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CHAPTER FOUR

The Landscape
Design of Nature
(2)

THE GEOMETRY OF SHAPES AND FORMS

 

   The contour lines of Nature's seas and lakes have been borrowedand are used as a device by the many professions concerned with land-use, so as toillustrate in a practical and accurate manner on paper, the shapes and the formsof land surfaces.

   A contour line surrounds the land. A contour line surroundsthe water--of lakes and ponds. The water line around a swimming pool or a bath arecontour lines.

   For the purpose of illustrating land on paper, the lines areused on 'contour' maps where the individual contour lines show where the land isthe same height as indicated by the contours. The lines are placed to show set verticaldistances below each other, such as one foot or ten feet.

   On a map the highest contour line is placed as if all the contourlines which indicate lower land, were under the water of an imaginary lake and thisfirst contour line was part of the shoreline of the lake or of an island in the lake.The next contour line of the map, say ten feet vertically lower than the top line,is again part of the shoreline when the water of the lake has dropped ten feet--andso on downwards.

   The contour lines on a map show the shapes and the forms ofthe land and the positions and relationships of water courses and ponds. They showalso how water will behave anywhere on the land, because the natural path of waterflowing over the surface is always at right angles to the contours of the land. Thisnatural path of water is the steepest and fastest route, but it is never a straightline; it always forms a flat S curve from ridge to valley.

   The main ridge is the top of the land, the backbone and theoutline of the landscape. Look again at the skyline!

   The contour diagram of the main ridge displays the contoursas a series of elongated loops, one outside the other downwards, with the distancefrom loop to loop wider at the crest line of the main ridge and narrower elsewhere.

   The head of the primary valley intrudes into this contour patternof the main ridge where part of a contour line swings in closer to the contour lineabove. The change of pattern shows the first slope at the head of the primary valleyto be steeper than the nearby slope of the main ridge.

   The elongated loop pattern of the main ridges changes to a seriesof flatter loop patterns of the primary ridges between the closer together contoursat the head of the primary valleys. The loop pattern of the primary ridge contoursapproach more the shape of the arcs of a circle than the hair-pin like loops of themain ridge. The contours are widest apart at the centre or divide line of the primaryridge and narrowest at the head of the primary valley.

   The primary valley has two slopes which change from steep tomuch flatter at the Keyline of the valley.

   At the Keyline the contour pattern changes. The contours becomecloser together near the primary valley before they open out to display the flatterslope of the primary valley below the Keyline. Then they converge again on the otherside of the primary valley to open out again to display the next primary ridge shape.A line through the contours, joining the points of greatest convergence on each sideof the primary valley, marks the boundary between valley and ridge shape.

   This combined contour pattern of the three shapes of the landmay change again near the creek below, by the contours coming closer together nearthe centre of the primary ridge and being wider apart in the primary valley. Thisnew pattern indicates that the primary ridge has 'nosed over' just above its lowerboundary--the creek below.

   The land forms of hill, saddle and pond also have their contourpatterns. If there is a saddle in the main ridge at the level, say, of the secondcontour, the two top contours will be elongated ovals to display the hill on themain ridge. Near the saddle they may be closer together or sometimes further apart.A saddle point is always on the crest line (water-divide line) of a ridge. A saddlepoint can be, on iiiiiioccasions, the Keypoint of a primary valley or more oftenbe at the top of the first steep slope of a primary valley. A hill on a primary ridgewill have the same closed contours, each outside the other, but with the oval formless pronounced or gone altogether.

   From a saddle point, contours go four ways. If there is anothersaddle at the same height or lower, the contours join up and form a figure 8.

   The contour diagram of a pond displays the same pattern as fora hill, but the inside contour is the lowest line and the outside contour, the highest.

   Since the main ridge rises into the rising country towards thehead of the watershed, the height of the Keylines of the series of primary valleystend to have a rising relationship also.

   The creek is the lower boundary of its tributary primary valleysand of the primary ridges on each side of the primary valleys.

The contour map has contours at 20 feet vertical intervals. It shows a portion of a main ridge, two primary valleys, two primary ridges and part of a third, and the creek below.

