DESIGNING FOR DISASTER
An aspect of good Permaculture design that must always be incorporated into our landuse is designing for disasters. Failure to design for extremes may lead to losing all our good work in one unconsidered event: fire, flood, drought, wind, storms, cold, heat. We can well say that Permaculture Design is Designing for Extremes since, no matter how ‘good’ our design may be for ‘normal’ conditions, it is how well it adapts to extremely strong, potential disasters that ultimately determines its sustainability and resilience. Of course Permaculture is much more than such a single theme, but failing to consider this one could put to waste all the other good work you have done, in one disastrous event.
It is not good enough to plan for averages. ‘Averages’ are becoming less and less ‘average’ as climate change effects increase. There are plenty of different considerations to be made as we enter the process of designing land. Disaster is one of them, and we must question the nature of any disaster possibilities.
Analysis of a Disaster
Design can’t be effective unless the designer has knowledge of the cause and conditions of any potential disasters. Specifically, can we avoid the impact of those disasters through good design? Start by asking these following questions:
* Cause of disaster – is it natural or man-made? Can we begin to reverse the cause?
* Frequency – how often does it occur? If it is once in 10,000 years, probably we need not put too much consideration into it. However, if it is likely to occur every few years – even every few decades – then we certainly should take it seriously.
* Duration – short or long-term?
* Speed of Onset – what is the warning period?
* Scope of Impact – is it concentrated or spread over a large area?
* Destructive Potential? – this can vary enormously.
* Predictability – does it follow a pattern? Seasonal, direction of source of disaster (wind, slope, situation/material supporting or limiting its impact).
* Controllability – are people helpless?
Fire, flood, cyclone, earthquake, tsunami, drought, landslide, famine, nuclear accident, epidemic, climate change, land degradation; all can be taken into account using these criteria.
Design…..General strategies to minimise the impact of disaster.
- Start with structure – apply permaculture principles of reducing risk.
Create autonomous housing;
have a small supplies of seed, store plants and water away from likely centre of disaster.
Cave, underground room (against fire, nuclear or other pollution disaster, small mud house,
- If practical, ensure escape routes (creeks, fire trails, green belts)
- Small emergency garden away from disaster centre – perhaps just hardy food spp
- Windbreaks or berms to protect home and garden, or to change the direction (of fire, flood, hurricane, cyclone).
- Swales and berms to enhance water holding capabilities
- Ponds to enhance water holding capabilities
- A good pitched roof to shed snow (if you live in a cold/temperate climate) and rain.
- The use of heavy materials in construction such as mud/concrete/stone formed walls and metal roofs to reduce damage from wind; wood against earthquake; bamboo flexible and easily replaceable.
- Certain species of trees such as mulberries, oaks, willows, poplars, and maples are fire resistant. These can be planted densely with succulent groundcovers and shrubs to form a dense firebreak.
- Refuge island if you have a large dam
Types of Disaster
- ‘Insure’ against these by creating and being involved in community-building and maintaining. Choose your company; support people; be generous and fearless.
- Create LETS (Local Energy Trading System)system or similar
- Work together; work co-ops build more than houses and gardens; they build friendships and community.
A. Flood, Cyclone, Drought
– often can anticipate by weather statistics
eg; 1:100yr flood contour must have all structures above it. Allow for Greenhouse Effect. Have emergency garden out of flood reach.
Create solid berm (stone, earth very heavily planted with deep-rooted trees and shrubs
Plant trees and shrubs heavily beside all river banks to reduce energy of the floods, and encourage water to remain in river bed (if river is not limited to its course, river bed gradually silts up, spreading the flood waters instead of digging the river bed deeper). Regrass catchment areas to reduce silting up, and hence flooding
– do not enter floodwater on foot; use car, boats, or wait to be evacuated. Climb to roof
– don’t drink floodwater – often contaminated by sewage; carry bottles of bottled water
– don’t panic!
these generally arrive from specific, predictable direction, and are anticipated by modern weather-forecasting, so we can design with a good degree of advanced information.
- houses need to be built with cyclone bolts, and as close to ground as possible, even underground. Or, use 45deg roof angle; cut stud into brace, and have it high pitched.
- Trees as windbreaks must be flexible – classically palms, bamboos, casuarinas, which absorb a lot of the force. Small-leafed and multi-stemmed shrubs with good root systems are priority plants
- Remain in shelter during and after passing of the ‘eye’. Every cyclone is dangerous, and must be treated as a real threat.
- Have a ‘famine’ garden in very sheltered area (eg; protected by wind arc of earth or vegetation to deflect wind)
Drought: will increase as climate change increases to bring more extreme conditions of wet/dry patterns
- normal part of many climates; never lose by greed or carelessness, supplies of seed or animals.
- Water must be kept clean and not fouled.
