MENANAM POHON UNTUK
MEMANEN AIR HUJAN
HIDROLOGI
Soemarno - psdl ppsub 2013
2
SISTEM HIDROLOGIA hydrologic system is as a structure or volume in space, surrounded by a boundary, that accepts water and other
inputs, operates on them internally, and produces them as outputs.
supit.net/main.php?q=aXRlbV9pZD02Mg==
Water supply to the roots, infiltration, runoff, percolation and redistribution of water in a one-dimensional profile are
derived from hydraulic characteristics and moisture storage capacity of the soil.
www.treemail.nl/.../treebook7/soil/chapt6.htm
The processes directly affecting the root zone soil moisture content can be defined as:
Infiltration: i.e. transport from the soil surface into the root zone;
Evaporation: i.e. the loss of soil moisture to the atmosphere;
Plant transpiration: i.e. loss of water from the interior root zone;
Percolation: i.e. downward transport of water from the root zone to the layer below the root zone;
Capillary rise: i.e. upward transport into the rooted zone.
PRELIMINARY INFILTRATION
The infiltration rate depends on the available water and the infiltration capacity of the soil. If the actual surface storage is
less then or equal to 0.1 cm, the preliminary infiltration capacity is simply described as:
WhereINp : Preliminary infiltration rate[cm d-1]FI : Maximum fraction of rain not infiltrating during time step t[-]CI : Reduction factor applied to FI as a function of the precipitation intensity[-]P : Precipitation intensity[cm d-1]Ie : Effective irrigation[cm d-1]SSt : Surface storage at time step t [cm]Dt : Time step[d]
The maximum fraction of rain not infiltrating during time step t, FI can be either set to a fixed value or assumed to be
variable by multiplying FI with a precipitation dependent reduction factor CI which is maximum for high rainfall and will be reduced for low rainfall. The user should provide FI. The CI table is included in the model and is assumed to be
fixed.
The calculated infiltration rate is preliminary, as the storage capacity of the soil is not yet taken into
account. If the actual surface storage is more than 0.1 cm, the
available water which can potentially infiltrate, is equal to the water amount on the surface (i.e. supplied via rainfall/irrigation and depleted via
evaporation):
WhereINp : Preliminary infiltration rate[cm d-1]P : Precipitation intensity[cm d-1Ie : Effective irrigation[cm d-1]Ew : Evaporation rate from a shaded water surface[cm d-1]SS : Surface storage at time step t [cm]Dt :Time step[d]
However, the infiltration rate is hampered by the soil conductivity and cannot exceed it. Soil conductivity is soil specific and should be given by the user.
LAJU INFILTRASI - KAPASITAS IMPANAN LENGAS TANAH
INFILTRASI TERKOREKSI
Total water loss from the root zone can now be calculated as the sum of transpiration, evaporation and percolation.
The sum of total water loss and available pore space in the root zone define the maximum infiltration rate.
The preliminary infiltration rate cannot exceed this value. The maximum possible infiltration rate is given by:
Where:INmax :Maximum infiltration rate[cm d-1]qmax :Soil porosity (maximum soil moisture)[cm3 cm-3]Qt :Actual soil moisture content[cm3 cm-3]RD :Actual rooting depth[cm]Dt :Time step[d]Ta:Actual transpiration rate[cm d-1Es :Evaporation rate from a shaded soil surface [cm d-1]Perc :Percolation rate from root zone to lower zone[cm d-1]
8
PERKOLASI
If the root zone soil moisture content is above field capacity, water percolates to the lower part of the potentially rootable
zone and the subsoil. A clear distinction is made between percolation from the actual rootzone to the so-called lower zone, and percolation from the lower zone to the subsoil.
