water balance intro + inputs and flows

Question 1

drainage basin

Answer 1

an area of land drained by a river and its tributaries

Question 2

what is water balance? and what does it monitor?

Answer 2

water balance is the annual balance between inputs and outputs at a particular time.

it helps to monitor the amount of water held in storages.

Question 3

role of precipitation?

whats the relationship between the intensity and duration of rainfall event?

Answer 3

precipitation is a major input of the system, often coming in the form of rain, snow, or hail.

it is derived through the condensation of clouds.

the greater the intensity, the shorter the rain period.

Question 4

infiltration

Answer 4

the downward entry of water into the surface of the soil by forces of gravity and capillary action.

Question 5

infiltration capacity

Answer 5

the maximum rate at which water can be absorbed at a steady state

Question 6

percolation + 3 facts

Answer 6

the verticle downward movement of water through the soils and its layers.

• occurs at a greater depth than infiltration
• underlying rocks must be permeable
• process is slower than infiltration due to the compactness of the underlying rocks

Question 7

throughflow + 3 facts

Answer 7

horizontal movement of water within soil layers

• slow process
• occurz when water that originally was moving downwards, starts moving sidewards due to the soil being more compacted and less permeable with increasing depth
• move at speed of 0.005m/h to 0.3m/h

Question 8

baseflow + 2 facts

Answer 8

the horizontal movement of GROUNDwater in the zone of saturation.

• slowest process amongst all
• contributes to channel flow

Question 9

overland flow + 1 fact

Answer 9

rain or melt water that travels over land surfaces from an area of higher elevation to an area of lower elevation.

• consist of IEF and SOF

Question 10

infiltration excess flow (3pts)

Answer 10

• occurs when rainfall intensity> infiltration capacity
• excess water accumulate on ground surface shortly after rainfall event
• normally occurs at urban areas due to impermeable surfaces and limited infiltration capacity

Question 11

saturation overland flow (SOF) (5pts)

Answer 11

• occurs when infimtration capacity> rainfall intensity
• does not occur shortly after rainfall event.
• requires antecedent soil in order for SOF to occur
• form at base of slopes
• contribute to channel flows

Question 12

interception storage + 2 facts

Answer 12

water caught by vegetation and stored on canopy

• intercept up to 50%
• greatest at early stage of rainfall

Question 13

soil water storage

Answer 13

amount of water held in the subsurface soil layer above the water table by gravity or capillary action.

Question 14

ground water storage + 1 fact

Answer 14

water stored in the pore spaces within the bed rock and regolith

• able to control level of water table

Question 15

ground water recharge

Answer 15

refilling if water in pore spaces that has been dried up by extraction or hunan activities

Question 16

channel storage + 2 fact

Answer 16

water that is stored along the depressions of the surface (aka river)

• contributed by direct rain, overland flow, through flow, and groundwater flow.
• largest during flood events

Question 17

evapotranspiration

Answer 17

the subsequent loss of water from soils, vegetation, and water bodies

• account for 75% of water loss in humid tropics and 100% in arid tropics

Question 18

river discharge

Answer 18

the movement of water into river channels (either through direct precipitation or diff flows)

-can vary seasonally due to climate