- All water recycled, preferably several times over (kitchen/bath water to toilet/plants
- all plants to be heavily mulched
- watering to be done under mulch layer
- no sprinkler watering; concentrate water with drip systems
- Animals: If drought is part of normal weather cycle, then pastures and feed can be ‘saved’, as silage. Animals need to be on a salt lick (urea?) to facilitate digestion of dry feed.
- 17-30 can be fed on 1ha permanent of cut and feed forage; free-range animals take 1-5ha in ave conditions (40-60 in desert and droughts). 2-4 draught and milkers average, so 6-8 farmers
– shade for 15-30 animals. Floor should have mulch of fronds and hard straw from sugar cane, Pennisetum grasses, or palms
– up to 1ha of perrenial forage, cut daily and fed as one third to one half of the ration. Species include Honey locust, Acacia, arrowroot (Canna), comfrey and Pennisetum
– careful groundplan of multiple cross slope swales to catch and infiltrate run-off water in rains – this is critical
– herd animals are better to be grazed close for a short, intensive time, then moved closely; stall fed and controlled movements preserve land for higher fodder productivity
– all adjoining fields edged and wind-breaked with same spp, planted at 20-30m intervals in rows through all other crop, on bunds, along swales and ditches
– basic survival ha can be cut and managed in good years, but in drought all essential livestock penned in or near forage system for survival feeding. As no crops in drought, families tend on rotation
In drought, cattle can be fed on chopped dry stalk, small branches, straw, crushed cane, cardboard/paper provided they have access to lick of 10%(molases with urea added – 50-50). (eg; petrol drum in half-drum bath of molasses-urea. It is molasses-urea plus high cellulose cheap bulk food that enables cattle to breakdown some of the cellulose in wood and straw. Rest is provided from perennial forages, cut in succession and carried to pen; all manure and bedding is carried back to forage fields as mulch, preferably deposited in swales – mulch develops cool humus soils with good water capacity over time, and the forage plants thrive on this humus.
Dangers on range following rains:
-woody and ephemerals in drylands may concentrate toxic substances in new growth after rains, to protect against grazing for 4-6weeks -nitrates, oxalic acids, cyandes, alkaloids
SO, cattle shouldn’t be released to range, esp on single sp stand. Mature leaf generally not toxic; wide range of foods, some cut forage, mature leaf from trees. Same after browsing and burning
B. Nuclear ‘Accident’/Chemical Pollution
Who is going to live beyond such an event, and how?
- Protected water sources will be essential
- protected emergency garden also; a greenhouse becomes even more important as a architectural design component of the house.
- Recycling within the house structure of all nutrients
- Earthship design system of autonomous housing including indoor food production. Aquaponics important.
- Land Degradation/Famine
This of course is a longer term theme; usually the degradation (and such consequences as starvation and malnutrition) is slow moving and evolves over a longer time.
Dramatic exceptions to this are volcanoes (the flow of lava and lahar ash which totally blanket existing land), and tsunamis. The impact of both these can be significantly reduced though, be creating significant earth arc-berms in the sector from which such potential catastrophes would arrive (ocean-side for tsunamis; volcanic mountain-side for volcanoes) so that the arrival of lava/ash/wave would be greatly diverted away from the habitation or cropland. Of course this must be designed so that the reduction in damage risk to one land area does not become greater damage to the neighbouring or down-slope land!
Follow Permaculture strategies on water management, earthworks and vegetation strategies
Small areas can be made fire-safe. Non-oily spp, low litter, earth berms, close openings under house/eaves.
Principles for house protection against fire:
- Create defendable space
- Remove flammable objects from around the house
- Break up fuel continuity
- Carefully select, locate and maintain trees and shrubs
Factors in Fire Risk
a. Fuel – doubling of floor fuel – quadrupling of fire intensity. Pine needles burn faster than thicker matter
b. Mulches – dry mulches of annual grass, cereal crops, pasture burn very fast. Fibrous barks burn more than smooth bark
- Dry Fuel and Winds – increase risk of fire
d Topography – fire moves faster uphill
Design in Fire Control
1. Zone 1 garden around house, damp mulches, green mulches, irrigated, no open eaves, underhouse gaps to start fire.
2. Water – storage in irrigation/aquaculture ponds and tanks about the house. Plug and fill gutters, basin and baths. Have hoses inside.
3. Roads/Paths – leading away from principal direction fires come. Keep clear.
4. Orchards – excellent fire breaks, but watch citrus for oil
5. Animal yards – doors open to cool area
6. Radiant heat barriers – stone walls, mud walls, earthbanks, concrete, bricks, thick low hedges, white walls, fly screens
- Fire resistent plants – eucalypts regenerate BUT volatile oils explode, add to fire heat.
No Proteacea, Myrtaceae, Rutaceae (all oil-rich species) in fire sector or near house
BUT fire-retardant – burn poorly, slow fire – wattles, succulent species (wandering jew), coprosma
8. Fire shelter – place where people can escape to if house burns -build of rock, mud, or inside hill, and whitewash it.