As one removes the
pavement, it is removed what was hiding the land, the natural support
of life. As the land is uncovered, the green has its way to come
back. Different dimensions of changes take place. Let’s consider
some aspects of the question of depaving.
The sun rays
incident on leaves are reflected more strongly than in the concrete.
In other words, the albedo of the leaves is, in general, bigger than
the albedo
of the pavement (1). As a result, the leaves absorb less energy. The
difference of albedo may be very important. When to pave is really
imperious all attention should be given to the difference of albedo
of the alternatives among types of pavement material. But when what
matters is the difference of the albedo of leaves and the albedo of
pavements, the differences of energy absorbed among alternative
pavements are not so important as the different destination the
leaves and the concrete or asphalt give to the solar energy absorbed. It as as comparing green roofs (2) and conventional or reflective roofs (3). The
vegetables convert the solar energy absorbed in input for vital
physical and chemical processes, including the photosynthesis. The
construction materials, in an opposite way, convert in heat the
solar energy absorbed. The pavement get heated and dissipate the heat
in the surrounding air by convection and directly in the entire
environment by increasing the emission of infrared rays. The
air over the pavement gets heated, contributing to the tormentors
urban heat island (UHI) effect. The air over green life, instead,
contributes to alleviate the UHI (4).
To better the
quality of life is good for all of us, and the green
space is positively correlated with quality of life (5). This is a
very important as the
green is favourable to mental health (6). Being opposite to the pro
depression pavement is a nice impact of depave, as more important as
the number of depressed people is growing.
Unpaved land has the
property of retaining and absorbing water. When it begins to rain the
firsts rain drops that fall over the leaves tend to stay there. After
the leaves become wet, the additional water flows. The land has a
more proeminent benefical behavior. The firsts drops that fall on the
land remains there instead of flowing. In the sequence the flow
begins to be divided, part being absorbed by percolation, part
flowing over the surface of the land. The flash floods are less
intense as the water takes more time to begin flowing over the
surface, and have a smaller flow. This property is invoked to
determining the choice among types of pavement.
To those who the
objective is solely to atenuate the flash floods, some poor
solutions alternative to depave are satisfactory. The porous
concretes that can percolate water are a kind of this type of solution.
But changing the building material of pavement does not give the
property of absorbing the solar energy incident not converting it in
heat. It does not give the contribution to the mental health and the
quality of life, it does not give contribution to alleviate the UHI.
It is an action of Adaptation to Global Warming, by decreasing the impetus of flash floods. But it is an action inferior in results than maintaining the land.
If the mistake of
paving what was not necessary is already done, Depave is the solution. Depave, a bright idea.
References
1 WANG, Shengyang (2015). Pavement albedo assessment: methods, aspects, and implication. Iowa State University. Digital Repository. Graduate Theses and Dissertations. Paper 14904. Avaiable at: http://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=5911&context=etd. Access July 13, 2017.
2 Inovação e Adaptação ao Aquecimento Global. Green roof as an universal tool for Adaptation to Global Warming. Disposable at: http://inovasmtp.blogspot.com.br/2012/01/green-roof-as-universal-tool-for.html.
Access: July 14, 2017.
3 Inovação e Adaptação ao Aquecimento Global. A comparison between reflective and green roofs as tools for Adaptation to Global Warming.Avaiable at: http://inovasmtp.blogspot.com.br/2012/01/comparison-between-reflective-and-green.html. Access: July 14, 2017.
4 YANG, Xiaoshan: ZHAO, Lihua (2016). Diurnal Thermal Behavior of Pavements, Vegetation, and Water Pond in a Hot-Humid City. Buildings, 6, 2; doi:10.3390/buildings6010002. Disposable at: www.mdpi.com/2075-5309/6/1/2/pdf. Access: July 03, 2017.
5 Land Use Consultants (2004). Making the links: greenspace and quality of life. Scottish Natural Heritage Commissioned Report No. 060 (ROAME No.F03AB01). Avaiable at: http://www.snh.org.uk/pdfs/publications/commissioned_reports/F03AB01.pdf. Access: July 12, 2017.
6 TOWNSEND, Mardie; WEERASURIYA, Rona (2010). Beyond Blue to Green: The benefits of contact with nature for mental health and well-being. Melbourne: Beyond Blue Limited. Avaiable at: http://www.hphpcentral.com/wp-content/uploads/2010/09/beyondblue_togreen.pdf. Access: July 03, 2017.
References
1 WANG, Shengyang (2015). Pavement albedo assessment: methods, aspects, and implication. Iowa State University. Digital Repository. Graduate Theses and Dissertations. Paper 14904. Avaiable at: http://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=5911&context=etd. Access July 13, 2017.
2 Inovação e Adaptação ao Aquecimento Global. Green roof as an universal tool for Adaptation to Global Warming. Disposable at: http://inovasmtp.blogspot.com.br/2012/01/green-roof-as-universal-tool-for.html.
Access: July 14, 2017.
3 Inovação e Adaptação ao Aquecimento Global. A comparison between reflective and green roofs as tools for Adaptation to Global Warming.Avaiable at: http://inovasmtp.blogspot.com.br/2012/01/comparison-between-reflective-and-green.html. Access: July 14, 2017.
4 YANG, Xiaoshan: ZHAO, Lihua (2016). Diurnal Thermal Behavior of Pavements, Vegetation, and Water Pond in a Hot-Humid City. Buildings, 6, 2; doi:10.3390/buildings6010002. Disposable at: www.mdpi.com/2075-5309/6/1/2/pdf. Access: July 03, 2017.
5 Land Use Consultants (2004). Making the links: greenspace and quality of life. Scottish Natural Heritage Commissioned Report No. 060 (ROAME No.F03AB01). Avaiable at: http://www.snh.org.uk/pdfs/publications/commissioned_reports/F03AB01.pdf. Access: July 12, 2017.
6 TOWNSEND, Mardie; WEERASURIYA, Rona (2010). Beyond Blue to Green: The benefits of contact with nature for mental health and well-being. Melbourne: Beyond Blue Limited. Avaiable at: http://www.hphpcentral.com/wp-content/uploads/2010/09/beyondblue_togreen.pdf. Access: July 03, 2017.