INFILTRATION Flashcards
is the process by
which water on the ground
surface enters the soil. It is a
key component of the
hydrological cycle and
influences groundwater
recharge, surface runoff, and
soil moisture levels.
INFILTRATION
Anywhere in the world, a portion of the water
that falls as ______- infiltrates into the
subsurface soil and rock.
RAIN AND SNOW
Some water that infiltrates will remain in the
shallow soil layer, where it will gradually _______ through the soil and
subsurface material.
MOVE VERTICALLY AND HORIZONTALLY
Water may travel long distances or remain in
________ for long periods before
returning to the surface or seeping into other
water bodies, such as streams and the ________
GROUND WATER STORAGE
OCEANS
FACTORS AFFECTING INFILTRATION
- PRECIPITATION
- BASE FLOW
- SOIL CHARACTERISTICS
- SOIL SATURATION
- SLOPE OF THE LAND
- EVAPOTRANSPIRATION
- LAND COVER
As precipitation infiltrates into the
subsurface soil, it generally forms an
______
unsaturated zone and a saturated zone.
the voids—that is,
the spaces between grains of gravel, sand,
silt, clay, and cracks within rocks—contain
both air and water
UNSATURATED ZONE
Although a lot of water
can be present in the unsaturated zone, this
water cannot be pumped by ______ because it
is held too tightly by _____.
WELLS
CAPILLARY FORCES
The upper part of the unsaturated zone is the ________. The soil zone is crisscrossed by roots,
openings left by decayed roots, and animal and
worm burrows, which allow the precipitation to
infiltrate into the soil zone
soilwater zone
Water in the soil is used
by plants in life functions and leaf transpiration, but
it also can evaporate directly to the
ATMOSPHERE
Below the unsaturated zone is a ________
where water completely fills the voids between rock
and soil particles.
SATURATED ZONE
replenishes aquifers,
INFILTRATION
gives
natural infiltration a push
ARTIFICIAL RECHARGE
STAGES OF INFILTRATION PROCESS
- INITIAL ABSTRACTION
- PONDING
- STEADY - STATE INFILTRATION
Occurs before ponding begins
Includes interception by
vegetation (grass, leaves),
surface depression storage
(puddles), and evaporation.
Reduces the amount of water
available for infiltration.
INITIAL ABSTRACTION
Begins when the rainfall
intensity exceeds the
infiltration capacity of the
soil.
Water accumulates on the soil
surface forming ponds or
puddles.
Marks the start of the actual
infiltration process into the
soil.
PONDING
Occurs when the infiltration rate reaches a constant value over time
Depends on soil properties (texture, structure) and initial moisture content
Governed by the soil’s saturated hydraulic conductivity (permeability)
Reached when the soil becomes fully saturated and cannot be absorb more water
STEADY - STATE INFILTRATION
describes how
infiltration capacity declines as the
precipitation event advances and is
based on generating runoff when
rainfall intensity exceeds the infiltration
capacity
.
HORTON METHOD
was an
American hydrologist
and engineer known as
the father of modern
hydrology
. He made
significant
contributions to the
understanding of
infiltration, runoff, and
watershed hydrology
.
ROBERT ELMER HORTON
The curve is called the ________ curve. the capacity decreases wth time and ultimately reaches a constant rate, caused by filling of soil pores with water, which reduces capillary suction
HORTON INFILTRATION CAPACITY
is an infiltration model used in hydrology to estimate the rate and volume
of water infiltration into the soil during a rainfall event
GREEN - AMPT MODEL
for cases of vertical infiltration
PHILIP’S EQUATION
METHODS OF MEASURING INFILTRATION
INFILTROMETER METHOD
DOUBLE-RING INFILTROMETER METHOD
RAINFALL SIMULATOR METHOD
TENSION INFILTROMETER METHOD
SOIL CORE METHOD
WEIGHING LYSIMETER METHOD
GUELPH PERMEAMETER METHOD
This involves using a
cylindrical infiltrometer
to measure the
infiltration rate
INFILTROMETER METHOD
This method uses two
concentric rings to
measure infiltration
DOUBLE-RING INFILTROMETER METHOD
This method involves using a
rainfall simulator to apply a
controlled amount of rainfall to a
plot of land.
RAINFALL SIMULATOR METHOD
This method is designed
to measure the
unsaturated hydraulic
properties of soils.
TENSION INFILTROMETER METHOD
This method involves
collecting soil cores
using a cylindrical core
cutter.
SOIL CORE METHOD
This method involves using a
weighing lysimeter to measure
the change in soil moisture over
time.
WEIGHING LYSIMETER METHOD
This method uses a
Guelph permeameter to
measure the infiltration
rate under saturated
conditions.
GUELPH PERMEAMETER METHOD
the infiltrometer inserted
into the soil, and water is
poured into it. The infiltration
rate is calculated by measuring
the decrease in water level
over time.
INFILTROMETER METHOD
The inner ring is used to apply
water, and the outer ring is
used to buffer the inner ring
from lateral flow.
DOUBLE-RING INFILTROMETER METHOD
The infiltration rate is calculated
by measuring the runoff and
subtracting it from the total
rainfall
RAINFALL SIMULATOR METHOD
This is accomplished by
maintaining a small negative
pressure on the water as it
moves out of the infiltrometer
disc into the soil
TENSION INFILTROMETER METHOD
The infiltration rate of the
cutter filled with soil is
measured in a laboratory
setting.
SOIL CORE METHOD
Uses data acquisition system, a
system to collect and record
weight data at regular intervals.
WEIGHING LYSIMETER METHOD
is an
easy-to-use instrument to
quickly and accurately
measure in-situ hydraulic
conductivity.
GUELPH PERMEAMETER
