Flinder University - Floating Land Project - V1

8/6/2019 Flinder University - Floating Land Project - V1

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EWB Challenge Floating Land Project

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Executive SummaryExecutive Summary

The floating docks we have designed, through the Engineers Without Borders challenge,

can dramatically improve the health and lifestyle of Cambodians living on the Tonle Sap

river. These docks are designed so the floating houses can be moored, giving stability to

the houses during storms. They also help families to support themselves financially

through the growing of vegetables on the docks. Permanent mooring allows a sense of

community to build among the locals because they have fixed neighbours. Our project's

goal is to find a way to integrate our floating vegetable gardens into Cambodian society

so it is beneficial and easily accepted by the villagers.

Our suggested garden design provides additional varieties of food to the staple diet, thus

improving health and general well-being of citizens. Currently, people in floating houses

own no land and therefore struggle to form a livelihood. Most families rely on fishing

but the fish supply is diminishing.

The docks are a simple design, using accessible materials to make it easy for local

Cambodians to learn how to make and maintain them. Each floating dock is a

rectangular structure consisting of 6 separate gardens, of approximately 3m2 each,

divided by walkways. For safety in extreme weather, each dock is anchored into

position. The docks can be connected to similar docks to form a village, if desired.

The materials used to make the docks are all able to survive exposure to water. For

buoyancy, 220L oil drums are roped into a frame made of plastic posts. Vine is

suggested as a cheap alternative to rope but it is not as strong or durable. Plastic garden

liner or tarpaulin protects the drums and keeps soil from escaping, while wood and

bamboo are used to create walkways between the gardens. Tyres along the sides assist

with safe mooring. These docks cost between $1507.66 and $2725.50 each, including

labour.

The oil drums can sustain approximately 112kg each. Unfortunately, soil weighs

between 1200kg and 1600kg per cubic metre. We have therefore designed the structure

to have narrow but deep strips of garden between drums to minimise the amount of soil

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needed. This allows the structure to stay afloat, taking into account that the docks must

also be able to support the weight of a number of people.

Research has been done into plants that can grow in the Cambodian climate with rootsystems that would work in our design. By planting a variety of these in their correct

seasons, vegetables can be harvested throughout the year. All produce that is not

required for immediate consumption by the family can be sold or traded. Each dock can

produce 675kg of vegetables a year, which will feed about 30 people, thus providing

enough for all the people living on the dock.

The soil quality in Cambodia is poor but, as the majority of the waste produced by

Cambodians is organic, assigning a separate vegetable patch for composting this waste

would lessen waste disposal problems and increase soil quality.

The project could be implemented in whole villages because there is a large expanse of

water for these environmentally-friendly docks to float on. The materials are found

locally, so the making of the docks engages local businesses as well as employing locals

as labourers. The design is culturally appropriate because Cambodians are typically

farmers and fishers, and their houses already float.

Throughout the world floating gardens are rare and none of the designs we found

elsewhere solved the problems of the Khmer people of Cambodia. Our design has

successfully found a way to enable locals who live in the floating villages of the Tonle

Sap to own land and supply their families with healthy food, as well as providing safety

and stability in extreme weather conditions.

This project has increased our knowledge of engineering concepts and our teamwork

skills. It has showed us how our skills can make a difference in the world and has taught

us to overcome problems and find alternative solutions.

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ReflectionReflection

Our group learned many skills, through this project. These included learning how to

work as a team and communicate effectively, as well as time management and

organisational skills. We now understand the importance of studying the culture and the

surroundings that the project is being designed for, and realise that the work we do, as

engineers, can have a huge impact on societies. It is exciting to know that, even as first

years, we can make a difference in the world. Our goal, through this challenge, was to

create something that can enable people that are too poor to survive without aid, to gain

the knowledge, skills and items needed to help themselves out of poverty.

When we began this project, through Engineers Without Borders, none of our group

knew each other. From the start we had to work as a team to brainstorm and plan our

design. This forced us to get to know each other and learn each person's strengths and

weaknesses so we could adapt the ideas and the design process to create a well

researched, high quality project. We set ourselves a time line so all the necessary work

would be achieved in our time limit. Our design process started by researching

Cambodian society and the needs of the people in the Tonle Sap area. This was because

our main goal was to design something that would improve the lifestyle of the locals,

and meet their needs. After discovering these needs, we brainstormed to find solutions to

the problems. The idea of creating floating islands seemed to have the potential to help

solve multiple problems that the Khmer people suffer. After much discussion, research

and design, we ended up with our final product. We feel this project was a success

because the design can dramatically improve the circumstances of the villagers, and our

group learned many new skills in the process.

Our group learned the importance of communication when doing group projects. We

met together regularly for meetings, and kept in contact via e-mail and phone. We

worked as a team to get ideas together and to help one another gain information on the

topic. This group work helped us to appreciate the need for effective communication,

when working as a team, in order to make it easier to tie all aspects together. As well as

giving us an appreciation of group dynamics, this exercise taught us organisation and

time management skills. Taking turns as chair for the group meetings helped us to

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develop leadership skills as well as helping us to learn how people work together in a

group.

This design exercise, not only taught us about Cambodian culture, it showed our groupthat we can make a difference in the world. Through the design process, we gained an

understanding of the need for our project to fit the culture, both in meeting the needs of

the people and environment, and in being culturally appropriate so that the people do not

lose their traditions. We also discovered the importance of enabling locals to contribute

to the making of the docks, so they can take up the project as their own initiative and

improve on it. This gives them a chance to be independent, rather than relying on

engineers. Our group learned much about community development and how to create a

sustainable product.

We increased our knowledge of what an engineer's job may involve, and the necessary

skills needed in order to be effective. We also learned many new engineering concepts

through this process. Sometimes we ran into difficulties but we learned how to

overcome these problems and find alternative solutions. This ability to overcome

problems will help us throughout our careers.

This project has been an excellent chance for us, as students, to use our skills to help

others, and to learn more about what is required as an engineer, in the workplace. The

skills we have learned through this engineering challenge will be of great value to us in

the future.

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Table of ContentsTable of Contents

Executive Summary...........................................................................................................2

Reflection...........................................................................................................................41 Introduction...................................................................................................................10

2 Cambodian Society........................................................................................................11

2.1 Purpose of Chapter............................................................................................11

2.2 Cambodian Culture............................................................................................11

2.3 Design................................................................................................................13

2.3.1 Cultural Aspects....................................................................................13

2.3.2 Health & Safety....................................................................................14

2.3.3 Available Resources..............................................................................15

2.3.4 Practicalities..........................................................................................16

2.4 Educating Locals About the Docks...................................................................17

2.4.1 Cambodian Communications................................................................17

2.4.2 Main Industries and Typical Work Practices........................................17

2.4.3 Optional Teaching Methods..................................................................18

2.4.3.1 Community Meetings...............................................................18

2.4.3.2 Teaching in Schools.................................................................18

2.4.3.3 Publicity...................................................................................19

2.4.3.4 Recommendations....................................................................19

2.5 Chapter Overview..............................................................................................19

3 Cambodian Environment..............................................................................................20

3.1 History...............................................................................................................20

3.2 Climate..............................................................................................................21

3.2.1 Dry Season............................................................................................23

3.2.2 Wet Season............................................................................................23

3.2.3 Typhoons...............................................................................................24

3.3 Geography.........................................................................................................24

3.3.1 Mekong River.......................................................................................25

3.3.2 Tonle Sap Lake.....................................................................................26

3.4 Wildlife and Ecology.........................................................................................27

3.4.1 Fauna.....................................................................................................27

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3.5 Effect of our Project on Environment................................................................27