The former is called Perc and the latter is called Loss. The percolation rate from the rooted zone can be calculated
as:
WherePerc : Percolation rate from the root zone to the lower zone[cm d-1]Wrz : Soil moisture amount in the root zone [cm]Wrz,fc Equilibrium soil moisture amount in the root zone [cm]Dt : Time step[d]Ta : Actual transpiration rate [cm d-1]Es : Evaporation rate from a shaded soil surface [cm d-1]
The equilibrium soil moisture amount in the root zone can be calculated as the soil
moisture content at field capacity times the depth of the rooting zone:
WhereWrz,fc : Equilibrium soil moisture amount in the root zone[cm]Qfc : Soil moisture content at field capacity[cm3 cm-3]RD : Actual rooting depth[cm]
KAPASITAS LAPANG
The percolation rate and infiltration rate are limited by the conductivity of the wet soil, which is soil specific and should be given by the user. Note that the percolation from the root zone to the lower zone can be limited by the uptake capacity of the lower
zone. The value calculated is preliminary and the uptake capacity
should first be checked. The percolation from the lower zone to the subsoil, the so-called
Loss, should take the water amount in the lower zone into account. If the water amount in the lower zone is less than the
equilibrium soil moisture amount, a part of the percolating water will be retained and the percolation rate will be reduced.
Water loss from the lower end of the maximum root zone can be calculated as:
Where1. Loss :Percolation rate from the lower zone to the subsoil[cm
d-1]2. Perc :Percolation rate from root zone to lower zone (see eq.
6.21)[cm d-1]3. Wlz :Soil moisture amount in the lower zone [cm]4. Wlz,fc :Equilibrium soil moisture amount in the lower zone
[cm]5. Dt :Time step
LAJU PERKOLASI
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Water loss from the potentially rootable zone, is also limited by the maximum percolation rate of the subsoil,
which is soil specific and should be provided by the user. The equilibrium soil moisture amount in the lower zone can be calculated as the soil moisture content at field
capacity times the root zone depth:
Where1. Wrz,fc : Equilibrium soil moisture amount in the
lower zone[cm]2. Qfc :Soil moisture content at field capacity[cm3 cm-
3]3. RDmax :Maximum rooting depth[cm]4. RD :Actual rooting depth[cm]
For rice an additional limit of five percent of the saturated soil conductivity is set to account for puddling (a rather
arbitrary value, which may be easily changed in the program).
The saturated soil conductivity and is calculated with pF= -1.0 (i.e. a hydraulic head of 0.1 cm). The percolation rate from the lower zone to the sub soil is not to exceed this
value (van Diepen et al., 1988). The value calculated should be regarded as preliminary; the storage capacity of the receiving layer may become
limiting.
KEHILANGAN AIR DARI ZONE AKAR
The storage capacity of the lower zone, also called the uptake capacity, is the amount of air
plus the loss.It can de defined as:
WhereUP :Uptake capacity of lower zone[cm d-1]RDmax :Maximum rooting depth[cm]RD :Actual rooting depth[cm]Wlz :Soil moisture amount in lower zone[cm]Qmax :Soil porosity (maximum soil moisture)[cm3 cm-3]Dt :Time step[d]Loss :Percolation rate from the lower zone to the subsoil[cm d-1]
Percolation to the lower part of the potentially rootable zone can not exceed the uptake capacity of the lower zone. Therefore the percolation rate is set equal to the minimum of the calculated percolation rate and the uptake.
KAPASITAS SIMPANAN LENGAS TANAH
LIMPASAN PERMUKAAN : Surface runoff
Surface runoff is also taken into account by defining a maximum value for surface storage. If
the surface storage exceeds this value the exceeding water amount will run off. Surface storage at time step t can be calculated as:
WhereSSt : Surface storage at time step t[cm d-1]P : Precipitation intensity[cm d-1]Ie : Effective irrigation rate[cm d-1]Ew : Evaporation rate from a shaded water surface[cm d-1]IN : Infiltration rate (adjusted)[cm d-1]
Surface runoff can be calculated as:
WhereSRt:Surface runoff at time step t[cm]SSt:Surface storage at time step t[cm]SSmax:Maximum surface storage[cm]SSmax is an environmental specific variable and should be provided by the user.
