Regional planning, Green Belt, Satellite Towns.

2. REGIONAL PLANNING *

Green Belt and Satellite Towns.*

One of the major evils consequent upon indiscriminate development in Great Britain has been the unrestricted growth of the large towns. These have expanded by constantly increasing their circumference, and sending ribbon-like tentacles along the main roads. This means that the country is driven further and further from the inhabitants and a nucleus intended for, and suited to, a reasonably compact city has to serve as a centre for a population far in excess of the capacity of the nucleus and the carrying power of its transport facilities.

It has for long been recognised that a limit should be set to the growth of a town, and the difficulty elsewhere has too often been that the town *(e.g., *London, Glasgow, Birmingham) was already too large and unwieldy when the problem of limiting its size first came under consideration, and by the time the requisite margin of growth was allowed for, things would become worse. Dublin, as we shall see, is in the fortunate position of being able to limit herself to a much more manageable size than would be possible in the great towns of England. *

Forecast of the Population of Metropolitan Area.*

The planner is not in a position to state a certain maximum population which should be contained within the area bounded by the green belt and to plan his belt accordingly. He has to take account of factors over which he has no control. Town growth possesses what we may call inertia, comparable with that of a moving train which cannot be stopped suddenly. In its previous unrestricted period of growth the town has sent out at great cost considerable services in drains and water, and any attempt to prohibit building where services are easily available would either inflict undue hardship or bring about compensation payments and other losses too heavy to be faced. We thus find ourselves with a green belt boundary which is virtually imposed upon us by the position of services. The urban area may be larger than it would be if the limit could be arbitrarily determined by the planner, since an increase of only 221 per cent. in the diameter of a circle will add about 50 per cent. to its area.

We cannot assume that at any time a city will grow up to its complete imposed limit all round the periphery, bounded by a green belt. Supposing that the demand is for houses on the South-West, it is no use to build on the North-East. These considerations indicate that the purpose of the green belt is primarily to concentrate development within an enclosed ring and so to prevent ribbons; it thus serves the purpose of securing the proper laying out of the “hinterland” in the various development schemes. It is not, therefore, a fair inference to assume that at any time the *whole *residential area bounded by the green belt will be built up.

To allow the requisite elasticity we must schedule some 20 per cent. of the area as what - to borrow an engineering metaphor - we describe as “balancing land” required to give freedom of choice: because as this freedom becomes restricted so building will correspondingly be retarded, and the ultimate size of the primary town limited.

The area between the existing Borough boundary and the green belt is divided into two regions: *(a) *“Free Entry” land where development takes place in the ordinary way subject to planning requirements. This is described as “Fringe Development” on the maps. *(b) *“Deferred Development” land, described as “Convertible” on the maps, which is released by stages as and when further expansion beyond the Free Entry region is required. This would in all probability take place in some areas leaving corresponding areas of Free Entry land in other sectors still undeveloped. The same principle would be observed in dealing with the satellites.

The table below indicates the populations we envisage. We base it on the assumption that the population of 477,000 within the present boundary can remain fixed since the residential land, still unbuilt on within the present boundary, is capable of accommodating some 70,000 people which is a sufficient approximation to the number to be removed from central areas under the “thinning out” programme.

(a) Free Entry Land between existing city boundary and Deferred Development Land 13,500 acres

Add reclamations 900 acres

  14,400 acres

Deduct  

Open spaces, Public 12½  per cent. local

2½ per cent city 15 per cent.

Private (including Institutions) 15 per cent.

Balancing Land 20 per cent

Non-residential 10 per cent

  60 per cent

Leaving 5,760 Acres  

Population (including existing) at 30 per acre 172,800

(b) Deferred Development Land  

Area 5,200 acres

Dedcut 60 per cent. as above, Leaving 2,080 acres

Population (including existing) at 30 per acre 62,400

Future Population in Area Bounded by Green Belt when Built Up as Contemplated Above.

District Acres Population

Dublin within existing boundary 18,740 477,000

Dun Laoghaire 4,180 40,300

Howth 2,925 4,800

Free Entry Land, including reclamations 14,400 172,800

Increase in Dun Laoghaire and Howth

8,000

(a) Free Entry Land 40,245 702,900

(b) Deferred Development Land 5,200 62,400

Total, including Free Entry and Deferred Development 45,445 765,300

The low density of 80 persons per acre which has been taken for the outer fringe must not be considered to preclude the erection of small houses on small plots. The land here is still comparatively cheap and many existing houses standing in large curtilages are likely to retain them. Also the new houses built with comparatively large gardens will further compensate for denser building elsewhere.

As regards this anticipated “Free Entry” population of some 700,000, it may be objected that this figure is excessive for a capital city of a country containing only three million people, or indeed (in the event of union with the North) of an island containing four and a quarter million inhabitants. It should, however, be borne in mind that Ireland in the year 1841 contained 8,175,124 inhabitants, and there is the possibility of similar conditions recurring in the future.

