Not Enough Brownfield in the UK - Special Report
Gordon Brown's Government has promised three million new homes, 60% of them on brownfield land. But according to a report from the respected think
tank, Social Market Foundation (SMF), there's just not enough brownfield to go around. SMF has done its sums, and reckons that at normal housing densities, only enough brownfield land exists for one million new homes. In a report titled "Should The Green Belt Be Preserved?" (published 15th August 2007), it presents its thoughts:
There are three types of land on which new housing development can take place, previously developed land (PDL, or brownfield), greenfield, and green belt. The government has targeted PDL and by incentivisation through land remediation tax relief, and obstruction by planning barriers on greenfield and green belt land, it has achieved a situation where almost three quarters of recent new build has been on brownfield. But, the report points out, not all land categorised as PDL has previously been built on. It also includes areas like gardens and open spaces in towns and cities. Forcing more housing onto PDL deprives existing residents of gardens and parks.
The concentration on PDL cannot continue. According to SMF, "…even if all PDL (including gardens and city parks) were built on, the UK would fall short of its 3 million target for new housing. On current density trends, PDL could only accommodate 1 million new homes." To hit the government's target of 60% of homes built on PDL would require the housing density to be raised from the current minimum of 30 dwellings per hectare to 80 dwellings per hectare. That level is comparable with current density levels in London, and SMF believes that development at that level would seriously undermine quality of life for both old and new residents. Difficult decisions therefore need to be faced regarding development on greenfield and green belt land.
SMF looks at what is meant by green belt land. Contrary to popular opinion, it is not all green. Some of it is scrub land, and some is ex-industrial. It is not land of with exceptional landscape value, nor of scientific interest, nor a wildlife haven. Its defining characteristic is simply that it circles major towns and cities.
Greenfield land is, effectively, all land that is not PDL or green belt. 31% of it is classified as Areas of Outstanding Natural Beauty, National Parks, Sites of Special Scientific Interest or similar. It includes undeveloped land that would not widely be considered as outstandingly beautiful, as well as land that used to have development on it, but of which little now remains.
Given that the majority of the UK population would prefer to live in low density communities, and given the common misunderstandings about the nature and beauty of both green belt and greenfield land, SMF thinks that it is time for a debate about loosening the green belt if those three million new homes are to be ones that people actually enjoy living in.
The green belt surrounds existing cities. It contains towns and cities rather than protecting countryside - much of it is far less picturesque than popular belief. It is close to existing infrastructure and established communities. Because of its location it is likely that green belt land would have the highest levels of demand.
SMF suggests the options are:
* Deregulating green belt land that is not of any significant natural value and is well placed for housing, while offsetting that with increased protection for environmentally valuable land.
* Easing planning restrictions on the green belt, thereby allowing the market to determine where development takes place.
* Infill development in existing villages to increase their housing density and help protect environmentally valuable land.
The SMF concludes "The UK needs to have a rational debate about where to build these houses. We have to build them somewhere, but building new houses anywhere involves trade offs and winners and losers. The current debate, though, is scarred by misunderstandings. More than one half of Britons believe that 50% of land is developed, when the true figure is 13%. Most people believe the Green Belt is to protect wildlife or areas of beauty, when it is actually there to prevent urban sprawl."
The report's last lines are "The key is to design a planning system that empowers local people to shape their communities, while ensuring that everyone is able to put a roof over their heads. The UK has not managed to do this over recent decades. It is essential we get it right for the coming decades."
Scala Land Group (http://www.scalalandgroup.co.uk)
Article Source: ArticlesBase.com
|
the current density J at any point is directed in direction that a + charge carrier would move at that point.?
is it true or false .explane?
Get the answers...
|
|
Long wire of radius R has current density J=Jo r/R. The wire has current I. Find Jo in terms of I and R.?
A long straight conducting wire of radius R has a nonuniform current density J=J_o r/R, where J_o is a constant. The wire carries total current I. Find an expression for Jo in terms of I and R. Also, find an expression for the magnetic field strength inside the wire at radius r.
Get the answers...
|
|
Magnetic Fields in a Cylinder?
Imagine a long cylindrical wire of radius ?R? that has a current density
J(r) = J0 ( 1 ? ( r² / R² ) ) for r ? R and J(r) = 0 for r > R, where ?r? is the distance from a point of interest to the central axis running along the length of the wire.
Find:
A.) Find the resulting magnetic field inside and outside the wire.
B.) Plot the magnitude of the magnetic field as a function of ?r?.
C.) Find the location where the magnetic field strength is a maximum.
D.) Find the value of the maximum field.
If someone could walk me through these, and help me understand the step by step process, I?d greatly appreciate it. This problem just seems intimidating and I don?t know how to tackle it.
Get the answers...
|
|
Find the magnitude of the current density J_3 in wire 3. The diameter of wire 3 is 1.5 millimeters.?
Current is going into wire 1 and out of wire 2.
Wire 1 has a current density of 3 A/mm^2 and a diameter of 2 mm.
Wire 2 has a current density of 5 A/mm^2 and a diameter of 3 mm.
For part a I calculated the current in wire 3 to be -26 A.
Find the magnitude of the current density J_3 in wire 3. The diameter of wire 3 is 1.5 millimeters.
Get the answers...
|
|
How can you determine the magnetic field in this problem?
A very large flat conducting sheet of thickness t carries a
uniform current density j throughout. Determine the magnetic
field at a distance y above the plane. Assume the plane is
infinitely long and wide. Use Ampere?s law with a rectangular
loop that extends a distance y above and below the current
sheet.
click on link to see a figure of the problem:
http://www.tarbon.com/uploads/jpg/231120081485_24_108_219_194_1.jpg
Get the answers...
|
|
Current Density in a Conductor Question - Please help?
A beam contains 4.0x 10^8 doubly charged positive ions per cubic centimeter, all of which are moving north with a speed of 1.2 x 10^5 m/s.
(a) What are the magnitude and direction of the current density J?
I know J=nev... I know it should be simple, but I'm having trouble discerning the n (4.0e8, I think?) and e in this equation. Thanks for the help!
Get the answers...
|
|
How do you derive Ohm's Law J=?E from V=IR? How do you prove it?
I would like to understand how the Ohm's law for the current density J=?E is the same as V=IR Ohm's Law
Get the answers...
|