Perubahan lengas tanah & pertumbuhan akar
The rates of change in the water amount in the root and lower zone are calculated straightforward from the flows found above:
Where1. DWrz :Change of the soil moisture amount in the root zone[cm]2. DWlz :Change of the soil moisture amount in the lower zone[cm]3. Ta :Actual transpiration rate[cm d-1]4. Es :Evaporation rate from a shaded soil surface[cm d-1];
IN :Infiltration rate[cm d-1]5. Perc :Percolation rate from root zone to lower zone[cm d-1]6. Loss :Percolation rate from lower zone to sub soil[cm d-1];
Dt :Time step[d]
Due to extension of the roots into the lower zone, extra soil moisture becomes available, which can be calculated as:
WhereRDt :Rooting depth at time step t[cm]RDt-1:Rooting depth at time step t-1[cm]RDmax:Maximum rooting depth[cm]Wlz:Soil moisture amount in the lower zone [cm]DWrz:Change of the soil moisture amount in the root zone[cm]DWlz:Change of the soil moisture amount in the lower zone[cm]
The actual water amount in the root zone and in the lower zone can be calculated according to:
Where:
1. Wrz,t : Soil moisture amount in the root zone at time step t[cm]
2. Wlz,t : Soil moisture amount in the lower zone at time step t[cm]
3. Wrz,t-1: Soil moisture amount in the root zone at time step t-1[cm]
4. Wlz,t-1: Soil moisture amount in the lower zone at time step t-1[cm]
5. DWrz : Rate of change of the soil moisture amount in the root zone[cm]
6. DWlz : Rate of change of the soil moisture amount in the lower zone[cm]
LENGAS TANAH DI ZONE AKAR TANAMAN
The actual soil moisture content can now be calculated according to :
Where1. qt : Actual soil moisture content at time step
t [cm3 cm-3]2. Wrz,t : Soil moisture amount in the root zone
at time step t [cm]3. RD : Actual rooting depth [cm]
KANDUNGAN LENGAS TANAH
www.tutorvista.com/search/effects-of-soil-erosion
EFEK PENEBANGAN HUTAN1) Percolation and ground water recharge has decreased.
2) Floods and drought have become more frequent. 3) Soil erosion has increased. 4) Pattern of rainfall has changed. 5) Land slides and
avalanches are on the increase. 6) Climate has become warmer in the deforested region due to lack of humidity added by the plants. 7)
Consumption of CO2 and production of O2 is adversely affected. 8) Man has been deprived of the benefits of trees and animals. 9) Extinction of many species of plants and animals, still not discovered by scientists.
(10) Shortage of fuel
Sumber: www.cluin.org/studio/2003phyto/abstracts.htm
www.worldagroforestry.org/af2/?q=node/122
GenRiver: Generic River model on river flow
Overview of the GenRiver model; the multiple subcatchments that make up the catchment as a whole can differ in basic soil properties, land cover fractions that affect interception, soil
structure (infiltration rate) and seasonal pattern of water use by the vegetation.
The subcatchment will also typically differ in ‘routing time' or in the time it takes the streams and river to reach the observation
point of main interest .
Genriver Components
GenRiver model consists of several sectors, which are related to one another. Those sectors are:
Water Balance is a main sector that calculating the input, output, and storage changes of water in the systems. Some
components which are in this sector, rainfall, interception, infiltration, percolation, soil water, surface flow, soil
discharge, deep infiltration, ground water area and base flow.
www.ecy.wa.gov/programs/sea/pubs/93-31/chap1.html
Pentingnya pohon dalam memanipulasi “lingkungan mikro” nya sehingga dapat meminimumkan ancaman erosi
tanah dan limpasan permukaan.
Sumber: www.ecolotree.com/applications.html
Pentingnya pohon dalam mengalokasikan air hujan yang jatuh di permukaan bumi: green water - grey water
…TREE PLANTING
http://savetherain.us/tree-planting/
Tree canopy coverage is vital for urban stormwater management as trees capture and store rainwater in their canopies and
root zones, eventually releasing this water over time into the atmosphere
through evapotranspiration.