3.5.1 Negatives..............................................................................................27

3.5.2 Positives................................................................................................27

3.6 Chapter Overview..............................................................................................284 Soil and Produce...........................................................................................................29

4.1 Introduction.......................................................................................................29

4.2 Soil.....................................................................................................................29

4.2.1 Soil weight............................................................................................29

4.2.2 Improving soil quality...........................................................................29

4.2.2.1 Fertiliser...................................................................................30

4.2.2.2 Composting..............................................................................30

4.2.2.3 Bone meal................................................................................30

4.3 Produce..............................................................................................................30

4.3.1 Growing Restrictions............................................................................30

4.3.2 Tropical Produce...................................................................................31

4.3.3 Seasonal Growth...................................................................................32

4.3.4 Amount Produced.................................................................................32


5 Flotation........................................................................................................................34

5.1.1 Scope.....................................................................................................34

5.1.2 Constraints............................................................................................34

5.1.3 Potential problems................................................................................34

5.2 Plastic Drums (220L)........................................................................................34

5.2.1 Dimensions...........................................................................................34

5.2.2 Load Handling......................................................................................35

5.2.3 Maintenance..........................................................................................37

5.2.4 Summary...............................................................................................37

5.3 Empty Containers Enclosed in Netting.............................................................37

5.3.1 Existing Examples................................................................................37

5.3.2 Netting..................................................................................................38

5.3.3 Waste bottles.........................................................................................38

5.3.4 Load handling ...................................................................................38

5.3.5 Maintenance..........................................................................................39

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5.3.6 Summary...............................................................................................39


6 Anchorage.....................................................................................................................40

6.1 Scope.................................................................................................................406.2 Problem..............................................................................................................40

6.3 Constraints.........................................................................................................40

6.4 Options..............................................................................................................41

6.4.1 Dead weight moorings..........................................................................41

6.4.1.1 Advantages...............................................................................41

6.4.1.2 Disadvantages .........................................................................41

6.4.1.3 Summary .................................................................................42

6.4.2 Pyramid Anchor....................................................................................42

6.4.2.1 Advantages...............................................................................42

6.4.2.2 Disadvantages..........................................................................42

6.4.2.3 Summary..................................................................................42

6.4.3 Danforth Anchor...................................................................................43

6.4.3.1 Advantages...............................................................................43

6.4.3.2 Disadvantages..........................................................................43

6.4.3.3 Summary..................................................................................43

6.4.4 Scope of Anchor System.......................................................................44

6.4.5 Multi-point Moorings...........................................................................44

6.4.6 Recommendations.................................................................................45

7 Structure and Materials.................................................................................................46

7.1 Introduction.......................................................................................................46

7.2 Structure............................................................................................................46

7.2.1 Dock for housing..................................................................................47

7.3 Materials............................................................................................................48

7.4 Final Dimensions...............................................................................................50

7.5 Cost....................................................................................................................51

7.5.1 Material Costs.......................................................................................51

7.5.2 Labour Costs.........................................................................................52

7.5.3 Currency Rates......................................................................................53

7.6 Funding the Project............................................................................................53

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7.6.1 Organisations........................................................................................53

7.6.2 Distribution...........................................................................................53


8 Conclusions..................................................................................................................559 References.....................................................................................................................57

10 Glossary of Terms.......................................................................................................59

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11 IntroductionIntroduction

The purpose of this report is to provide Engineers Without Borders with a feasible way

for Cambodians who live in floating houses on the Tonle Sap to supply their families

with healthy food by creating floating vegetable gardens. It also aims to provide a dock

for floating houses to moor to so as to stabilise the houses, which gives some protection

from the violent storms, and builds a sense of community amongst the refugees and

marginalised Cambodians.

Our solution is explained in detail on the following pages. Different approaches have

been looked at and our reasons for choosing the final design over the alternatives have

been explained. Our priorities have been to achieve the most affordable, effective, safe

and sustainable option. By designing our project to fit the community in the Tonle Sap

we hope Cambodians will take this project on as their own.

The floating docks have been designed so local Cambodians can be taught how to make

and maintain these floating gardens themselves, giving them an opportunity to help

themselves get out of poverty. This report explains the value, both short and long term,

of having these floating docks that can grow vegetables.

This report aims to predict the economic, social, environmental, cultural and political

implications our project will have on Khmer society as accurately as possible with the

resources available to us. This is based on our research through books, websites,

interviews and other sources.

Few places around the world have floating land in place. None of the techniques we

found elsewhere fitted culturally or economically into Khmer society so our design is

based on similar projects but is necessary because no other project could work in place

of ours. The aim of this report is to get aid organisations who already work in the Tonle

Sap area to read it and look at the possibility of funding the project so that the project

can be put into action.

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22 CambodianCambodian SocietySociety

2.12.1 Purpose of ChapterPurpose of Chapter

The purpose of this chapter is to determine the best way to integrate our floating

vegetable gardens into Cambodian society so it is most beneficial and easily accepted by

the villagers. Due to lack of education and financial struggles, many families do not

have the knowledge or the means to keep their families healthy. They lack food and an

income. Most rely on fishing for their main income generator as well as food for the

family, but the supplies of fish are running out (Lim Song 2005).

The poorest people in the Tonle Sap area live in floating houses (EWB 2009). Many arerefugees from Vietnam and people rejected from Cambodia's wealthier society

(Dhammataree 2007). Our aim is to build a dock for houses to be permanently moored

to that provides an atmosphere of community where people can get to know one another

and look out for each other. The dock will be designed to grow vegetables on, so the

families can satisfy some of their dietary needs and perhaps even produce enough to sell

or trade small amounts.

Building floating docks that houses can be attached to gives the houses added stability

during the violent storms that frequent the area of the Tonle Sap. By training the people

to make their own on-water farms we give them the chance to have pride in their home

and give them a hope for a brighter future.

To work out the best way to create our project so it is the most accepted and beneficial

design for the people of the Tonle Sap, we must know something about the culture they

live in.

2.22.2 Cambodian CultureCambodian Culture

This report is aimed at improving the quality of living for the people who live on

houseboats in the Tonle Sap area in Cambodia. The reason for choosing this is because

37% of the 340 000 people who live on and around the Tonle Sap river system live

below the poverty line (EWB 2009). Most of these people live in floating villages (EWB

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2009). They own no land and struggle to form a livelihood or even to obtain enough

food to feed their families.

Much of Khmer culture is based around status, including where a person sleeps in thehouse and how much a person is allowed to eat (Dittmeier 2008). Men have a higher

status than women, who themselves have a higher status than children. The average size

of a Cambodian family is 5.1 people (Cambodian Herald 2008, p.2). The whole family

sleeps on one wooden platform with parents at the head and the youngest children at the

foot. Most houses are between 3m2 and 7m2 and contain one or two rooms (EWB 2009).

Cambodia became independent from France in 1953 and has both a king and a prime

minister. The government is a multi-party democracy (Central Intelligence Agency

2009). During the Pol Pot regime and thirty years of civil war, many Khmer fled to the

West as refugees. This political turmoil has caused the majority of remaining

Cambodians to fear change in case it creates instability once more. Most do not wish to

stand out from the crowd because of this fear. There is also distrust due to the different

races and religions of villagers on the lake.

