CLASSICAL LANDSCAPE PROFILES The Humid Landscape: The humid landscape can be found in both tropical and temperate climates, it is a gently rounded landscape due to the forces of water on substrate. This classical profile decides our whole strategy in the placement of water and structures. It is very important to know what landscape we are designing in. (diagram from curriculum page 5)
High Point • • • •
Mists and humid air Collection area for precipitation Wide bald ridges may be grazed, but narrow ridges should be forested Collection of water as ridge, plateau, saddle dams
Upper Slopes • • • •
Forests as warming systems for cold air flow (there are no frosts in forests) Forests as a stabilizing mechanism Instability of soils greater than 18% (about 3.5:1) slope; less in fragile soils or slump country. These should be forested. Collection of water as plateau or contour dams, or as a power source (hydro electricity)
Key Point is where the landscape changes from convex to concave. It’s in the valley at the highest point with a concave profile. (drawing) it’s the highest point in the valley where a dam can be constructed. The water floods back to the key point. •
Diversion drains in to key point to accumulate water here because it’s impossible to swale above this point on convex surface
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Critical water control point for lower slope irrigation. Water can be directed from this point and organically enriched. Because from here is where we enrich the living system. Irrigation canals out from keypoint as key points tend to line up from one valley to the next. Passing through flat points on ridges, which often make good sites for ridge point dams. This path is the keyline. Dams pages (158 and 159 in manual) Cultivation below keypoint because we can aim water and nutrient from this point down. Plus the land is more stable for cultivation. Links from keypoint to keypoint along keyline Housing suited to this area or just below, with forest above Clean water above, soiled water below
Lower Slopes • •
Terracing and mini-terrace, gardens and small crop areas. If it’s really flat we probably don’t need to terrace. Mixed cultivation area, crops
Keyline Systems of ( page 218-220 manual) Water Control • Dams at saddles or skyline • Contour, ridgepoint, and plateau edge dams. The latter is a contour dam on the edge of a plateau. Each dam may have up to 3 channels in or out: These can be swales or diversion drains. (Page 169 to 171 in manual) Spillways the way in which we spill water i.e. spillways of dams, swales, and irrigation canals. There are many creative ways to use a spillway, which is a release point for the water we design into landscape. Irrigation: drip irrigation is the most effective use of water because it reduces evaporation.
Selection of keypoint in major landscape plan • Laying out of the keyline system: multiple dams and channels ( page 162 manual) Soil conditioning as required. • Diversion to keypoint • Irrigation from keypoint Chisel plough or soil conditioner in keyline • principle of soil reconditioning deep ripping to relieve compaction. • the soil as the main water storage system. Swales and dams • effects of conditioning on soil -
Aeration of soil Water infiltration Temperature increase Life in soil increases (worms, bacteria) pH normalizes Mineral availability increase Plant growth increases
Treatment of individual slopes • • • • • • •
Steep and stony slopes: net and pan structures. Fish scale pattern (page 395 manual) Steep and grassy: create shelves for houses, livestock. Very steep: classical intensive terrace Flow-down and kick-down systems i.e. use gravity to advantage. Use the ideal species. As slopes descend to deep soils, high quality trees. Ridge top plantings for free nutrient run off. Plant photosynthesis. Fire control on slopes. Swales, fire resistant plants. Release points for spillways.
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Mini-catchments: small terraces, bunds, footpaths.
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Irrigation layouts and techniques i.e. windmills, open drains and canals. Swale interception of run-off the run hits the swale and soaks in e.g. village homes, Davis, California. Swales in forest to bring the forest nutrition into our system. especially off-garden. For run off of extra garden water. Spiral earth bank designs and use of earth banks use soil from excavation to create features in the landscape and more vertical edge. Flatland check dams. (Page 160 manual) Earthbanks and earthworks.
Flatland •
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The Arid Landscape. See Drylands section. Minor Landscapes: Volcanic, high and low islands, coasts, wetlands, estuaries Volcanic Islands • • •
rich soil; range of crops almost unlimited Pahoehoe (rock lava only good for run-off) U’u (pumice like lava with lots of holes. Can be planted in).
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Are either granite or basalt Humid to arid aspects Keyline, ridge dams, terrace Rock wall and cave shelters Rich flora and fauna Importance of winds and rainfall Lagoon catchments and shorelines Special problem: cyclone and tsunami; earthquake; mudflow, lava flow, cinder flow, volcanisms.
High Islands
Low Islands • • • • • • •
are usually arid islands need essential foreshore plantings need essential windbreaks bi-model and bi-directional winds caliche or platin-removal techniques necessary (mulch pits) gley for tanks (species of plants atoll structures in lagoons
Coasts • • •
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need frontline vegetation so that beach is not undermined Salt-resistant frontline species, e.g. Casurina, coprosma have waxy or needle leaves. Establishing plants in sand: sawdust and paper lowers ph. And holds moisture; Chinese plant in woven baskets to hold in moisture Sand-blast resistant thick bark or very fibrous barked trees (pines and palms, casuarinas) The alkaline sand needs humus; soluble sulphates and oxides offset alkalinity Deficiencies in zinc, copper, iron (non soluble in alkaline)
Wetlands •
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Chinampa system – world’s most productive agriculture, using banks next to water, maximises productive edge. Swampy or marshy land is ideal for its development. System of water-land nutrient exchange in harmonic effect. Mexico and Thailand Ducks are the main livestock they cycle nutrients and return potash to water and land Fish are marginal feeders Azolla is a fern which contains Anabeana (nitrogen fixing bacteria); can be scooped up and used as a mulch on land Trellis crop over water saves space; can be harvested by small boat
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Occasionally streams are drained and nitrogen-rich mud scooped onto the banks Marshes and wetlands support rich yields of wild rice (zizania aquatica) fresh water mussels, fish, and honey production species (marsh marigold)
Estuaries • • • •
Rich species area (oysters, fish, sea-grass, molluscs, fowl, geese) Sea-grass (Zostera) good insulation Can make traps and high-tide ponds for catching or rearing fish, molluscs. Spartina: mulch catches silt from land. Good fodder, returns nutrient from sea to land (see ch 12 aquaculture and Mariculture)