Trees also help to slow down and temporarily store stormwater runoff due to their physical presence and the ability of tree roots to improve soil conditions to
promote infiltration.
Urban trees also provide a host of other community benefits including those
related to aesthetics, air quality, shading, property values, and energy.
… How Much Stormwater Can Trees Manage?
http://www.americanforests.org/magazine/article/trees-the-new-sewers/
Sometimes it is hard to imagine how this one-by-one approach to tree planting could really make
a difference to the city’s overall stormwater problem.
How much water can trees really manage?
Scientists have studied how trees absorb rainwater, and the relationship between urban
trees and stormwater, but the number of studies is still relatively low.
Portland’s tree-planting program is well underway, but no one is sure how much stormwater the city’s trees can manage.
trees manage stormwater in three basic ways: Roots take up the water and distribute it to the tree; some water lands on leaves and branches and evaporates there; and roots create gaps in
the soil that allow water to seep through.
…Right Tree in the Right Place
http://www.extendonondaga.org/natural-resources/urban-forestry/save-the-rain-street-tree-planting-program/
Trees will be sited as far as possible from existing infrastructure to reduce instances of
utility and sidewalk conflicts.
If there are no overhead utility wires, a tall growing tree will be chosen for the location. If wires are present, a lower growing tree will be
chosen.
The trees will be about 8-10 feet tall when planted.
Environmental conditions such as soil compaction, road salt exposure and drainage
will be assessed for each potential tree planting site.
An appropriate species will then be selected according to the conditions of each site.
…Benefits of Trees
Trees are an important aspect of the Save the Rain program.
Trees naturally soak up storm water and use the precipitation to feed their root systems.
A tree canopy slows the rainwater with its leaves allowing the soil to become fully
saturated with water.
The tree is then able to absorb more rain water and reduce run-off entering the sewer
system.
http://www.extendonondaga.org/natural-resources/urban-forestry/save-the-rain-street-tree-planting-program/
…TREE PLANTING PROGRAM…..
http://savetherain.us/green-programs/urban-forestry-program/
Trees are an important aspect of Save the Rain.
Trees naturally soak up stormwater and use the precipitation to feed their root systems.
A tree canopy slows the rainwater with its leaves allowing the soil to become fully saturated with
water.
The tree is then able to absorb more rain water and reduce run-off entering the sewer system.
…Street Tree Planting
http://savetherain.us/str_project/street-trees-2012/
Tree canopy coverage is vital for urban stormwater management, as trees capture and
store rainwater in their canopies and root zones, eventually releasing this water over time into the
atmosphere through evapotranspiration.
Trees also help to slow down and temporarily store stormwater runoff due to their physical
presence and the ability of tree roots to improve soil conditions to promote infiltration.
Urban trees also provide a host of other community benefits including those related to
aesthetics, air quality, shading, property values, and energy.
…Reasons Living Trees Are Valuable
http://forestry.about.com/od/treephysiology/tp/tree_value.htm
1. Trees Produce Oxygen
Let's face it, we could not exist as we do if there were no trees.
A mature leafy tree produces as much oxygen in a season as 10 people inhale in
a year.
What many people don't realize is the forest also acts as a giant filter that
cleans the air we breath.
…Reasons Living Trees Are Valuable
http://forestry.about.com/od/treephysiology/tp/tree_value.htm
2. Trees Clean the Soil
The term phytoremediation is a fancy word for the absorption of dangerous
chemicals and other pollutants that have entered the soil.
Trees can either store harmful pollutants or actually change the pollutant into less
harmful forms.
Trees filter sewage and farm chemicals, reduce the effects of animal wastes, clean roadside spills and clean water runoff into
streams.
…Reasons Living Trees Are Valuable
http://forestry.about.com/od/treephysiology/tp/tree_value.htm
3. Trees Control Noise Pollution
Trees muffle urban noise almost as effectively as stone walls.
Trees, planted at strategic points in a neighborhood or around your house, can
abate major noises from freeways and airports.