Khmer have their own style of Buddhism which mixes Theravada Buddhism, Hinduism,

animism and ancestor-spirit worship. The Tonle Sap river system, however, is also home

to many Vietnamese migrants and Cham people (Dhammataree 2007). The Cham people

are mostly Muslim (Tsui 2007, p. 96). This means that despite 95% of the 14.2 million

people in Cambodia (Central Intelligence Agency 2009) speaking the same language,

Khmer, communal activities are unlikely to run smoothly due to differences in culture

and beliefs.

In rural areas, the poorest half of the population own around 10% of the land. Some

areas are reserved for traditional fishing for families, but not for large-scale produce.

The Ministry of Agriculture, Forestry and Fisheries gives land ownership rights to

people (Fisheries Administration 2007). Despite this, laws on land use and distribution

are not followed closely.

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2.32.3 DesignDesign

2.3.12.3.1 Cultural AspectsCultural Aspects

Cambodian society places a strong emphasis on traditional practices. Because of this andthe unrest caused by thirty years of civil war, people are suspicious of change (Asker

2004). As there is low tolerance of the new, we must implement our project by showing

the locals that there is great benefit but little change from their original practices.

Each dock could be designed as a community farm looked after by the locals working

together, or it could be divided into small connected blocks with one vegetable garden

per house. By looking at the way people relate to one another an option can be chosen

that will work in the chosen community.

TABLE 2.1: Comparing communal farms and individual gardens (author created)

COMMUNAL FARMS INDIVIDUAL VEGETABLE PATCHES

POSITIVES NEGATIVES POSITIVES NEGATIVES

- Builds

interdependence

and community.

- People can use

their strengths and

count on others to

compensate for

their weaknesses.

- People will gain

from being selfish

and lazy.

- Arguments

between practices,

race and religion are

likely to occur.

- Difficult to

distribute fairly.

- Builds a sense of

ownership and

responsibility.

- Families can choose

how they use the

space and what to

grow.

- Less change from

the way local gardens

are run presently.

- Could cause

jealousy.

- Less overall

monetary profit.

- Hard to choose

who gets to own

land.

- Could cause rivalry

between neighbours.

Looking at the pros and cons of both options our group have decided to design small

vegetable patches for each family, joined together to form a larger dock. This has less

chance of failing because of being similar to original practices and avoiding problems

with harvest distribution.

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2.3.22.3.2 Health &Health & SafetySafety

It is necessary to decide whether these garden blocks should all be joined permanently

or whether they should be able to move and reconnect to other docks.

TABLE 2.2: Small connectable docks versus a permanent dock (author created)

POSITIVES OF SMALL JOINED

DOCKS

POSITIVES OF A SINGLE FIXED

DOCK

-Easier to move.

-More likely to fit in convenient places.

-Easier to fix faults like leaking floatation

devices.

-Able to escape noisy neighbours.

-Easier to increase size as wealth increases.

-Easier to stabilise the dock.

-Less likely to be destroyed by storms.

-Less likely that the garden will sink if

something goes wrong.

-Greater sense of community formed

because of having permanent neighbours.

Based on the table above, a single, permanent dock was chosen because we felt that

safety was a higher priority than convenience.

For purposes of floating the dock it is important to know how many people are likely to

be on a floating dock at a time. The average family size in Cambodia is 5.1 people(Cambodian Herald 2008). The dock should at least be able to hold the weight of all

family members from each houseboat, and not tip with the movement of people walking

around the dock. Having the houses moored to the dock will help to keep it steady and

afloat but the weight of people and soil is a large amount. Overcoming this problem will

be dealt with in following chapters.

Some safety considerations that need to be looked at are how to connect the houses

securely to the docks, what the effect of a leaking barrel would have on the dock, and

how to fix any problems, including those created by storms and fires, safely.

Tyres have been placed in regular intervals along the sides of the docks so that houses

can moor without being damaged. There are mooring poles by these tyres to secure the

houses firmly, using rope. The dock has been designed large enough and buoyant

enough that a hole in one of the barrels will not cause it to sink. By putting the barrels

with the opening upwards, it is easy to examine the damage and pump water out of a

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barrel if water gets in. The bamboo walkways could be lifted to get at the barrels

because they are directly over them. The size of the dock and the easy accessibility also

means it can be fixed without too much difficulty if damaged by storms, fires or other

calamities.

2.3.32.3.3 AvailableAvailable ResourcesResources

Most of the soil around the Tonle Sap is poor quality, lacking the necessary nutrients

needed to grow productive crops (EWB 2009). This means to get decent soil we cannot

take it from surrounding areas. Many of the farmers have taken up using pesticides and

fertilizers (EWB 2009). These create more pollution in the Tonle Sap river system.

Because 66% of the weight of overall waste products produced by Cambodian society is

organic, with only 5% being recyclable materials (Parizeaua 2005), it would be sensible

to incorporate a technique for dealing with compost into our dock. This would help with

the waste disposal problem in the Tonle Sap as well as enriching the soil so that the

gardens can be more productive. Composting techniques are covered in chapter 4.

Plastic bottles are frequently used for drinks. These bottles are often refilled with oil orpetrol to be resold to neighbours as a small business. These bottles could be resealed

after use, cleaned and tied together to form a flotation device. Double L-Ring drums are

also available reasonably cheaply for using as floatation devices (EWB 2009). Plastic

bags are commonly used in Cambodia. It may be possible to combine these with plastic

bottles, melting them down and shaping them into large platforms that reusable bottles

could float under to keep the platform buoyant. These would not be easy for locals to

make though. As can be seen, the materials are available but the feasibility of these ideaswill be discussed in a later chapter.

Boats and housing are generally made out of wood from local forests. Wood is also used

as fuel for the fire. The three types of boats used on the lake are houseboats (EWB

2009), temporary houses built from light materials so they can be moved when the water

levels rise (Dhammataree 2007), and houses built on stilts that are about 10m high so

that they stay out of the water in the wet season (Dhammataree 2007). Farmers often

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live near the edge of the forest. Most of the villagers in the Tonle Sap Basin do not

expect to ever be able to own their own land.

2.3.42.3.4 PracticalitiesPracticalitiesMaximising the size of the dock will increase the amount of land owned by each family

and thus increase the productivity and benefit of the farm. This is countered, however,

by the inconvenience of each dock having less manoeuvrability and costing more. To

come to a compromise we looked at the smallest amount of space needed for the garden

to be beneficial, and how few dwellings can be docked together and still have a stable

structure and a neighbouring community (see later chapters for reasons). We decided

that 3m2 would be enough for each household. A sensible structure, therefore, would be

around 6 by 9m with 6 houses moored to each dock. The docks could be connected to

form a village if desired. The image below is an example of our project (created in

Photoshop) to give a basic idea of how the final product will look.

Figure 2.1 Final Structure (created in Photoshop)

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2.42.4 Educating Locals About theEducating Locals About the DocksDocks

2.4.12.4.1 Cambodian CommunicationsCambodian Communications

Telephones are still uncommon in Cambodia. In 2004, research showed thatapproximately 3.5% of the population had access to a phone on a regular basis. They

estimated that 8% would have access by 2008 (Dittmeier 2008). Because of the lack of

telecommunications and infrastructure such as roads, news travels slowly. This mostly

affects the people living rurally, such as those in the Tonle Sap area. The lack of roads

and communication limits job opportunities and chances for farmers to sell their

produce.

Cambodian culture is one in which people must save face. To not know the answer to a

question is of great embarrassment to a Cambodian. A person must ask anyone they

meet where they are going and tell people where they themselves are going and when

they plan to return, so the opportunity does not arise for the other person to lose face if

someone asks where that person went. This also provides a safety net where

telecommunication is lacking (Dittmeier 2008). These communication practices have

implications for teaching Cambodians about the new docks.

