Chapter 4 Flashcards
- refers to rainfall caught by vegetation or crown of trees
INTERCEPTION
- Process by which raindrops are prevented from falling directly on to the soil surface by the presence of a layer of vegetation
INTERCEPTION
Factors in Influencing Interception:
A.) Rainfall intensity, duration, and distribution
B.) Vegetation characteristics
Importance of Interception:
1.) Influences soil moisture distribution
2.) Reduces the type and quantity of precipitation to be converted to overland flow.
Types of Interception:
1.) Through fall
2.) Stem-flow
3.) Interception loss via evaporation
- precipitation which is initially or not all intercepted by vegetation then falling directly to the ground.
Through fall
- precipitation that is initially intercepted and flows through the stem.
Stem-flow
– precipitation which is initially intercepted, then converted to water vapor.
Interception loss via evaporation
- refers to the vertical entry of water
from the surface into the soil
INFILTRATION
- process of entering rain water in to soil strata of earth
INFILTRATION
the infiltrated water first meets the soil moisture deficiency if any and excess water moves vertically downwards to reach the groundwater table. This vertical movement is called _________
PERCOLATION
the maximum rate at which it is capable of absorbing water is called ____________
INFILTRATION CAPACITY
Factors Affecting Infiltration Capacity:
1.) Thickness of saturated layer
2.) Soil moisture
3.) Compaction caused by rain
4.) In wash of fine materials
5.) Entrapped air
6.) Microbial activities
7.) Soil porosity
8.) Land uses – logging, road construction, kaingin, grazing
- water that percolate to a great depth and then appears after long time intervals often as distant points as springs, artesian wells, and geysers (below water table)
PERCOLATION
- the process of a liquid slowly passing through a filter
PERCOLATION
FACTORS AFFECTING PERCOLATION:
1.) water content of soil
2.) vegetation
3.) depth of soil
- refers to water flowing on soil surface as a result of soil saturation ____________ occurs when rate of precipitation exceeds the rates of which water infiltrates.
SURFACE RUNOFF
FACTORS AFFECTING SURFACE RUNOFF:
1.) Climate factors
2.) Physiographic factors
Climate factors
a.) Type of precipitation
b.) Rainfall intensity
c.) Duration of rainfall
d.) Distribution of rainfall on basin
Physiographic factors
a.) Land use
b.) Area
c.) Shape
d.) Elevation
e.) Slope
d.) Orientation
- the ground water aquifer and then slowly finds its way to streams. (above water table)
SUBSURFACE FLOW
- flow of water below earth’s surface as part of the hydrologic cycle
SUBSURFACE FLOW
- movement of water under the force of gravity through a defined semi-permanent channel.
STREAM FLOW
- _________ or discharge, is the volume of water that moves over a designated point over a fixed period of time
STREAM FLOW
IMPORTANCE OF STREAM-FLOW:
1.) Planning for flood control
2.) Estimating the dependability of water supply
3.) Designing reservoir storage
PARTS OF STREAM-FLOW HYDROGRAPH:
1.) Rising limb
2.) Falling limb/recession
3.) Peak flow
– refers to abrupt or gradual increase in water level in rivers depending on the condition of watershed or intensity of rainfall.
Rising limb
- refers to either abrupt or gradual decrease in water level in rivers depending on the condition of watershed or intensity of rainfall.
Falling limb/recession
– refers to the highest water level in the river or stream.
Peak flow
- graphical representation on the rise and fall of water volume or discharge in a river for certain period of time expressed in cubic meter per second
HYDROGRAPH
SEDIMENTATION:
1.) Sediment
2.) Sedimentation
3.) Sediment yield
4.) Suspended load
5.) Bed load
6.) Total sediment load
– refers to soil particles that are transported by stream flow
Sediment
- process of deposition of transported soil particles, gravels and cobbles
Sedimentation
– total sediment outflow from the watershed
Sediment yield
– portion of the sediment discharge consist of fie soil particles, such as silt and clay which are transported in suspension.
Suspended load
– portion of the sediment discharge consist of sand gobbles and gravels
Bed load
– bed loads and suspended loads
Total sediment load
Mode of Transport of sediments:
1.) Suspension
2.) Saltation
3.) Bed load
- sediments are suspended in water
Suspension
– bouncing sediments
Saltation
- sediments that move constantly in
contact with the stream bed.
Bed load
