Design A New City
The basis of design for any landscape is the control and useof the water which has greatest significance for the efficiency and aggrandisementof the landscape. On the farm there are two general water resource avenues; one isthe water which flows from rain on the farm, the other is water which flows to thefarm from outside it. On some occasions the most significant source may be waterfrom underground.
The provision of household and stock water at the several pointswhere it is needed and where it must always be available even in the longest drought,is a subject for good design. But it is a flexible feature within the landscape andnot of particular significance to landscape design.
The principal water for city design, in like manner, is notthe water supply for houses and industry but the run-off from rainfall and the wastewater of the effluents from the city. This water is to move by gravity flow.
The first three factors of the scale of permanence have beennamed, "the inseparable trinity of landscape design;" they are climate,land shape and water. These same factors are the special considerations for the selectionof a site for a new city. Climate is eternally the most discussed aspect of anywhere--itis always of importance. It is the most permanent factor of the landscape.
Land shape will guide site selection by the influence of suchmatters as the size of the primary ridges and their lengths and slopes downwardsand the size of the unit-regions and their association with regional unities. Landshape is second to climate in the order of permanencies.
Water for the city is a site consideration but it comes fromoutside and may be brought in from a considerable distance. City water must be reliable,pure and permanent.
A great influence for site selection may well be, in the firstplace, some geographical or geological feature of the wide landscape which offersparticular advantages for city considerations.
The basis of design for the new city is the same as for thefarmscape, it is designed from the Keylines or the primary valleys which have greatestlandscape significance.
The city should have a definite size and a boundary which maybe selected as an appropriately sized natural region. The boundary of the city maybe principally the crest line of a large main ridge. The land for the city wouldfirst be surveyed and put on paper as a contour map. The natural drainage lines andthe natural water-divide lines would clearly display the natural unit-regions withinever larger regions within the boundary of the design.
The flow of water of greatest landscape and design significanceis the run-off from rainfall. While these flows in aggregate may be little more thanthat from city waste water, their peak flows will greatly exceed the flows of wastewater. The average percentage of rainfall which becomes run-off from the naturallandscape may be under 30 or even less than 12 per cent. But from the roofed andsealed areas of a city, rainfall run-off is very high. It is necessary to designfor 100 per cent run-off from the biggest storm rains.
New water lines would be added to the map in similar fashionto the diversion channel lines for the farmscape; but there is a difference in slopeconsideration: On the farmscape the gradient of the channels are governed by twofactors, firstly, being made flatter than the creek below and secondly by being flatenough so that the flowing water does not wash out the channels in the earth. Inthe city these slope matters are critical. They arise from the movements of waterwhich carries and transports such materials as raw sewerage. They become the governinggradients and determine the lines of the design for the new city. These grades mayvary in relation to rates and distances of flow which in turn determines the sizesof the underground conduits. The levels of population density for the designed citywould be determined beforehand so the conduits and their special gradients and marginsof safety, become a matter of routine for water and sewerage authorities.
The gradients for the lines of run-off control and for seweragetransport would be plotted in on the contour map but with this difference; they wouldbe designed to flow at uniform depths below the surface of the land. These linesfor water control would not result in straights but would be made up of curves relatedto the contours of the land. Conduits for the main lines of a particular size wouldalways lie at a set depth below the surface of the land. Roads would follow alongthese lines. Sub-mains would be smaller and be at a uniform but lesser depth belowthe surface.
The notable visual effects of the roads would be the emphasisof the great beauty that resides in the natural shapes and forms of the land. Thehomesites would finally be arranged like seats in a great amphitheatre.
The layout of the new water lines and their roads would dividethe land into its characteristic zones as was illustrated for the farmscape. Thehigher land of the first zone would have a lower boundary related to the particularfeatures and shapes of the primary valleys at their Keylines. But there would beother water lines within this zone. For instance the first of such lines would belocated along the main ridge just above the first steep heads of the significantprimary valleys.
The underground conduits for the two classes of water--fromrain run-off and from sewerage--could be placed near each other and lie under a commonroad, or be some distance apart and have their own separate roads.
The principal road of the first zone would follow, as in farmscapedesign, along the crest line of the main ridges.
The new city, like all landscapes, is designed from the mainridges downwards, and not as in the past, upwards from the shore lines and the riverlines.
The second zone would lie between the lines of control and linesfor use of the rain run-off water. The run-off from the two higher zones would bedirected to City Forest areas located in the third zone--the zone on the farmscapewhich contains the blocks of irrigation land.
The sewage treatment works, which remove the clutter of thelarger solids and grease, and partly clean the effluents, would be located at selectedplaces along the lower boundary of the third zone. They would discharge their finaleffluents to irrigate the City Forests located in the fourth zone. The various waterlines would then be connected by pipe lines with valve control up and down selectedprimary ridges. Their roads would lie above them.
Reverting to the scale of permanence: the first two factorsof the scale, climate and land shape, have aided the selection of the site for thenew city. The third factor, water--and the control and the use of the water of greatestlandscape significance--has laid in the broad and basic water-line design of thecity. The other water--for city homes and industries--is brought in from outsidevia PUMP, pipeline and/or gravity flow, to be delivered to water towers located onthe hills of the main ridges. The present manner and considerations for its supplyare fully adequate.
The fourth factor of the scale, roads, have followed along theuniquely located water lines to provide their service access. They have connectedup the main ridges and the new zones of the landscape. They have added the finallines to the anatomy of the cityscape.
The fifth factor of the scale, trees, have been located to usefor the benefit of the landscape, the rain run-off and the waste water of the city.
The sixth factor of the scale is buildings. On the farms theyare the homesteads which are the centres for control, administration and management.
The sixth factor for city design is the location of centres;for control, administration and management. The locations of these centres fit intothe overall pattern of the water lines, the roads and the City Forests, so that theyall serve their particular purposes.
The seventh factor of the scale of permanence is subdivision.
The design thus far is skeletal and on the surface is illustratedby the interconnected system of roads, run-off water holding areas at the Keylinesof the selected primary valleys and the layout for the City Forests. Each of theseseparated areas are subdivided by appropriate further water lines, roads and streets.The rain run-off from every road and street and from the roofed and paved areas,and the waste water of the sewer lines from homes and buildings, are guided to theirspecial underground mains to flow by gravity to their proper places. Such designsin detail within the design of the cityscape are the province of the municipal councils,the planners and the architects.
Soil is the eighth and last factor on the scale of permanence.Just how important this factor is, will be made clear in Chapter 10, Soil Sense.