Reduce Global Warming with Roof Garden
The urban heat island is a dome of higher air temperatures above a city. The urbanization of the natural landscape from forests and farmland into buildings, roadways, and other man made structures has caused average ambient air temperatures in the metropolitan areas to be anywhere from 2-12 º F warmer than their surrounding rural areas. Heat islands occur in almost every urban center around the world and, with the exception of minor variations in geographical and climatological features, the pattern of heat islands are quite similar from city to city. Several factors are known to influence the formation of the heat islands within urban areas. The most influential being the transformation of the natural land cover from permeable soil and vegetation into relatively impermeable roadways and buildings. Natural landscapes of vegetation and soil have the ability through evapotranspiration ( the loss of water from the soil both by evaporation and transpiration from the plants growing thereon) to reduce the heating potential of incoming solar radiation.
Many solution to reduce global warming, one of all is making roof garden in the city. Some country have create this step to reduce global warming, and the effect is great for our city environment like in Tokyo and Hongkong-China ( flying green project) , Singapura ( skyrise greening project) , Berlin ( ecoroof project) , New York and Washington ( green roof project) .
in 1996, German government have made their city with roof garden on 28, 8 hectare, and in every city one of ten building have roof garden. Since 2000, Hongkong and Japan government bring some rule to every building to make it green with minimal 20% from wide of the roof of buildings that s about 250 - 1000 metre square.
And now the time for Indonesia, especially in every big city like Jakarta, Bandung, Semarang, Yogyakarta, Surabaya, Medan, Makassar, until Manado to create roof garden as solution for optimalitation of city green open space. This program will add green space in the city significantly.
If there 100.000 houses create roof garden in every 100 metre square, so, the city will get green open space significantly about 1.000 hectare or 10.000 metre square. For example, ( grass roof, floor roof, roof garden, and another green open space) may create the city more cold. Because this green element can reduce air pollution ( Carbon Diocsida and Dust Particlle) , reduce heat island and reduce sound pollution, and of course reduce global warming also.
Roof garden can save rain water and make roof top building more cold, So we can save our energy for AC. So roof garden can fix soil water too. In America, England and Singapore, roof garden become a social public area. Roof Garden will help to reduce the urban heat island effect, thereby reducing added energy demands to keep our buildings cool and reduce smog.
There are many good reasons, ecological, technical and economic, for installing a Roof Garden. One of these reasons is stormwater management. Stormwater management can be simply defined as the control of the run-off or detention of rain water that falls on any given roof surface. Controlling this run-off can be beneficial to storm drain/ sewer systems by reducing the amount and the rate of rainfall run-off that enters these systems.
The combination of the soil and Hydrotech' s Garden Roof components can retain between 50% - 90% of a typical rain that falls on the roof surface. This retained water is then available for use by the vegetation instead of being added to the storm drains. In addition, the run-off that does occur is obviously slowed by having to percolate through the Garden Roof system. This slowing of the run-off also aids the storm drain network by reducing the intensity of the wave that travels through the network.
Besides being aesthetically pleasing, a green roof can provide numerous environmental, technical and owner benefits. Roof garden have two functions, the first can create a social public area ( for people) and the other is for reduce many pollutan and global warming ( not for people) . Roof garden has different garden like usual, because roof garden get view just in the top of roof.
Roof garden structure have a different concept from a usual roofing. It must have 10 -20 centimtre for soil and grass. The compotition is waterproofing, sub drainage, geotextile, topsoil and grass. And for trees have a special box planter.
Roof garden concept become a commercil places, because have a great view and beauty place so can be created to many facilities like roof café , swimming pool, roof sport centre, mini golf, an organic plant, a therapis garden, etc. The roof garden provides building owners and tenants with many ecological, technical and economic benefits. Some of the advantages of the roof garden Assembly include:
Enhances building' s appearance
Adds space for tenant use and recreation
One answer to the " Urban Heat Island " problem
Stormwater management - retain 50% -90% of a typical rain fall on the roof
Improves building' s energy efficiency
Processes airborne toxins and re-oxygenates the air
Creates therapeutic and peaceful environments
Total assembly warranted, from the deck up
Mitigates Urban Heat Island :
Green roofs cool and humidify the surrounding air creating a microclimate which has beneficial effects within the immediate area.
Natural Habitat for Animals and Plants:
Green roofs create biodiversity, encouraging wildlife, such as birds, butterflies and insects, to remain within urban areas.
Reduction of Dust and Smog Levels:
Green roof vegetation helps to fi lter out dust and smog particles. Nitrates and other aerosol contaminants are absorbed out of the air and rainfall and bound within the soil.
Storm Water Retention :
Depending on the design, a green roof can typically reduce storm water run-off by 50 to 90% . Additionally, the peak flow volume is greatly reduced and the peak flow period is delayed by as much as 4 hours, minimizing the impact on existing sewer systems.
Additional Thermal Resistance:
Green roofs can improve the thermal resistance of the roof
assembly throughout the year, especially in summer months by helping to reduce cooling costs.
Reduced noise levels: Typical extensive green roofs ( 3 - 4 growing media) reduce reflective sound by up to 3 dB and improve sound insulation by up to 8 dB. This is most effective with buildings near airports, factories or busy freeways.
Increased Life Expectancy of the Roof:
A green roof, much like a PMR ( Protected Membrane Roof ) Assembly, protects the roof membrane from climatic extremes and physical abuse, thereby greatly increasing the life expectancy of the roof.
Additional Usable Space:
Converting or designing normally unused roof areas into green roofs, simply makes sense. Increase your property value by reclaiming the fifth elevation of a building and make it an amenity to be used by the buildings occupants.
More and more municipalities and other government agencies are providing incentives that can help off-set the cost of a green roof.
In some modern country have a sun cell for an alternative energy in every their roof garden, like in New York, Toronto, Berlin, Tokyo, and Singapura.
This green concept may change people sight about landscape planning, great living places, urban planning, etc. all of this concept just to make our world be cold and can create a fresh and great environments.
Ariestio, Landscape Architecture ( Trisakti University, Jakarta, Indonesia)
Phone : + 628562255378 or + 622199994378
Email : garishijau@ gmail.com
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