LE2

Question 1

The Philippines receives an average of ____________. However, this amount is not evenly distributed over time and space.

Answer 1

2,360 mm of rainfall evert year

Question 2

What is the average annual rainfall is approximately 2,360 mm. but this varies geographically from __________.

Answer 2

960 mm in southeast Mindanao to over 4,050 mm in central Luzon.

Question 3

What type of Philippine’s Climate is two pronounced season: dry from November to April wet during the rest of the year.

Answer 3

Type 1

Question 4

What type of Philippine’s Climate is No dry season with a very pronounced rainfall from November to January.

Answer 4

Type II

Question 5

What type of Philippine’s Climate is Seasons are not very pronounced relatively dry from November to April and wet during the rest of the year.

Answer 5

Type III

Question 6

What type of Philippine’s Climate is Rainfall is more or less evenly distributed through the year.

Answer 6

Type IV

Question 7

Any product of condensation of atmospheric water vapor in the free air or at earth’s surface.

Answer 7

Hydrometer

Question 8

Consists of tiny liquid water droplets, usually with diameters between 0.1 and 0.5 mm, has slow settling rate.

Answer 8

Drizzle or mist

Question 9

Consists of liquid water drops mostly larger than 0.5 mm in diameter.

Answer 9

Rain

Question 10

Ice coating formed on exposed surfaces by the freezing of supercooled water deposited by rain or drizzle.

Answer 10

Glaze

Question 11

White opaque deposit of ice granules more or less separated by trapped air and formed by rapid freezing of supercooled water drops impinging on exposed objects.

Answer 11

Rime

Question 12

Composed of ice crystals, chiefly in complex branched hexagonal form, and often agglomerated into snowflakes.

Answer 12

Snow

Question 13

Precipitation in the form of balls of ice, produced in convective clouds.

Answer 13

Hail

Question 14

Consists of transparent, globular, solid grains of ice formed by the freezing of raindrops or refreezing or largely melted ice crystals falling through a layer subfreezing air near the earth’s surface.

Answer 14

Sleet

Question 15

Caused by unequal heating of land masses.

Answer 15

Convective Lifting

Question 16

Mechanical lifting over mountain barriers.

Answer 16

Orographic Lifting

Question 17

Lifting of warm air on one side of a frontal surface over colder, denser air on the other side (front).

Answer 17

Frontal Lifting

Question 18

Bounding surface between two distinct air masses.

Answer 18

Frontal Lifting

Question 19

Lifting of air converging into a low-pressure area.

Answer 19

Cyclonical Lifting

Question 20

Three (3) rainfall characteristics

Answer 20

• Intensity
• Duration
• Frequency

Question 21

It is expressed in mm/hr

Answer 21

Intensity

Question 22

It is period within which magnitude of hydrologic event will be equaled or exceeded once in the average.

Answer 22

Frequency

Question 23

It is 8” diameter standard rain gage – has a measuring tube 1/10 of the area of the collector.

Answer 23

Non-recording rain gage

Question 24

It is accumulated rain

Answer 24

Weighing type

Question 25

Rise of float with increasing catch of rainfall is recorded.

Answer 25

Float recording

Question 26

The Isohyetal method generally provides a more accurate representation of precipitation distribution, especially in regions with highly variable rainfall.

Answer 26

More Accurate than Thiessen Polygons

Question 27

It helps estimate precipitation over areas where rainfall stations are few, as long as there's a reasonable distribution of stations.

Answer 27

Works Well with Sparse Data

Question 28

Unlike simple methods like Thiessen polygons, which assume a uniform distribution of rainfall within each polygon, the Isohyetal method allows for more detailed and realistic representation of rainfall gradients.

Answer 28

Provides Detailed Distribution

Question 29

The process by which water on the ground surface enters the soil.

Answer 29

Infiltration

Question 30

Movement of water through the soil profile going to grounwater.

Answer 30

Percolation

Question 31

Infiltration per unit time; expressed in volume per unit time per unit area depth per unit time.

Answer 31

Infiltration rate

Question 32

Velocity of flow caused by a unit gradient; flow through soils in any direction.

