Landform plans should indicate areas for protection, excavation and deposition. Historic cities often grew on sites where the topography was significant for trade or defense: beside a natural harbour, on a hill, at the mouth of a valley, round a castle, at the lowest bridging point of a river. The scenic qualities of these sites came to be appreciated. Church and castle builders often accentuated the character of the landform by building the tallest structures on the highest land. New settlements can also be related to the existing landform, but often this is not done. Modern man has tended to conceal or destroy the landform of cities. We have found it easy to adjust land-shape for various purposes and, in making a city, enormous volumes of earth are moved from site to site. It is usually done without any overall plan and requires the use of vast energy resources. Holes are dug to obtain useful minerals or to make space for sub-structures. Huge quantities of sand and gravel are dug to make concrete. Waste material, both organic and inorganic, is placed in tips. Embankments are formed for roads and other structures. All this work is done on a project-by-project basis, without co-ordination. Water channels are dug. New hills and new depressions are formed. Old hills are quarried. Old depressions are filled with rubbish. Towns lose their distinctive landform. Yet the old landform often remains as a feature to be exploited in urban renewal. Landscape planners should seek out landform, just as Michelangelo looked at a block of marble and "saw" a statue concealed within [Fig 2.10]. Fig 2.10 In many towns, parks function as windows through which one can glimpse the underlying topography. Birmingham , in the middle of England , has a significant landform which is substantially concealed by buildings. In many American cities "the indifference to geographic contours" was "nothing short of sublime: the engineers' streets swept through swamps, embraced dumpï¾heaps, accepted piles of slag and waste, climbed cliffs" (Mumford 1938: 185). In such places the old landform awaits rediscovery, like buried treasure. Mineral extraction can also have a great influence on the landform of cities. At Duisberg, in Germany , the water in the port was deepened by carefully planned underground coal mining (Spirn 1984: 118). The same principle could be used to create new water bodies where underground coal is available. Subsidence is normally regarded as a constraint on mining operations. It is also an opportunity for imaginative landscape planners. At Kansas City , in the USA , subsurface mining of limestone took place. This created large caverns which have become very popular for commercial and industrial use. Rents are low, heating and cooling are inexpensive, security is high. This has changed the economic equation. Previously, the caverns were a side effect of mineral extraction. Today, the sale of limestone is a side effect of excavating commercial space (Spirn 1984: 118). With landform planning, it is not simply a case of protecting what exists or recovering what used to exist. There are heroic opportunities to create new topographic patterns, of landform, water, vegetation and buildings. The city of Reading , in the Thames valley 65 km west of London , is a case in point. It grew as a nineteenth century railway town and is rather a dull place. But it is surrounded by sand and gravel deposits which the mineral companies wish to extract and are extracting. The local planning authority has done its best to oppose their wishes, in the interests of "conservation". At one time the aim was to conserve agricultural land. Later, the aim was to preserve scenic quality. When permission for mineral extraction has been obtained, the companies have dug the mineral and then fenced off the water bodies for private fishing and sailing interests. Instead, they should be planning a great Water City . [Fig 2.11] Reading could become a dramatic Water City with an intermixture of land and lakes. There could be tongues of water running into the town and spits of housing interweaving the lakes. All the necessary powers exist. So why hasn't it been done? Lack of vision. Cities suffer from geological hazards. Earthquake risks are now appreciated and, in the developed world, seismic building codes are in force. Shrinkable clays are less obvious but probably cause more damage. Foundations are cracked in periods of drought. Hazardous soils must be mapped, so that suitable foundations can be put in place before new structures are built. In existing urban areas the problem is exacerbated by conducting surface water off the land in drains. This accentuates the fluctuation in ground water levels and aggravates the shrinkage and swellage problem. Every city needs a Landform Plan to guide future development, to gain positive side-effects, to avoid hazards. The plan should be visionary, to serve as a lighthouse for the local development process.