2.4.22.4.2 Main Industries and Typical Work PracticesMain Industries and Typical Work Practices

25% of the Tonle Sap area is used for farming. These farmers generally fish in the rice

farms or nearby streams to supplement their income. 70% of the protein in an average

Cambodian's diet comes from fish. With 200 different species of fish in the waters of the

Tonle Sap Basin, it is one of the richest fisheries in the world. However, this supply of

fish is diminishing over time. This means fishermen are keeping the smaller fish whichare now not living to spawn offspring (Lim Song 2005). Any produce from the garden

docks that is not needed to sustain the family can be sold or traded without a permit, as

there are no health codes, food restrictions or regulations (Dittmeier 2008). By providing

another way to create income, our project will hopefully provide some relief to the

fishery.

The most farmed crop in Cambodia is rice, which is their staple food. Other crops grown

include corn, beans, cucumber and various spices. These tend to take three to six months

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from sowing to harvest time. Many of the local families own livestock but these are

expensive to look after and often get sick. It is rare to find large scale rearing of

livestock.

Cambodians are used to long hours of hard physical labour. Waking up after sunrise is asign of laziness (Dittmeier 2008). A job is often not done efficiently by Australian

standards though, because Khmer culture holds proper behaviour and good relationships

with those in power above getting the work done (Dittmeier 2008). Only those of high

ranking may make decisions. Those of lesser status are wise to agree even if they find

fault with the chosen outcome (Dittmeier 2008). It is important to take account of such

cultural norms when seeking to encourage new practices.

2.4.32.4.3 Optional Teaching MethodsOptional Teaching Methods

In order to train the locals in how to build and run these garden docks efficiently it is

important to discover the teaching methods and structures already in place in the Tonle

Sap. Teaching in ways that are traditional to the Khmer people helps participants to cope

better with taking risks (Asker 2004, p39).

2.4.3.12.4.3.1 Community MeetingsCommunity MeetingsIn Khmer society it is expected that an expert such as elders, monks and Khmer

traditional singers will teach the people. This means it would be wise to train people

who have a high profile in society to teach their own community. Unfortunately people

live busy lives and are unlikely to fit training or information sessions into their schedule.

This means community meetings are unlikely to be well attended.

2.4.3.22.4.3.2 Teaching in SchoolsTeaching in Schools

The floating land project could be taught in schools. The project would need to be

proven to fit the Cambodian main education goals for it to be considered as part of the

curriculum (Asker 2004). This would be a long and laborious process. On top of this

problem, children have little chance to impact the community. They have the lowest

status and are expected not to question their elders. This means that putting their training

into practice would be difficult before the children grow into leaders in society.

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2.4.3.32.4.3.3 PublicityPublicity

Many in rural Cambodian society cannot read or write so creating an instruction book or

manual would not help people. Many do listen to radio shows though. By explaining the

idea on popular radio shows, people might listen and take an interest.

Creating a video, documentary or another form of entertainment with locals acting in it

could be used to educate people while entertaining them. All people need time to relax,

so if we could teach in a way that entertained, people might make the effort to listen.

2.4.3.42.4.3.4 RecommendationsRecommendations

We suggest that the best option for teaching locals of the benefits of the docks and how

to make and maintain them is to train locals to teach. Training people who have a high

status in Khmer society to teach the villagers means that the villagers will be taught in

ways appropriate to the culture and they will be taught by people they trust and respect.

By paying locals to teach, we are supplying them with jobs and a chance to take this

project on as their own. They might wish to teach the locals via radio shows or other

forms of entertainment or they may have other ways that would suit their personal style

or the culture better.

2.52.5 Chapter OverviewChapter Overview

By researching Cambodian culture our group has a better idea of what design is

appropriate for the area and how best to integrate our floating vegetable gardens into

Cambodian society so it is most beneficial and easily accepted by the villagers. In order

to help reduce the poverty of those who live in floating villages on the Tonle Sap, ourgroup has designed a floating dock that is divided into individual gardens for families to

grow food on. This will give the families dignity and hope as well as helping to feed the

family and expand their income. It should also help with endurance and stability of the

houses during storms and create an atmosphere where community can thrive. The

project has been designed with a focus on low cost and safety. We hope that elders,

monks and others in positions of power in the villages will see the benefit of having

these docks and choose to take this project on, training others in the building and

maintenance of them.

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33 CambodianCambodian EnvironmentEnvironment

3.13.1 HistoryHistory

For thousands of years, the people of Cambodia and those who populate the Lower

Mekong Basin have fashioned a life amid a landscape unlike any other found on Earth.

From adapting to the fluctuations of the water level in the Tonle Sap Lake, to utilising

the fertile lands of the floodplain, Cambodias populace had thrived for many centuries.

Likewise, the environment with which they lived remained relatively unharmed due to

their care for the rich and diverse flora and fauna.

However, as the rest of the world became more interested in this unique country, outsideinfluences began to change the lives of the Cambodian people. Organic materials were

replaced with synthetic products and without sufficient knowledge of the effects that

dumping these products can have on the environment, their surroundings grew more and

more polluted.

The world evolved at such a rapid rate, Cambodia was unable to remain up-to-date and

as a result, much of its people are facing conditions that classify them as living belowthe poverty line. We feel that by developing a sustainable farming system atop the Tonle

Sap Lake, this will provide the opportunity for additional varieties of food and

consequently, an improvement to the publics health and general well-being. With a

farming system in place and the education to use it effectively, Cambodian people will

have the ability to utilise the environment to a much higher standard, thus improving

their quality of life.

By building these floating structures from pollutants found in the vicinity of the Tonle

Sap, e.g. empty plastic barrels, the lake may be beautified in the process. Creating

another food source also eases the pressure on the ecology of the Tonle Sap, as the

demand for over-fishing in the area diminishes.

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3.23.2 ClimateClimate

Due to Cambodias close proximity to the equator (between 10 and 14 north of the

equator) it, much like the rest of south-east Asia, experiences warm to hot temperatures

all year round. To give an idea of what it would be like to live in Cambodia, we will

compare Cambodia to Adelaide. Generally, Cambodia is considerably warmer than

Adelaide (refer Figure 3.1 and Figure 3.2) and has a much higher average annual

precipitation (refer Figure 3.3).

Figure 3.1 Daily Mean Minimum Temperature adapted from www.bom.gov.au and

http://www.worldweather.org/145/c00347.htm

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Figure 3.2 Daily Mean Maximum Temperature adapted from www.bom.gov.au and


Figure 3.3 Mean Monthly Rainfall adapted from www.bom.gov.au and


Similar to many neighbouring countries, Cambodia has only two individual seasons: a

wet season and a dry season. Monsoonal airflows that change direction seasonally

govern the beginning of the wet and dry seasons.

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3.2.13.2.1 Dry SeasonDry Season

Brought about by the monsoonal winds from the north-east, which begin in October and

last through to May of the following year, the hot inland breezes ensure the average

daily maximum temperature remains above the 30C mark throughout (refer Figure 3.2).

The dry season brings Cambodia very small amounts of rain for the duration; the driest

month of the year is January, averaging less than 1 millimetre of precipitation over the

five-year 1996 to 2001 period (refer Figure 3.3).

As well as having the driest months, Cambodias dry season has both the hottest and

coldest annual average temperatures, April being the hottest month of the year with an

average daily maximum temperature of 35.5C and November being their coldest month

with an average daily maximum temperature of 30.6C. When compared with the data

of the same months in Adelaide, they are 13.4C and 7.2C higher respectively (refer

Figure 3.1 and Figure 3.2).