…Reasons Living Trees Are Valuable
http://forestry.about.com/od/treephysiology/tp/tree_value.htm
4. Trees Slow Storm Water Runoff
Flash flooding can be dramatically reduced by a forest or by planting trees.
One Colorado blue spruce, either planted or growing wild, can intercept more than 1000 gallons of water annually when fully
grown.
Underground water-holding aquifers are recharged with this slowing down of
water runoff.
…Reasons Living Trees Are Valuable
http://forestry.about.com/od/treephysiology/tp/tree_value.htm
5. Trees Are Carbon Sinks
To produce its food, a tree absorbs and locks away carbon dioxide in the wood,
roots and leaves.
Carbon dioxide is a global warming suspect.
A forest is a carbon storage area or a "sink" that can lock up as much carbon
as it produces. This locking-up process "stores" carbon
as wood and not as an available "greenhouse" gas.
…Reasons Living Trees Are Valuable
http://forestry.about.com/od/treephysiology/tp/tree_value.htm
6. Trees Clean the Air
Trees help cleanse the air by intercepting airborne particles, reducing heat, and absorbing such pollutants as carbon
monoxide, sulfur dioxide, and nitrogen dioxide.
Trees remove this air pollution by lowering air temperature, through
respiration, and by retaining particulates.
…Reasons Living Trees Are Valuable
http://forestry.about.com/od/treephysiology/tp/tree_value.htm
7. Trees Shade and Cool
Shade resulting in cooling is what a tree is best known for. Shade from trees reduces the need
for air conditioning in summer.
In winter, trees break the force of winter winds, lowering heating costs.
Studies have shown that parts of cities without cooling shade from trees can literally be "heat
islands" with temperatures as much as 12 degrees Fahrenheit higher than surrounding
areas.
…Reasons Living Trees Are Valuable
http://forestry.about.com/od/treephysiology/tp/tree_value.htm
8. Trees Act as Windbreaks
During windy and cold seasons, trees located on the windward side act as windbreaks.
A windbreak can lower home heating bills up to 30% and have a significant effect on reducing
snow drifts. A reduction in wind can also reduce the drying
effect on soil and vegetation behind the windbreak and help keep precious topsoil in
place.
…Reasons Living Trees Are Valuable
http://forestry.about.com/od/treephysiology/tp/tree_value.htm
9. Trees Fight Soil Erosion
Erosion control has always started with tree and grass planting projects.
Tree roots bind the soil and their leaves break the force of wind and rain on soil.
Trees fight soil erosion, conserve rainwater and reduce water runoff and
sediment deposit after storms.
…Reasons Living Trees Are Valuable
http://forestry.about.com/od/treephysiology/tp/tree_value.htm
10. Trees Increase Property Values
Real estate values increase when trees beautify a property or neighborhood.
Trees can increase the property value of your home by 15% or more.
…How Trees Can Retain Stormwater Runoff
Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor
Trees in our communities provide many services beyond the inherent beauty they
lend to streets and properties.
One of the most overlooked and underappreciated is their ability to reduce
the volume of water rushing through gutters and pipes following a storm.
This means less investment in expensive infrastructure and – importantly – cleaner water when the runoff reaches rivers and
lakes.
…How Trees Can Retain Stormwater Runoff
Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor
The leaves and bark of a tree retain a huge amount of water, allowing some of it to
evaporate and some to more slowly reach the ground.
Depending on size and species, a single tree may store 100 gallons or more, at least until it
reaches saturation after about one to two inches of rainfall.
When multiplied by the number of trees in a community, this interception and redistribution
can be significant.
It is estimated that the urban forest can reduce annual runoff by 2 – 7 percent. This reduction can be converted into dollar savings due to the use of smaller drainage and artificial retention
systems.
…How Trees Can Retain Stormwater Runoff
Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor
When trees are combined with other natural landscaping, studies have shown
that as much as 65 percent of storm runoff can be reduced in residential
developments.
In fact, sometimes even 100 percent of rainfall can be retained on site.