The limitation in size of a capital city in this way does not mean that its wider functions would be limited to its own population. The city itself, which the call the “parent” or primary” city, grows up to its limit by adding rings to its circumference after the manner of a tree. Concurrently with this, it is possible to form “satellite ” towns, each with its own life; the satellites are not “dormitories ” for the primary city, but they have their own churches, schools, factories and amusements. They depend upon the primary for major centralised activities such as universities, museums, and so on. It is essential, however, that the satellites should be separated from the primary, and from each other, by a wide open belt. This “Green Belt” may be in the form of farms, golf courses, woodlands, aerodromes and so on. Parts of it will be in public ownership, but the greater portion will be privately owned and used for food production.

Table.

Satellites - Areas and Population.

Satellites within Green Belt.

Name Present Population Free Entry Holding at

• 20 to acre Deferred Land Holding at 20 to Acre

Malahide

Portmarnock 2,000 600 acres 12,000 People 400 acres 8,000 People

Swords 1,000 300 6,000 220 4,400

Lucan 1,000 80 1,600 80 1,600

Blanchardstown

Castleknock 1,000 200 4,000 150 3,000

Clondalkin 600 300 6,000 120 2,400

Tallaght 500 80 1,600 80 1,600

St. Margaret’s

80 1,600 80 1,600

  6,100   32,800 new

add 6,100 existing   22,600 new

add 38,900

• To allow of open spaces, etc.     38,900 Final total including existing rural population 61,500

The width of this Green Belt for Dublin varies between 4 and 6 miles and its approximate acreage is 120,000. It will be seen that it corresponds with the County Boundary of Dublin except on the North. The restrictions to be imposed upon it must be severe - it is not merely a Rural Zone preserved primarily for agricultural use, but it must be a protective belt for the capital. Outside this Belt, in the northern parts of Dublin County and in the surrounding counties of Meath, Kildare and Wicklow, a less stringent agricultural Reservation or Rural Zone may be prescribed. The inner limits of the Green Belt, as we have seen, have been carefully determined as lying beyond existing or easily extended services. The part of the Green Belt which lies along the Dublin foothills will require special treatment: a few sites for cottages and houses, provided they do not mar the scenery, may have to be allowed: they are not an extension of Dublin in the strict sense but a recreational aspect of its life.

The question of defence from air attack is one which has to be faced and it is obvious that the reasonably sized nucleus with its ring of satellites - an urban pattern set on an agricultural background - is not only infinitely better and healthier in peace time, but also has immeasurable advantages over the sprawling and overgrown town, in time of war. Thus the desirability of forming the Green Belt is unchallengeable. In the case of Dublin it can, fortunately, be done by allowing sufficient expansion and growth to eliminate hardship to the individual without at the same time allowing the city to grow to monstrous dimensions. The system of primary city and satellites outlined in these proposals would thus entail a primary containing from 700,000 to 760,000 people, and a group of satellites with populations varying between 20,000 and 8,200 people. We may mention that a satellite of 10,000 is given the opportunity of becoming as populous as the largest existing inland town in Ireland. Intimate contact with open food producing land, capable of use for sports, and evacuation purposes if required, is retained. As in all constructive effort of this kind, it is necessary to obtain the understanding and co-operation of the public in its formation.

Any further growth of Dublin beyond that of these figures, must take place outside the green belt. On the regional diagram several places where external satellites might be expected to occur at a later stage are indicated.

It may be of interest to give a population density comparison between Dublin as existing, and as we envisage it under “A” and “B,” with that of other large towns. “A” excludes deferred development land, “B” includes it. None of the others are, of course, completely built, as to residential land, up to the city boundaries, but in many cases all that remains is the “balancing land” which takes its place in our calculations:

Comparative Densities of Large Towns in Persons per Acre.

Town Acreage Population Density

Cork 2,685 80,765 30.0

Belfast 15,289 436,122 28.5

Manchester 27,257 766,378 28.0

Glasgow 39,725 1,088,461 27.4

DUBLIN (Existing) 18,740 477,000 25.4

Dundee 7,317 175,583 24.0

Hull 14,433 319,400 22.2

Birmingham 51,147 1,048,000 17.4

DUBLIN “A” 40,245 702,900 17.4

DUBLIN “B” 45,445 765,300 16.8

Bristol 24,406 397,012 16.2

Aberdeen 11,021 167,258 15.2

Edinburgh 32,402 439,010 13.5

Sheffield 39,596 518,200 13.0

Leeds 38,299 482,789 12.6

Bradford 25,514 298,041 11.7

Aerodromes.

We understand that the aerodrome at Baldonnell is to be utilised in the future as a military aerodrome, and that the new aerodrome at Collinstown, containing up to 700 acres, will be available for passenger and commercial purposes. The Collinstown area could be increased, if necessity arose, at the expense of diverting some roads. The Plan should include safeguards for building as to position and height, in relation to the aerodromes. Further small scale provision could be made for the use of aero clubs, and the like, within the Green Belt.

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