3.2.23.2.2 Wet SeasonWet Season

As the dry monsoonal winds from the north-east subside and the moisture-rich winds

from the south-west begin to sweep across Cambodia from the Gulf of Thailand, the wet

season begins to have an effect. The winds during the wet season bring large amounts of

rain to the region. The wet season endures from the middle of May to approximately

October and during this time, Siem Reap, a town on the Tonle Sap, can expect

somewhere in the range of 1000 to 1500 millimetres of precipitation; the highlands of

Cambodia averages even more. This figure is four to five times greater than the average

annual rainfall in Adelaide of the same months (refer to Figure 3.3).

Additional rain, however, does not decrease the temperature, with mean daily maximum

temperatures remaining in the mid to low 30C range. The warm weather combined with

the increased moisture creates high humidity, often exceeding 90% and rarely falling

below 60% (World Facts Index 2008), and this can result in evenings being relatively

uncomfortable for the lakes residents.

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3.2.33.2.3 TyphoonsTyphoons

A typhoon (known as a tropical cyclone in the southern hemisphere) is an important

natural event that acts as a regulator of global heat, by travelling toward the poles,

distributing energy as it goes. Without typhoons, countries close to the equator would be

far hotter and those further from the equator would be significantly colder.

Typhoons form over deep, warm waters, generally warmer than 26C. This difference

between the temperature of the water and the atmospheric temperature causes unstable

conditions in the troposphere above, resulting in storms. When the air above the water is

cool, as the warm air rises, it rapidly decreases in temperature.

The gusts related to a typhoon can be in excess of 300km/hr with sustained winds of

over 250km/hr. Coupled with torrential rain and electrical storms, typhoons have the

ability of leaving catastrophe in their wake. As damaging as the winds and rain may be,

the deadliest and most feared element of this natural disaster is the extremely high seas

which have been known to wash many kilometres inland, leaving coastal communities

completely flooded.

Typhoons very rarely form within 5 of the equator as the deflection of any moving

object air included due to the rotation of Earth, increases as the distance from the

equator increases (NASA Jet Propulsion Laboratory 2003). Cambodia, however, is

between 10 and 14 north of the equator.

Compared to Cambodias surrounding countries, particularly Vietnam, it is relatively

sheltered from typhoons; however they have occurred and affected Cambodian

communities in years past. As such, it is necessary to take certain precautions to ensurethat the floating land structures we are proposing will be able to withstand the high

winds and remain afloat once saturated by the rain and turbulent waters of the Tonle Sap

in the event of a powerful storm.

3.33.3 GeographyGeography

Covering a total land area of 181,040 square kilometres, Cambodia is the 63rd largest

country in the world. Cambodia is a country located in south-east Asia, sharing its

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border with Thailand, Laos, Vietnam and the Gulf of Thailand to the south. Gifted with

an abundance of flora and fauna, the expansive and relatively untouched Cambodian

environment is steeped with history and culture, drawing thousands of tourists every

year. From the lofty Cardamom Mountains and Dangrek Mountains located in thesouthwest and north of the country respectively, to the sprawling expanses of the Tonle

Sap Basin-Mekong Lowlands, the geographical features are impressive and varied

(World Facts Index 2008).

3.3.13.3.1 Mekong RiverMekong River

Winding its way through five different countries before entering Cambodia, the Mekong

River is 4909km in length (Knowledgerush.com 2003), making it the worlds twelfth

longest river (University of Kyoto 2006). As well as being a significant river on a global

scale, its importance to Cambodia and the mechanics of the Tonle Sap Basin are

significant. Along the entirety of the river, more than 90 million people depend on it for

their livelihoods.

Starting in northern China, the Mekong River flows southward towards Cambodia until

it reaches the Mekong delta in Phnom Penh. The flow rate of the river during the dryseason allows for the water to continue south-east through Vietnam and escape into the

South China Sea.

However, as the monsoonal winds bring excessive rain to south-east Asia, the Mekong

river swells and flow rate increases from approximately 2000m3/s in the dry season to as

much as 50,000m3/s in the wet season (GIS Development 2004). The previously

manageable release of floodwater reaches a level far greater than the system canwithstand, and to accommodate and minimise flooding in Cambodia, the river system

reverses its flow. All of the excess run-off is carried up the Tonle Sap River and into the

Tonle Sap Lake, having a dramatic effect on the geography of the area. Study shows that

each year approximately 45 billion m3 of water travels into the Tonle Sap Lake via the

Tonle Sap River during this reversal period (Infrastructure Development Institute of

Japan, 2002).

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3.3.23.3.2 Tonle Sap LakeTonle Sap Lake

As the largest body of freshwater in south-east Asia, Lake Tonle Sap naturally has a

huge impact on the lifestyles of Cambodians. Its importance extends far beyond being a

unique geographical landmark. The 340,000 people living on the lake (EWB 2009)

depend on it for their livelihoods, to provide for their families and to boost the overall

economy of Cambodia. This dependence is so great that the Tonle Sap Lake has often

been referred to as The Beating Heart of Cambodia.

In the midst of the dry season (refer to 3.1.1), the Tonle Sap covers a total land area of

2,500km2 to 3,000km2 with a depth of no more than about 1m. It is during these months

that the fertile floodplain is dry and landowners are able to capitalise by planting crops,

both for personal consumption and for trade.

The monsoonal winds swing around to the south-west bringing the wet season and

enormous amounts of rain teems down upon Cambodia, causing the Mekong River to

reverse its flow (refer to 3.2.1). The millions of cubic litres of water that now flow into

the Tonle Sap cause the lake to swell approximately fivefold. Now covering 10,000km 2

to 16,000km2

and rising to up to 10m deep in certain places, the areas where farmingwas happening during the drier months are now under water (refer Figure 3.4). As a

result, the fishing industry is put under immense pressure and the lake is over-fished.

Figure 3.4 Floodplain of the Tonle Sap

http://www.fao.org/DOCREP/005/Y4586E/y4586e4_01.gif

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3.43.4 Wildlife and EcologyWildlife and Ecology

3.4.13.4.1 FaunaFauna

The cyclic rise and fall of the Tonle Sap Lake promotes an abundance of animal life,none more so than a plethora of fish species which use the lake as an annual breeding

ground. 3 million people living on the lake take full advantage of this, fishing

approximately 41,740 tons/year (University of Kyoto 2006). Although this accounts for

a large portion of Cambodias fishing industry and feeds much of the countrys

population, overfishing places strain on the ecology of the area.

Our floating land scheme does not aim to eliminate the need for fishing in the Tonle

Sap, but rather complements it. By offering Cambodians an additional food source, the

pressure felt by the environment will be reduced and fish numbers can continue to

prosper. Additional to the decrease in fish consumption by the people of the Tonle Sap,

Cambodias economy will be boosted with the extra reserves of fish allocated for trade

and export.

3.53.5 Effect of our Project onEffect of our Project on EnvironmentEnvironment3.5.13.5.1 NegativesNegatives

Although this design solves many problems in Cambodia, it is not without a slight

environmental drawback. Aquatic plant life directly beneath the floating pontoon will

suffer if the structure is moored in the same position for extended periods, due to a lack

of sunlight. Like all plants, if they are not able to harness sunlight, a vital component of

photosynthesis, they are not able to survive. This issue however, will be confined to

flora in close proximity to the floating land itself, so will not have an adverse effect on

the aquatic environment as a whole.