   Run-off water from rainfall on the main ridge and the higherparts of the primary ridges, flows to the primary valley by the steepest path andthe fastest route. The pattern of flow is at right angles to the contours. The contourdiagram illustrates that the steepest slopes of land are in the primary valley abovethe Keyline. The contours show also that the run-off from rain converges from thesteep head of the primary valley to concentrate at the Keypoint. Therefore the stabilityand permanence of the natural landscapes depend largely on the fertility and thusthe strength of the primary valley to resist the force of flowing water.

The diagram has contours at 10 feet vertical intervals. It illustrates the pattern of water flow. The primary valley shape is proportionately larger for the sake of clarity.

Upper: The flow paths of run-off water from the primary ridges to the primary valleys are flat S curve.

Lower: Depicts one flow path to illustrate the increasing volume of flow from the centre of the primary ridge to the primary valley.

   The combined contour diagram of the land illustrates further,the paramount efficiency of Nature's landscape design for getting rid of water quickly.

   If you look for a primary valley in the city you may not recogniseit so easily. It has been disguised by being overlooked and by our education whichignores it. Even if you look at a primary valley in the cleared countryside you willnot see the Keyline, unless a farmer has marked it with a water channel or has disclosedit with the water line of a farm dam. But you may discern the. Keypoint where thetwo slopes of the primary valley meet.

   If you do go out in the country and find the Keypoint of a primaryvalley and stand there, you will see the family place of the three shapes of landwhere they meet; you may look upwards and see THE AMPHITHEATRE OF THE LANDSCAPE.If this place were filled with people, you would be the centre of all eyes--the centreof the stage. In the same way, if a sheet of water flowed from all around the highesttier of the theatre, you would cop the lot.

   The functions of the primary valleys in the landscape have beenoverlooked by those who were responsible for devising the special purpose landscapesof man--with one exception. By accident or by instincts developed from long and intimateassociation with land, a few farming families have improved and strengthened theprimary valleys. In doing so they increased the fertility and the durability of theirfarmscape.

   There are thus special characteristics disclosed by Nature'slandscape design for consideration when we attempt to superimpose on them the specialpurpose

   landscapes for ourselves. There is the efficiency of the shapesof land for getting rid of water and the only way water is retained for the benefitof the land, by being slowed down and some of it being stored by the soil, the grassand the trees--by all the life in the landscape. Then the water which falls as rainon all the ridges, which occupy so. much of the land, flows as run-off to concentratein the primary valleys which are so little of the land surface; yet the value ofland--rural land in Australia certainly--is as high as 80% a water value.

   Water flows from farming land in the same efficient manner asit does from the natural landscapes. Therefore much water passes without being usedeffectively in the landscape. NATURAL WASTE PRODUCTS FROM PLANTS AND ANIMALS ANDFROM ARTIFICIAL SUBSTANCES USED ON THE FARM, ARE RUSHED TO THE WATER COURSES TO POLLUTETHE COMMON WATERS OF THE LAND AND THE SEAS. This type of pollution, when it doesnot contain artificial substances, is named Primitive Pollution.

   The natural landscapes had come to terms with the water. A stateof balance existed which was in accord with the amount of water available to theland. Where the rainfall was high and reliable, rain forests had developed; wherethe rainfall was moderate and its incidence less reliable, the grasslands of naturewere found. When the man-made landscapes of farm and city were imposed on those ofnature, the balance of the association of land and water was changed. The flow ofwater off the land was speeded-up, instead of being slowed down.

   It is evident that landscape design must firstly be concernedwith water to (1), to control positively and to use more effectively the water whichflows from the land to the water courses and (2), to improve on or change the patternof behaviour of water which falls on the ridge shapes.

   The design which achieves the optimum control and beneficialuse of water for the development of high fertility, efficiency and balance for thefarmscape, will be the logical design for townscape and cityscape and for all thespecial purposes landscapes of man. And the control and better use of water is thefirst answer for the control and final elimination of pollution.

   The life in the landscape of Nature was principally a processof slowly moving water: even our own bodies are 70% water. Nature slowed down thewater, with the life of the landscape. Surely the next step which is up to us isto control and to use every drop of water before it reaches the streams and the rivers,for the aggrandisement of all the special purpose landscapes of man.



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