…How Trees Can Retain Stormwater Runoff
Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor
Through the collective action of leaves and the anchoring and absorbing effects
of roots, trees also contribute to soil stabilization, cleaner water and the
recharge of groundwater that serves as the drinking supply for over half the
nation’s population.
The role of trees in stormwater retention and its resulting benefits to public health and municipal budgets deserves greater
appreciation.
It is one more reason why the planting and care of trees in our communities is of
critical importance.
… Important Ways a Tree Helps with Stormwater Management
Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor
Trees help reduce stormwater runoff in several ways. One is to intercept falling rain and hold a
portion of it on the leaves and bark. Part of this intercepted water will evaporate and
part will be gradually released into the soil below.
At the surface of the soil, fallen tree leaves help form a spongy layer that moderates soil
temperature, helps retain soil moisture, and harbors organisms that break down organic matter and recycle elements for use in plant
growth. This important layer also allows rain water to percolate into the soil rather than rushing off carrying with it oil, metal particles and other
pollutants. Below ground, roots hold the soil in place and
absorb water that will eventually be released into the atmosphere by transpiration.
Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor
… Important Ways a Tree Helps with Stormwater Management
…How Trees Can Retain Stormwater Runoff
Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor
Vegetative Swales
As impervious surfaces spread with the increase of paved roads, parking lots, driveways and even former lawn
areas, the use of swales is more important than ever. The potential of this facility was well demonstrated by the
Center for Urban Forest Research in a Davis, California, parking lot. Using a control area for comparison and after
50 storm events and 22 inches of rain, the researchers credited the swale with reducing surface runoff by 89
percent and reducing pollutants by 95 percent.
While some communities require swales in new developments, the vegetated aspect is sometimes
overlooked. Designing with plant materials appropriate to the climate and site is important, as is a plan for
occasional maintenance, but the effort is most worthwhile. Not only can trees and other vegetation provide the
benefits described on page 3, they add to the beauty of the area, help ‘calm’ traffic, and offer the welcome cooling
effect of shade in the summer. A swale with only rock or sod is depriving the neighborhood of a full return on its
investment.
…How Trees Can Retain Stormwater Runoff
Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor
Stormwater Basins
A stormwater basin is similar to a swale but is generally not linear.
Basins are often used in housing developments, especially if the streets and lots do not lend
themselves to swales.
Designs of basins vary widely. Some are simply concrete boxes that look like fenced, un-peopled
swimming pools.
They are often eyesores and reduce the space to a single use that contributes little else than the
retention of water. On the other hand, stormwater basins can be built to serve as picnic grounds or free play
areas during dry weather. Others appear as natural areas, providing open
space, wildlife habitat and a touch of beauty.
…How Trees Can Retain Stormwater Runoff
Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor
Structural SoilOne of the most significant urban forestry developments
in recent decades has been the design and use of structural soil. Pioneered by Dr. Nina Bassuk at Cornell
University, structural soil can be used beneath sidewalks and parking lots to provide both the strength needed for paving or compaction and a livable environment for tree
roots.
…How Trees Can Retain Stormwater Runoff
Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor
Tree Pits
Even traditional tree pits can contribute to retaining stormwater runoff.
If engineered for water to drain into the pits (sloping pavement, curbs with inlets, etc.), these
are called ‘stormwater-capturing tree pits.’
Their usefulness is enhanced with greater soil volume and by connecting individual pits with
trenches.
Of course, as with structural soil, it is important for the subsoil to be able to receive percolating water or a drain system is necessary to prevent
drowning the root system.
…How Trees Can Retain Stormwater Runoff
Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor
Riparian Buffers
Trees along the shores of lakes and the banks of rivers and streams are more than decorations.
Not only do their canopies intercept some of the rain and reduce its impact, their roots anchor the soil and help take up leached chemicals before
they reach the body of water.
Shrubs in the riparian zone also help slow flood water. Where banks are washed away or heavily impacted, a range of bioengineering techniques
are available using natural materials for restoration.
… TREE PITS…
http://savetherain.us/tree-planting/
…menanam pohon di kampus UB…
Smno.kampus.ub.maret2013