3.5.23.5.2 PositivesPositives

Despite the aforementioned downfall associated with the floating land scheme, a raft of

positives suggests that this project is an effective and viable solution to numerous

problems faced by the people of Cambodia each and every day.

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Securing housing together upon the lake by connecting multiple houses to floating farms

will increase the strength of structures so that they can weather the ferocious storms that

frequent Cambodia.

When the lake swells and much of the agricultural land is under water, a great deal of

pressure is placed upon the fishing industry to provide for Cambodias nutritional needs.

With the 'floating land' scheme in place, houses will be relatively self-sufficient and the

demand on fish will decrease, thus the fish population will thrive and the Tonle Sap

ecology will benefit.

Additionally, our proposition of building our design using, if possible, discarded plastic

containers which currently pollute the area will ultimately lead to beautification as well

as improving the general cleanliness of the lake.


Having researched the environment of Cambodia, our group have come to realise what a

unique and picturesque place it is, but with its beauty comes fragility. The geological

mechanics and plant and animal species are currently functioning as they should buthumans have become a bad influence on nature. The rubbish that is being disposed of in

the Tonle Sap Lake is having a detrimental effect on the life on the lake and it is only a

matter of time before these harsh pollutants take their toll. The 'floating land' scheme

will remove litter from the delicate environment and use it to better the lifestyles of the

occupants of the Tonle Sap Lake.

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44 Soil and ProduceSoil and Produce

4.14.1 IntroductionIntroduction

Many problems arise when trying to grow vegetables on a floating vegetable patch.

Vegetables require a certain amount of space to grow properly, which means that

designing the container to grow the vegetables needs to be done carefully to maximise

productivity. Another problem is that the soil needs to be of a certain quality so that the

vegetables are able to get the nutrients they need to grow properly.

4.24.2 SoilSoil

Soil is a natural compound that is formed from minerals, organic matter, gases and

liquids on the earths surface. It is a vital part of growth and development of land-based

plants.

4.2.14.2.1 Soil weightSoil weight

Table 4.1 Soil weight (Adapted fromEngineeringToolbox)

Type of SoilApproximate Weight

(kg/m3)

Loose earth 1200

Rammed earth 1600

Average 1400

The weight of the soil will affect how we need to design the container, as it will need to

be able to hold the weight of all the soil and vegetables while still being able to stay

above the water. As we will not be ramming the earth solid we will use 1400kg per cubic

metre as an estimated weight for soil.

4.2.24.2.2 Improving soil qualityImproving soil quality

Soil quality will affect how well the produce will grow. Poor quality soil is unlikely to

grow anything whereas top quality soil will produce the best yield. A perfect quality soil

is almost impossible to come by but it is possible to improve soil quality through various

methods of fertilisation.

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4.2.2.14.2.2.1 FertiliserFertiliser

Fertiliser adds essential minerals to soil to help produce the best quality produce. The

problem with improving soil quality with commercial fertiliser is that although it is easy,

it is also very expensive to buy. This causes affordability problems for the people on the

Tonle Sap.

4.2.2.24.2.2.2 CompostingComposting

Composting is one way to help improve the soil through natural means. It would also

enable the people to dispose of organic waste safely, lessening pollution in the lake.

When composting, there are several things that need to be kept in mind, such as it

cannot be under too much sun. For composting to be done, a community group would

have to have a separate vegetable patch that they could cover just for composting.

4.2.2.34.2.2.3 Bone mealBone meal

Bone meal is both an effective and natural fertiliser. It is made up of any kind of bone

which has been ground down to a powder. It is possible to make an effective bone meal

at home. Families on the Tonle Sap could use bones such as fish bones which theywould normally discard. They can boil the flesh off the bone, then charcoal the bones

either on the stove or in a fire place. This makes the bones easier to grind. The family

can then grind the bone and spread it onto the garden as a fertiliser.

4.34.3 ProduceProduce

It is important to investigate what can grow in the area and what the Cambodians will

eat, in order to design a useful floating island.

4.3.14.3.1 Growing RestrictionsGrowing Restrictions

Vegetables require varying amounts of room to grow in. This makes growing in a

restricted amount of space a little more complicated as everything cannot just be placed

in randomly to grow. To maximise the space, each variety of vegetable needs to be taken

into consideration.

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Table 4.2 Agriculture and Natural Resources (Adapted from

http://celosangeles.ucdavis.edu/garden/articles/pdf/container-growing-vegetables.pdf)

Plant Plant Spacing (Inches) Soil depth (Inches)

Beets 3 9 to 12

Leaf Lettuce 6 9 to 12Onions 3 9 to 12

Radishes 1 to 2 9 to 12Spinach 5 9 to 12

Swiss Chard 6 9 to 12Broccoli 12 12 to 14Cabbage 12 12 to 14

Cauliflower 12 12 to 14Cherry tomatoes 12 14 to 16

Eggplant 12 14 to 16Peas 3 14 to 16

Peppers (Capsicum) 12 14 to 16Carrots 2 9 to 18Beans 5 16 to 18

Cucumbers 12 16 to 18Potatoes 6 16 to 18

Summer Squash 18 16 to 18Tomatoes 18 16 to 18

In a 3m by 3m (118 inches by 118 inches) vegetable garden it would be possible to fit

approximately 2000 radishes but this does not factor in the climate nor does it give muchof a variety, let alone fit the culinary practices of Cambodians. This means we need to

find other alternatives that produce a lot in a little space and work in the climate.

4.3.24.3.2 Tropical ProduceTropical Produce

The season affects what type of vegetables people will be able to grow. There are many

varieties of the vegetables listed in Table 4.2. Some of particular interest are:

Suyo long: A variety of cucumber which can withstand hotter weather then regular

varieties of cucumber.

Open leaf lettuce: These are more heat resistant then the closed leaf lettuce.

Cabbage: Many of the cabbage family grow well in warm weather. These include

Chinese cabbage, bok choi, rocket and Asian greens.

Shallots: A smaller version of the onion which can grow in tropical conditions. A bonus

is that it will require less space to grow.

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Some vegetables, such as eggplants, chillies, capsicums and sweet corn will grow no

matter how hot it gets (Bradtke, 2009). Using the information below, we can plan how

much of each type of vegetable should be grown, taking into account what seasons the

vegetables grow in, so people will be able to grow vegetables throughout the year.

4.3.34.3.3 Seasonal GrowthSeasonal Growth

Table 4.3 Seasonal Produce (Adapted from

http://www.tropicalpermaculture.com/tropical-vegetables.html)

Wet Season Produce Dry Season Produce

Suyo Long (Cucumber) Cabbage

Lettuce (Open Leaf) Shallots

Shallots

Eggplant

Chillies

Capsicums

Sweet Corn

Sweet Potato

The people of the Tonle Sap should be able to utilise their floating land to the full extent

by exploiting the seasons in which produce grows. By swapping between the wet season

vegetables such as capsicums, lettuce and suyo lang and then growing various types of

cabbage and some shallots during the dry season, the people will frequently have

produce that is ready to harvest.

4.3.44.3.4 Amount ProducedAmount Produced

To fit the dimensions of our floating land, there will be 12 strips of soil 8.80m long by

20 centimetres wide.For suyo long, cabbage and capsicums which require the most

spacing they will be able to grow up to 30 plants per row whereas for sweet potato they

will be able to fit closer to 45 plants per row. From these numbers they will be able to

grow approximately 360 cabbages during the dry season. During the wet season,

depending on how the rows are split between vegetable, they will be able to grow up to

540 plants per dock. This gives a total of up to 900 plants grown on a dock each year.

