is the proportion of a volume of soil (or sediment or rock) that is open space.

Answer 2

Porosity

Question 3

______ is a proportion of a soil (or sediment or rock) that consists of interconnected pores

Answer 3

effective porosity

Question 4

______ is the ability of a soil (or sediment or rock) to transmit fluid

Answer 4

Permeability

Question 5

_____ is adsorbed water, a thin film held at very high pressures
“unavailable water”

Answer 5

Hygroscopic

Question 6

______ is water held by surface tension, moves in response to moisture gradients
“available water

Answer 6

Capillary water

Question 7

______ is water held at low pressures that will drain freely

“unavailable water”

Answer 7

Gravitational water

Question 8

_____ is the amount of water retained after capillary water is removed

Answer 8

Wilting Point

Question 9

______ is the amount of water retained after gravitational water has drained

Answer 9

Field capacity

Question 10

True or False: fine grained soils have higher field capacities than coarse grained soils

Answer 10

True

Question 11

True or False: the proportion of unavailable water (hygroscopic) to the total water content increases with fine grained soils

Answer 11

True

Question 12

True or False: the amount of available water is maximum in a medium textured soil

Answer 12

True

Question 13

True or False: coarse grained soils retain less moisture

Answer 13

True

Question 14

A ______ is a budget of inputs and outputs of water in a system. The system could be an entire watershed or a smaller area (e.g. a soil profile on a hillslope).

Answer 14

Water balance

Question 15

What is the equation for water balance?

Answer 15

Q = P - E ± ÄS

Q is Runoff (Discharge)
P is Precipitation
E is Evapotranspiration (Actual: AE)
ÄS is change in Storage

Question 16

______is all of the evaporative losses from the soil and surface water bodies to the atmosphere plus the transpiration of water through plant tissues to the atmosphere.

Answer 16

Evapotranspiration

Question 17

What are the variables evapotranspiration is influenced by?

Answer 17

temperature, type of vegetation, relative humidity, and wind speed.

Question 18

______ (PE) is the amount of water that would evaporate and transpire under moist soil conditions, ______ (AE) is the amount of water that evaporates and transpires under the actual moisture conditions.

Answer 18

Evapotranspiration, Actual Evapotranspiration

Question 19

What is the equation for precipitation?

Answer 19

Precipitation = Actual Evapotranspiration + Surplus ± Change in Storage