Answer 32

Hydraulic conductivity

Question 33

Used interchangeably with hydraulic conuctivity.

Answer 33

Permeability

Question 34

The summation of the depth of water absorbed by a soil in a specified elapsed time in reference to the time of initial water application.

Answer 34

Cumulative infiltration

Question 35

The infiltrated water first meets the moisture deficiency if any excess water moved vertically downwards to reach the ground water table. the vertical water movement is called _________.

Answer 35

Percolation

Question 36

Often rich in humus and minerals

Answer 36

Topsoil (A horizon)

Question 37

Poor in humus, rich in minerals

Answer 37

Subsoil (B horizon)

Question 38

Little or no plant or animal life

Answer 38

Weathered rock fragments (C horizon)

Question 39

Infiltration is a primary method for replenishing groundwater supplies, which are crucial for drinking water, irrigation, and industrial use.

Answer 39

Groundwater Recharge

Question 40

By allowing water to enter the soil, infiltration reduces surface runoff, which can help prevent flooding and erosion.

Answer 40

Reducing Runoff

Question 41

Infiltration helps maintain soil moisture levels, supporting plant growth and sustaining ecosystems.

Answer 41

Supporting Ecosystems

Question 42

Other importance of soil infiltration:

Answer 42

- Water Conservation - Reduced soil erosion by runoff - Irrigation (manner of application) - Critical and maximum depth determination in water reservoir design

Question 43

The larger the pore size and the greater the continuity of the pores, the greater is the infiltration rate.

Answer 43

Soil

Question 44

Formation of thin compact layer on the surface as a result of severe breakdown of soil structure caused by the beating action of raindrops and flow of water over the surface.

Answer 44

Surface sealing or Puddling of soil

Question 45

The clay surfaced soil are compacted even by the impact of rain drops which reduce infiltratoin.

Answer 45

Soil Characteristics / Compaction

Question 46

Clay has ______ and ______ slow infiltration compared to sand and gravely soil.

Answer 46

Low and Slow

Question 47

The more saturated the loose Earth material are, the less infiltratoin.

Answer 47

Soil's degree of saturation

Question 48

Typically refers to the collection of standing water at the ground surface due to the presence of an impermeable layer within the soil.

Answer 48

Ponding

Question 49

The amount, intensity, and duration of precipitation significantly impact infiltration. Heavy, short-duration rainfall can lead to more runoff, while light, long duration rainfall allows more water to infiltrate.

Answer 49

Precipitation

Question 50

Vegetation and land use affect infiltration. Vegetated areas typically have higher infiltration rates due to root systems creating pathways for water.

Answer 50

Land Cover

Question 51

_______ vegetation, _______ infiltration

Answer 51

More ; Slower

Question 52

A portion of the stream flow that is not runoff; it is water from the ground, flowing into the channel over a long time and with a certain delay.

Answer 52

Base Flow

Question 53

Lateral movement of water

Answer 53

Base Flow

Question 54

Rivers near city has _______ baseflow because of impervious surface.

Answer 54

Low

Question 55

Steeper sloped tend to have higher runoff and lower infiltration rates compared to flat areas.

Answer 55

Slope of the land

Question 56

Chemicals that improve the soil structure hence increase infiltration ; other chemicals cause soil particles to swell and to become hydrophilic hence reduce infiltration.

Answer 56

Use of soil additives

Question 57

Water first enters the soil at the surface, influenced by gravity and capillary forces.

Answer 57

Surface Entry

Question 58

Water moves vertically and horizontally through soil layers, filling pore spaces and cracks.

Answer 58

Movement Through Soil

Question 59

Some infiltrated water reached deeper soil layers and recharges groundwater aquifers.

Answer 59

Recharge of Groundwater

Question 60

Involves direct measurement of water applied and water flowing from the field.

Answer 60

Direct Measurement

Question 61

Showed that when the rainfall rate i exceeds the infiltration rate f, water infiltrates the surface soils at a rate that generally decreases in time.

Answer 61

Horton (1933)

Question 62

The capacity decreases with time and ultimately reaches a constant rate, caused by filling of soil pores with water, which reduces capillary suntion.

Answer 62

Horton infiltration capacity curve