MENANAM POHON UNTUK MEMANEN AIR HUJAN HIDROLOGI

1. MENANAM POHON UNTUKMEMANEN AIR HUJANHIDROLOGI Soemarno - psdlppsub2013

2. SISTEM HIDROLOGI • A 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.

3. 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.

4. 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.

5. 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: Where INp : 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.

6. LAJU INFILTRASI - KAPASITAS IMPANAN LENGAS TANAH 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): Where INp : Preliminary infiltration rate[cm d-1] P : Precipitation intensity[cm d-1 Ie : 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.

7. 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-1 Es :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: Where Perc : 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]

9. KAPASITAS LAPANG 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: Where Wrz,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]

10. LAJU PERKOLASI 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: Where Loss :Percolation rate from the lower zone to the subsoil[cm d-1] Perc :Percolation rate from root zone to lower zone (see eq. 6.21)[cm d-1] Wlz :Soil moisture amount in the lower zone [cm] Wlz,fc :Equilibrium soil moisture amount in the lower zone [cm] Dt :Time step

11. KEHILANGAN AIR DARI ZONE AKAR 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: Where Wrz,fc : Equilibrium soil moisture amount in the lower zone[cm] Qfc :Soil moisture content at field capacity[cm3 cm-3] RDmax :Maximum rooting depth[cm] 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 Diepenet al., 1988). The value calculated should be regarded as preliminary; the storage capacity of the receiving layer may become limiting.

12. KAPASITAS SIMPANAN LENGAS TANAH 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: Where UP :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.

13. 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: Where SSt : 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: Where SRt: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.

14. Perubahanlengastanah & pertumbuhanakar The rates of change in the water amount in the root and lower zone are calculated straightforward from the flows found above: Where DWrz :Change of the soil moisture amount in the root zone[cm] DWlz :Change of the soil moisture amount in the lower zone[cm] Ta :Actual transpiration rate[cm d-1] Es :Evaporation rate from a shaded soil surface[cm d-1]; IN :Infiltration rate[cm d-1] Perc :Percolation rate from root zone to lower zone[cm d-1] 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: Where RDt :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]

15. LENGAS TANAH DI ZONE AKAR TANAMAN The actual water amount in the root zone and in the lower zone can be calculated according to: Where: Wrz,t : Soil moisture amount in the root zone at time step t[cm] Wlz,t : Soil moisture amount in the lower zone at time step t[cm] Wrz,t-1: Soil moisture amount in the root zone at time step t-1[cm] Wlz,t-1: Soil moisture amount in the lower zone at time step t-1[cm] DWrz : Rate of change of the soil moisture amount in the root zone[cm] DWlz : Rate of change of the soil moisture amount in the lower zone[cm]

16. KANDUNGAN LENGAS TANAH The actual soil moisture content can now be calculated according to : Where qt : Actual soil moisture content at time step t [cm3 cm-3] Wrz,t : Soil moisture amount in the root zone at time step t [cm] RD : Actual rooting depth [cm]

17. www.tutorvista.com/search/effects-of-soil-erosion EFEK PENEBANGAN HUTAN 1) 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

18. Sumber: www.cluin.org/studio/2003phyto/abstracts.htm

19. 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 .

20. 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.

21. 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.

22. Sumber: www.ecolotree.com/applications.html Pentingnya pohon dalam mengalokasikan air hujan yang jatuh di permukaan bumi: green water - grey water

23. …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. http://savetherain.us/tree-planting/

24. … How Much Stormwater Can Trees Manage? 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. http://www.americanforests.org/magazine/article/trees-the-new-sewers/

25. …Right Tree in the Right Place 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. http://www.extendonondaga.org/natural-resources/urban-forestry/save-the-rain-street-tree-planting-program/

26. …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/

27. …TREE PLANTING 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. http://savetherain.us/green-programs/urban-forestry-program/

28. …Street 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. http://savetherain.us/str_project/street-trees-2012/

29. …Reasons Living Trees Are Valuable 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. http://forestry.about.com/od/treephysiology/tp/tree_value.htm

30. …Reasons Living Trees Are Valuable 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. http://forestry.about.com/od/treephysiology/tp/tree_value.htm

31. …Reasons Living Trees Are Valuable 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. http://forestry.about.com/od/treephysiology/tp/tree_value.htm

32. …Reasons Living Trees Are Valuable 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. http://forestry.about.com/od/treephysiology/tp/tree_value.htm

33. …Reasons Living Trees Are Valuable 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. http://forestry.about.com/od/treephysiology/tp/tree_value.htm

34. …Reasons Living Trees Are Valuable 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. http://forestry.about.com/od/treephysiology/tp/tree_value.htm

35. …Reasons Living Trees Are Valuable 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. http://forestry.about.com/od/treephysiology/tp/tree_value.htm

36. …Reasons Living Trees Are Valuable 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. http://forestry.about.com/od/treephysiology/tp/tree_value.htm

37. …Reasons Living Trees Are Valuable 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. http://forestry.about.com/od/treephysiology/tp/tree_value.htm

38. …Reasons Living Trees Are Valuable 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. http://forestry.about.com/od/treephysiology/tp/tree_value.htm

39. …How Trees Can Retain Stormwater Runoff 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. Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor

40. …How Trees Can Retain Stormwater Runoff 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. Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor

41. …How Trees Can Retain Stormwater Runoff 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. Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor

42. …How Trees Can Retain Stormwater Runoff 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. Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor

43. … Important Ways a Tree Helps with Stormwater Management 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

44. … Important Ways a Tree Helps with Stormwater Management Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor

45. …How Trees Can Retain Stormwater Runoff 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. Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor

46. …How Trees Can Retain Stormwater Runoff 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. Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor

47. …How Trees Can Retain Stormwater Runoff Structural Soil One 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. Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor

48. …How Trees Can Retain Stormwater Runoff 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. Tree City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor

49. …How Trees Can Retain Stormwater Runoff 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 City USA. BULLETIN No. 55 Dr. James R. Fazio, Editor

50. … TREE PITS… http://savetherain.us/tree-planting/