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A cucumber plant produces approximately 1kg of cucumbers per plant and a lettuce

weighs approximately 500g. Based on these plants, we can assume that each plant

produces approximately 750g. This means the maximum amount grown on a dock is

675kg per year.

We could not find any information on how much an average Cambodian eats so we have

based our results on the following statistics, to give a rough estimate of how many

people each dock will sustain. The average adult American consumes approximately

10kg of green vegetables, 1.8kg of cucumber, 3.2kg of corn and 8kg of onion a year

(Jeavons 1999). This totals 23kg per person, per year. This is obviously not all the types

of vegetables eaten by an American, but as Cambodians are poorer, smaller in build, and

we are including children in our calculations, this amount should be enough for a

Cambodian to stay healthy.

As each dock can produce 675kg, we divide that number by the amount of vegetables

eaten by each person to get approximately 30 people able to be sustained on a 7.5m by

9.2m dock, which is the size of our final design. As each dock supports 6 families, and

each family has approximately 5 people in it, the dock should be able to provide the

vegetable requirements for all 30 people living there.


By investigating and researching into how soil and produce factors are going to affect

the floating land, we can analyse how best to design the land so that it can support the

weight of the soil. It also helps us to provide information on what families can grow

there. The ability to grow their own variety of vegetable will help provide a healthier

diet as well as some income as excess produce can be sold. Growing vegetables will

help reduce some of the financial pressure on a family to buy food as well as helping to

slightly decrease some pressure on the decreasing fish number ecosystem.

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55 FlotationFlotation

5.1.15.1.1 ScopeScope

The scope of this chapter is to design a system to make our structure float. Our focus is

on durability, cost, use of local materials, and ease of implementation. Our research has

led us to two obvious flotation ideas: the first comprising the use of 220-litre plastic

drums, the second involving placing empty sealable containers into netting.

5.1.25.1.2 ConstraintsConstraints

The design choices we make will be guided by factors such as, the weight of the

structure, the environment factors such as current, storms, and river height, and existing

infrastructure e.g. floating housing and moorings. It is also important to consider the

cost of the project because it is of no use to the community if the they cannot afford to

implement the design.

5.1.35.1.3 Potential problemsPotential problems

Our biggest concerns are weight, freeboard and durability (strength). If our structure(above water) is too heavy, we run the risk that our underwater structure will sit too deep

in the water, creating a problem with clearance when water levels drop in the dry season.

5.25.2 Plastic Drums (220L)Plastic Drums (220L)

5.2.15.2.1 DimensionsDimensions

Figure 5.1 220l plastic drums (pac tech, 2007)

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All dimensions are based on the pac tech product specification sheet. We are assuming

barrels to be of similar type and dimensions to these.

Length: 920mmWidth: 580mm

Wall thickness: >2.8mm

Weight: 9.5kg

Cost: $2 each (EWB, 2009)

The barrels can be roped together and put in a bamboo or plastic framework. This

structure is discussed in chapter 7.

5.2.25.2.2 Load HandlingLoad Handling

The aim of this section is to calculate the maximum weight that each barrel can support,

and the combined weight handling of combinations of barrels. Our target is half

submersion of each barrel. This will allow for spikes in weight such as unknown number

of people on the structure, and water from monsoonal weather.

Figure 5.2 Half submersion of cylinder (Blankleider, 2009)

weight of structure = m

empty weight of barrel = mo=9 . 5kg

radius of barrel = r = 580mm

length of barrel= l =920mm

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density of water = =1000

m+mo=mw =V=r

2l

2

m=r

2

l2m0

(Blankleider, Parappily,2009)

m=1000.290

2.920

29 .5=112.036kg

This means the target maximum weight is 112.036kg per barrel.

Now we will work out the weight it takes for a barrel to sink.

Figure 5.3 Full submersion of cylinder ( Blankleider, 2009)

m=r2lm0

m=1000.2902.9209 .5=233.571 kg

So 233.571kg are needed for the barrel to reach equilibrium.

Proposed dock configuration:number of barrels = x = 1310=130

Target maximum weight is:

mx=112 .036130=14564.68kg

Weight applied for barrel equilibrium (almost sinking) is:

Mx=233.571130=30364. 23kg

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5.2.35.2.3 MaintenanceMaintenance

The barrels' maintenance and durability will depend on the actual drums used. We are

assuming the barrels will be of a similar type to our reference (pac tec, 2007). The

barrels from pac tech use high density polyethylene (HDPE) for the main body and

HDPE for the bungs (lids). HDPE is commonly recycled and is preferred over other

materials for use in applications such as pyrotechnics, water pipes, food grade

containers, plastic lumbar etc.(Wikipedia, 2009). HDPE has good chemical resistance, is

temperature resistant, has good impact resistance, and a good overall toughness.(ides,

2009). If we leave a bung above the water line, we can easily inspect and syphon any

water that may be present (i.e. leaks).

5.2.45.2.4 SummarySummary

This configuration is a realistic and viable solution to our problem. Using these barrels is

a good way to recycle while creating a solid base for our structure.

5.35.3 Empty Containers Enclosed in NettingEmpty Containers Enclosed in Netting

5.3.15.3.1 Existing ExamplesExisting Examples

figure 5.4 Spiral Island and netting (Ecoble, 2007)

Through our initial brainstorming, we identified plastic bottles as a means to float our

structure. Further investigation revealed Spiral Island. 'The original Spiral Island was (as

its successor will be) built upon a floating collection of used plastic bottles, all netted

together to support a bamboo and plywood structure above. Located in Mexico, the

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original was 66 by 54 feet and was able to support full-sized mangroves to provide

shade and privacy, yet also able to be moved from place to place by its creator at need

with a simple motorized system' (Ecoble, 2007).

5.3.25.3.2 NettingNetting

After looking at pictures of existing infrastructure on the EWB website, we noticed

various fishing nets (EWB, 2009). These nets would be a feasible way to hold the waste

bottles together. Nets are durable, repairable and light weight. Locals would be able to

make them to almost any shape.

5.3.35.3.3 Waste bottlesWaste bottles

Waste bottles are available in the Tonle Sap region. Waste bottles are sold in bulk from

major cities such as Phnom Penh and Siem Reap for US$600 tonne (EWB f&q, 2009) or

from general collecting. The size and shape will vary so we have picked some common

shapes for our calculations.

5.3.45.3.4 Load handlingLoad handlingThe following calculations are only approximations because of unknown variables such

as size and shape of plastic bottles to be used in actual construction. Here, we assume

that bottles that are in the water are fully submerged (due to unknown variable, shape).

Our benchmark will be our target weight for 220-litre plastic drums (chapter 5.3.3).

Type Volume Weight

Plastic bottle 600ml 40gPlastic bottle 1500ml 70g

average 1050ml 55g

m=Vm

o

m=1 000. 001 050. 055=. 995 kg

each unit could support approximately 0.995kg at equilibrium.

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our target benchmark is 112.036kg.

1 1 2. 036. 995

=1 1 2 . 598=1 1 3 bottles

For our waste bottles to have similar characteristics as the 220l barrels,

we double the amount of bottles to give us our 290mm of freeboard.

1 1 32=2 2 6 bottles

For our proposed structure size, we need:

22 699=2 2 ,37 4 bottles

5.3.55.3.5 MaintenanceMaintenanceFood grade plastic bottles are mainly made from Polyethylene Terephthalate (PET);

some examples include soft drink bottles, food and produce containers (matweb, 2009).

PET has a good resistance to mineral oils, solvents, and acids but not to bases

(alkaline)(designinsite, 2006). Inspecting and repairing the bottles could cause a

problem as access in limited.

5.3.65.3.6 SummarySummaryThe main concern with this configuration is the uncertainty of available bottles. It is a

viable solution, as the Spiral Island example proves, but the strength and durability is

unknown because each bottle has different characteristics, and nets will vary. We would

need to build a prototype to examine how the concept would behave.


The final design for the floating land project uses the barrels for floatation because they

are easier to fix than the structure made from bottles in netting, and more uniform for

purposes of calculation.

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66 AnchorageAnchorage

6.16.1 ScopeScope

For our project to work effectively we need to secure our floating structure in a fixed

position. Part of our design is for existing housing to have a dock that is fixed so that

they can be safe in extreme weather and when the tide is strong. Our aim is to identify a

means to efficiently secure the structure while maintaining our focus on affordability. It

would be more convenient for the locals if the mooring system is able to move with the

seasons (see chapter 3.3.1) so people can be near the lake's edge for transport purposes.

6.26.2 ProblemProblem

A problem identified while looking though the pictures on the EWB photo gallery is that

many of the floating houses/structures are arranged in a disorganised fashion. Further

research found that there are very limited, and highly sought after, 'permanent moorings'.

People mostly attach their houses to another structure or a tree. In a storm, some

moorings are known to shift, which causes some major problems (EWB, f&q, 2009).

Figure 6.1 Disorganised housing (EWB, 2009)

6.36.3 ConstraintsConstraints

Some facts to take into consideration when choosing an appropriate anchor for the docks

include the potential force on the anchor system due to tides, the river bed composition,

made of sand and silt, and the movement of communities as the seasons change. It is

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also important to look at the materials available and the expertise of locals. The

movement (yaw) of the docks needs to be studied to keep the floating land from

collisions.

6.46.4 OptionsOptions

After research we decided on some systems to pursue further. These include dead

weight, pyramid and danforth anchors. We also considered multi point anchor setups.

6.4.16.4.1 Dead weightDead weight mooringsmoorings

Figure 6.2 Dead weight mooring (Sandifer,2009)

6.4.1.16.4.1.1 AdvantagesAdvantages

The dead weight mooring is a very reliable system which gains greater holding power

over time as the weight embeds into the bottom, creating suction. If a dead weight

anchor breaks free, the weight provides constant force (Parenti, 2000). They are

uncomplicated and the materials are readily available.

6.4.1.26.4.1.2 DisadvantagesDisadvantages

The dead weight anchor's effectiveness depends on material choice. When concrete is

submerged, approximately 50% of its weight is reduced due to buoyant force (Parenti,

2000). Steel works the best as approximately only 20% of its weight is lost.

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6.4.1.36.4.1.3 SummarySummary

Dead weight would be a good solution if our final design required permanent mooring.

6.4.26.4.2 Pyramid AnchorPyramid Anchor

Figure 6.3 Pyramid anchor (Sandifer, 2009)


The pyramid anchor is a simple design which easily penetrates into the river bed. It has

good holding power in soft sand and silt river beds (Sandifer, 2009). If the anchor drags,it will still try to bite into the river bed.


These anchors cost a lot because they are made of steel. They are also subject to

corrosion. Because they are so heavy, it would be very hard to retrieve the anchor.


This anchor is an ideal solution, as it could either be permanent or temporary. Our main

concerns are weight and cost.

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6.4.36.4.3 Danforth AnchorDanforth Anchor

Figure 6.4 Danforth open (holiday sailover, 2008)

Figure 6.5 Danforth (boatbits.co.nz, 2009)


The danforth anchor is extremely light and therefore could be easily retrieved and fixed.

It has good holding power in sand and silt. This simple design could be locally made

without much cost.


The problems with the design of the danforth anchor are that it has moving parts and is

not very durable, so will need regular maintenance, and it is going to corrode over time.


The danforth anchor is ideal for a temporary solution because of its light weight and

lower cost (it contains less steel than a pyramid anchor). Locals could make these

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anchors themselves. By increasing their size, these anchors would have considerable

holding power.

6.4.46.4.4 Scope of Anchor SystemScope of Anchor SystemTo ensure that the anchors hold, we need to allow for a scope of no less than 2:1. A

scope of 3:1 would be ideal as the greater the scope there is less chance of the anchor

breaking out.

Figure 6.6 Scope

6.4.56.4.5 Multi-point MooringsMulti-point Moorings

We have identified that we need to control the yaw of our structure. We recommend that

two anchors are deployed one at either end. This will help limit the yaw and provide

greater holding power.

Figure 6.7 Mooring

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6.4.66.4.6 RecommendationsRecommendations

We would recommend using two danforth style anchors on each dock due to their

temporary nature and the community's needs to move with the seasons. We believe this

configuration would help to keep the yaw of the structure to a minimum.

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77 Structure and MaterialsStructure and Materials

7.17.1 IntroductionIntroduction

The floating land project requires many different materials in order for it to be built.

This chapter outlines the basic structure and the materials as well as the costs involved

in making our final product.

7.27.2 StructureStructure

The designed structure has been kept simple to make it easier to be maintained. If the

structure is too complex the floating island would be more likely to have problems that

would not be able to be fixed by the local Cambodians. If they cannot fix it, then they

are unlikely to use it.

The chosen structure is rectangular in shape, with a strong but lightweight frame.

Bamboo, rope, wood and plastic are the main materials used on the top structure. The

top structure will fit onto the bottom structure made of floating barrels (explained in

chapter 5).

There have been many different designs created for the floating island, which have come

from brainstorming useful features. However, the final design was decided to consist of

narrow strips of soil which are separated by bamboo walkways. The idea is to allow for

houses to dock to the island and use the soil to grow food to either eat or sell.

The dimensions of the structure are approximately 9x6m with a depth of 1m. Each of the

six sections of 3x3m will have rows of soil. The idea of this is to keep the weight of the

structure to a minimum. It also allows for six families to grow a variety of vegetables at

any time.

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7.2.17.2.1 Dock for housingDock for housing

The pictures below show the design of our proposed dock.

Figure 7.1 The Dock

Figure 7.2 Cross sectional view

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Figure 7.3 Top view

7.37.3 MaterialsMaterialsBelow is a list and detailed explanation of the materials that will be used.

Bamboo Grown in many regions in Asia, bamboo is a tough, durable and inexpensive

material. For this project it is being used on the walkway in between the garden patches.

The cost of bamboo varies depending in quality and size.

Empty plastic barrels - (oil drums 220L) These barrels will provide the buoyancy

needed to keep the island above water. They will be placed on the bottom of the

structure for efficiency. The cheaper alternative to the barrels is using recycled plastic

bottles.

Soil/compost The soil used for farming on the island must have all the right

components in order for the vegetation to thrive. Soil and compost can be bought from

retailers in either Cambodia or can be transported at a cost from another country.

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Another option is to use the pre-existing soil found around the Tonl Sap Lake.

However, the soil around the lake does not contain enough nutrients to grow the

necessary crops. It has been suggested that villagers create a compost heap and to use

worms to improve the soil.

Rope The ropes will be used to hold much of the structure in place. Rope is tough and

durable and can be used to create strong connections between materials.

Vines These are the cheaper alternative to using ropes. They are not as strong as rope

and may deteriorate over time. The locals are able to weave the vines in a rope-like

manner. They can also twine together water reeds and palm fronds. However, they still

need to be tested for thei

Documents

Flinder University - Floating Land Project - V1